WO2006004171A1

WO2006004171A1 - Photosensitive film, process for producing the same, process for forming permanent pattern

Info

Publication number: WO2006004171A1
Application number: PCT/JP2005/012522
Authority: WO
Inventors: Masayuki Iwasaki
Original assignee: Fuji Photo Film Co Ltd
Current assignee: Fujifilm Holdings Corp
Priority date: 2004-07-06
Filing date: 2005-06-30
Publication date: 2006-01-12
Anticipated expiration: 2007-01-06
Also published as: TW200612200A

Abstract

Disclosed is a photosensitive film for forming permanent patterns of solder resist utilized as insulating films or protective films on printed wiring boards for example, that exhibits higher thermal resistance, higher surface hardness, and lower thermal expansion, and represents superior conformability to irregularities of substrate surface and less possibility of inferior adhesion of solder resist. The photosensitive film according to the present invention comprises a support, a cushion layer, and a photosensitive layer, in this order, wherein the photosensitive layer is formed of a photosensitive composition which comprises (A) a binder, (B) a polymerizable compound, (C) a photopolymerization initiator, and (D) a filler, and the photosensitive film is utilized for forming a permanent pattern.

Description

DESCRIPTION

PHOTOSENSITIVE FILM, PROCESS FOR PRODUCING THE SAME, PROCESS FOR FORMING PERMANENT PATTERN

5 Technical Field

The present invention generally relates to photosensitive films for forming permanent patterns of solder resist utilized as insulating films or protective films on printed wiring boards for example, processes for producing the photosensitive films, and processes for forming permanent patterns. 0

Background Art

Printed wiring boards, on which electric parts such as semiconductors, capacitors, and resistors are soldered, are typically covered over the areas, where no solders being applied, with solder resist for use of insulating films or 5 protective films, thereby being prevented from continuity of adjacent

. electrodes. The solder resist is typically formed into a predetermined pattern through exposing and developing a photosensitive resin layer by way of photolithography processes.

Solder resist obtained through exposing and developing photosensitive o layers is essentially demanded for higher thermal resistance, higher surface hardness, and lower thermal expansion. In addition, the solder resist has been demanded for more fine and precise patterns, while printed wiring boards with a high density pattern such as build-up wiring boards have been utilized for potable electronic devices such as personal phones and digital 5 cameras. Conventionally, photosensitive resin layers are produced by way of coating a resin solution, containing a photosensitive resin in an organic solvent, on surfaces of printed wiring boards etc. (Patent Literature No. 1, for example).

However, such processes suffer from various problems that special coating apparatuses such as a roll coater or spinner device are required, thickness of photosensitive layers is hardly adjustable into a uniform thickness, environmental issues are inevitable due to organic solvents, and waste products containing organic solvents should be discarded or treated.

Therefore, various photosensitive films have been proposed to solve these problems; for example, a photosensitive layer containing a photosensitive resin and other layers having various functions are laminated and dried on a support to form a photosensitive film (Patent Literature Nos. 2 and 3, for example). Solder resist is formed by way of laminating the photosensitive film on a substrate having a predetermined pattern through heating and/ or pressing, peeling off only the support, and exposing and developing the photosensitive layer.

However, the photosensitive layer is not satisfactory in that the resulting resist is insufficient as to various properties such as thermal resistance, surface hardness, thermal expansion coefficient, and shelf stability. In addition, the photosensitive layer suffers from the problem that the photosensitive layer does not conform sufficiently to irregularities of substrate surface when laminating on substrates having a wiring pattern, which tends to generate bubbles and inferior adhesion between the solder resist and the , substrate. On the other hand, exposure apparatuses with a photomask are conventionally utilized for photolithography processes. However, the finely patterned solder resist has brought about a serious object in terms of position deviation, namely, fine patterns or through holes tend to undergo deviation or alternation of their positions due to expansion and contraction of substrates in the photolithography processes or due to expansion and contraction of photo mask films derived from variations of temperature and humidity. Therefore, expensive glass plates or substrates with less def ormability have been utilized in order to avoid the problem in terms of the position deviation.

Recently, various exposure apparatuses have been developed on the base of laser direct imaging systems (hereinafter referring to as "LDI") in order to solve the problem of the position deviation, in which patterns are formed by way of scanning a laser beam from a semiconductor laser or gas laser onto a photosensitive composition directly, the scanning is controlled depending on an exposure pattern formed by compensating digital data of a wiring pattern and the like. However, conventional solder resist suffers from insufficient sensitivity to laser beams having a wave length of 395 to 415 nm that are typically utilized for LDI described above.

As such, photosensitive films for forming permanent patterns available currently are insufficient in thermal resistance, surface hardness, thermal expansion coefficient, shelf stability, adhesion to substrates, and sensitivity to LDIs.

Patent Literature No. 1:

Japanese Patent Application Laid-Open (JP-A) No. 61-243869 Patent Literature No. 2: JP-A No. 2003-162055 Patent Literature No. 3: JP-A No. 09-188745 Disclosure of Invention

Accordingly, it is an object of the present invention to provide photosensitive films for forming permanent patterns that may exhibit higher thermal resistance, higher surface hardness, and lower thermal expansion, may represent superior conf ormability to irregularities of substrate surface and less possibility of inferior adhesion of solder resist, are less likely to degrade the exposure sensitivity; may afford proper working properties at forming solder resist, namely release characteristics from supports and cleaning properties of substrates surface are appropriate; may represent prolonged shelf stability, and also may exhibit appropriate sensitivity to LDIs. The other objects of the present invention are to provide processes for producing the photosensitive film and processes for forming permanent patterns that utilize the photosensitive films. These objects can be attained in accordance with the present invention.

In an aspect, the present invention provide a photosensitive film which comprises a support, a cushion layer, and a photosensitive layer, in this order, wherein the photosensitive layer is formed of a photosensitive composition which comprises (A) a binder, (B) a polymerizable compound, (C) a photopolymerization initiator, and (D) a filler, and the photosensitive film is utilized for forming a permanent pattern.

Preferably, a barrier layer capable of suppressing substance mobility is disposed between the cushion layer and the photosensitive layer; the barrier layer contains at least one polymer selected from the group consisting of vinyl polymers and vinyl copolymers. Preferably, the peel strength between the cushion layer and the photosensitive layer is lower than the peel strength between the cushion layer and the support; and the adhesive strength between the cushion layer and the photosensitive layer exhibits the minimum level among the adhesive strengths between two materials within the photosensitive film.

Alternatively, the adhesive strength between the support and the cushion layer exhibits the minimum level among the adhesive strengths between two materials within the photosensitive film; or the adhesive strength between the cushion layer and the barrier layer exhibits the minimum level among the adhesive strengths between two materials within the photosensitive film.

Preferably, the content of the (D) filler is 10 % by mass to 60 % by mass on the base of the photosensitive layer; the thickness of the photosensitive layer is 10 μm to 100 μm, and the thickness of the cushion layer is 5 μm to 100 μm.

Preferably, the cushion layer is hardly soluble in alkaline liquids, and contains a thermoplastic resin of which the glass transition temperature is 80 °C or less; alternatively, the cushion layer is soluble in alkaline liquids, and contains a thermoplastic resin of which the glass transition temperature is 80 ⁰C or less.

Preferably, the thermoplastic resin contains a copolymer of an olefin and (meth) aery late; the (A) binder contains a copolymer synthesized by reaction of anhydride group of a precursor copolymer with a primary amine compound in an equivalent ratio of 1 : 0.1 to 1, in which the precursor copolymers are formed from (a) maleic anhydride, (b) aromatic vinyl monomers, and (c) vinyl monomers of which the homopolymer represents a glass transition temperature of less than 80 °C; the (B) polymerizable compound contains a monomer unit having a (meth)acrylic group; the (C) photopolymerization initiator comprises a compound selected from the group consisting of halogenated hydrocarbon derivatives, phosphine oxides, hexaaryl-biimidazoles, oxime derivatives, organic peroxides, thio compounds, ketone compounds, aromatic onium salts, and ketoxime ethers.

Preferably, the sensitivity fluctuation of the photosensitive film is — 2 points to + 2 points after subjecting to the condition of 40 °C and 65 % relative humidity for three days.

In another aspect, the present invention provides a process for producing a photosensitive film, which comprises forming a cushion layer, and forming a photosensitive layer, wherein the cushion layer is formed by way of coating an aqueous emulsion containing a thermoplastic resin, and drying the coated emulsion, the photosensitive layer is formed by way of coating a liquid for a photosensitive composition which comprises (A) a binder, (B) a polymerizable compound, (C) a photopolymerization initiator, and (D) a filler, and drying the coated liquid.

Preferably, a barrier layer is formed, after the cushion layer being formed, by way of coating a liquid for barrier layer composition on the cushion layer and drying the coated liquid.

In another aspect, the present invention provides a process for forming a permanent pattern, which comprises laminating a photosensitive film on a front side of a substrate through at least one of heating and pressuring, irradiating a laser beam from a laser source onto a photosensitive layer, and developing the irradiated photosensitive layer, wherein the photosensitive film comprises a support, a cushion layer, and a photosensitive layer, in this order, the photosensitive layer is formed of a photosensitive composition which comprises (A) a binder, (B) a polymerizable compound, (C) a photopolymerization initiator, and (D) a filler, and the photosensitive film is utilized for forming a permanent pattern.

Preferably, a barrier layer capable of suppressing substance mobility is disposed between the cushion layer and the photosensitive layer.

Preferably, the support and the cushion layer are simultaneously separated from the photosensitive layer by peeling between the cushion layer and the photosensitive layer after irradiating the laser beam, then the photosensitive layer is developed; alternatively, the support and the cushion layer are simultaneously separated from the photosensitive layer by peeling between the cushion layer and the photosensitive layer after laminating the photosensitive film, then the photosensitive layer is irradiated.

Preferably, at least one of a protective film and an interlayer insulating film is provided into the photosensitive film.

Preferably, the laser beam from the laser source is modulated by means of a laser modulator which comprises plural imaging portions each capable of receiving the laser beam and outputting the modulated laser beam, the modulated laser beam is compensated by transmitting through plural microlenses, being arranged into a microlens array, each having a non-spherical surface capable of compensating the aberration due to distortion of the output surface of the imaging portions, and the photosensitive layer is irradiated by the modulated and transmitted laser beam; alternatively, the laser beam from the laser source is modulated by means of a laser modulator, the modulated later beam is transmitted through a microlens array which has an aperture configuration of the plural microlenses capable of substantially shielding incident light other than the modulated laser beam from the laser modulator.

Preferably, each of the microlenses has a non-spherical surface capable of compensating the aberration due to distortion of the output surface of the imaging portions; the non-spherical surface is a toric surface; each of the microlenses has a circular aperture configuration; the aperture configuration of the plural microlenses is defined by light shielding portion provided on the microlens surface.

Preferably, the laser modulator is capable of controlling a part of the plural imaging portions depending on pattern information.

Preferably, the laser modulator is a spatial light modulator; the spatial light modulator is a digital micromirror device (DMD); the exposing is performed by a laser beam transmitted through an aperture array; the exposing is performed while moving relatively the laser beam and the photosensitive layer; the laser source is capable of irradiating two or more types of laser beams together with. Preferably, the laser source comprises plural lasers, a multimode optical fiber, and a collective optical system that collects the laser beams from the plural lasers into the multimode optical fiber.

Preferably, the wavelength of the laser beam is 395 nm to 415 nm; the photosensitive layer is hardened after the developing; the photosensitive layer is hardened by at least one of irradiating onto the entire surface of the photosensitive layer and heating the entire surface of the photosensitive layer to 120 °C to 200 °C.

Brief Description of Drawings FIG. 1 is a partially enlarged view that shows exemplarily a construction of a digital micromirror device (DMD).

FIG. 2A is a view that explains exemplarily the motion of the DMD. FIG. 2B is a view that explains exemplarily the motion of the DMD. FIG. 3A is an exemplary plan view that shows the exposing beam and the scanning line in the case that the DMD is not inclined.

FIG. 3B is an exemplary plan view that shows the exposing beam and the scanning line in the case that the DMD is inclined.

FIG. 4A is an exemplary view that shows an available region of the DMD. FIG. 4B is an exemplary view that shows another available region of the DMD.

FIG. 5 is an exemplary plan view that explains a way to expose a photosensitive layer in one scanning by means of a scanner.

FIG. 6A is an exemplary plan view that explains a way to expose a photosensitive layer in plural scannings by means of a scanner.

FIG. 6B is another exemplary plan view that explains a way to expose a photosensitive layer in plural scannings by means of a scanner.

FIG. 7 is a schematic perspective view that shows exemplarily a pattern forming apparatus. FIG. 8 is a schematic perspective view that shows exemplarily a scanner construction of a pattern forming apparatus.

FIG. 9A is an exemplary plan view that shows exposed regions formed on a photosensitive layer.

FIG. 9B is an exemplary plan view that shows regions exposed by respective exposing heads.

FIG. 10 is a schematic perspective view that shows exemplarily an exposing head containing a laser modulator.

FIG. 11 is an exemplary cross section that shows the construction of the exposing head shown in FIG. 10 in the sub-scanning direction along the optical axis.

FIG. 12 shows an exemplary controller to control the DMD based on pattern information.

FIG. 13A is an exemplary cross section that shows a construction of another exposing head in other connecting optical system along the optical axis.

FIG. 13B is an exemplary plan view that shows an optical image projected on an exposed surface when a microlens array is not employed.

FIG. 13C is an exemplary plan view that shows an optical image projected on an exposed surface when a microlens array is employed. FIG. 14 is an exemplary view that shows distortion of a reflective surface of a micromirror that constitutes a DMD by means of contour lines.

FIG 15A is an exemplary graph that shows height displacement of a micromirror along the X direction.

FIG 15B is an exemplary graph that shows height displacement of a micromirror along the Y direction. FIG. 16 A is an exemplary front view that shows a microlens array employed in a pattern forming apparatus.

FIG. 16B is an exemplary side view that shows a microlens array employed in a pattern forming apparatus. FIG. 17 A is an exemplary front view that shows a microlens of a microlens array.

FIG. 17B is an exemplary side view that shows a microlens of a microlens array.

FIG. 18A is an exemplary view that schematically shows a laser collecting condition in a cross section of a microlens.

FIG. 18B is an exemplary view that schematically shows a laser collecting condition in another cross section of a microlens.

FIG. 19A is an exemplary view that shows a simulation of beam diameters near the focal point of a microlens in accordance with the present invention.

FIG. 19B is an exemplary view that shows another simulation similar to FIG. 19A in terms of other sites in accordance with the present invention.

FIG. 19C is an exemplary view that shows still another simulation similar to FIG. 19A in terms of other sites in accordance with the present invention.

FIG. 19D is an exemplary view that shows still another simulation similar to FIG. 19A in terms of other sites in accordance with the present invention.

FIG. 2OA is an exemplary view that shows a simulation of beam diameters near the focal point of a microlens in a conventional pattern forming process.

FIG. 2OB is an exemplary view that shows another simulation similar to FIG. 2OA in terms of other sites.

FIG. 20C is an exemplary view that shows still another simulation similar to FIG. 20A in terms of other sites.

FIG. 20D is an exemplary view that shows still another simulation similar to FIG. 20A in terms of other sites.

FIG. 21 is an exemplary plan view that shows another construction of a combined laser source. FIG. 22 A is an exemplary front view that shows a microlens of a microlens array.

FIG. 22B is an exemplary side view that shows a microlens of a microlens array.

FIG. 23A is an exemplary view that schematically shows a laser collecting condition in the cross section of the microlens shown in FIG. 22B.

FIG. 23B is an exemplary view that schematically shows a laser collecting condition in another cross section of the microlens shown in FIG. 22B.

FIG. 24A is an exemplary view that explains the concept of compensation by an optical system of optical quantity distribution compensation.

FIG. 24B is another exemplary view that explains the concept of compensation by an optical system of optical quantity distribution compensation. FIG. 24C is another exemplary view that explains the concept of compensation by an optical system of optical quantity distribution compensation.

FIG. 25 is an exemplary graph that shows an optical quantity distribution of Gaussian distribution without compensation of optical quantity. FIG. 26 is an exemplary graph that shows a compensated optical quantity distribution by an optical system of optical quantity distribution compensation.

FIG. 27A (A) is an exemplary perspective view that shows a constitution of a fiber array laser source. FIG. 27A (B) is a partially enlarged view of FIG. 27 A (A).

FIG. 27A (C) is an exemplary plan view that shows an arrangement of emitting sites of laser output.

FIG. 27A (D) is an exemplary plan view that shows another arrangement of laser emitting sites. FIG. 27B is an exemplary front view that shows an arrangement of laser emitting sites in a fiber array laser source.

FIG. 28 is an exemplary view that shows a construction of a multimode optical fiber.

FIG. 29 is an exemplary plan view that shows a construction of a combined laser source.

FIG. 30 is an exemplary plan view that shows a construction of a laser module.

FIG. 31 is an exemplary side view that shows a construction of the laser module shown in FIG. 30. FIG. 32 is a partial side view that shows a construction of the laser module shown in FIG. 30.

FIG. 33 is an exemplary perspective view that shows a construction of a laser array.

FIG. 34 A is an exemplary perspective view that shows a construction of a multi cavity laser.

FIG. 34B is an exemplary perspective view that shows a multi cavity laser array in which the multi cavity lasers shown in FIG. 34A are arranged in an array.

FIG. 35 is an exemplary plan view that shows another construction of a combined laser source.

FIG. 36A is an exemplary plan view that shows still another construction of a combined laser source.

FIG. 36B is an exemplary cross section of FIG. 36A along the optical axis. FIG. 37A is an exemplary cross section of an exposing device that

, shows focal depth in the pattern forming process of the prior art.

FIG. 37B is an exemplary cross section of an exposing device that shows focal depth in the pattern forming process according to the present invention. FIG. 38 A is a front view of another exemplary microlens that constitute a microlens array.

FIG. 38B is a side view of another exemplary microlens that constitute a microlens array.

FIG. 39 A is a front view of still another exemplary microlens that constitute a microlens array. FIG. 39B is a side view of still another exemplary microlens that constitute a microlens array.

FIG. 40 is an exemplary graph that shows a lens configuration.

FIG. 41 is an exemplary graph that shows another lens configuration. "

FIG. 42 is an exemplary perspective view that shows a microlens array. FIG. 43 is an exemplary plan view that shows another microlens array.

FIG. 44 is an exemplary plan view that shows still another microlens array..

FIG. 45A is an exemplary longitudinal section that shows still another microlens array. FIG. 45B is an exemplary longitudinal section that shows still another microlens array.

FIG. 45C is an exemplary longitudinal section that shows still another microlens array.

Best Mode for Carrying Out the Invention

(Photosensitive Film)

The photosensitive film according to the present invention, which is adapted to form a permanent pattern, comprises a support, a cushion layer, and a photosensitive layer in this order. The photosensitive film according to the present invention preferably comprises a barrier layer between the cushion layer and the photosensitive layer, and the other layers depending on requirements.

The peel strength, i.e. the force to separate two layers in a manner of peeling, may be properly adjusted depending on the application. Preferably, the peel strength between the cushion layer and the photosensitive layer is less than that between the cushion layer and the support. The peel strength between the cushion layer and the photosensitive layer less than that between the cushion layer and the support may desirably bring about the condition that the cushion layer is peeled together with the support at peeling the support. In a first aspect, the interlayer adhesive strength between the cushion layer and the photosensitive layer (hereinafter referring to as "adhesive strength A") is less than that between the support and the cushion layer (hereinafter referring to as "adhesive strength B"). Preferably, the adhesive strength A exhibits a minimum value among adhesive strengths between existing layers, and the level of adhesive strength A is significantly different from adhesive strength B.

The adhesive strength A less than the adhesive strength B may bring about the condition that the cushion layer is peeled together with the support when the support is peeled, thus the step in order only to peel the cushion layer may be appropriately eliminated. When the adhesive strength A is larger than the adhesive strength B, the additional step is possibly required for separating the cushion layer from the photosensitive layer by means of a self-adhering tape for example.

The way to adjust the adhesive strength A into the minimum level may be properly selected; for example, the adhesive strength A may be decreased by way of incorporating a release agent into the cushion layer for example, alternatively the adhesive strength A may be relatively decreased by way of increasing the adhesive strength B. These ways may be employed alone or in combination. In a second aspect, the interlayer adhesive strength between the cushion layer and the barrier layer (hereinafter referring to as "adhesive strength C") exhibits a minimum value among adhesive strengths between existing layers. The interlay er adhesive strength between the support and the cushion layer (hereinafter referring to as "adhesive strength B") and the interlayer adhesive strength between the barrier layer and the photosensitive layer (hereinafter referring to as "adhesive strength D") may be equivalent or different; preferably, the adhesive strength D is larger than the adhesive strength B and the adhesive strength C, from the viewpoint of less load for separating remaining layers. The adhesive strength C less than the adhesive strength B may bring about the condition that the cushion layer is peeled together with the support when the support is peeled, thus the step in order only to peel the cushion layer may be appropriately eliminated. When the adhesive strength C is larger than the adhesive strength B, the additional step is possibly required for separating the cushion layer from the photosensitive layer by means of a self-adhering tape for example.

The way to adjust the adhesive strength C into the minimum level may be properly selected; for example, the adhesive strength A may be decreased by way of incorporating a release agent into the cushion layer for example, alternatively the adhesive strength C may be decreased relatively by way of increasing the adhesive strengths B and D. These ways may be employed alone or in combination.

In a third aspect, the interlayer adhesive strength between the cushion layer and the support (hereinafter referring to as "adhesive strength B") exhibits a minimum value among adhesive strengths between existing layers. The interlayer adhesive strength between the barrier layer and the cushion layer (hereinafter referring to as "adhesive strength C") and the interlayer adhesive strength between the barrier layer and the photosensitive layer (hereinafter referring to as "adhesive strength D") may be equivalent or different.

The way to adjust the adhesive strength B into the minimum level may be properly selected; for example, the adhesive strength B may be decreased by way of incorporating a release agent into the cushion layer and/ or the support for example, alternatively the adhesive strength B may be decreased relatively by way of increasing the adhesive strengths C and D. These ways may be employed alone or in combination.

The release agent may be properly selected from commercially available release agents; examples thereof include silicone compounds, compounds having a fluorinated alkyl group, and the like. Specific examples of the silicone compounds include Ebecryl 1360, 350 (by Daicel UCB Co.); dimethylsilicone oil TSF400, methylphenylsilicone oil TSF4300, silicone polyether copolymers TSF4445, TSF4446, TSF4460, and TSF4452 (by GE Toshiba Silicone Co.).

Specific examples of the compounds having a fluorinated alkyl group include fluorinated surfactants such as F-171 (oligomer containing a perfluoroalkyl group and a hydrophilic group), F-173 (oligomer containing a perfluoroalkyl group and a lipophilic group), F-177 (oligomer containing a perfluoroalkyl group, a hydrophilic group, and a lipophilic group), and F-183 and F-184 (urethane containing a perfluoroalkyl group and a lipophilic group) manufactured respectively by Dainippon Ink and Chemicals, Inc.; and fluorinated graft polymers such as Aron GF-300 and GF-150 (by Toagosei Co.).

The way to increase the interlayer adhesive strength described above may be properly selected depending on the application; examples thereof include (i) surface treatment of the support and the cushion layer, (ii) content 5 adjustment of at least an ingredient within the support and the cushion layer, (iii) incorporation of an ingredient for enhancing adhesion into the cushion layer or coating of an ingredient for enhancing adhesion onto the substrate, and (iv) incorporation of a crosslinking agent and/ or silane coupling agent into the cushion layer. These ways may be used alone or in combination. o The surface treatment described above may be performed by use of plasma, electron beam, glow discharge, corona discharge, or UV ray irradiation.

The content adjustment described above may be exemplified by adjusting the ethylene content in a copolymer into 60 % by mass or less when 5 the cushion layer contain an ethylene-based copolymer. When the content is . above 60 % by mass, the adhesive strength A may be lower than the adhesive strength B.

Examples of ingredients for enhancing adhesion include phenol resins such as phenol-novolak resins, cresol-novolak resins, and phenol-resolcinol o resins, polyvinylidene chloride, styrene-butadiene rubbers, zelatine, gelatins, polyvinyl alcohol, and celluloses.

Examples of the crosslinking agents include borax, boric acid, borates such as orthoborates, InBO₃, ScBO₃, YBO₃, LaBO₃, Mg₃(BOs)₂, Co₃(BO₃)₂; diborates such as Mg₂B₂Os and Co₂B₂Os; metaborates such as LiBO₂, Ca(BO₂)₂, 5 NaBO₂ and KBO₂; tetraborates such as Na₂B₄Oz -1OH₂O; and pentaborates such as KB5O8 -4U2O, Ca2B6θii 7H2O, and CSB5O5. Among these, borax, boric acid, and borates are preferable, and boric acid is particularly preferable from the viewpoint of rapid crosslinking reaction.

In addition, examples of preferable compounds or substances are aldehyde compounds such as formaldehyde, glyoxal, glutaraldehyde and the like; ketone compounds such as deacetyl, cyclopentanedione, and the like; active halogen compounds such as bis(2-chloroethyl urea)-2-hydroxy-4,6-dichloro-l,3,5-triazine, 2,4-dichloro-6-S-triazine sodium salt, and the like; active vinylcompounds such as divinylsulfonic acid, l,3-vinylsulfonyl-2-propanol, N,N'-ethylene bis(vinylsulfonyl acetamide),

1,3,5-triacryloyl-hexahydro-S-triazine, and the like; N-methylol compounds such as dimethylol urea, methylol dimethylhydantoin, and the like; melamine resins such as methylol melamine, alkylated methylol melamine, and the like; epoxy resins; isocyanate compounds such as 1,6-hexamethylene diisocyanate, and the like; aziridine compounds disclosed in US Patent Nos. 3017280,

2983611, and the like; carboxyimide compounds disclosed in US Patent No.

3100704, and the like; epoxy compounds such as glycerol triglycidyl ether, and the like; ethylene imino compounds such as l,6-hexamethylene-N,N'-bisethylene urea, and the like; halogenated carboxy aldehyde compounds such as mucochloric acid, mucophenoxy chloric acid, and the like; dioxane compounds such as 2,3-dihydroxy-l,4-dioxane, and the like; metal-containing compounds such titanium lactate, aluminum sulfate, chromium alum, potash alum, zirconium acetate, chromium acetate, and the like; polyamine compounds such as tetraethylenepentamine, and the like; hydrazide compounds such as hydrazide adipate, and the like; and low molecular weight compounds or polymers containing two or more oxazoline groups, and the like. These crosslinking agents may be used alone or in combination.

Examples of the silane coupling agents include N-2-(aminoethyl)-3-aminopropylmethyl dimethoxysilane, N-2-(aminoethyl)-3-aminopropyl trimethoxysilane, N-2-(aminoethyl)-3-aminopropyl triethoxysilane, 3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, 3-triethoxysilyl-N-(l,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxy silane,

N-(vinylbenzil)-2-aminoethyl-3-aminopropyltrimethoxysilane, and the other commercially available silane coupling agents by Shin-Etsu Chemical Co. for example.

Preferably, the inventive photosensitive film for forming a permanent pattern represents less sensitivity fluctuation as low as ± 2 points. The term "sensitivity fluctuation" as used herein means a property that is determined from a light quantity required to harden a photosensitive film to the level of 7 points (total: 15 points), in which the light quantity of the photosensitive film is determined after allowing to stand the photosensitive film under the condition of 40 °C temperature and 65 % relative humidity for three days.

[Support]

The support may be properly selected depending on the application. Preferably, the adhesive strength between the support and the cushion layer is higher than the adhesive strength between the cushion layer and the photosensitive layer. Preferably, the support exhibits higher light transmittivity and higher surface smoothness.

Preferably, the support is formed from a transparent synthetic resin; examples of the synthetic resin include polyethylene terephthalate, polyethylene naphthalate, polypropylene, polyethylene, triacetyl cellulose, diacetyl cellulose, polyalkyl(meth)acrylate, poly(meth) aery late copolymers, polyvinyl chloride, polyvinyl alcohol, polycarbonate, polystyrene, cellophane, polyvinylidene chloride copolymers, polyamide, polyimide, vinylchloride-vinylacetate copolymers, polytetrafluoroethylene, polytrifluoroethylene, cellulose film, and nylon film; among these resins, polyethylene terephthalate is particularly preferable. These resins may be used alone or in combination.

The thickness of the support may be properly selected depending on the application; preferably, the thickness is 4 to 300 μm, more preferably is 5 to 175 μm. The shape of the support may be properly selected depending on the application; preferably, the shape is elongated. The length of the elongated support is selected from 10 to 20,000 meters, for example. [Cushion Layer]

The cushion layer may be properly selected in terms of the material, physical property, thickness, structure and the like without particular limitations. Preferably, the cushion layer is hardly soluble in alkaline liquids, i.e. the cushion layer does not completely dissolve into alkaline liquids at least at room temperature. The term "hardly soluble" as used herein embraces the condition that the cushion layer does not dissolve into alkaline liquids at all. Preferably, the cushion layer contains a thermoplastic resin of which the Tg or softening temperature is 80 ⁰C or less, more preferably is 60 °C or less, still more preferably is 50 ⁰C or less.

When the Tg or softening temperature of the thermoplastic resin in the cushion layer is above 80 °C, the temperature of the photosensitive film should be raised at transferring the photosensitive film onto the substrate in order to make the photosensitive film conform to the irregularity of the substrate surface, which may adversely effect on dimensional stability of substrates having a film-like shape and may disadvantageously effect on operation period for heating-cooling and on electric power for heating. The softening temperature of the thermoplastic resins may be determined in accordance with ASTM D1525 for Vicat softening temperature. Examples of the thermoplastic resin include polyolefin resins such as polyethylene, polypropylene, and polyolefin copolymers; ethylene-vinyl acetate copolymers, ethylene-ethyl acrylate copolymers, ethylene acrylate copolymer and ethylene copolymer resins such as saponificated products thereof, polyvinyl chloride, vinylchloride copolymers and vinylchloride copolymer resins such as saponificated products thereof, polyvinylydene chloride, polyvinylydene chloride copolymers, polystyrene, styrene-(meth)acrylate copolymers and styrene-(meth)acrylate copolymer resins such as saponificated products thereof, polyvinyltoluene, vinyltoluene-(meth) acrylate copolymers and vinyltoluene copolymer resins such as saponificated products thereof, poly(meth)acrylate, butyl(meth)acrylate-vinylacetate copolymers, polyamido resins such as vinylacetate copolymer nylon, copolymer nylon, N-alkoxydimethyl nylon, and N-dimethylamino nylon and ionomer resins thereof. Among these copolymers or resins, ethylene-vinyl acetate copolymers and polyolefin ionomers are preferable from the viewpoint of appropriate adhesive strength described above such that adhesive strength A between the cushion layer and the photosensitive layer exhibits the minimum level for example, protection of migration of ingredients within the photosensitive layer into the thermoplastic resin during preservation thereof.

Specific examples of the ethylene-vinyl acetate copolymer include Chemi-Pearl V (by Mitsui Chemical Co.), and specific examples of polyolefin ionomer include Chemi-Pearl S (by Mitsui Chemical Co.). These thermoplastic resins may be used alone or in combination.

Further, organic polymers available for the thermoplastic resins are those exemplified in "Plastic Property Handbook, edited by Japan Plastic Molding Industry Union of The Japan Plastics Industry Federation, published by Kogyo Chosakai Publishing Inc., Oct.25, 1968" and that have a softening temperature of 80 ⁰C or less. In addition, thermoplastic resins having a softening temperature of above 80 °C may be tailored in many cases with respect to the softening temperature into 80 ⁰C or less by way of incorporating a plasticizer compatible with the thermoplastic resin, for example.

The thermoplastic resin may be selected from those having the similar or the same solubility characteristic as that of the ingredients in the photosensitive layer or from those having significantly different solubility characteristic such that the soluble solvents are remarkably different between the selected resin and the ingredients in the photosensitive layer.

Into the cushion layer, various ingredients may be incorporated that are selected from various polymers, supercooled materials, adhesion promoter, release agents, and the like.

In another preferable aspect, the cushion layer is soluble in alkaline liquids, and contains a thermoplastic resin of which the glass transition temperature is 80 °C or less, more preferably is 60 °C or less, still more preferably is 50 °C or less. Such a thermoplastic resin may be selected from those available commercially as described above.

The thickness of the cushion layer may be properly selected depending on the application; the thickness is preferably 5 to 100 μm, more preferably is 10 to 50 μm, and still more preferably is 15 to 40 μm. When the thickness is less than 5 μm, the conf ormability to irregularities such as roughened surface or bubbles may be insufficient for producing fine and precise permanent patterns, and when the thickness is more than 100 μm, problems in production processes may generate such that the load for drying the cushion layer is enlarged excessively. The cushion layer may be formed by proper methods without particular limitations; for example, a composition of the cushion layer containing the thermoplastic resin is melted and formed into a film, a composition of the cushion layer is formed into a film by way of casting, an aqueous emulsion of a composition of the cushion layer containing the thermoplastic resin is formed into a film by way of casting, or the like. [Barrier Layer]

The barrier layer may be properly selected depending on the application as long as migration of substances can be suppressed. The barrier layer may be soluble in water, dispersible in water, soluble in alkaline liquids, or insoluble in alkaline liquids. Above described "migration of substances may be suppressed" means that the content of certain substances is suppressed to increase or to decrease at a layer adjacent to the barrier layer.

The substances of which the migration should be suppressed by the barrier layer are, for example, oxygen, water, or ingredients contained in the photosensitive layer or the cushioning layer.

When the barrier layer is water soluble, the barrier layer preferably contains a water soluble resin; when the barrier layer is dispersible in water, the barrier layer preferably contains a resin dispersible in water; when the barrier layer is soluble in alkaline liquids, the barrier layer preferably contains a resin soluble in alkaline liquids; and when the barrier layer is insoluble in alkaline liquids, the barrier layer preferably contains a resin insoluble in alkaline liquids.

Above described "water soluble" means that the barrier layer or the resin, referred to as such, is preferably soluble in a concentration of 0.1 % by mass or more in water at 25 °C, more preferably 1 % by mass or more.

The resin may be properly selected depending on the application; examples of the resins include various resins soluble in alcohols, water, or alkaline liquids, various resins dispersible into alcohols or water, and resins capable of being emulsified. Specifically, the resins may be vinyl polymers such as polyvinyl alcohols, modified polyvinyl alcohols, polyvinyl pyrrolidones, vinyl copolymers described above, water soluble polyamides, gelatin, celluloses, derivatives thereof, various resins and compounds described in JP-B No. 2794242, or binders described above. These may be used alone or in combination. The resins insoluble in alkaline liquids are exemplified by copolymers containing ethylene as the main and essential unit thereof. Examples of the copolymer may be ethylene-vinyl acetate copolymers (EVA) and ethylene-ethylacrylate copolymers.

The thickness of the barrier layer may be properly selected depending on the application; preferably, the thickness is less than 10 μm, more preferably is 0.1 to 6 μm, and still more preferably is 1 to 5 μm.

When the thickness of the barrier layer is 10 μm or more, light or laser is likely to be scattered during exposure, thus the resolution and/ or the adhesive property may degrade. In the photosensitive film according to the present invention, substances such as polymerizable compounds in the photosensitive layer may be prevented from migrating into the cushion layer owing to the barrier layer between the cushion layer and the photosensitive layer, thus the sensitivity decrease at the photosensitive layer may be effectively suppressed during exposure.

[Photosensitive Layer]

The photosensitive layer is formed from a photosensitive composition that comprises (A) binder, (B) polymerizable compound, (C) photopolymerization initiator, (D) filler, and other ingredients depending on requirements. < Binder >

The (A) binder may be properly selected depending on the application; examples thereof include copolymers obtained from a maleic anhydride copolymer by reaction of the anhydride group with at least one of primary amine compound, epoxyacrylate compounds having an acidic group illustrated in JP-A Nos. 51-131706, 52-94388, 64-62375, 02-97513, 03-289656, 61-243869, and 2002-296776, and the like.

Preferably, the binder is at least swellable in alkaline aqueous solutions, more preferably, the binder is soluble in alkaline aqueous solutions. Binders swellable or soluble in alkaline aqueous solutions are exemplified by those having an acidic group, specifically, copolymers obtained from a maleic anhydride copolymer by reaction of one equivalence of the anhydride group with 0.1 to 1.2 equivalence of one or more primary amine compounds.

Examples of the epoxyacrylate compounds having an acidic group include phenolnovolak epoxy acrylates, cresolnovolak epoxyacrylates, and bisphenol A epoxyacrylates in which these compounds are obtained by reaction of an epoxy resin or multi-functional compound with an monomer containing a carboxyl group such as (meth)acrylic acid, followed by adding a dibasic anhydride such as phthalic anhydride. The molecular mass of the epoxyacrylate compounds is preferably 1,000 to 200,000, more preferably is 2,000 to 100,000. When the molecular mass is less than 1,000, the surface of the photosensitive layer is likely to be excessively tacky, cured film is likely to be brittle or insufficient in surface hardness, and when the molecular mass is more than 200,000, the developing characteristics may be poor.

Further, acrylic resins containing at least a polymerizable group such as double bond and an acidic group illustrated in JP-A No. 06-295060 may be utilized as the (A) binder. Specifically, acrylic resins having at least a polymerizable double bond such as (meth) aery late group, (meth)acrylic amide group, vinylcarboxylate group, vinyl ether group, and allylether group may be employed.

More specifically, such acrylic compounds are exemplified that are produced by reaction of acrylic resins having a carboxylic group with glycidyl esters of unsaturated aliphatic acid such as glycidyl acrylate, glycidyl methacrylate, and cinnamic acid, or by additional reaction of the acrylic resins with polymerizable compounds containing an epoxy group e.g. cyclohexeneoxide and (meth)acryloyl group in a molecule. In addition, such compounds are exemplified as those obtained by reaction of acrylic resins containing an acidic group and an hydroxyl group with polymerizable compounds containing an isocyanate group such as isocyanate ethyl (meth) acrylate, and those obtained by reaction of acrylic resins containing an anhydride group with polymerizable compounds containing a hydroxyl group such as hydroxyalkyl(meth)acrylate. Commercially available acrylic resins are exemplified by Kaneka Resin AXE (by Kaneka Co.), Cyclomer A-200, Cyclomer M-200 (by Daicel Chemical Industries, Ltd.).

In addition, such products may be utilized as obtained by reaction of hydroxylalkylacrylate or hydroxylalkylmethacrylate and polycarboxylic acid anhydride or epihalohydrin illustrated in JP-A No. 50-59315.

In addition, such compounds may be available as addition reaction products of epoxyacrylate having a fluorene skeleton and acid anhydrides as illustrated in JP-A No. 05-70528; polyamides and polyimides as illustrated in JP-A No. 11-288087; copolymers of styrene or styrene derivatives containing an amide group and acid anhydrides as illustrated in JP-A Nos. 02-097502 and 2003-20310; and polyimide precursors as illustrated in JP-A No. 11-282155. These may be used alone or in combination. Preferably, the molecular mass of the binders such as epoxyacrylates having a fluorene skeleton, polyamides and polyimides, copolymers of styrene or styrene derivatives containing an amide group, or polyimide precursors described above is 3,000 to 500,000, more preferably is 5,000 to 100,000. When the molecular mass is less than 3,000, the surface of the photosensitive layer is likely to be excessively tacky, and the cured film is likely to be brittle or insufficient in surface hardness, and when the molecular mass is more than 500,000, the developing characteristics may be poor.

The copolymers obtained from a maleic anhydride copolymer by reaction of the anhydride group with at least one of primary amine compound may be properly selected depending on the application; preferably, the copolymer is a maleamic acid copolymer comprising unit A and unit B expressed by formula (1).

The unit A may be composed of one type of moiety or no less than two types of moiety. When the unit A is composed of one type of moiety and the unit B is also composed of one type of moiety, the maleamic acid copolymer is a binary copolymer; and when the unit A is composed of two types of moiety and the unit B is composed of one type of moiety, the maleamic acid copolymer is a ternary copolymer. Preferable example of the unit A is the combination of an aryl group and a vinyl monomer of which the homopolymer represents a glass transition temperature of less than 80 °C. )

A B

In the formula (1), R³ and R⁴ are each a hydrogen atom or lower alkyl group. Each of "x" and "y" is the mole fraction of the repeated unit; for example, when the unit A is composed of one type of moiety, "x" is 85 to 50 mole %, and "y" is 15 to 50 mole %.

Examples of R¹ in the formula (1) include substituents such as -COOR¹⁰, -CONR¹¹R^, substituted or unsubstituted aryl group, -OCOR¹³, -OR¹⁴, and -COR¹⁵, wherein R¹⁰ to R¹⁵ are each selected from hydrogen atom, and substituted or unsubstituted alkyl groups, aryl groups, and aralkyl groups. Each of the alkyl groups, aryl groups, and aralkyl groups may be of cyclic or branched structure.

Examples of R¹⁰ to R¹⁵ include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, pentyl, allyl, n-hexyl, cyclohexyl, 2-ethylhexyl, dodecyl, methoxyethyl, phenyl, methylphenyl, methoxyphenyl, benzyl, phenethyl, naphtyl, and chlorophenyl.

Examples of R¹ include benzene derivatives such as phenyl, α-methylphenyl, 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, and 2,4-dimethylphenyl; n-propyloxycarbonyl, n-butyloxycarbonyl, pentyloxycarbonyl, 2-ethylhexyloxycarbonyl, n-2-ethylhexyloxycarbonyl, 2-ethyl-2-ethylhexyloxycarbonyl, and methyloxycarbonyl.

Examples of R² in the formula (1) include substituted or unsubstituted alkyl groups, aryl groups, and aralkyl groups, which may be of cyclic or branched structure; specific examples of R² include benzyl, phenethyl, 3-phenyl-l-propyl, 4-pheny 1-1 -butyl, 5-phenyl-l-pentyl, 6-phenyl-l-hexyl, α-methylbenzyl, 2-methylbenzyl, 3-methylbenzyl, 4-methylbenzyl, 2-(p-tolyl)ethyl, β-methylphenethyl, l-methyl-3-phenylpropyl, 2-chlorobenzyl, 3-chlorobenzyl, 4-chlorobenzyl, 2-fluorobenzyl, 3-fluorobenzyl, 4-fluorobenzyl, 4-bromophenethyl, 2-(2-chlorophenyl)ethyl, 2-(3-chlorophenyl)ethyl, 2-(4-chlorophenyl)ethyl, 2-(2-fluorophenyl) ethyl, 2-(3-fluorophenyl)ethyl, 2-(4-fluorophenyl)ethyl, 4-fluoro-α,α-dimethylphenethyl, 2-methoxybenzyl, 3-methoxybenzyl, 4-methoxybenzyl, 2-ethoxybenzyl, 2-methoxyphenethyl, 3-methoxyphenethyl, 4-methoxyphenethyl, methyl, ethyl, propyl, 1-propyl, butyl, t-butyl, sec-butyl, phenyl, hexyl, cyclohexyl, heptyl, octyl, lauryl, phenyl, 1-naphthyl, methoxymethyl, 2-methoxy ethyl, 2-ethoxy ethyl, 3-methoxypropyl, 2-butoxyethyl, 2-cyclohexyloxyethyl, 3-ethoxypropyl, 3-propoxypropyl, and 3-isopropoxypropylamine.

Preferable binders are copolymers synthesized by way of reacting anhydride group of precursor copolymers with primary amine compounds in an equivalent ratio of 1 : 0.1 to 1, in which the precursor copolymers are formed from (a) maleic anhydride, (b) aromatic vinyl monomers, and (c) vinyl monomers of which the homopolymer represents a glass transition temperature of less than 80 °C.

The copolymers formed from (a) and (b) indicated above may be insufficient in laminating ability while the photosensitive layer may exhibit higher surface hardness: The copolymers formed from (a) and (c) indicated above may exhibit lower surface hardness while the photosensitive layer may be sufficient in laminating ability.

The (b) aromatic vinyl monomers may be properly selected depending on the application; preferable are the aromatic vinyl monomers of which the homopolymer represents a glass transition temperature (Tg) of 80 °C or more, more preferably is 100 °C or more from the viewpoint of higher surface hardness of photosensitive layers.

Specific examples of the aromatic vinyl monomers include styrene of which the homopolymer represents a Tg of about 100 °C, and styrene derivatives such as α-methylstyrene of which the homopolymer represents a Tg of about 168 ⁰C, 2-methylstyrene of which the homopolymer represents a Tg of about 136 °C, 3-methylstyrene of which the homopolymer represents a Tg of about 97 °C, 4-methylstyrene of which the homopolymer represents a Tg of about 93 °C, and 2,4-dimethylstyrene of which the homopolymer represents a Tg of about 112 ⁰C. These may be used alone or in combination. The (c) vinyl monomer described above is required that the homopolymer of the vinyl polymer represents a Tg of less than 80 ⁰C, preferably 40 °C or less, more preferably 0 ⁰C or less. Specific examples of the vinyl monomers include n-propylacrylate of which the homopolymer represents a Tg of - 37 ⁰C, n-butylacrylate of which the homopolymer represents a Tg of - 54 °C, pentylacrylate or hexylacrylate of which the homopolymers represent a Tg of - 57 °C, n-butylmethacrylate of which the homopolymer represents a Tg of - 24 °C, and n-hexylmethacrylate of which the homopolymer represents a Tg of - 5 °C. These may be used alone or in combination.

Examples of the primary amine compounds described above include benzylamine, phenethylamine, 3-phenyl-l-propylamine, 4-phenyl-l-butylamine, 5-phenyl-l-pentylamine, 6-phenyl-l-hexylamine, α-methylbenzylamine, 2-methylbenzylamine, 3-methylbenzylamine, 4-methylbenzylamine, 2-(p-tolyl)ethylamine, β-methylphenethylamine, l-methyl-3-phenylpropylamine, 2-chlorobenzylamine, 3-chlorobenzylamine, 4-chlorobenzylamine, 2-fluorobenzylamine, 3-fluorobenzylamine, 4-fluorobenzylamine, 4-bromophenethylamine, 2-(2-chlorophenyl)ethylamine, 2-(3-chlorophenyl)ethylamine, 2-(4-chlorophenyl)ethylamine, 2-(2-fluorophenyl)ethylamine_/ 2-(3-fluorophenyl)ethylamine_/ 2-(4-fluorophenyl)ethylamine, 4-fluoro-α_/α-dimethylphenethylamine, 2-methoxybenzylamine, 3-methoxybenzylamine, 4-methoxybenzylamine, 2-ethoxybenzylamine, 2-methoxyphenethylamine, 3-methoxyphenethylamine, 4-methoxyphenethylamine, methylamine, ethylamine, propylamine,

1 -propylamine, butylamine, t-butylamine, sec-butylamine, pentylamine, hexylamine, cyclohexylamine, heptylamine, octylamine, laurylamine, aniline, octylaniline, anisidine, 4-chloroaniline, 1-naphthylamine, methoxymethylamine, 2-methoxyethylamine, 2-ethoxyethylamine, 3-methoxypropylamine, 2-butoxyethylamine, 2-cyclohexyloxy ethylamine,

3-ethoxypropylamine, 3-propoxypropylamine, and 3-isopropoxypropylamine. Among these, benzylamine and phenethylamine are preferable in particular. These primary amines may be used alone or in combination.

The reactive amount of the primary amine compound is required to be 0.1 to 1.2 equivalent, preferably 0.1 to 1.0 equivalent, based on one equivalent of the anhydride group.- When the reactive amount is above 1.2 equivalents, the solubility of the resulting binder may be lowered.

The content of (a) maleic anhydride unit in the binder or the copolymer is preferably 15 to 50 mole %, more preferably 20 to 45 mole %, and still more preferably 20 to 40 mole % based on the molecules of the binder or the copolymer described above. When the content is less than 15 mole %, alkaline developing may not been conducted, and when the content is more than 50 mole %, the alkaline resistance may be poor, and the synthesizing of the copolymer described above tends to be difficult, thus proper permanent patterns may not be formed. Preferably, the contents of (b) aromatic vinyl monomer and (c) vinyl monomer, of which the homopolymer represents a glass transition temperature of less than 80 °C, are 20 to 60 mole % and 15 to 40 mole % respectively. When the contents are within the ranges, both of the surface hardness and the laminating ability may be satisfactory. The molecular mass of the binder described above is preferably 1,000 to

1,000,000, more preferably is 8,000 to 15,0000. When the molecular mass is less than 1,000, the film of the photosensitive layer may be brittle after curing and the surface hardness may be poor, and when the molecular mass is above 1,000,000, the flowability of the photosensitive composition is likely to be lower at heating and laminating, thus the laminating ability may be insufficient and also developing property may be deteriorated.

Preferably, the solid content of the binder based on the entire solid of the photosensitive composition is 5 to 80 % by mass, more preferably is 10 to 70 % by mass. When the solid content is less than 5 % by mass, the film strength of the photosensitive layer is likely to be lower, and the tackiness on the surface of the photosensitive layer may be deteriorated, and when the solid content is more than 80 % by mass, the exposure sensitivity may be lower. < Polymerizable Compound >

The polymerizable compound may be properly selected depending on the application. The polymerizable compound contains at least one group that enables addition polymerization, and preferably has a boiling point of 100 ⁰C or more at normal pressure; examples of the polymerizable compound include monomers having a (meth)acrylic group.

The monomer having a (meth)acrylic group may be properly selected depending on the application; examples of the monomer include mono-functional acrylate and mono-functional methacrylate such as polyethylene glycol momo(meth) acrylate, polypropylene glycol momo(meth) acrylate, and phenoxyethyl (meth) acrylate; polyethylene glycol di(meth) acrylate, polypropylene glycol di(meth)acrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, trimethylolpropane diacrylate, neopentylglycol di (meth) acrylate, pentaerythritol tetra(meth) acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth) acrylate, hexanediol di(meth)acrylate, trimethylolpropane tri(acryloyloxypropyl)ether, tri(acryloyloxyethyl)isocyanurate, tri(acryloyloxyethyl)cyanurate, glycerin tri(meth)acrylate; additional reaction products of polyfunctional alcohols such as trimethylolpropane, glycerin, and bisphenol and ethylene oxide or propylene oxide followed by (meth)acrylation; urethane acrylates described in JP-B Nos. 48-41708 and 50-6034, and JP-A No. 51-37193; and polyester acrylates described in JP-A No. 48-64183, JP-B Nos. 49-43191 and 52-30490; polyfunctional acrylate or methacrylate such as epoxyacrylate obtained from epoxy resins and (meth) acrylic acid.

Among these, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra(meth) acrylate, dipentaerythritol hexa(meth) acrylate, and dipentaerythritol penta(meth)acrylate are preferable in particular.

Preferably, the solid content of the polymerizable compound based on the entire solid of the photosensitive composition is 2 to 50 % by mass, more preferably is 4 to 40 % by mass, and still more preferably is 5 to 30 % by mass.

When the solid content is less than 2 % by mass, the developing property may be insufficient and the exposure sensitivity may be lower, and when the solid content is more than 50 % by mass, the tackiness of the photosensitive layer may be disadvantageously remarkable.

< Photopolymerization Initiator >

The (C) photopolymerization initiator may be properly selected from conventional ones without particular limitations as long as having the property to initiate polymerization; preferable is the initiator that exhibits photosensitivity from ultraviolet rays to visual lights. The photopolymerization initiator may be an active substance that generates a radical due to an effect with a photo-exited photosensitizer, or an active substance that initiates cation polymerization depending on the monomer species.

Preferably, the photopolymerization initiator is sensitive from ultraviolet to visual rays, more preferably is sensitive to laser beams having a wavelength of 395 nm to 415 nm. Preferably, the photopolymerization initiator contains at least one compound selected from the group consisting of halogenated hydrocarbon derivatives, phosphine oxides, hexaaryl-biimidazoles, oxime derivatives, organic peroxides, thio compounds, ketone compounds, aromatic onium salts, and ketoxime ethers.

Preferably, the photopolymerization initiator contains at least one component that has a molecular extinction coefficient of about 50 M-¹Cm-¹ in a range of about 300 nm to 800 nm, more preferably about 330 nm to 500 nm. Examples of the photopolymerization initiator include halogenated hydrocarbon derivatives such as having a triazine skeleton or an oxadiazole skeleton, and phosphine oxides, hexaaryl-biimidazoles, oxime derivatives, organic peroxides, thio compounds, ketone compounds, aromatic onium salts, and ketoxime ethers.

Examples of the halogenated hydrocarbon compounds having a triazine skeleton include the compounds described in Bulletin of the Chemical Society of Japan, by Wakabayasi et al., 42, 2924 (1969); GB Pat. No. 1388492; JP-A No. 53-133428; DE Pat. No. 3337024; Journal of Organic Chemistry, by F.C. Schaefer et. al. 29, 1527 (1964); JP-A Nos. 62-58241, 5-281728, and 5-34920; and US Pat. No. 4212976.

Examples of the compounds described in Bulletin of the Chemical Society of Japan, by Wakabayasi, 42, 2924 (1969) described above include 2-phenyl-4,6-bis(trichloromethyl)-l,3,5-triazine,

2-(4-chlorophenyl)-4,6-bis(trichloromethyl)-l,3,5-triazine, 2-(4-tolyl)-4,6-bis(trichloromethyl)-l,3,5-triazine, 2-(4-methoxyphenyl)-4,6-bis(trichloromethyl)-l,3,5-triazine, 2-(2,4-dichlorophenyl)-4,6-bis(trichloromethyl)-l,3,5-triazine, 2,4,6-tris(trichloromethyl)-l,3,5-triazine, 2-methyl-4_/6-bis(trichloromethyl)-l_/3_/5-triazine_/ 2-n-nonyl-4_/6-bis(trichloromethyl)-l,3_/5-triazine_/ and 2-(α_/α,β-trichloroethyl)-4_/6-bis(trichloromethyl)-l_/3_/5-triazine.

Examples of the compounds described in GB Pat. No. 1388492 described above include 2~styryl-4_/6-bis(trichloromethyl)-l_/3,5-triazine, 2-(4-methylstyryl)-4_/6-bis(trichloromethyl)-l_/3_/5-triazine_/ 2-(4-methoxystyryl)-4_/6-bis(tricrdoromethyl)~l,3_/5-triazine, and 2-(4-methoxystyryl)-4-amino-6~trichloromethyl-l,3,5-triazine.

Examples of the compounds described in JP-A No. 53-133428 described above include 2-(4-methoxynaphtho-l-yl)-4_/6-bistrichloromethyl-l,3_/5-triazine_/ 2-(4-ethoxynaphtho-l-yl)-4_/6-bistrichloromethyl-l,3,5-triazine_/ 2-[4-(2-ethoxyethyl)-naphtho-l-yl]-4_/6-bistrichloromethyl-l,3,5-triazine_/ 2-(4_/7-dimethoxynaptho-l-yl)-4_/6-bistrichloromethyl-l_/3,5-triazine, and 2-(acenaphtho-5-yl)-4,6-bistrichloromethyl-l,3_/5-triazine. Examples of the compounds described in DE Pat. No. 3337024 described above include

2- (4-sty r y lpheny l)-4, 6-bis (tr ichlor omethy 1) -1 ,3,5-tr iazine, 2-(4-(4-methoxystyryl)phenyl)-4_/6-bis(trichloromethyl)-l,3_/5-triazine_/ 2-(l-naphthylvmylenephenyl)-4,6-bis(trichloromethyl)-l,3,5-triazine, 2-chlorostyrylphenyl-4_/6-bis(trichloromethyl)-l_/3_/5-triazine_/

2-(4-thiophene-2-vinylenephenyl)-4_/6-bis(trichloromethyl)-l,3_/5-triazine_/ 2-(4-thiophene-3-vinylenephenyl)-4,6-bis(trichloromethyl)-l_/3_/5-triazine_/ 2-(4-furan-2-vinylenephenyl)-4_/6-bis(trichloromethyl)-l,3_/5-triazine_/ and 2-(4-benzofuran-2-vinylenephenyl)-4_/6-bis(trichloromethyl)-l,3_/5-triazine. Examples of the compounds described in Journal of Organic Chemistry, by F.C. Schaefer et al. 29, 1527 (1964) described above include 2-methyl-4,6-bis(tribromomethyl)-l_/3_/5-triazine, 2_/4,6-tris(tribromomethyl)-l_/3,5-triazine_/ 2_/4_/6-tris(dibromomethyl)-l,3_/5-triazine, 2-amino-4-methyl-6-tribromomethyl-l,3_/5-triazine and 2-methoxy-4-methyl-6-trichloromethyl-l_/3,5-triazine.

Examples of the compounds described in JP-A No. 62-58241 described above include 2-(4~phenylethylphenyl)-4,6-bis(trichloromethyl)-l,3,5-triazine, 2-(4-naphthyl-l-ethynylphenyl)-4_/6-bis(trichloromethyl)-l,3,5-triazine_/ 2-(4~(4-triethynyl)phenyl)-4,6-bis(trichloromethyl)-l,3,5-triazine,

2-(4-(4-methoxyphenyl)ethynylphenyl)-4_/6-bis(trichloromethyl)-l_/3_/5-triazine, 2-(4-(4-isopropylphenylethynyl)phenyl)-4_/6-bis(trichloromethyl)-l_/3,5-triazine_/ and 2-(4-(4-ethylphenylethynyl)phenyl)-4_/6-bis(trichloromethyl)-l_/3,5-triazine. Examples of the compounds described in JP-A No. 5-281728 described above include

2-(4-trifluoromethylphenyl)-4_/6-bis(trichloromethyl)-l,3,5-triazine_/ 2-(2_/6-difluorophenyl)-4,6-bis(trichloromethyl)-l,3,5-triazine, 2-(2,6-dichlorophenyl)-4_/6-bis(trichloromethyl)-l_/3_/5-triazine_/ and 2-(2,6-dibromophenyl)-4_/6-bis(trichloromethyl)-l,3_/5-triazine. Examples of the compounds described in JP-A No. 5-34920 described above include 2,4-bis(trichloromethyl)-6-

^-(N_/N-diethoxycarbonylmethylamino)- S-bromophenylJ-l^δ-triazine, trihalomethyl-s-triazine compounds described in US Pat. No. 4239850, and also 2_/4_/6-tris(trichloromethyl)-s-triazine_/ and 2-(4-chlorophenyl)-4_/6-bis(tribromomethyl)-s-triazine. Examples of the compounds described in US Pat. No. 4212976 described above include the compounds having an oxadiazole skeleton such as

2-trichloromethyl-5-phenyl-l,3 ,4-oxadiazole,

2-trichloromethyl-5-(4-chlorophenyl)-l_/3_/4-oxadiazole, 2-trichloromethyl-5-(l-naphthyl)-l_/3_/4-oxadiazole_/

2-trichloromethyl-5-(2-naphthyl)-l_/3_/4-oxadiazole_/

2-tribromomethyl-5-phenyl-l,3_/4-oxadiazole_/

2-tribromomethyl-5-(2-naphthyl)-l_/3_/4-oxadiazole,

2-trichloromethyl-5-styryl-l,3,4-oxadiazole, 2-trichloromethyl-5-(4-chlorostyryl)-l,3_/4-oxadiazole,

2-trichloromethyl-5~(4-methoxystyryl)-l,3,4-oxadiazole_/

2-tricruoromethyl-5-(l-naphthyl)-l,3,4-oxadiazole,

2-trichloromethyl-5-(4-n-butoxystyryl)-l,3_/4-oxadiazole, and

2-tribromomethyl-5-styryl-l,3_/4-oxadiazole. Examples of oxime derivatives utilized properly in the present invention include 3-benzoyloxyiminobutan-2-one, 3-acetoxyiminobutan-2-one,

3-propionyloxyiminobutan-2-one, 2-acetoxyiminopentan-3-one,

2-acetoxyimino-l-phenylpropane-l-one,

3-benzoyloxyimino-l-phenylpropane-l-one, 3-(4-toluenesulf onyloxy)iminobutan-2-one, and

2-ethoxy carbony loxy imino-pheny lpr op ane-1 -one .

As for photopolymerization initiators other than described above, the following substances are further exemplified: acridine derivatives such as

9-phenyl acridine and l,7-bis(9_/9'-acridinyl)heptane; N-phenylglycine, polyhalogenated compounds such as carbon tetrabromide, phenyltribromomethylsulfone, and phenyltrichloromethylketone; coumarins such as 3-(2-benzofuroyl)-7-diethylaminocoumarin, 3-(2-benzofuroyl)-7-(l-pyrrolidinyl)coumarin_/ 3-benzoyl-7-diethylaminocoumarin, 3-(2-methoxybenzoyl)-7-diethylaminocoumarin_/

3-(4-dimethylaminobenzoyl)-7-diethylaminocoumarin_/ 3_/3'-carbonylbis(5,7-di-n-propoxycouπiarin)_/

3_/3^/-carbonylbis(7-diethylaminocoumarin)_/ 3-benzoyl-7-methoxycoumarin_/ 3-(2-furoyl)-7-diethylaminocoumarin_/ 3-(4-diethylaminocinnamoyl)-7-diethylaminocoumarin_/

7-methoxy-3-(3-pyridylcarbonyl)coumarin, 3-benzoyl-5,7-dipropoxycoumarin, and 7-benzotriazol-2-ylcoumarin_/ and also the coumarin compounds described in JP-A Nos. 5-19475, 7-271028, 2002-363206, 2002-363207, 2002-363208, and 2002-363209; amines such as ethyl 4-dimethylamibenzoate, n-butyl 4-dimethylamibenzoate, phenethyl 4-dimethylamibenzoate, 2-phthalimide 4-dimethylamibenzoate, 2-methacryloyloxyethyl 4-dimethylamibenzoate, pentamethylene-bis(4-dimethylaminobenzoate), phenethyl 3-dimethylamibenzoate, pentamethylene esters, 4-dimethylamino benzaldehyde, 2-chloro-4-dimethylamino benzaldehyde, 4-dimethylaminobenzyl alcohol, ethyl(4-dimethylaminobenzoyl)acetate, 4-piperidine acetophenone, 4-dimethyamino benzoin, N,N-dimethyl-4-toluidine, N,N-diethyl-3-phenetidine, tribenzylamine, dibenzylphenylamine, N-methyl-N-phenylbenzylamine, 4-bromo-N,N-diethylaniline, and tridodecyl amine; amino fluorans such as ODB and ODBII; crystal violet lactone; leucocrystal violet; acylphosphine oxides such as bis(2_/4_/6-trimethylbenzoyl)phenylphosphine oxide, bis(2,6-dimethylbenzoyl)-2,4,4-tximethyl-pentylphenylphosphine oxide, and Lucirin TPO; metallocenes such as bis(η5-2,4-cyclopentadiene-l-yl)- bis(2,6-difluoro-3-(lH-pyrrole-l-yl)-phenyl)titanium_/

5 η5-cyclopentadienyl-η6-cumenyl-iron(l+)-hexafluorophosphate(l-); and the compounds described in JP-A No. 53-133428, JP-B Nos. 57-1819 and 57-6096, and US Pat. No. 3615455.

Examples of the ketone compounds described above include benzophenone, 2-methylbenzophenone, 3-methylbenzophenone, 0 4-methylbenzophenone, 4-methoxybenzophenone, 2-chlorobenzophenone, 4-chlorobenzophenone, 4-bromobenzophenone, 2-carboxybenzophenone, 2-ethoxycarbonylbenzophenone, benzophenone-tetracarboxylic acid and its tetramethyl ester; 4,4'-bis(dialkylamino)benzophenones such as 4,4'-bis(dimethylamino)benzophenone, 5 4,4'-bis(dicyclohexylamino)benzophenone, . 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(dihydroxyethylamino)benzophenone,

4-methoxy-4'-dimethylaminobenzophenone, 4,4'-dimethoxybenzophenone, and 4-dimethylaminobenzophenone; 4-dimethylaminoacetophenone, benzyl, o anthraquinone, 2-tert-butylanthraquinone, 2-methylanthraquinone, phenanthraquinone, xanthone, thioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, fluorene,

2-benzyl-dimethylamino-l-(4-morpholinophenyl)-l-butanone, 2-methyl-l-[4-(methylthio)phenyl]-2-morpholino-l-propanone, 5 2-hydroxy-2-methyl-[4-(l-methylvinyl)phenylJpropanol oligomer, benzoin; benzoin ethers such as benzoin methylether, benzoin ethylether, benzoin propylether, benzoin isopropylether, benzoin phenylether, and benzyl dimethyl ketal; acridone, chloroacridone, N-methylacridone, N-butylacridone, and N-butyl-chloroacridone. The solid content of the photopolymerization initiator is preferably 0.1 to 30 % by mass, more preferably is 0.5 to 20 % by mass, and still more preferably is 0.5 to 15 % by mass based on the total solid within the photosensitive composition.

In order to adjust the exposure sensitivity and photosensitive wavelength for exposing of the photosensitive layer, a photosensitizer may be incorporated in addition to the photopolymerization initiator. The photosensitizer may be properly selected depending on the laser beam or optical irradiation from the laser source utilized in the present invention. The photosensitizer may be exited by active irradiation, and may generate a radical, an available acidic group and the like through interaction with other substances such as radical generators and acid generators by transferring energy or electrons.

The photosensitizer may be properly selected without particular limitations from conventional substances; examples of the photosensitizer include polynuclear aromatics such as pyrene, perylene, and triphenylene; xanthenes such as fluorescein, Eosine, erythrosine, rhodamine B, and Rose Bengal; cyanines such as indocarbocianine, thiacarbocianine, and oxacarbocianine; merocianines such as merocianine and carbomerocianine; thiazins such as thionine, methylene blue, and toluidine blue; acridines such as acridine orange, chloroflavine, and acrif lavine; anthraquinones such as anthraquinone; scariums such as scarium; acridones such as acridone, chloroacridone, N-methylacridone, N-butylacridone, N-butyl-chloroacridone; coumarins such as 3-(2-benzofuroyl)-7-diethylaminocoumarin_/

3-(2-benzofuroyl)-7-(l-pyrrolidinyl)coumarin_/ S-benzofuroyl-Z-diethylaminocoumarin,

3-(2-methoxybenzoyl)-7-diethylaminocoumarin,

3-(4-dimethylaminobenzoyl)-7-diethylaminocoumarin_/

3_/3'-carbonylbis(5_/7-di-n-propoxycoumarin)_/

3,3'-carbonylbis(7-diethylaminocoumarin)_/ 3-benzoyl-7-methoxycoumarin_/ 3-(2-furoyl)-7-diethylaminocournarin,

3-(4-diethylaminocinnamoyl)-7-diethylaminocouinarin_/

7-methoxy-3-(3-pyridylcarbonyl)coumarin, 3-benzoyl-5,7-dipropoxycoumarin, and also the coumarin compounds described in JP-A Nos. 5-19475, 7-271028,

2002-363206, 2002-363207, 2002-363208, and 2002-363209. As for the combination of the photopolymerization initiator and the photosensitizer, the initiating mechanism that involves electron transfer may be exemplified such as combinations of (1) an electron donating initiator and a photosensitizer dye, (2) an electron accepting initiator and a photosensitizer dye, and (3) an electron donating initiator, and an electron accepting initiator, and a photosensitizer dye (ternary mechanism) as described in JP-A No.

2001-305734.

The content of the photosensitizer is preferably 0.05 to 30 % by mass based on the entire ingredients of the photosensitive composition, more preferably is 0.1 to 20 % by mass, and still more preferably is 0.2 to 10 % by mass. When the content is less than 0.05 % by mass, the sensitivity toward the active energy ray may decrease, longer period may be required for exposing process, and the productivity tends to decrease, and when the content is more than 30 % by mass, the photosensitizer may precipitate from the photosensitive layer during preservation period.

The photopolymerization initiator may be used alone or in combination. Examples of the photopolymerization initiators utilized properly in the present invention are those activated at 405 nm of laser beam wavelength in exposing step and selected from phosphine oxides, α-aminoalkylketones, complex initiators of halogenated hydrocarbons having a triazine skeleton and amine compounds as a photosensitizer described later, hexaaryl biimidazole compounds, and titanocenes.

The content of the photopolymerization initiator in the photosensitive composition is preferably 0.1 % by mass to 30 % by mass, more preferably is 0.5 % by mass to 20 % by mass, and still more preferably is 0.5 % by mass to 15 % by mass. - Filler -

The (D) filler described above may be incorporated into the photosensitive composition in order to increase surface hardness of permanent patterns, to reduce thermal expansion coefficient, or to lower dielectric constant or loss tangent of cured films, and may be selected from commercially available inorganic fillers and organic fillers depending on the application.

Examples of the inorganic fillers include kaoline, barium sulfate, barium titanate, silicon oxide powder, silicon oxide fine particles, vapor-deposited silica, amorphous silica, crystalline silica, molten silica, spherical silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, and mica.

The average particle size of the inorganic pigments is preferably 10 μm or less, more preferably is 3 μm or less. When the average particle size is more than 10 μm, the resolution may be deteriorated due to optical scattering.

The organic fine may be properly selected depending on the application; examples thereof include melamine resins, benzoguanamine resins, and crosslinked polystyrene resins.

In addition, porous spherical fine particles may be available such as of silica and a crosslinked resin having an average particle size of 1 μm to 5 μm and an oil absorption of 100 ml/lOOg to 200 ml/100g.

The content of the filler in the photosensitive composition is preferably 10 % by mass to 60 % by mass. When the content is less than 10 % by mass, the purpose to increase surface hardness etc. described above may be unsuccessful, and when the content is more than 60 % by mass, the cured film on the photosensitive layer may be brittle, and the ability for protecting wirings may be deteriorated after the permanent patterns are formed. - Other Components -

As for the other components, thermal crosslinkers, thermal polymerization inhibitors, plasticizers, coloring agents, and colorants are exemplified; in addition, the other auxiliaries such as adhesion promoters on substrate surface, pigments, conductive particles, fillers, defoamers, fire retardants, leveling agents, peeling promoters, antioxidants, perfumes, adjustors of surface tension, chain transfer agents, and the like may be utilized together with. By way of incorporating these components properly, properties of photosensitive films for forming permanent patterns such as stability with time, photographic property, film property, and the like may be desirably tailored. - Thermal Crosslinker - The thermal crosslinker described above may be incorporated into the photosensitive composition in order to enhance the film strength of the resulting photosensitive layer or the like. Examples of the thermal crosslinker include epoxy compounds containing at least two oxirane groups in one molecule, oxetane compounds containing at least two oxetanyl groups in one molecule, and the like.

Specific examples of the epoxy compound include bixylenol or biphenol epoxy resins and mixtures thereof such as Epikote™ YX4000 (by Japan Epoxy Resins Co.), heterocyclic epoxy resins containing an isocyanurate skeleton such as TEPIC™ (by Nissan Chemical Industries, Ltd.) and Araldite™ PT810 (Ciba Specialty Chemicals Co.); bisphenol A epoxy resins, novolac epoxy resins, bisphenol F epoxy resins, hydrogenated bisphenol A epoxy resins, glycidylamine epoxy resins, hydantoin epoxy resins, alicyclic epoxy resins, trihydroxyphenylmethane epoxy resins, bisphenol S epoxy resins, bisphenol A novolac epoxy resins, tetraphenylethane epoxy resins, glycidyl phthalate resins, tetraglycidyl xylenoyl ethane resins, epoxy resins containing a naphthalene group such as ESN-190, ESN-360 (by Nippon Steel Chemical Co.), HP-4032, EXA-4750, and EXA-4700 (by Dainippon Ink and Chemicals, Inc.); epoxy resins containing a dicyclopentadiene skeleton such as HP- 7200 and HP-7200H (by Dainippon Ink and Chemicals, Inc.); glycidylmethacrylate copolymer epoxy resins such as CP-50S and CP-50M (by NOF Co.), copolymer epoxy resins of cyclohexylmaleimide and glycidylmethacrylate, and the like. These may be used alone or in combination.

Specific examples of the oxetane compound include bis[(3-methy-3-oxetanylmethoxy)methyl]ether_/ bis [(3-ethy-3-oxetanylmethoxy)methyl] ether, l_/4-bis[(3-methy-3-oxetanylmethoxy)methyl]benzene_/ l,4-bis[(3-ethy~3-oxetanylmethoxy)methyl]benzene, (3-methy-3-oxetanyl)methylacrylate, (3-ethy-3-oxetanyl)methylacrylate, (3-methy-3-oxetanyl)methylmethacrylate, (3-ethy-3-oxetanyl)methylmethacrylate, multi-functional oxetanes such as oligomers or copolymers thereof; ether compounds synthesized from compounds containing an oxetane group and resins containing a hydroxyl group such as novolac resins, poly(p-hydroxystyrene), cardo type bisphenols, calixarenes, calixresorcinarenes, and silsesquioxane; copolymers of an unsaturated monomer containing an oxetane ring and alkyl(meth) aery late, and the like. The solid content of the epoxy compounds, oxetane compounds, or thermal polymerization promoters is preferably 1 % by mass to 50 % by mass, more preferably is 3 % by mass to 30 % by mass based on the solid of the photosensitive composition. When the solid content is less than 1 % by mass, the cured film tends to absorb moisture, thereby possibly degrading the insulation property or deteriorating the thermal resistance for soldering or resistance for electroless plating; and when the solid content is more than 50 % by mass, developing property may degrade and/ or exposure sensitivity may lower disadvantageously.

In order to enhance the thermal polymerization of the epoxy compound and/ or the oxetane compounds, such compounds may be utilized as amine compounds such as dicyandiamide, benzyldimethylamine, 4-(dimethylamino)-N_/N-dimethylbenzylamine_/ 4-methoxy-N,N-dimethylbenzylamine, and

4-methyl-N_/N-dimethylbenzylamine; quaternary ammonium salts such as triethylbenzylammonium chloride; block isocyanate compounds such as of dimethylamine; bicyclic amidine compounds of imidazole such as imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethy-4-methylimidazole,

2-phenylimidazole, 4-phenylimidazole, l-cyanoethyl-2-phenylimidazole, l-(2-cyanoethyl)-2-ethyl-4-methylimidazole; phosphorus compounds such as triphenylphosphine; guanamine compounds such as melamine, guanamine, acetoguanamine, and benzoguanamine; S-triazine derivatives such as 2,4-diamino-6-methacroyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, isocyanuric acid adduct of 2-vinyl-4,6-diamino-S~triazine, and isocyanuric acid adduct of 2,4-diamino-6-methacryloyloxyethyl-S-triazine. The other catalysts for curing epoxy compounds and oxetane compounds, or those effective to promote the reaction of carboxylic group may possibly be employed. The solid content of the compounds described above for promoting the thermo polymerization of the epoxy compounds etc. is usually 0.01 to 15 % by mass based on the solid content of the photosensitive composition.

As for the thermal crosslinker, polyisocyanate compounds illustrated in JP-A No. 05-9407 may be employed, in which the polyisocyanate compounds may be those derived from aliphatic compounds, alicyclic compounds, or aliphatic compounds containing an aromatic group. Specific examples thereof include bifunctional isocyanate such as a mixture of 1,3-phenylene diisocyanate and 1,4-phenylene diisocyanate, 2,4-toluene diisocyanate and 2,6-toluene diisocyanate, 1,3-xylylene diisocyanate and 1,4-xylylene diisocyanate, bis(4-isocyanatephenyl)methane, bis(4-isocyanatecyclohexyl)methane, isophorone diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate; multifunctional alcohols obtained from these bifunctional isocyanates and trimethylolpropane, pentaerythritol, glycerin, or the like; adducts obtained from alkyleneoxide adducts of these multifunctional alcohols and these bifunctional isocyanates; and cyclic trimers such as hexamethylene diisocyanate, hexamethylene-l,6-diisocyanate, and derivatives thereof.

Polyisocyanate compounds, in which the isocyanate group thereof is blocked by a compound, may be employed so as to improve the shelf stability of the photosensitive film for forming permanent patterns.

Examples of the compound for blocking the isocyanate group include alcohols such as isopropanol and tert-butanol; lactams auch as epsilon-caprolactam; phenols such as phenol, cresol, p-tert-butylphenol, p-sec-butylphenol, p-sec-aminophenol, p-octylphenol, and p-nonylphenol; heterocyclic hydroxyl compounds such as 3-hydroxypyridine and

8-hydroxyquinoline; active methylene compounds such as dialkylmalonate, methylethylketokime, acetylacetone, alkylacetoxime, acetoxime, and cyclohexanone oxime. In addition, the compounds containing a double bond and a blocked isocyanate group may be employed as illustrated in JP-A No. 06-295060. Aldehyde condensation products and resin precursors may also be employed. Specific example thereof include N,N'-dimethylolurea, N,N'-dimethylolmalonamide, N,N'-dimethylolsuccinimide, trimethylolmelamine, tetramethylolmelamine, hexamethylolmelamine, l,3-N,N'-dimethylolterephthalamide, 2,4,6-trimethylolphenol,

2_/6-dimethylol-4-methylanisole_/ and l,3-dimethylol-4,6-diisopropylbenzene. Further, in place of these methylol compounds, such compounds may be employed as etylol compounds, butylol compounds, and esters of acetic acid or propionic acid that corresponds to the methylol compounds respectively. In addition, hexamethylmethylolmelamine obtained by condensation reaction of melamine or urea and formaldehyde, and butylether of condensation product by reaction of melamine and formaldehyde may also be available.

The solid content of the thermal crosslinker is preferably 1 % by mass to 40 % by mass, more preferably is 3 % by mass to 20 % by mass, still more preferably is 5 % by mass to 25 % by mass based on the solid content of the photosensitive composition. When the solid content is less than 1 % by mass, the cured film may not exhibit significant increase in terms of the film strength, and when the solid content is more than 40 % by mass, developing property may degrade and/ or exposure sensitivity may lower disadvantageously. - Thermal Polymerization Inhibitor -

The thermal polymerization inhibitor may be added to prevent the polymerization of the polymerizable compounds due to higher temperature and/ or longer duration.

Examples of the thermal polymerization inhibitor include 4-methoxy phenol, hydroquinone, hydroquinone substituted with alkyl or aryl, t-butylcatechol, pyrogallol, 2-hydroxybenzophenone, 4-methoxy-2-hydroxybenzophenone, cuprous chloride, phenothiazine, chloranil, naphthylamine, β-naphthol, 2_/6-di-t-butyl-4-cresol, 2,2'-methylenebis(4-methyl-6-t-butylphenol), pyridine, nitrobenzene, dinitrobenzene, picric acid, 4-toluidine, methylene blue, reaction products of copper and organic chelators, methyl salicylate, phenothiazine, nitroso compounds, and chelate compounds of nitroso compounds and Al.

The content of the thermal polymerization inhibitor is preferably 0.001 % by mass to 5 % by mass based on the polymerizable compound, more preferably is 0.005 % by mass to 2 % by mass, and still more preferably is

0.01 % by mass to 1 % by mass. When the content is less than 0.001 % by mass, the reservation stability may be insufficient, and when the content is more than 5 % by mass, the sensitivity against active energy beams may be lowered. - Coloring Agent - The coloring agent may be properly depending on the application; example thereof include Victoria Pure Blue BO (C.I. 42595), Auramine (CI. 41000), Fat Black HB (CI. 26150), Monolite Yellow GT (CI. Pigment Yellow 12), Permanent Yellow GR (CI. Pigment Yellow 17), Permanent Yellow HR (CI. Pigment Yellow 83), Permanent Carmine FBB (CI. Pigment Red 146), Hosterberm Red ESB (CI. Pigment Violet 19), Permanent Ruby FBH (CI. Pigment Red 11), Fastel Pink B Supra (CI. Pigment Red 81), Monastral Fast Blue (CI. Pigment Blue 15), Monolite First Black B (CI. Pigment Black 1), carbon black, CL Pigment Red 97, CI. Pigment Red 122, CI. Pigment Red 149, CI. Pigment Red 168, CI. Pigment Red 177, CL Pigment Red 180, CL Pigment Red 192, CL Pigment Red 215, CL Pigment Green 7, CL Pigment Green 36, CL Pigment Blue 15:1, C.I. Pigment Blue 15:4, C.I. Pigment Blue 15:6, C.I. Pigment

Blue 22, C.I. Pigment Blue 60, and C.I. Pigment Blue 64. These may be used alone or in combination.

The solid content of the coloring agent in the solid of the photosensitive composition may be properly selected depending on the exposure sensitivity and resolution of the photosensitive layer when the permanent pattern is produced, preferably the content is 0.05 % by mass to 10 % by mass, more preferably is 0.075% by mass to 8 % by mass, and still more preferably is 0.1 % by mass to 5 % by mass. - Adhesion Promoter -

In order to enhance the adhesion between layers or between the photosensitive layer and the substrate, so-called adhesion promoters may be employed.

Examples of the adhesion promoters described above include those described in JP-A Nos. 5-11439, 5-341532, and 6-43638; specific examples of adhesion promoters include benzimidazole, benzoxazole, benzthiazole,

2-mercaptobenzimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzthiazole,

3-morpholinomethyl-l-phenyl-triazole-2-thion,

3-morpholinomethyl-5-phenyl-oxadiazole-2-thion, 5-amino-3-morpholinomethyl-thiadiazole-2-thion,

2-mercapto-5-methylthio-thiadiazole, triazole, tetrazole, benzotriazole, carboxybenzotriazole, benzotriazole containing an amino group, and silane coupling agents.

The content of the adhesion promoter is preferably 0.001 % by mass to 20 % by mass based on the total components in the photosensitive layer, more preferably is 0.01 % by mass to 10 % by mass, and still more preferably is 0.1 % by mass to 5 % by mass.

By virtue of incorporating the adhesion promoter into the photosensitive composition, the adhesion may be improved between adjacent layers or between the photosensitive layer and the substrate.

The thickness of the photosensitive layer in the photosensitive film may be properly selected depending on the application; preferably, the thickness is 3 μm to 100 μm, more preferably is 10 μm to 70 μm.

The photosensitive film may contain the other layers such as a peeling layer, optical absorption layer, surface protective layer, or the like depending on the application. The position, thickness, and the like of the other layers may be properly selected depending on the application. (Process for Producing Photosensitive Film for Permanent Pattern)

The photosensitive film for forming a permanent pattern according to the present invention may be produced by the process for producing a photosensitive film for forming a permanent pattern according to the present invention.

Initially, a solution containing a thermoplastic resin, which is soluble or hardly soluble in alkaline liquids, is coated on the support and dried on it to form a cushion layer. When required, ingredients for a barrier layer are dissolved, emulsified, or dispersed to prepare a coating liquid for a barrier layer, then the coating liquid is coated on the cushion layer and dried to form a barrier layer. Then, the coating liquid of the photosensitive composition is coated and dried to form a photosensitive layer, thereby a photosensitive film for forming a permanent pattern is obtained. Preferably, the cushion layer is formed by way of coating an aqueous emulsion based on a thermoplastic resin and drying the coating. An organic solvent may be added to the aqueous emulsion in order to improve working properties. Preferably, an emulsifier is added to the aqueous emulsion in order to improve the disperse ability. The emulsifier may be properly selected depending on the application; examples thereof include anionic emulsifiers such as dodecylbenzene sodium sulfonate, dodecylsodium sulfate, dialkylsodium sulfosuccinate, condensate of formaldehyde and naphthalene sulfonic acid, and polyoxyethylene alkylphenolether ammoniumsulfate; nonionic emulsifier such as polyoxyethylene nonylphenylether, polyethyleneglycol monostearate, and sorbitan monostearate.

When the cushion layer is formed from the aqueous emulsion containing an alkaline-soluble thermoplastic resin, the exhaust gas containing organic solvents may be reduced in the process for forming the photosensitive layer, thus environmental and/ or explosion-proof issues may be relatively easily addressed.

The barrier layer may be formed by way of applying a coating liquid for the barrier layer on the surface of the cushion layer after the cushion layer is formed, and drying the coating. The photosensitive layer is formed by way of applying a coating liquid for the photosensitive layer on the surface of the barrier layer after the barrier layer is formed, and drying the coating.

The solvents of the coating liquids for the barrier layer and cushion layer may be properly selected depending on the application; examples of the solvent include alcohols such as ethanol, methanol, n-propanol, isopropanol, n-butanol, sec-butanol, n-hexanol; ektones such as acetone, methylethylketone, methylisobutylketone, cyclohexanone, and diisobutylketone; esters such as ethyl acetate, butyl acetate, n-amyl acetate, methyl sulfate, ethyl propionate, dimethyl phthalate, ethyl benzoate, and methoxy propyl acetate; aromatic hydrocarbons such as toluene, xylene, benzene, and ethyl benzene; halogenated hydrocarbons such as carbon tetrachloride, trichloroethylene, chloroform, 1,1,1-trichloroetahne, methylene chloride, monochloro benzene; ethers such as tetrahydrofuran, diethylene ether, ethyleneglycol monomethyl ether, ethyleneglycol monoethyl ether, and l-methoxy-2-propanol; dimethyl formamide, dimethyl acetamide, dimethyl sulfoxide, and sulforane. These may be used alone or in combination. Further, a conventional surfactant may be added to the solvent.

The process for applying the respective coating liquids may be properly selected depending on the application; for example, the respective coating liquids may be directly coated on the support by means of a spin coater, slit spin coater, roll coater, die coater, curtain coater, and the like.

The drying conditions may be properly selected depending on the ingredients in the coating liquids, and the species and/ or content of the solvent; usually the temperature is 60 to 110 °C and the duration is 30 seconds to 15 minutes.

Preferably, the photosensitive layer of the photosensitive film is covered with a protective film prior to laminating onto a substrate. The protective film is, for example, overlapped to the surface of the photosensitive layer while transportation thereof, thereby protecting the photosensitive layer from damages, soils, and the like, and is peeled off when the photosensitive film is laminated on the substrate.

The material of the protective film may be those exemplified with respect to the support described above, and also may be silicone paper, paper laminated with polypropylene or polyethylene, polyethylene or polypropylene film, sheets of polyolefin or polytetrafluoroethylene, or the like. Among these materials, polyethylene film and polypropylene film are preferable.

The thickness of the protective film may be properly selected without particular limitations; preferably, the thickness is 5 to 100 μm, and more preferably is 8 to 30 μm. In the application of the protective film, preferably, the adhesive strength X between the photosensitive layer and the support, and the adhesive strength Y between the photosensitive layer and the protective film represent the relation: adhesive strength X > adhesive strength Y.

The combinations of the support and the protective film, i.e. (support/ protective film), are exemplified by (polyethylene terephthalate/ polypropylene), (polyethylene terephthalate/ polyethylene), (polyvinyl chloride/ cellophane), (polyimide/ polypropylene), and (polyethylene terephthalate/ polyethylene terephthalate). Further, the surface treatment of the support and/ or the protective film may result in the relation of the adhesive strength described above. The surface treatment of the support may be utilized for enhancing the adhesive strength with the photosensitive layer; examples of the surface treatment include deposition of under-coat layer, corona discharge treatment, flame treatment, UV-rays treatment, RF exposure treatment, glow discharge treatment, active plasma treatment, and laser beam treatment. The static friction coefficient between the support and the protective film is preferably 0.3 to 1.4, more preferably is 0.5 to 1.2.

When the static friction coefficient is less than 0.3, winding displacement may generate in roll configuration due to excessively high slipperiness, and when the static friction coefficient is more than 1.4, winding of the material into roll configuration tends to be difficult.

The protective film may be subjected to surface treatment in order to control the adhesive property between the protective film and the photosensitive layer. The surface treatment is performed, for example, by providing an under-coat layer of polymer such as polyorganosiloxane, fluorinated polyolefin, polyfluoroethylene, and polyvinyl alcohol on the surface of the protective film. The under-coat layer may be formed by coating the liquid of the polymer on the surface of the protective film, then drying the coating at 30 ⁰C to 150 ⁰C, in particular 50 °C to 120 ⁰C for 1 minute to 30 minutes.

Preferably, the photosensitive film for forming a permanent pattern is wound on a cylindrical winding core, and is stored in an elongated roll configuration. The length of the elongated photosensitive film may be properly selected without particular limitations, for example the length is from 10 meters to 20,000 meters. Further, the photosensitive layer may be subjected to slit processing for easy handling in the usages, and may be provided as a roll configuration for every 100 meters to 1,000 meters. Preferably, the photosensitive film is wound such that the support exists at outer most side of the roll configuration. Further, the photosensitive film may be slit into a sheet configuration. In the storage, preferably, a moistureproof separator "with a desiccant is provided at the end surface of the photosensitive film, and the package is formed from a higher moistureproof material for preventing edge fusion.

The photosensitive film for forming a permanent pattern according to the present invention comprises a photosensitive layer of a laminated photosensitive composition that represents little tackiness of the resulting surface, proper laminating ability, and appropriate shelf stability, and may display superior chemical resistance, higher surface hardness, and sufficient thermal resistance. Accordingly, the photosensitive films according to the present invention may be widely applied to, for example, printed wiring boards such as multilayer wiring boards and build-up wiring boards; display members such as column members, rib members, spacers, and partition members; permanent patterns such as holograms, micro machines, and proofs. In particular, the photosensitive films according to the present invention may be uniform in film thickness, therefore, the photosensitive films may be laminated on a substrate in highly fine and precise manner.

Preferably, the permanent patterns formed from the photosensitive film according to the present invention are protective films or insulating films, more preferably are interlayer insulating films. The permanent patterns are capable of protecting various wirings from external shock or bending stress, thus may be appropriately utilized for insulating films for multilayer wiring substrates, build-up wiring substrates, and the like. (Process for Forming Permanent Pattern)

The process for forming a permanent pattern comprises a laminating step, exposing step, developing step, and the other steps selected properly depending on the application.

Specifically, the process for forming a permanent pattern according to the present invention comprises a laminating step in which a photosensitive layer is laminated on a surface of a substrate by way of heating and/ or pressurizing, an exposing step in which the photosensitive layer laminated in the laminating step is exposed, and an developing step in which the photosensitive layer exposed in the exposing step is developed, consequently the photosensitive layer remains on the substrate in a predetermined pattern, thereby a certain permanent pattern i.e. a solder resist is produced on the substrate.

In the first aspect of the process for forming a permanent pattern, besides the steps described above, preferably, the support and the cushion layer are separated simultaneously from the photosensitive layer between the cushion layer and the photosensitive layer after the exposing step, then the photosensitive layer is developed in the developing step.

In accordance with the process for forming a permanent pattern in the first aspect, the photosensitive layer is far from sensitivity decrease and/ or inhabitation of polymerization reaction due to the adverse effect of oxygen, even when a photosensitive composition of optical radical type is employed as a higher sensitive photosensitive composition by way of interrupting the oxygen passage into the photosensitive layer when exposing by means of the support and the cushion layer.

In the second aspect of the process for forming a permanent pattern, besides the steps described above, preferably, the support and the cushion layer are separated simultaneously from the photosensitive layer between the cushion layer and the photosensitive layer after the laminating step, then the photosensitive layer is exposed in the exposing step.

In accordance with the process for forming a permanent pattern in the second aspect, images may be formed with higher resolution on the photosensitive layer without image blur, apart from being adversely affected by optical scattering or refraction due to the support or the cushion layer.

The protective film, interlayer insulating film, or the like that is formed from the photosensitive film for forming a permanent pattern is the permanent pattern that is obtained in accordance with the process for forming a permanent pattern according to the present invention. [Laminating Step]

In the laminating step, a photosensitive layer for forming a permanent pattern is laminated on a surface of a substrate by way of heating and/ or pressurizing. The heating temperature and the pressure in the laminating step may be properly selected depending on the application; preferably the heating temperature is 70 ⁰C to 130 °C, more preferably is 80 ⁰C to 110 °C; preferably the pressure is 0.01 MPa to 1.0 MPa, more preferably is 0.05 MPa to 1.0 MPa.

The apparatus for the heating and the pressuring may be properly selected depending on the application; examples of the apparatuses include a heat press, heat roll laminator (e.g., VP-II by Taisei-Laminator Co.), and vacuum laminator (e.g., MVLP500 by Meiki Co., Ltd.). < Substrate >

The substrate may be properly selected from commercially available materials, which may be of nonuniform surface or of highly smooth surface. Preferably, the substrate is plate-like; specifically, the substrate may be selected from the materials such as printed wiring boards e.g. copper-laminated plate, glass plates e.g. soda glass plate, synthetic resin films, paper, and metal plates. [Exposing Step]

In the exposing step, a process for forming a permanent pattern is provided that comprises modulating a laser beam irradiated from a laser source, compensating the modulated laser beam, and exposing a photosensitive layer by means of the modulated and compensated laser beam, wherein the modulating is performed by a laser modulator that comprises plural imaging portions each capable of receiving the laser beam and outputting the modulated laser beam, and the compensating is performed by transmitting the modulated laser beam through plural microlenses each having a non-spherical surface capable of compensating the aberration due to distortion of the output surface of the imaging portion, and the plural microlenses are arranged to a microlens array. - Laser Modulator -

The laser modulator may be properly selected depending on the application as long as it comprises plural imaging portions. Preferable examples of the laser modulator include a spatial light modulator.

Specific examples of the spatial light modulator include a digital micromirror device (DMD), spatial light modulator of micro electro mechanical systems, PLZT element, and liquid crystal shatter; among these, the DMD is preferable. The laser modulator will be specifically explained with reference to figures in the following.-

DMD 50 is a mirror device that has lattice arrays of many micromirrors 62, e.g. 1024 x 768, on SRAM cell or memory cell 60 as shown in FIG. 1, wherein each of the micromirrors performs as an imaging portion. At the 5 upper most portion of the each imaging portion, micromirror 62 is supported by a pillar. A material having a higher reflectivity such as aluminum is vapor deposited on the surface of the micromirror 62. The reflectivity of the micromirrors 62 is 90 % or more; the array pitches in longitudinal and width directions are respectively 13.7 μm, for example. Further, SRAM cell 60 of a o silicon gate CMOS produced by conventional semiconductor memory producing processes is disposed just below each micromirror 62 through a pillar containing a hinge and yoke. The mirror device is entirely constructed as a monolithic body.

When a digital signal is written into SRAM cell 60 of DMD 50, 5 micromirror 62 supported by a pillar is inclined toward the substrate, on which DMD 50 is disposed, within ± alpha degrees, e.g. + 12 degrees, around the diagonal as the rotating axis. FIG. 2A indicates the condition that micromirror 62 is inclined + alpha degrees at on state, FIG. 2B indicates the condition that micromirror 62 is inclined - alpha degrees at off state. As such, o each incident laser beam B on DMD 50 is reflected depending on each inclined direction of micromirrors 62 by controlling each inclined angle of micromirrors 62 in imaging portions of DMD 50 depending on pattern information as shown in FIG. 1.

Incidentally, FIG. 1 exemplarily shows a magnified condition of DMD 5 50 partly in which micromirrors 62 are controlled at an angel of - alpha degrees or + alpha degrees. Controller 302 connected to DMD 50 carries out on-off controls of the respective micromirrors 62. An optical absorber (not shown) is disposed on the way of laser beam B reflected by micromirrors 62 at off state. Preferably, DMD 50 is slightly inclined in the condition that the shorter side presents a pre-determined angle, e.g. 0.1 degree to 5 degrees, against the sub-scanning direction. FIG. 3A shows scanning traces of reflected laser image or exposing beam 53 by the respective micromirrors when DMD 50 is not inclined; FIG. 3B shows scanning traces of reflected laser image or exposing beam 53 by the respective micromirrors when DMD 50 is inclined. In DMD 50, many micromirrors, e.g. 1024, are disposed in the longer direction to form one array, and many arrays, e.g. 756, are disposed in the shorter direction. Thus, by means of inclining DMD 50 as shown in FIG. 3B, the pitch P2 of scanning traces or lines of exposing beam 53 from each micromirror may be more reduced than the pitch Pi of scanning traces or lines of exposing beam 53 without inclining DMD 50, thereby the resolution may be improved remarkably. On the other hand, the inclined angle of DMD 50 is small, therefore, the scanning direction W2 when DMD 50 is inclined and the scanning direction Wi when DMD 50 is not inclined are approximately the same.

The process to accelerate the modulation rate of the laser modulator (hereinafter referring to as "high rate modulation") will be explained in the following.

Preferably, the laser modulator is able to control any imaging portions of less than "n" disposed successively among the imaging portions depending on the pattern information (n: an integer of 2 or more). Since there exist a limit in the data processing rate of the laser modulator and the modulation rate per one line is defined with proportional to the utilized imaging portion number, the modulation rate per one line may be increased through only utilizing the imaging portions of less than "n" disposed successively.

The high rate modulation will be explained with reference to figures in the following.

When laser beam B is irradiated from fiber array laser source 66 to DMD 50, the reflected laser beam, at the micromirrors of DMD 50 on state, is imaged on photosensitive layer 150 by lens systems 54, 58. As such, the laser beam irradiated from the fiber array laser source is turned into on or off by the respective imaging portions, and the photosensitive layer 150 is exposed in approximately the same number of imaging portion units or exposing areas 168 as the imaging portions utilized in DMD 50. In addition, when photosensitive layer 150 is conveyed with stage 152 at a constant rate, photosensitive layer 150 is sub-scanned to the direction opposite to the stage moving direction by scanner 162, thus exposed regions 170 of band shape are formed correspondingly to the respective exposing heads 166.

In this example, micromirrors are disposed on DMD 50 as 1024 arrays in the main-scanning direction and 768 arrays in sub-scanning direction as shown in FIGs. 4A and 4B. Among these micromirrors, a part of micromirrors, e.g. 1024 x 256, may be controlled and driven by controller 302 (see FIG. 12).

In such control, the micromirror arrays disposed at the central area of DMD 50 may be employed as shown in FIG. 4A; alternatively, the micromirror arrays disposed at the edge portion of DMD 50 may be employed as shown in FIG. 4B. In addition, when micromirrors are partly damaged, the utilized micromirrors may be properly altered depending on the situations such that micromirrors with no damage are utilized.

Since there exist a limit in the data processing rate of DMD 50 and the modulation rate per one line is defined with proportional to the utilized imaging portion number, partial utilization of micromirror arrays leads to higher modulation rate per one line. Further, when exposing is carried out by moving continuously the exposing head relative to the exposing surface, the entire imaging portions are not necessarily required in the sub-scanning direction.

When the sub-scanning of photosensitive layer 150 is completed by scanner 162, and the rear end of photosensitive layer 150 is detected by sensor 164, the stage 152 returns to the original site at the most upstream of gate 160 along guide 158 by action of stage drive device 304, and the stage 152 is moved again from upstream to downstream of gate 160 along guide 158 at a constant rate.

For example, when 384 arrays are utilized among the 768 arrays of micromirrors, the modulation rate may be enhanced two times compared to utilizing all of 768 arrays; further, when 256 arrays are utilized among the 768 arrays of micromirrors, the modulation rate may be enhanced three times compared to utilizing all of 768 arrays

As explained above, in accordance with the process for forming a permanent pattern according to the present invention, when DMD 50 is provided with 1024 micromirror arrays in the main-scanning direction and 768 micromirror arrays in the sub-scanning direction, controlling and driving of partial micromirror arrays may lead to higher modulation rate per one line compared to controlling and driving of entire micromirror arrays.

In addition to the controlling and driving of partial micromirror arrays, elongated DMD on which many micromirrors are disposed on a substrate in planar arrays may increase similarly the modulation rate when the each angle of reflected surface is changeable depending on the various controlling signals, and the substrate is longer in a specific direction than its perpendicular direction.

Preferably, the exposing is performed while moving relatively the exposing laser and the thermosensitive layer; more preferably, the exposing is combined with the high rate modulation described before, thereby exposing may be carried out with higher rate in a shorter period.

As shown in FIG. 5, photosensitive layer 150 may be exposed on the entire surface by one scanning of scanner 162 in X direction; alternatively, as shown in FIGs. 6 A and 6B, photosensitive layer 150 may be exposed on the entire surface by repeated plural exposing such that photosensitive layer 150 is scanned in X direction by scanner 162, then the scanner 162 is moved one step in Y direction, followed by scanning in X direction. In this example, scanner 162 comprises eighteen exposing heads 166; each exposing head comprises a laser source and the laser modulator.

The exposure is performed on a partial region of the photosensitive layer, thereby the partial region is hardened, followed by un-hardened region other than the partial hardened region is removed in developing step as described later, thus a permanent pattern is formed. A pattern forming apparatus comprising the laser modulator will be exemplarily explained with reference to figures in the following.

The pattern forming apparatus comprising the laser modulator is equipped with flat stage 152 that absorbs and sustains sheet-like photosensitive layer 150 on the surface. On the upper surface of thick plate table 156 supported by four legs 154, two guides 158 are disposed that extend along the stage moving direction. Stage 152 is disposed such that the elongated direction faces the stage moving direction, and supported by guide 158 in reciprocally movable manner. A driving device is equipped with the pattern forming apparatus (not shown) so as to drive stage 152 along guide 158.

At the middle of the table 156, gate 160 is provided such that the gate 160 strides the path of stage 152. The respective ends of gate 160 are fixed to both sides of table 156. Scanner 162 is provided at one side of gate 160, plural (e.g. two) detecting sensors 164 are provided at the opposite side of gate 160 in order to detect the front and rear ends of photosensitive layer 150. Scanner 162 and detecting sensor 164 are mounted on gate 160 respectively, and disposed stationarily above the path of stage 152. Scanner 162 and detecting sensor 164 are connected to a controller (not shown) that controls them. As shown in FIGs. 8 and 9B, scanner 162 comprises plural (e.g. fourteen) exposing heads 166 that are arrayed in substantially matrix of "m rows x n lines" (e.g. three x five). In this example, four exposing heads 166 are disposed at third line considering the width of photosensitive layer 150. The specific exposing head at "m" th row and "n" th line is expressed as exposing head 166mn hereinafter. The exposing area 168 formed by exposing head 166 is rectangular having the shorter side in the sub-scanning direction. Therefore, exposed areas 170 are formed on photosensitive layer 150 of a band shape that corresponds to the respective exposing heads 166 along with the movement of stage 152. The specific exposing area corresponding to the exposing head at "m" th row and "n" th line is expressed as exposing area 168πuι hereinafter.

As shown in FIGs. 9 A and 9B, each of the exposing heads at each line is disposed with a space in the line direction so that exposed regions 170 of band shape are arranged without space in the perpendicular direction to the sub-scanning direction (space: (longer side of exposing area) x natural number; two times in this example). Therefore, the non-exposing area between exposing areas 16S₁I and I6812 at the first raw can be exposed by exposing area I6821 of the second raw and exposing area I6831 of the third raw.

Each of exposing heads I6611 to 166πuι comprises a digital micromirror device (DMD) 50 (e.g., by US Texas Instruments Inc.) as a laser modulator or spatial light modulator that modulates the incident laser beam depending on the pattern information as shown in FIGs. 10 and 11. Each DMD 50 is connected to controller 302 that comprises a data processing part and a mirror controlling part as shown in FIG. 12. The data processing part of controller 302 generates controlling signals to control and drive the respective micromirrors in the areas to be controlled for the respective exposing heads

166, based on the input pattern information. The area to be controlled will be explained later. The mirror driving-controlling part controls the reflective surface angle of each micromirror of DMD 50 per each exposing head 166 based on the control signals generated at the pattern information processing part. The control of the reflective surface angle will be explained later. At the incident laser side of DMD 50, fiber array laser source 66 that is equipped with a laser irradiating part where irradiating ends or emitting sites of optical fibers are arranged in an array along the direction corresponding with the longer side of exposing area 168, lens system 67 that compensates the laser beam from fiber array laser source 66 and collects it on the DMD, and mirrors 69 that reflect laser beam through lens system 67 toward DMD 50 are disposed in this order. FIG. 10 schematically shows lens system 67.

Lens system 67 is comprised of collective lens 71 that collects laser beam B for illumination from fiber array laser source 66, rod-like optical integrator 72 (hereinafter, referring to as "rod integrator") inserted on the optical path of the laser passed through collective lens 71, and image lens 74 disposed in front of rod integrator 72 or the side of mirror 69, as shown FIG. 11. Collective lens 71, rod integrator 72, and image lens 74 make the laser beam irradiated from fiber array laser source 66 enter into DMD 50 as a luminous flux of approximately parallel beam with uniform intensity in the cross section. The shape and effect of the rod integrator 72 will be explained in detail later. Laser beam B irradiated from lens system 67 is reflected by mirror 69, and is irradiated to DMD 50 through a total internal reflection prism 70 (not shown in FIG. 10). At the reflecting side of DMD 50, imaging system 51 is disposed that images laser beam B reflected by DMD 50 onto photosensitive layer 150. The imaging system 51 is equipped with the first imaging system of lens systems 52, 54, the second imaging system of lens systems 57, 58, and microlens array 55 and aperture array 59 interposed between these imaging systems as shown in FIG. 11. Arranging two-dimensionally many microlenses 55a each corresponding to the respective imaging portions of DMD 50 forms microlens array 55. In this example, micromirrors of 1024 rows x 256 lines among 1024 rows x 768 lines of DMD 50 are driven, therefore, 1024 rows x 256 lines of microlenses 55a are disposed correspondingly. The pitch of disposed microlenses 55a is 41 μm in both of raw and line directions. Microlenses 55a have a focal length of 0.19 mm and a numerical aperture (NA) of 0.11 for example, and are formed of optical glass BK7. The shape of microlenses 55a will be explained later. The beam diameter of laser beam B is 41 μm at the site of microlens 55a.

Aperture array 59 is formed of many apertures 59a each corresponding to the respective microlenses 55a of microlens array 55. The diameter of aperture 59a is 10 μm, for example.

The first imaging system forms the image of DMD 50 on microlens array 55 as a three times magnified image. The second imaging system forms and projects the image through microlens array 55 on photosensitive layer 150 as a 1.6 times magnified image. Therefore, the image by DMD 50 is formed and projected on photosensitive layer 150 as a 4.8 times magnified image.

Incidentally, prism pair 73 is installed between the second imaging system and photosensitive layer 150; through the operation to move up and down the prism pair 73, the image pint may be adjusted on the image forming material 150. In FIG. 11, photosensitive layer 150 is fed to the direction of arrow F as sub-scanning.

The imaging portions may be properly selected depending on the application provided that the imaging portions can receive the laser beam from the laser source or irradiating means and can output the laser beam; for example, the imaging portions are pixels when the permanent pattern formed by the process for forming a permanent pattern according to the present invention is an image pattern, alternatively the imaging portions are micromirrors when the laser modulator contains a DMD.

The number of imaging portions contained in the laser modulator may be properly selected depending on the application. The alignment of imaging portions in the laser modulator may be properly selected depending on the application; preferably, the imaging portions are arranged two dimensionally, more preferably are arranged into a lattice pattern. - Microlens Array -

The microlens array may be properly selected depending on the application as long as each of the arrayed plural microlenses has a non-spherical surface capable of compensating the aberration due to distortion of the output surface of the imaging portions; the representative examples are an array of plural microlenses each having a non-spherical surface capable of compensating the aberration due to distortion of the output surface of the imaging portions, and an array of plural microlenses each having an aperture configuration capable of substantially shielding incident light other than the modulated laser beam from the laser modulator.

The non-spherical surface may be properly selected depending on the application; preferably, the non-spherical surface is toric surface, for example.

The microlens array, aperture array, imaging system described above will be explained with reference to figures. FIG. 13A shows an exposing head that is equipped with DMD 50, laser source 144 to irradiate laser beam onto DMD 50, lens systems or imaging optical systems 454 and 458 that magnify and image the laser beam reflected by DMD 50, microlens array 472 that arranges many microlenses 474 corresponding to the respective imaging portions of DMD 50, aperture array that aligns many apertures 478 corresponding to the respective microlenses of microlens array 472, and lens systems or imaging systems 480 and 482 that image laser beam through the apertures onto exposed surface 56.

FIG. 14 shows the flatness data as to the reflective surface of micromirrors 62 of DMD 50. In FIG. 14, contour lines express the respective same heights of the reflective surface; the pitch of the contour lines is five nano meters. In FIG. 14, X direction and Y direction are two diagonal directions of micromirror 62, the micromirror 62 rotates around the rotation axis extending in Y direction. FIGs. 15A and 15B show the height displacements of micromirrors 62 along the X and Y directions respectively. As shown in FIGs. 14, 15 A and 15B, there exist strains on the reflective surface of micromirror 62, the strains of one diagonal direction (Y direction) is larger than another diagonal direction (X direction) at the central region of the mirror in particular. Accordingly, a problem may be induced that the shape is distorted at the site that collects laser beam B by microlenses 55a of microlens array 55.

In order to prevent such a problem, microlenses 55a of microlens array 55 are of special shape that is different from the prior art as explained later in the process for forming a permanent pattern according to the present invention. FIGs. 16 A and 16B show the front shape and side shape of the entire microlens array 55 in detail. In FIGs. 16A and 16B, various parts of the microlens array 55 are indicated as the unit of mm (millimeter). In the process for forming a permanent pattern according to the present invention, micromirrors of 1024 rows x 256 lines of DMD 50 are driven as explained above; microlens arrays 55 are correspondingly constructed as 1024 arrays in length direction and 256 arrays in width direction. In FIG. 16A, the site of each microlens is expressed as "j" th line and "k" th row.

FIGs. 17A and 17B show respectively the front shape and side shape of one microlens 55a of microlens array 55. FIG. 17A shows also the contour lines of microlens 55a. The end surface of each microlens 55a of irradiating side is of non-spherical shape to compensate the strain aberration of reflective surface of micromirrors 62. Specifically, microlens 55a is a toric lens; the curvature radius Rx of optical X direction is - 0.125 mm, and the curvature radius Ry of optical Y direction is - 0.1 mm. Accordingly, the collecting condition of laser beam B within the cross section parallel to the X and Y directions are approximately as shown in FIGs. 18A and 18B respectively. Namely, comparing the X and Y directions, the curvature radius of microlens 55a is shorter and the focal length is also shorter in Y direction. FIGs. 19A, 19B, 19C, and 19D show the simulations of beam diameter near the focal point of microlens 55a in the above noted shape by means of a computer. For the reference, FIGs. 20A, 2OB, 2OC, and 20D show the similar simulations for microlens of Rx = Ry = - 0.1 mm. The values of "z" in the figures are expressed as the evaluation sites in the focus direction of microlens 55a by the distance from the beam irradiating surface of microlens 55a. The surface shape of microlens 55a in the simulation may be calculated by the following equation (1).

C x ² X ² + C y ² Y ²

1 +S Q R T ( 1 - C _x ² X ² C _y ² Y ²)

In the. above equation, Cx means the curvature (= 1/Rx) in X direction, Cy means the curvature (= 1/Ry) in Y direction, X means the distance from optical axis O in X direction, and Y means the distance from optical axis O in Y direction.

From the comparison of FIGs. 19A to 19D, and FIGs. 2OA to 2OD, it is apparent in the process for forming a permanent pattern according to the present invention that the employment of the toric lens as the microlens 55a that has a shorter focal length in the cross section parallel to Y direction than the focal length in the cross section parallel to X direction may reduce the strain of the beam shape near the collecting site. Accordingly, images can be exposed on photosensitive layer 150 with more clearness and without strain. In addition, it is apparent that the inventive mode shown in FIGs. 19A to 19D may bring about a wider region with smaller beam diameter, i.e. longer focal depth.

Incidentally, when the larger or smaller strain at the central region appears at the central region of micromirror 62 inversely with those described above, the employment of microlenses that has a shorter focal length in the cross section parallel to X direction than the focal length in the cross section parallel to Y direction may make possible to expose images on photosensitive layer 150 with more clearness and without strain or distortion. Aperture arrays 59 disposed near the collecting site of microlens array 55 are constructed such that each aperture 59a receives only the laser beam through the corresponding microlens 55a. Namely, aperture array 59 may afford the respective apertures with the insurance that the light incidence from the adjacent apertures 55a may be prevented and the extinction ratio may be enhanced.

Essentially, smaller diameter of apertures 59a provided for the above noted purpose may afford the effect to reduce the strain of beam shape at the collecting site of microlens 55a. However, such a construction inevitably increases the optical quantity interrupted by the aperture array 59, resulting in lower efficiency of optical quantity. On the contrary, the non-spherical shape of microlenses 55a does not bring about the light interruption, thus leading to maintain the higher efficiency of optical quantity.

In the process for forming a permanent pattern explained above, microlens 55a of toric lens is applied that has different curvature radiuses in X and Y directions that respectively correspond to two diagonal directions of micromirror 62; alternatively, another microlens 55a' of toric lens may be applied that has different curvature radiuses in XX and YY directions that respectively correspond to two side directions of rectangular micromirror 62, as shown in FIGs. 38 A and 38B that exhibit the front and side shapes with contour lines.

In the process for forming a permanent pattern according to the present invention, the microlenses 55a may be non-spherical shape of secondary or higher order such as fourth or sixth. The employment of higher order non-spherical surface may lead to higher accuracy of beam shape. In the mode described above, the end surface of irradiating side of microlens 55a is non-spherical or toric; alternatively, substantially the same effect may be derived by constructing one of the end surface as a spherical surface and the other surface as cylindrical surface and thus providing the microlens. In addition, such lens configuration is available that has the same curvature radiuses in X and Y directions corresponding to the distortion of reflective surface of micromirrors 62. Such lens configuration will be discussed in detail.

The microlens 55a", of which the front shape and the side shape are shown in FIGs. 39 A and 39B respectively, has the same curvature radiuses in X and Y directions, and the curvature radiuses are designed such that the curvature Cy of spherical lens is compensated depending on the distance 'h' from the lens center. Namely, the configuration of spherical lens of microlens 55a" is designed in terms of lens height 'z' (height of curved lens surface in optical axis direction) based on the following equation (2), for example.

_ . ^C v ^{h 2}

1 +S Q R T ( 1 - C_y ²h² )

The relation between the lens height 'z' and the distance 'h' is expressed in FIG. 40 in the case that the curvature Cy = 1/0.1 mm.

Then, the curvature radius of the spherical lens is compensated depending on the distance 'h' from the lens center based on the following equation (3), thereby the lens configuration of microlens 55a" is designed.

C _y ² h ²

Z = + a h ⁴ + b h

1 +S Q R T ( 1 - C ² h ²) In equations (2) and (3), the respective two Z mean the same concept; in equation (3), the curvature Cy is compensated using the fourth coefficient 'a' and sixth coefficient 'b' . The relation between the lens height 'z' and the distance 'h' is expressed in FIG. 41 in the case that the curvature Cy = 1/0.1 5 mm, the fourth coefficient 'a' = 1.2 x 10³, and the sixth coefficient 'b' = 5.5 x 107.

Further, in the mode described above, each microlens 55a of microlens array 55 is non-spherical so as to compensate the aberration due to the strain of reflective surface of micromirror 62; alternatively, substantially the same effect 0 may be derived by providing each microlens of the microlens array with the distribution of refractive index so as to compensate the aberration due to the strain of reflective surface of micromirror 62.

FIGs. 22A and 22B show exemplarily such a microlens 155a. FIGs. 22A and 22B respectively show the front shape and side shape of microlens 155a. 5 The entire shape of microlens 155a is a planar plate as shown in FIGs. 22A and 22B. The X and Y directions in FIGs. 22A and 22B mean the same as described above.

FIGs. 23A and 23B schematically show the condition to collect laser beam B by microlens 155a in the cross section parallel with X and Y directions o respectively. The microlens 155a exhibits a refractive index distribution that the refractive index increases gradually from the optical axis O to outward direction; the broken lines in FIGs. 23A and 23B indicate the positions where the refractive index decreases a certain level from that of optical axis O. As shown in FIGs. 23A and 23B, comparing the cross section parallel to the X 5 direction and the cross section parallel to the Y direction, the latter represents a rapid change in the refractive index distribution, and shorter focal length. Thus, the microlens array having such a refractive index distribution may provide the similar effect as the microlens array 55 described above.

In addition, the microlens having a non-spherical surface as shown in FIGs. 17A, 17B, 18A and 18B may be provided with such a refractive index distribution, and both of the surface shape and the refractive index distribution may compensate the aberration due to strain or distortion of the reflective surface of micromirror 62.

Another microlens array will be exemplarily discussed with reference to figures. The exemplary microlens array the microlens array has an aperture configuration of the plural microlenses capable of substantially shielding incident light, as shown in FIG. 42.

As discussed before with reference to FIGs. 14 and 15A and 15B, distortions exist on the reflective surface of micromirror 62 in DMD50, and the distortion level tends to gradually increase from the central portion toward the , peripheral portions of micromirror 62. Further, the distortion level at the peripheral portions is larger in one diagonal direction e.g. Y direction of micromirror 62 compared to in the other diagonal direction e.g. X direction, and the tendency explained above is more significant in Y direction. The exemplary microlens array is prepared to address such problems.

Each of the microlens 255a of the microlens array 255 has a circular aperture configuration; therefore, the laser beam reflected or transmitted at the periphery portions of the micromirror 62 where the distortion level is relatively large, particularly the laser beam B reflected at the four corners cannot be collected by microlens 255a, thus the distortion of laser beam B may be prevented at the collecting site. Accordingly, highly fine and precise images may be exposed on photosensitive layer 150 with reducing distortions. Additionally, in the microlens array 255 as shown in FIG. 42, shielding mask 255c is prepared at the back side of transparent members 255b, which are 5 usually formed monolithically with microlenses 255a, that sustains microlenses 255a; namely shielding mask 255c is provided such that outer regions of plural microlens apertures are covered at the opposite side of the plural microlenses 255a as shown in FIG. 42. The shielding mask 255c can surely reduce the distortion of collected laser beam B, since the laser beam reflected or 0 transmitted at the periphery portions of the micromirror 62, particularly the laser beam B reflected at the four corners is absorbed or interrupted by the shielding mask 255c.

The aperture configuration of the microlens is not limited to circular in the microlens array 255, but other aperture configurations are applicable as 5 microlens 455a with elliptic aperture configuration shown in FIG. 43, microlens . 555a with polygonal aperture configuration e.g. rectangular in FIG. 44, and the like. Incidentally, microlenses 455a or 555a is of the configuration that symmetrical lens is cut into circular or polygonal shape, thus microlenses 455a or 555a may exhibit light-collecting performance similarly to conventional o symmetrical spherical lenses.

Additionally, the aperture configurations shown in FIGs. 45A, 45B, and 45C are applicable in the present invention. Microlens array 655 shown in FIG. 45A is constructed such that plural microlenses 655a are disposed adjacently at the side of transparent member 655b from where laser beam B 5 outputs, and mask 655c is disposed at the side of transparent member 655b to where laser beam inputs." Incidentally, mask 255c is provided at the outer region of the lens aperture in FIG. 42, whereas mask 655c is provided at the inner region of the lens aperture in FIG. 45A.

Microlens array 755 shown in FIG. 45B is constructed such that plural microlenses 755a are disposed adjacently at the side of transparent member 755b from where laser beam B outputs, and mask 755c is disposed between the microlenses 755a. Microlens array 855 shown in FIG. 45C is constructed such that plural microlenses 855a are disposed adjacently at the side of transparent member 855b from where laser beam B outputs, and mask 855c is disposed at the peripheral portion of each microlens 855a.

All of the exemplary masks 655c, 755c, and 855c have a circular aperture similarly to mask 255c, thereby the aperture of each microlens is defined to be circular.

The aperture configuration of plural microlenses, wherein the mask substantially shields incident light other than from micromirrors 62 of DMD50 as shown in microlenses 255a, 455a, 555a, 655a, and 755a, may be combined with non-spherical lenses capable of compensating the aberration due to distortion of micromirror 62 as microlens 55a shown in FIGs. 17A and 17B, or lenses having a refractive index distribution capable of compensating the aberration as shown in FIGs. 22 A and 22B; thereby the effect to prevent distortion of exposed images due to distortion of reflective surface of micromirror 62 may be enhanced synergistically.

Particularly, in the construction that mask 855c is provided on the lens surface of microlens 855a in microlens array 855 as shown in FIG. 45C, when microlens 855a have a non-spherical surface or a refractive index distribution and also the imaging site of the first imaging system is determined at the lens surface of microlens 855a as lens systems 52 and 54 shown in FIG. 11, the optical efficiency may be higher in particular, thus photosensitive layer 150 may be exposed with more intense laser beam. Namely, although the laser beam refracts such that the stray light due to the reflective surface of micromirror 62 focuses at the imaging site by action of the first imaging system, mask 855c provided at appropriate site does not shield light other than the stray light, thereby the optical efficiency may be enhanced remarkably.

In the respective microlens array described above, the aberration due to strain of reflective surface of micromirror 62 in DMD 50 is compensated; similarly, in the pattern forming process according to the present invention that employs a spatial light modulator other than DMD, the possible aberration due to strain may be compensated and the strain of beam shape may be prevented when the strain appears at the surface of imaging portion of the spatial light modulator.

The imaging optical system described above will be explained in the following.

In the exposing head, when laser beam is irradiated from the laser source 144, the cross section of luminous flux reflected to on-direction by DMD 50 is magnified several times, e.g. two times, by lens systems 454, 458. The magnified laser beam is collected by each microlens of microlens array 472 correspondingly with each imaging portion of DMD 50, then passes through the corresponding apertures of aperture array 476. The laser beam passed through the aperture is imaged on exposed surface 56 by lens systems 480, 482. In the imaging optical system, the laser beam reflected by DMD 50 is magnified into several times by magnifying lenses 454, 458, and is projected onto exposed surface 56, therefore, the entire image region is enlarged. When microlens array 472 and aperture array 476 are not disposed, one drawing size or spot size of each beam spot BS projected on exposed surface 56 is enlarged 5 depending on the size of exposed area 468, thus MTF (modulation transfer function) property that is a measure of sharpness at exposing area 468 is decreased, as shown in FIG. 13B.

On the other hand, when microlens array 472 and aperture array 476 are disposed, the laser beam reflected by DMD 50 is collected correspondingly 0 with each imaging portion of DMD 50 by each microlens of microlens array 472. Thereby, the spot size of each beam spot BS may be reduced into the desired size, e.g. 10 μm x 10 μm, even when the exposing area is magnified, as shown in FIG. 13C, and the decrease of MFT property may be prevented and the exposure may be carried out with higher accuracy. Incidentally, inclination 5 of exposing area 468 is caused by the DMD 50 that is disposed with inclination . in order to eliminate the spaces between imaging portions.

Further, even when beam thickening exists due to aberration of microlenses, the beam shape may be arranged by the aperture array so as to form spots on exposed surface 56 with a constant size, and the crosstalk o between the adjacent imaging portions may be prevented by passing the beam through the aperture array provided correspondingly to each imaging portion.

In addition, employment of higher luminance laser source as laser source 144 may lead to prevention of partial entrance of luminous flux from adjacent imaging portions, since the angle of incident luminous flux is 5 narrowed that enters into each microlens of microlens array 472 from lens 458; namely, higher extinction ratio may be achieved. - Other Optical System -

In the process for forming a permanent pattern according to the present invention, the other optical system may be combined that is properly selected from conventional systems, for example, an optical system to compensate the optical quantity distribution may be employed additionally.

The optical system to compensate the optical quantity distribution alters the luminous flux width at each output site such that the ratio of the luminous flux width at the periphery region to the luminous flux width at the central region near the optical axis is lower in the output side than the input side, thus the optical quantity distribution at the exposed surface is compensated to be approximately constant when the parallel luminous flux from the laser source is irradiated to DMD. The optical system to compensate the optical quantity distribution will be explained with reference to figures in the following.

Initially, the optical system will be explained as for the case that the entire luminous flux widths HO and Hl are the same between the input luminous flux and the output luminous flux, as shown in FIG. 24A. The portions denoted by reference numbers 51, 52 in FIG. 24A indicate imaginarily the input surface and output surface of the optical system to compensate the optical quantity distribution.

In the optical system to compensate the optical quantity distribution, it is assumed that the luminous flux width hO of the luminous flux entered at central region near the optical axis Zl and luminous flux width hi of the luminous flux entered at peripheral region near are the same (hO = hi). The optical system to compensate the optical quantity distribution affects the laser beam that has the same luminous fluxes hθ, hi at the input side, and acts to magnify the luminous flux width h0 for the input luminous flux at the central region, and acts to reduce the luminous flux width hi for the input luminous flux at the periphery region conversely. Namely, the optical system affects the output luminous flux width MO at the central region and the output luminous flux width hll at the periphery region to turn into hll < hlO. In other words concerning the ratio of luminous flux width, (output luminous flux width at periphery region) / (output luminous flux width at central region) is smaller than the ratio of input, namely [hll/ hi 0] is smaller than (hl/hθ = 1) or (hll/ hi 0 < 1).

Owing to altering the luminous flux width, the luminous flux at the central region representing higher optical quantity may be supplied to the periphery region where the optical quantity is insufficient; thereby the optical quantity distribution is approximately uniformed at the exposed surface without decreasing the utilization efficiency. The level for uniformity is controlled such that the nonuniformity of optical quantity is 30 % or less in the effective region for example, preferably is 20 % or less.

When the luminous flux width is entirely altered for the input side and the output side, the operation and effect due to the optical system to compensate the optical quantity distribution are similar to those shown in FIGs. 24B and 24C.

FIG. 24B shows the case that the entire optical flux bundle HO is reduced and outputted as optical flux bundle H2 (HO > H2). In such a case also, the optical system to compensate the optical quantity distribution tends to process the laser beam, in which luminous flux width hO is the same as hi at input side, into that the luminous flux width hlO at the central region is larger than the spherical region and the luminous flux width hll is smaller than the central region in the output side. Considering the reduction ratio of the luminous flux, the optical system affects to decrease the reduction ratio of input luminous flux at the central region compared to the peripheral region, and affects to increase the reduction ratio of input luminous flux at the peripheral region compared to the central region. In the case also, (output luminous flux width at periphery region) / (output luminous flux width at central region) is smaller than the ratio of input, namely [H11/H10] is smaller than (hl/hθ = 1) or (hll/hlO < 1).

FIG. 24C explains the case that the entire luminous flux width HO at input side is magnified and output into width H3 (HO < H3). In such a case also, the optical system to compensate the optical quantity distribution tends to process the laser beam, in which luminous flux width h0 is the same as hi at input side, into that the luminous flux width hlO at the central region is larger than the spherical region and the luminous flux width hll is smaller than the central region in the output side. Considering the magnification ratio of the luminous flux, the optical system affects to increase the magnification ratio of input luminous flux at the central region compared to the peripheral region, and affects to decrease the magnification ratio of input luminous flux at the peripheral region compared to the central region. In the case also, (output luminous flux width at periphery region) / (output luminous flux width at central region) is smaller than the ratio of input, namely [H11/H10] is smaller than (hl/hθ = 1) or (hll/hlO < 1). As such, the optical system to compensate the optical quantity distribution alters the luminous flux width at each input site, and lowers the ratio (output luminous flux width at periphery region) / (output luminous flux width at central region) at output side compared to the input side; therefore, the laser beam having the same luminous flux turns into the laser beam at output side that the luminous flux width at central region is larger compared to that at the peripheral region and the luminous flux at the peripheral region is smaller compared to the central region. Owing to such effect, the luminous flux at the central region may be supplied to the periphery region, thereby the optical quantity distribution is approximately uniformed at the luminous flux cross section without decreasing the utilization efficiency of the entire optical system.

Specific lens data of a pair of combined lenses will be described exemplarily that is utilized for the optical system to compensate the optical quantity distribution. In this discussion, the lens data will be explained in the case that the optical quantity distribution shows Gaussian distribution at the cross section of the output luminous flux, such as the case that the laser source is a laser array as described above. In a case that one semiconductor laser is connected to an input end of single mode optical fiber, the optical quantity distribution of output luminous flux from the optical fiber shows Gaussian distribution. The process for forming a permanent pattern according to the present invention may be applied, in addition, to such a case that the optical quantity near the central region is significantly larger than the optical quantity at the peripheral region as the case that the core diameter of multimode optical fiber is reduced and constructed similarly to a single mode optical fiber, for example.

The essential data for the lens are summarized in Table 1 below. Table 1

As demonstrated in Table 1, a pair of combined lenses is constructed from two non-spherical lenses of rotational symmetry. The surfaces of the lenses are defined that the surface of input side of the first lens disposed at the light input side is the first surface; the opposite surface at light output side is the second surface; the surface of input side of the second lens disposed at the light input side is the third surface; and the opposite surface at light output side is the fourth surface. The first and the fourth surfaces are non-spherical.

In Table 1, 'Si (surface No.)' indicates "i" th surface (i = 1 to 4), 'ri (curvature radius)' indicates the curvature radius of the "i" th surface, di (surface distance) means the surface distance between "i" th surface and "i+1" surface. The unit of di (surface distance) is millimeter (mm). Ni (refractive index) means the refractive index of the optical element comprising "i" th surface for the light of wavelength 405 nm.

In Table 2 below, the non-spherical data of the first and the fourth surface are summarized.

Table 2 non-spherical data first surface fourth surface

C -1. 4098 x to-² -9. 8506 x io-³

K -4. 2192 -3. 6253 X lO a 3 -1. 0027 X l(T⁴ -8. 9980 x io-⁵ a 4 3. 0591 X l(T⁵ 2. 3060 x io-⁵ a 5 -4. 5115 X lO^"7 -2. 2860 x io-⁶ a 6 -8, 2819 X l(T⁹ 8. 7661 X lO^"8 a 7 4. 1020 X 1(T¹² 4. 4028 X 10^"10 a 8 L 2231 X 1(T¹³ 1. 3624 X 10-¹² a 9 5. 3753 X 1(T¹⁶ 3. 3965 x lo-¹⁵ a ] [ 0 1. 6315 X 1(T¹⁸ 1, 4823 X IQ-¹⁸

The non-spherical data described above may be expressed by means of the coefficients of the following equation (A) that represent the non-spherical shape.

In the above formula (A), the coefficients are defined as follows:

Z: length of perpendicular that extends from a point on non-spherical surface at height p from optical axis (mm) to tangent plane at vertex of non-spherical surface or plane vertical to optical axis; p: distance from optical axis (mm);

K: coefficient for circular conic;

C: paraxial curvature (1/r, r: radius of paraxial curvature); ai: "i" st ήon-spherical coefficient (i = 3 to 10).

FIG. 26 shows the optical quantity distribution of illumination light obtained by a pair of combined lenses shown in Table 1 and Table 2. The abscissa axis represents the distance from the optical axis, the ordinate axis represents the proportion of optical quantity (%). FIG. 25 shows the optical quantity distribution (Gaussian distribution) of illumination light without the compensation. As is apparent from FIGs. 25 and 26, the compensation by means of the optical system to compensate the optical quantity distribution brings about an approximately uniform optical quantity distribution significantly exceeding that without the compensation, thus uniform exposing may be achieved by means of uniform laser beam without decreasing the optical utilization efficiency. - Optical Irradiating Means or Laser Source -

The optical irradiating means or laser source may be properly selected depending on the application; examples thereof include an extremely high - pressure mercury lamp, xenon lamp, carbon arc lamp, halogen lamp, fluorescent tube, LED, semiconductor laser, and the other conventional laser source, and also combination of these means. Among these means, the means capable of irradiating two or more types of lights or laser beams is preferable. Examples of the light or laser irradiated from the optical irradiating means or laser source include UV-rays, visual light, X-ray, laser beam, and the like. Among these, laser beam is preferable, more preferably are those containing two or more types of laser beams (hereinafter, sometimes referring to as "combined laser"). The wavelength of the UV-rays and the visual light is preferably 300 to 1500 nm, more preferably is 320 ran to 800 nm, most preferably is 330 nm to 650 nm.

The wavelength of the laser beam is preferably 200 nm to 1500 nm, more preferably is 300 run to 800 nm, still more preferably is 330 nm to 500 nm, and most preferably is 395 nm to 415 nm.

As for the means to irradiate the combined laser beams, such a means is preferably exemplified that comprises plural laser irradiating devices, a multimode optical fiber, and a collecting optical system that collect respective laser beams and connect them to a multimode optical fiber. The means to irradiate combined laser beams or the fiber array laser source will be explained with reference to figures in the following.

Fiber array laser source 66 is equipped with plural (e.g. fourteen) laser modules 64 as shown in FIG. 27 A. One end of each multimode optical fiber 30 is connected to each laser module 64. To the other end of each multimode optical fiber 30 is connected optical fiber 31 of which the core diameter is the same as that of multimode optical fiber 30 and of which the clad diameter is smaller than that of multimode optical fiber 30. As shown in FIG. 27B specifically, the ends of multimode optical fibers 31 at the opposite end of multimode optical fiber 30 are aligned as seven ends along the main scanning direction perpendicular to the sub-scanning direction, and the seven ends are aligned as two rows, thereby laser output portion 68 is constructed.

The laser output portion 68, formed of the ends of multimode optical fibers 31, is fixed by being interposed between two flat support plates 65 as shown in FIG. 27B. Preferably, a transparent protective plate such as a glass plate is disposed on the output end surface of multimode optical fibers 31 in order to protect the output end surface. The output end surface of multimode optical fibers 31 tends to bear dust and to degrade due to its higher optical density; the protective plate described above may prevent the dust deposition on the end surface and may retard the degradation. In this example, in order to align optical fibers 31 having a lower clad diameter into an array without a space, multimode optical fiber 30 is stacked between two multimode optical fibers 30 that contact at the larger clad diameter, and the output end of optical fiber 31 connected to the stacked multimode optical fiber 30 is interposed between two output ends of optical fibers 31 connected to two multimode optical fibers 30 that contact at the larger clad diameter.

Such optical fibers may be produced by connecting concentrically optical fibers 31 having a length of 1 to 30 cm and a smaller clad diameter to the tip portions of laser beam output side of multimode optical fiber 30 having a larger clad diameter, for example, as shown in FIG. 28. Two optical fibers are connected such that the input end surface of optical fiber 31 is fused to the output end surface of multimode optical fiber 30 so as to coincide the center axes of the two optical fibers. The diameter of core 31a of optical fiber 31 is the same as the diameter of core 30a of multimode optical fiber 30 as described above.

Further, a shorter optical fiber produced by fusing an optical fiber having a smaller clad diameter to an optical fiber having a shorter length and a larger clad diameter may be connected to the output end of multimode optical fiber through a ferrule, optical connector, or the like. The connection through a connector and the like in an attachable and detachable manner may bring about easy exchange of the output end portion when the optical fibers having a smaller clad diameter are partially damaged for example, resulting advantageously in lower maintenance cost for the exposing head. Optical fiber 31 is sometimes referred to as "output end portion" of multimode optical 5 fiber 30.

Multimode optical fiber 30 and optical fiber 31 may be any one of step index type optical fibers, grated index type optical fibers, and combined type optical fibers. For example, step index type optical fibers produced by Mitsubishi Cable Industries, Ltd. are available. In one of the best mode 0 according to the present invention, multimode optical fiber 30 and optical fiber 31 are step index type optical fibers; in the multimode optical fiber 30, clad diameter = 125 μm, core diameter = 50 μm, NA = 0.2, transmittance = 99.5 % or more (at coating on input end surface); and in the optical fiber 31, clad diameter = 60 μm, core diameter = 50 μm, NA = 0.2. 5 Laser beams at infrared region typically increase the propagation loss

. while the clad diameter of optical fibers decreases. Accordingly, a proper clad diameter is defined usually depending on the wavelength region of the laser beam. However, the shorter is the wavelength, the less is the propagation loss; for example, in the laser beam of wavelength 405 nm o irradiated from GaN semiconductor laser, even when the clad thickness (clad diameter - core diameter) ÷ 2 is made into about 1/2 of the clad thickness at which infrared beam of wavelength 800 nm is typically propagated, or made into about 1/4 of the clad thickness at which infrared beam of wavelength 1.5 μm for communication is typically propagated, the propagation loss does not 5 increase significantly. Therefore, the clad diameter can be as small as 60 μm. Needless to say, the clad diameter of optical fiber 31 should not be limited to 60 μm. The clad diameter of optical fiber utilized for conventional fiber array laser sources is 125 μm; the smaller is the clad diameter, the deeper is the focal depth; therefore, the clad diameter of the multimode optical fiber is preferably 80 μm or less, more preferably is 60 μm or less, still more preferably is 40 μm or less. On the other hand, since the core diameter is appropriately at least 3 to 4 μm, the clad diameter of optical fiber 31 is preferably 10 μm or more.

Laser module 64 is constructed from the combined laser source or the fiber array laser source as shown in FIG. 29. The combined laser source is constructed from plural (e.g. seven) multimode or single mode GaN semiconductor lasers LDl, LD2, LD3, LD4, LD5, LD6 and LD7 disposed and fixed on heat block 10, collimator lenses 11, 12, 13, 14, 15, 16, and 17, one collecting lens 20, and one multimode optical fiber 30. Needless to say, the number of semiconductor lasers is not limited to seven. For example, with respect to the multimode optical fiber having clad diameter = 60 μm, core diameter = 50 μm, NA = 0.2, as much as twenty semiconductor lasers may be inputted, thus the number of optical fibers may be reduced while attaining the necessary optical quantity of the exposing head. GaN semiconductor lasers LDl to LD7 have a common oscillating wavelength e.g. 405 nm, and a common maximum output e.g. 100 mW as for multimode lasers and 30 mW as for single mode lasers. The GaN semiconductor lasers LDl to LD7 may be those having an oscillating wavelength of other than 405 nm as long as within the wavelength of 350 nm to 450 nm. The combined laser source is housed into a box package 40 having an upper opening with other optical elements as shown in FIGs.30 and 31. The package 40 is equipped with package lid 41 for shutting the opening. Introduction of sealing gas after evacuating procedure and shutting the opening of package 40 by means of 5 package lid 41 presents a closed space or sealed volume constructed by package 40 and package lid 41, and the combined laser source is disposed in a sealed condition.

Base plate 42 is fixed on the bottom of package 40; the heat block 10, collective lens holder 45 to support collective lens 20, and fiber holder 46 to support the input end of multimode optical fiber 30 are mounted to the upper surface of the o base plate 42. The output end of multimode optical fiber 30 is drawn out of the package from the aperture provided at the wall of package 40.

Collimator lens holder 44 is attached to the side wall of heat block 10, and collimator lenses 11 to 17 are supported thereby. An aperture is provided at the side wall of package 40, and wiring 47 that supplies driving power to GaN 5 semiconductor lasers LDl to LD7 is directed through the aperture out of the package.

In FIG.31, only the GaN semiconductor laser LD7 is indicated with a reference mark among plural GaN semiconductor laser, and only the collimator lens 17 is indicated with a reference number among plural collimators, in order not to make the figure excessively complicated. 0 FIG. 32 shows a front shape of attaching part for collimator lenses 11 to

17. Each of collimator lenses 11 to 17 is formed into a shape that a circle lens containing a non-spherical surface is cut into an elongated piece with parallel planes at the region containing the optical axis. The collimator lens with the elongated shape may be produced by a molding process. The collimator lenses 11 to 17 are closely disposed in the aligning direction of emitting points such that the elongated direction is perpendicular to the alignment of the emitting points of GaN semiconductor lasers LDl to LD7.

On the other hand, as for GaN semiconductor lasers LDl to LD7, the following laser may be employed that comprises an active layer having an emitting width of 2 μm and emits the respective laser beams Bl to B7 at a condition that the divergence angle is 10 degrees and 30 degrees for the parallel and perpendicular directions against the active layer. The GaN semiconductor lasers LDl to LD7 are disposed such that the emitting sites align as one line in parallel to the active layer. Accordingly, laser beams Bl to B7 emitted from the respective emitting sites enter into the elongated collimator lenses 11 to 17 in a condition that the direction having a larger divergence angle coincides with the length direction of each collimator lens and the direction having a less divergence angle coincides with the width direction of each collimator lens. Namely, the width is 1.1 mm and the length is 4.6 mm with respect to respective collimator lenses 11 to 17, and the beam diameter is 0.9 mm in the horizontal direction and is 2.6 mm in the vertical direction with respect to laser beams Bl to B7 that enter into the collimator lenses. As for the respective collimator lenses 11 to 17, focal length f i = 3 mm, NA = 0.6, pitch of disposed lenses = 1.25 mm. Collective lens 20 formed into a shape that a part of circle lens containing the optical axis and non-spherical surface is cut into an elongated piece with parallel planes and is arranged such that the elongated piece is longer in the direction of disposing collimator lens 11 to 17 i.e. horizontal direction, and is shorter in the perpendicular direction. As for the collective lens, focal length £2 = 23 mm, NA = 0.2. The collective lens 20 may be produced by molding a resin or optical glass, for example.

Further, since a high luminous fiber array laser source is employed that is arrayed at the output ends of optical fibers in the combined laser source for the illumination means to illuminate the DMD, a pattern forming apparatus may be attained that exhibits a higher output and a deeper focal depth. In addition, the higher output of the respective fiber array laser sources may lead to less number of fiber array laser sources required to take a necessary output as well as a lower cost of the pattern forming apparatus.

In addition, the clad diameter at the output ends of the optical fibers is smaller than the clad diameter at the input ends, therefore, the diameter at emitting sites is reduced still, resulting in higher luminance of the fiber array laser source. Consequently, pattern forming apparatuses with a deeper focal depth may be achieved. For example, a sufficient focal depth may be obtained even for the extremely high resolution exposure such that the beam diameter is 1 μm or less and the resolution is 0.1 μm or less, thereby enabling , rapid and precise exposure. Accordingly, the pattern forming apparatus is appropriate for the exposure of thin film transistor (TFT) that requires high resolution.

The illumination means is not limited to the fiber array laser source that is equipped with plural combined laser sources; for example, such a fiber array laser source may be employed that is equipped with one fiber laser source, and the fiber laser source is constructed by one arrayed optical fiber that outputs a laser beam from one semiconductor laser having an emitting site. Further, as for the illumination means having plural emitting sites, such a laser array may be employed that comprises plural (e.g. seven) tip-like semiconductor lasers LDl to LD7 disposed on heat block 100 as shown in FIG. 33. In addition, multi cavity laser 110 is known that comprises plural (e.g. five) emitting sites 110a disposed in a certain direction as shown in FIG. 34A. In the multi cavity laser 110, the emitting sites can be arrayed with higher dimensional accuracy compared to arraying tip-like semiconductor lasers, thus laser beams emitted from the respective emitting sites can be easily combined. Preferably, the number of emitting sites 110a is five or less, since deflection tends to generate on multi cavity laser 110 at the laser production process when the number increases.

Concerning the illumination means, the multi cavity laser 110 described above, or the multi cavity array disposed such that plural multi cavity lasers 110 are arrayed in the same direction as emitting sites 110a of each tip as shown in FIG. 34B may be employed for the laser source. The combined laser source is not limited to the types that combine plural laser beams emitted from plural tip-like semiconductor lasers. For example, such a combined laser source is available that comprises tip-like multi cavity laser 110 having plural (e.g. three) emitting sites 110a as shown in FIG. 21. The combined laser source is equipped with multi cavity laser 110, one multimode optical fiber 130, and collecting lens 120. The multi cavity laser 110 may be constructed from GaN laser diodes having an oscillating wavelength of 405 ran, for example.

In the above noted construction, each laser beam B emitted from each of plural emitting sites 110a of multi cavity laser 110 is collected by collective lens 120 and enters into core 130a of multimode optical fiber 130. The laser beams entered into core 130a propagate inside the optical fiber and combine as one laser beam then output from the optical fiber.

The connection efficiency of laser beam B to multimode optical fiber 130 may be enhanced by way of arraying plural emitting sites 110a of multi cavity laser 110 into a width that is approximately the same as the core diameter of multimode optical fiber 130, and employing a convex lens having a focal length of approximately the same as the core diameter of multimode optical fiber 130, and also employing a rod lens that collimates the output beam from multi cavity laser 110 at only within the surface perpendicular to the active layer.

In addition, as shown in FIG. 35, a combined laser source may be employed that is equipped with laser array 140 formed by arraying on heat block 111 plural (e.g. nine) multi cavity lasers 110 with an identical space between them by employing multi cavity lasers 110 equipped with plural (e.g. three) emitting sites. The plural multi cavity lasers 110 are arrayed and fixed in the same direction as emitting sites 110a of the respective tips.

The combined laser source is equipped with laser array 140, plural lens arrays 114 that are disposed correspondingly to the respective multi cavity lasers 110, one rod lens 113 that is disposed between laser array 140 and plural lens arrays 114, one multimode optical fiber 130, and collective lens 120. Lens arrays 114 are equipped with plural micro lenses each corresponding to emitting sites of multi cavity lasers 110.

In the above noted construction, laser beams B that are emitted from plural emitting sites 110a of plural multi cavity lasers 110 are collected in a certain direction by rod lens 113, then are paralleled by the respective microlenses of microlens arrays 114. The paralleled laser beams L are collected by collective lens 120 and are inputted into core 130a of multimode optical fiber 130. The laser beams entered into core 130a propagate inside the optical fiber and combine as one beam then output from the optical fiber. 5 Another combined laser source will be exemplified in the following.

In the combined laser source, heat block 182 having a cross section of L-shape in the optical axis direction is installed on rectangular heat block 180 as shown in FIGs. 36A and 36B, and a housing space is formed between the two heat blocks. On the upper surface of L-shape heat block 182, plural (e.g. two) 0 multi cavity lasers 110, in which plural (e.g. five) emitting sites are arrayed, are disposed and fixed each with an identical space between them in the same direction as the aligning direction of respective tip-like emitting sites.

A concave portion is provided on the rectangular heat block 180; plural (e.g. two) multi cavity lasers 110 are disposed on the upper surface of heat 5 block 180, plural emitting sites (e.g. five) are arrayed in each multi cavity laser . 110, and the emitting sites are situated at the same vertical surface as the surface where are situated the emitting sites of the laser tip disposed on the heat block 182.

At the laser beam output side of multi cavity laser 110, collimate lens o arrays 184 are disposed such that collimate lenses are arrayed correspondingly with the emitting sites 110a of the respective tips. In the collimate lens arrays 184, the length direction of each collimate lens coincides with the direction at which the laser beam represents wider divergence angle or the fast axis direction, and the width direction of each collimate lens coincides with the 5 direction at which the laser beam represents less divergence angle or the slow axis direction. The integration by arraying the collimate lenses may increase the space efficiency of laser beam, thus the output power of the combined laser source may be enhanced, and also the number of parts may be reduced, resulting advantageously in lower production cost. At the laser beam output side of collimate lens arrays 184, disposed are one multimode optical fiber 130 and collective lens 120 that collects laser beams at the input end of multimode optical fiber 130 and combines them.

In the above noted construction, the respective laser beams B emitted from the respective emitting sites 110a of plural multi cavity lasers 110 disposed on laser blocks 180, 182 are paralleled by collimate lens array 184, are collected by collective lens 120, then enter into core 130a of multimode optical fiber 130. The laser beams entered into core 130a propagate inside the optical fiber and combine as one beam then output from the optical fiber.

The combined laser source may be made into a higher output power source by multiple arrangement of the multi cavity lasers and the array of collimate lenses in particular. The combined laser source allows to construct a fiber array laser source and a bundle fiber laser source, thus is appropriate for the fiber laser source to construct the laser source of the pattern forming apparatus in the present invention. By the way, a laser module may be constructed by housing the respective combined laser sources into a casing, and drawing out the output end of multimode optical fiber 130.

In the explanations described above, the higher luminance of fiber array laser source is exemplified that the output end of the multimode optical fiber of the combined laser source is connected to another optical fiber that has the same core diameter as that of the multimode optical fiber and a clad diameter smaller than that of the multimode optical fiber; alternatively a multimode optical fiber having a clad diameter of 125 μm, 80 μm, 60 μm or the like may be utilized without connecting another optical fiber at the output end, for example.

The pattern forming process according to the present invention will be explained further.

As shown in FIG. 29, in each exposing head 166 of scanner 162, the respective laser beams Bl, B2, B3, B4, B5, B6, and B7, emitted from GaN semiconductor lasers LDl to LD 7 that constitute the combined laser source of fiber array laser source 66, are paralleled by the corresponding collimator lenses 11 to 17. The paralleled laser beams Bl to B7 are collected by collective lens 20, and converge at the input end surface of core 30a of multimode optical fiber 30. In this example, the collective optical system is constructed from collimator lenses 11 to 17 and collective lens 20, and the combined optical system is constructed from the collective optical system and multimode optical fiber 30. Namely, laser beams Bl to B7 that are collected by collective lens 20 enter into core 30a of multimode optical fiber 30 and propagate inside the optical fiber, combine into one laser beam B, then output from optical fiber 31 that is connected at the output end of multimode optical fiber 30.

In each laser module, when the coupling efficiency of laser beams Bl to B7 with multimode optical fiber 30 is 0.85 and each output of GaN semiconductor lasers LDl to LD7 is 30 mW, each optical fiber disposed in an array can take combined laser beam B of output 180 mW (= 30 mW x 0.85 x 7). Accordingly, the output is about 1 W (= 180 mW x 6) at laser emitting portion 68 of the array of six optical fibers 31.

Laser emitting portions 68 of fiber array source 66 are arrayed such that the higher luminous emitting sites are aligned along the main scanning direction. The conventional fiber laser source that connects laser beam from one semiconductor laser to one optical fiber is of lower output, therefore, a desirable output cannot be attained unless many lasers are arrayed; whereas the combined laser source of lower number (e.g. one) array can produce the desirable output since the combined laser source may generate a higher output.

For example, in the conventional fiber where one semiconductor laser and one optical fiber are connected, a semiconductor laser of about 30 mW output is usually employed, and a multimode optical fiber that has a core diameter of 50 μm, a clad diameter of 125 μm, and a numerical aperture of 0.2 is employed as the optical fiber. Therefore, in order to take an output of , about 1 W (Watt), 48 (8 x 6) multimode optical fibers are necessary; since the area of emitting region is 0.62 mm² (0.675 mm x 0.925 mm), the luminance at laser emitting portion 68 is 1.6 x 10⁶ (W/ m²), and the luminance per one optical fiber is 3.2 x 10⁶ (W/ m²). On the contrary, when the laser emitting means is one capable of emitting the combined laser, six multimode optical fibers can produce the output of about 1 W. Since the area of the emitting region in laser emitting portion 68 is 0.0081 mm² (0.325 mm x 0.025 mm), the luminance at laser emitting portion 68 is 123 x 10⁶ (W/ m²), which corresponds to about 80 times the luminance of conventional means. The luminance per one optical fiber is 90 x 10⁶ (W/ m²), which corresponds to about 28 times the luminance of conventional means.

The difference of focal depth between the conventional exposing head and the exposing head in the present invention will be explained with reference to FIGs. 37A and 37B. For example, the diameter of exposing head is 0.675 mm in the sub-scanning direction of the emitting region of the bundle-like fiber laser source, and the diameter of exposing head is 0.025 mm in the sub-scanning direction of the emitting region of the fiber array laser source. As shown in FIG. 37A, in the conventional exposing head, the emitting region of illuminating means or bundle-like fiber laser source 1 is larger, therefore, the angle of laser bundle that enters into DMD3 is larger, resulting in larger angle of laser bundle that enters into scanning surface 5. Therefore, the beam diameter tends to increase in the collecting direction, resulting in a deviation in focus direction.

On the other hand, as shown in FIG. 37B, the exposing head of the pattern forming apparatus in the present invention has a smaller diameter of the emitting region of fiber array laser source 66 in the sub-scanning direction, therefore, the angle of laser bundle is smaller that enters into DMD50 through lens system 67, resulting in lower angle of laser bundle that enters into scanning surface 56, i.e. larger focal depth. In this example, the diameter of the emitting region is about 30 times the diameter of prior art in the sub-scanning direction, thus the focal depth approximately corresponding to the limited diffraction may be obtained, which is appropriate for the exposing at extremely small spots. The effect on the focal depth is more significant as the optical quantity required at the exposing head comes to larger. In this example, the size of one imaging portion projected on the exposing surface is 10 μm x 10 μm. The DMD is a spatial light modulator of reflected type; in FIGs. 37A and 37B, it is shown as developed views to explain the optical relation.

The pattern information corresponding to the exposing pattern is inputted into a controller (not shown) connected to DMD50, and is memorized once to a flame memory within the controller. The pattern information is the data that expresses 5 the concentration of each imaging portion that constitutes the pixels by means of two-values i.e. presence or absence of the dot recording.

Stage 152 that absorbs photosensitive layer 150 on the surface is conveyed from upstream to downstream of gate 160 along guide 158 at a constant velocity by a driving device (not shown). When the tip of photosensitive layer 150 is detected by o detecting sensor 164 installed at gate 160 while stage 152 passes under gate 160, the pattern information memorized at the flame memory is read plural lines by plural lines sequentially, and controlling signals are generated for each exposing head 166 based on the pattern information read by the data processing portion. Then, each micromirror of DMD50 is subjected to on-off control for each exposing head 166 5 based on the generated controlling signals.

When a laser beam is irradiated from fiber array laser source 66 onto DMD50, the laser beam reflected by the micromirror of DMD50 at on-condition is imaged on exposed surface 56 of photosensitive layer 150 by means of lens systems 54, 58. As such, the laser beams emitted from fiber array laser source 66 are subjected to on-off o control for each imaging portion, and photosensitive layer 150 is exposed by imaging portions or exposing area 168 of which the number is approximately the same as that of imaging portions employed in DMD50. Further, through moving the photosensitive layer 150 at a constant velocity along with stage 152, photosensitive layer 150 is subjected to sub-scanning in the direction opposite to the stage moving 5 direction by means of scanner 162, and band-like exposed region 170 is formed for each exposing head 166. ^•

[Developing Step]

In the developing step, the developing is performed by way of exposing the photosensitive layer in the exposing step, and then removing the unexposed portions. The method for removing the unexposed portions may be properly selected, for example, the unexposed portions may be removed by use of a developer.

The developer may be properly selected depending on the application; examples of the developers include alkaline aqueous solutions, aqueous developing liquids, and organic solvents; among these, weak alkali aqueous solutions are preferable. The basic ingredients of the weak alkali aqueous solutions are exemplified by lithium hydroxide, sodium hydroxide, potassium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, lithium hydrogencarbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, sodium phosphate, potassium phosphate, sodium pyrophosphate, potassium pyrophosphate, and borax.

Preferably, the weak alkali aqueous solution exhibits a pH of about 8 to

12, more preferably is about 9 to 11. Examples of such a solution are aqueous solutions of sodium carbonate and potassium carbonate at a concentration of 0.1 to 5 % by mass. The temperature of the developer may be properly selected depending on the developing ability of the developer; for example, the temperature of the developer is about 25 to 40 °C.

The developer may be combined with surfactants, defoamers; organic bases such as ethylene diamine, ethanol amine, tetramethylene ammonium hydroxide, diethylene triamine, Methylene pentamine, morpholine, and triethanol amine; organic solvents to promote developing such as alcohols, ketones, esters, ethers, amides, and lactones. The developer described above may be an aqueous developer selected from aqueous solutions, aqueous alkali solutions, and combined solutions of aqueous solutions and organic solvents, or may be an organic solvent. [Other Steps]

The other steps may be properly carried out by applying the conventional steps for forming patterns such as peeling step, hardening step, and plating step. These steps may be used alone or in combination. - Peeling Step -

Examples of the peeling step are those described above as to the process for forming a permanent pattern in the first aspect and the second aspect described above. - Hardening Step - Preferably, the hardening step is performed for the photosensitive layer after the developing step, when the process for forming a permanent pattern according to the present invention forms a permanent pattern such as a protective film and interlayer insulating film. The hardening step may be properly selected depending on the application, for example, the hardening step may be of exposing an entire surface or heating an entire surface.

Exposing an entire surface described above may be carried out by way of exposing the entire surface of a laminated structure on which a permanent pattern is formed, after the developing step. The exposing may promote the hardening of the resin in the photosensitive composition within the photosensitive layer, thereby the surface of the permanent pattern is hardened. The apparatus for carrying out the exposing may be properly selected depending on the application, and UV exposure devices such as a super high-pressure mercury lamp are exemplified.

Heating an entire surface described above may be carried out by way of heating the entire surface of a laminated structure on which a permanent pattern is formed, after the developing step. The heating may enhance the film strength of the permanent pattern.

The heating temperature of the entire surface is preferably 120 °C to 250 °C, more preferably is 120 °C to 200 ⁰C. When the heating temperature is below 120 ⁰C, the film strength may not be enhanced even after the heating, and when the heating temperature is above 250 °C, the resin in the photosensitive composition may decompose, resulting possibly in a week and brittle film.

The period for the heating is preferably 10 minutes to 120 minutes, more preferably is 15 minutes to 60 minutes. The apparatus for the heating • may be properly selected from conventional ones; examples of the apparatus include a dry oven, hot plate, IR heater, and the like. - Plating Step -

The plating step may be performed by a method selected from conventional plating treatment methods.

Examples of the plating treatment include copper plating such as copper sulfate plating and copper pyrophosphate plating, solder plating such as high flow solder plating, nickel plating such as watt bath (nickel sulfate-nickel chloride) plating and nickel sulfamate plating, and gold plating such as hard gold plating and soft gold plating. A permanent pattern may be formed by performing a plating treatment in the plating step, followed by removing the pattern forming material and optional etching treatment on unnecessary portions.

The process for forming a permanent pattern according to the present invention may effectively provide permanent patterns with superior fineness and preciseness by way of controlling the distortion of images formed on photosensitive films, therefore, the process according to the present invention may be applied to various patterns to which highly fine and precise exposure are required, in particular to highly fine and precise wiring patterns. - Process for Forming Protective Film and Interlayer Insulating Film -

When the process for forming a permanent pattern according to the present invention is applied for forming a protective film or interlayer insulating film using solder resist, a permanent pattern is formed on a printed wiring board by the inventive process, then soldering step may be carried out as follows, for example.

Namely, a hardened layer of the permanent pattern is formed by the developing step, and a metal layer is revealed on the surface of the printed wiring board. Au plating is provided at the site of the metal layer that is revealed on the surface of the wiring board and soldering is performed, then electric parts such as semiconductors and the like are mounted to the site where the soldering is performed. In such a construction, the permanent pattern of the hardened layer performs as a protective film, insulating film, or interlayer insulating film, thereby external shocks are mitigated and mechanical damages such as shortening of electrodes may be effectively prevented. In the processes for forming permanent patterns according to the present invention, when the permanent pattern is a protective or an interlayer insulating film, wiring patterns may be protected from external shock or bending, which is particularly advantageous for highly densified parts such as 5 semiconductors or parts on multi-layer wiring substrates or build-up wiring substrates. Example

The present invention will be illustrated in more detailed with reference to examples given below, but these are not to be construed as o limiting the present invention. All parts and percent are expressed by mass unless indicated otherwise.

(Example A-I)

[Preparation of Photosensitive Film for Permanent Pattern]

To polyethylene terephthalate (PET) film of 20 μm thick as a support, 5 an emulsion of olef in-acrylic acid (Chemi-Pearl S-100, solid content: 27 %, by . Mitsui Chemical Co.) was coated using a wire bar and dried, thereby to form a cushion layer of 20 μm thick.

Then, the liquid of the photosensitive composition, having the following formula, was coated on the cushion layer formed on the support 0 described above, thereby to form a photosensitive layer of 10 μm thick on the cushion layer. Then, a protective film of polypropylene sheet of 12 μm thick was laminated on the photosensitive layer, thereby to form a photosensitive film for forming a permanent pattern. [Formula of Photosensitive Composition] Dispersion of barium sulfate 24.75 parts Addition reaction product dissolved in MEK **) 13.36 parts

R712 (bifunctional acrylic monomer, by Nippon Kayaku Co.) 3.06 parts

Dipentaerithritol hexaacrylate 4.59 parts

Irgacure 819 (by Ciba Specialty Chemicals Co.) 1.98 parts F780F ²*⁾ dissolved in MEK at 30 % concentration 0.066 part

Hydroquinone monomethylether 0.024 part

Methylethylketone (MEK) 8.60 parts

**) concentration: 35 %, MEK: methylethylketone addition reaction product of between copolymer of styrene/maleic anhydride/ butylacrylate (mole ratio: 40/32/28) and benzylamine (the benzylamine corresponds to 1.0 equivalence to anhydride group of the copolymer)

²*⁾ by Dainippon Ink and Chemicals, Inc.

The dispersion of barium sulfate was prepared in the following manner, i.e. 30 parts of barium sulfate (B30, by Sakai Chemical Industry Co.), 34.29 parts of methylethylketone solution of 35 % by mass of styrene/maleic anhydride/ butyl acrylate copolymer described above, and 35.71 parts of l-methoxy-2-propylacetate were mixed, then the mixture was subjected to dispersing in a condition of circumferential velocity of 9 meters per second for 3.5 hours by means of Motor Mill M-200 (by Iger Co.) and zirconia beads of diameter 1.0 nun. < Laminating Step >

A substrate laminated with copper film of 12 μm thick, to which a wiring pattern was formed already, was surface-treated by chemical polishing to prepare a substrate. The photosensitive film for forming a permanent pattern was laminated on the copper-laminated sunstrate while peeling off the protective film of the photosensitive film using a vacuum laminator (MVLP500, by Meiki Co.), under a condition of temperature 90 °C and pressure 0.4 MPa, thereby a laminated body was prepared. The surface of the photosensitive layer was not sticky, and the protective film could be peeled easily.

< Exposing Step >

A pattern was irradiated onto the photosensitive layer of the photosensitive film using a laser beam having a wavelength of 405 nm to 415 nm through the support, thereby a part of the photosensitive layer was hardened.

< Pattern Forming Apparatus >

A pattern forming apparatus was employed that comprised the combined laser source shown in FIGs. 27A to 32 as the laser source; DMD50 as the laser modulator, in which 1024 micromirrors are arrayed as one array in the main scanning direction shown in FIGs. 4 A and 4B, 768 sets of the arrays are arranged in the sub-scanning direction, and 1024 rows x 256 lines among these micromirrors can be driven; microlens array 472 in which microlenses 474, of which one surface is toric surface as shown in FIG. 13A, are arrayed; and optical systems 480, 482 that images the laser through the microlens array onto the photosensitive layer.

As shown in FIGs. 17A to 18B, toric lens 55a was utilized for the microlens; the curvature radius Rx of optical X direction was - 0.125 mm, and the curvature radius Ry of optical Y direction was - 0.1 mm.

Further, aperture arrays 59 disposed near the collecting site of microlens array 55 were constructed such that each aperture 59a received only the light through the corresponding microlens 55a.

< Developing Step >

Following the exposing, the laminated body was allowed to stand for 10 minutes at room temperature. Then the support and the cushion layer were peeled away, and 1 % aqueous solution of sodium carbonate was sprayed on the entire surface of the photosensitive layer for 60 seconds under the condition of 30 °C and spraying pressure 0.15 MPa, thereby the unhardened region was dissolved away, followed by rinsing and drying. Thereafter, heating was carried out at 160 °C for 30 minutes to form a solder resist film. From visual inspection, no peeling, swelling, or discoloring was observed for the solder resist film. [Evaluation]

The photosensitive film and the laminated body obtained in Example A-I were evaluated with respect to peeling property and laminating property in the following ways. The results are shown in Table 3.

Also, the photosensitive film and the laminated body were evaluated with respect to sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the following ways. The results are shown in Table 4.

< Evaluation of Peeling Property > The photosensitive film was fitted to a copper surface of a flexible substrate that was formed by laminating a thin copper film onto a polyimide film. The photosensitive film was overlapped to the thin copper film while peeling off the protective film, then the photosensitive film and the thin copper film were laminated under a condition of 0.4 MPa and 80 ⁰C by means of a vacuum laminator (MVLP500, by Meiki Co., Ltd.), thereby to form a laminated body. After cooling the laminated body to the ambient temperature, the laminated body was cut into a rectangular shape of 1 cm x 10 cm to prepare a sample for evaluation. A self-adhesive tape was adhered to the support and to the polyimide film of the resulting sample, then each edge of the self-adhesive tape was gripped and pulled by means of Tensilon tensile tester till the peeling occurred. The peeled condition was evaluated on the base of the following criteria. The results are shown in Table 3.

- Evaluation Criteria -

A: peeling occurred between cushion layer and photosensitive layer B: peeling occurred at a portion other than between cushion layer and photosensitive layer < Evaluation of Laminating Property >

The laminated body prepared in Example A-I was visually evaluated with respect to bubbles between the photosensitive layer and the substrate having a wiring pattern, and was rated on the base of the following criteria. The results are shown in Table 3.

- Evaluation Criteria -

A: no bubbles were present B: bubbles were present < Resolution >

(1) Evaluation of Shortest Developing Period

The support and the cushion layer was peeled away from the laminated body, then an aqueous solution of sodium carbonate at 1 % concentration was sprayed on the entire surface of the photosensitive layer at 30 °C and 0.15 MPa. The period from the initial spraying to the dissolving away of the photosensitive layer was measured, and the period was defined as the shortest developing period. As the result, the shortest developing period was about 40 seconds.

(2) Evaluation of Sensitivity Laser beam was irradiated to the photosensitive layer of the resulting laminated body, in which the laser beam was varied as to the optical energy quantity from 0.1 mj/cm² to 100 mj/cm² in every increments of 2¹/² times. The laser beam was irradiated from the side of the support by means of a pattern forming apparatus that was equipped with a laser source of 405 nm, thereby a part of the photosensitive layer was hardened.

After allowing to stand for 10 minutes at room temperature, the support and the cushion layer were peeled away from the laminated body, then an aqueous solution of sodium carbonate at 1 % concentration was sprayed on the entire surface of the photosensitive layer on the copper laminated substrate at 30 ⁰C and 0.15 MPa for the period of two times the shortest developing period described above, thereby the unhardened portion was removed away, and the thickness of the remaining hardened layer was measured. Then, a sensitivity curve was prepared by plotting the relation between irradiated optical quantity and the thicknesses of the hardened layers. From the resulting sensitivity curve, the energy of the laser beam at which the thickness of the hardened region corresponded to 4 μm was determined, and the energy of the laser beam corresponding to 4 μm was determined as the minimum energy of the laser beam that was required to harden the photosensitive layer, and the minimum energy was defined as the "sensitivity". The results are shown in Table 3. The pattern forming apparatus described above was equipped with a laser modulator of DMD. (3) Evaluation of Resolution

The resulting laminated body was allowed to stand in the ambient condition of 23 °C and 55 % relative humidity for 10 minutes. From the side of the support, a pattern of lines was irradiated by means of the pattern forming apparatus described above in a configuration of line/ space = 1/1, line widths: 5 μm to 20 μm under an increment of line: 1 μm/line, and line widths: 20 to 50 μm. under an increment of line: 5 μm/line. The optical quantity in the exposure was adjusted to the minimum energy of the laser beam necessary to cure the photosensitive layer described above. After allowing to stand in the ambient condition for 10 minutes, the support and the cushion layer were peeled away from the laminated body, then an aqueous solution of sodium carbonate at 1 % concentration was sprayed on the entire surface of the photosensitive layer at 30 ⁰C and 0.15 MPa for the period of two times the shortest developing period described above, thereby the unhardened portion was removed away. The resultant copper laminated plate with hardened resin pattern was observed by means of an optical microscope; and the narrowest line width, where abnormality of lines such as clogging, deformation, or the like did not exist, was determined, then the narrowest width was defined as the resolution. Namely, the smaller value means the better resolution. The results are shown in Table 4. < Shelf Stability >

The resulting laminated body was measured in terms of the minimum energy of the laser beam that was required to harden into 7 points within 15 points in the similar manner as Evaluation of Sensitivity described above. Another laminated body, prepared in the same manner, was subjected to a promoting condition of 40 °C and 65 % relative humidity for three days, then the laminated body was hardened under the resulting minimum energy and the hardened level was measured with respect to the 15 points. The hardened levels were compared between the laminated bodies with and without the promoting condition, and the shelf stability was evaluated on the base of the following criteria. It has been experienced that the difference of "- 2 points to + 2 points", in other words within a range from - 2 points to + 2 points, shown below brings about substantially no problem in actual usages. The results are shown in Table 4.

- Evaluation Criteria -

A: - 2 points to + 2 points B: — 3 points to + 3 points C: less than - 4 points or more than + 4 points < Thermal Resistance >

The solder resist film on the substrate was rinsed with an acidic solution, then the solder resist film was provided with a water soluble flux and dipped three times into a solder bath at 260 °C for 5 seconds, thereafter the water soluble flux was rinsed away. The solder resist film was visually observed and was evaluated on the base of the following criteria. The results are shown in Table 4.

- Evaluation Criteria -

A: no peeling, swelling, or discoloring was detected B: at least one of peeling, swelling, and discoloring was detected < Surface Hardness > The solder resist film, subjected to dipping into the solder bath in the same manner as the thermal resistance, was evaluated in terms of the surface hardness in accordance with JIS K 5400. The results are shown in Table 4. (Example A-2) A photosensitive film and a laminated body were prepared in the same manner as Example A-I, except that 5 parts of methoxymethylol melamine was incorporated into the photosensitive composition as a thermal crosslinker.

The resulting photosensitive film and the laminated body were evaluated with respect to peeling property, laminating property, sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example A-I. The results are shown in Tables 3 and 4. (Example A-3)

A photosensitive film and a laminated body were prepared in the same manner as Example A-I, except that the formula of the photosensitive composition was as follows.

The resulting photosensitive film and the laminated body were evaluated with respect to peeling property, laminating property, sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example A-I. The results are shown in Tables 3 and 4. [Formula of Photosensitive Composition]

ZFR resin ⁱ*) ' 35 parts

ESLV-80XY ²*⁾ 8 parts

2-methyl-l-[4-(methylthio)phenyl]-2-morpholinopropane-l-one 4.5 parts 2,4-diethylxanthone 0.5 part Silicone elastomer (SY series, by Wacker Co.) 5 parts Dipentaerithritol hexaac^'rylate 3 parts

Melamine 4 parts

Phthalocyanine blue 1 part

Silica 20 parts Precipitated barium sulfate 15 parts

**⁾ product by reaction of a reaction product of an epoxy compound and an ester compound derived from an unsaturated mono carboxylic acid, and saturated or unsaturated polybasic acid anhydride, by Nippon Kayaku Co. ²*⁾ epoxy resin containing two or more epoxy groups in one molecule, by Nippon Steel Chemical Co. (Example A-4)

The resulting photosensitive film and the laminated body were evaluated with respect to peeling property, laminating property, sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example A-I. The results are shown in Tables 3 and 4. - Liquid of Photosensitive Composition -

The total 85 parts of the following ingredients were kneaded by means of a roll mill to prepare ink composition (a), then 15 parts of trimethylolpropane triglycidylether was mixed to ink composition (a), thereby a liquid for photosensitive composition was prepared. [Formula of Ink Composition (a)] Resin A **^{) "} 40 parts

2-hydroxyethyl acrylate 15 parts

Benzyldiethylketal 2.5 part l-benzyl-2-methylimidazole 1.0 part Leveling agent (Modaflow™, by Monsanto Co.) 1.0 part Barium sulfate 25 parts

Phthalocyanine green 0.5 part

^!*) Resin A is a viscous liquid obtained by reaction of one equivalent of a cresolnovolak epoxy resin having an epoxy equivalent of 217 and 7 groups on average of phenol residue and epoxy group in one molecule and 1.05 equivalent of acrylic acid, and 0.67 equivalent of tetrahydrophthalic anhydride with a solvent of phenoxyethyl acrylate. Resin A contains 35 parts of phenoxyethyl acrylate and has an acid value of 63.4 mg KOH/g as a mixture. (Example A-5)

A photosensitive film and a laminated body were prepared in the same manner as Example A-I, except that an emulsion of ethylene-vinyl acetate copolymer (mixture of 50 parts of Chemi-Pearl V-200 (solid content: 40 %, by Mitsui Chemical Co.) and 50 parts of water) was coated on the support and dried, thereby to form a cushion layer.

The resulting photosensitive film and the laminated body were evaluated with respect to peeling property, laminating property, sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example A-I. The results are shown in Tables 3 and 4. (Example A-6) A photosensitive film and a laminated body were prepared in the same manner as Example A-I, except that a liquid of ethylene-vinyl acetate copolymer (mixture of 17 parts of Evaflex™ 45X (content of vinyl acetate: 46 %, by Mitsui DuPont Chemical Co.) and 83 parts of toluene) was coated on the support and dried, thereby to form a cushion layer.

The resulting photosensitive film and the laminated body were evaluated with respect to peeling property, laminating property, sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example A-I. The results are shown in Tables 3 and 4. (Example A-7)

A photosensitive film and a laminated body were prepared in the same manner as Example A-I, except that the amount of the dispersion of barium sulfate was changed into 5 parts in the photosensitive composition.

The resulting photosensitive film and the laminated body were evaluated with respect to peeling property, laminating property, sensitivity, - resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example A-I. The results are shown in Tables 3 and 4. (Example A-8)

The resulting photosensitive film and the laminated body were evaluated with respect to sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example A-I, except that the microlens array was not mounted to the pattern forming apparatus in Example A-I. The results are shown in Tables 3 and 4. (Comparative Example A-I) A photosensitive film and a laminated body were prepared in the same manner as Example A-I^", except that no cushion layer was formed on the support.

The resulting photosensitive film and the laminated body were evaluated with respect to peeling property, laminating property, sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example A-I. The results are shown in Tables 3 and 4. (Reference Example A-2)

A photosensitive film and a laminated body were prepared in the same manner as Example A-I, except that the coating liquid for cushion layer having the formula as follows was coated on the support and dried, thereby to form a cushion layer.

The resulting photosensitive film and the laminated body were evaluated with respect to peeling property, laminating property, sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example A-I. The results are shown in Tables 3 and 4. • [Formula for Cushion Layer]

Copolymer of methylmethacrylate/2-ethylhexylacrylate/ 15.0 parts benzylmethacrylate/methacrylic acid **)

2,2-bis(4-(methacryloyloxypentaethoxy)phenyl)propane ²*⁾ 7.0 parts Fluorine-containing surfactant ³*⁾ 0.3 part

Methanol 30.0 parts

Methylethylketone 19.0 parts l-methoxy-2-propanol 10.0 parts

^!*⁾ mole ratio of monomers: 55/11.7/4.5/28.8, mass-averaged molecular mass: 80,000 ²*) BPE-500, by Shin-Nakamura Chemical Co. 3*) p277P, by Dainippon Ink and Chemicals, Inc. (Comparative Example A-3)

A photosensitive film and a laminated body were prepared in the same manner as Example A-I, except that no dispersion of barium sulfate was added to the photosensitive composition.

The resulting photosensitive film and the laminated body were evaluated with respect to peeling property, laminating property, sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example A-I. The results are shown in Tables 3 and 4. Table 3

Resin (1)

A: aqueous dispersion of olefin-acrylic acid copolymer B: aqueous dispersion of ethylene-vinyl acetate copolymer C: solvent solution of ethylene-vinyl acetate copolymer D: alkaline solution of acrylate-acrylic acid copolymer

Resin (2)

E: maleamide resin F: epoxy acrylate resin

The results of Tables 3 and 4 demonstrate that the photosensitive films of Examples A-I to A-8 represent higher conformability to irregularities and easy peeling ability between the photosensitive layer and the cushion layer compared to those of Comparative or Reference Examples A-I to A-3. Further, the results demonstrate that the permanent patterns of Examples A-I and A-2, • and A-5 to A-8 exhibit higher sensitivity and resolution, prolonged shelf stability, and superior thermal resistance and hardness of the solder resist film compared to those of Comparative or Reference Examples A-I to A-3. The permanent patterns of Examples A-3 and A-4 represent somewhat insufficient sensitivity and resolution, which is believed due to the epoxyacrylate resin for the binder. On the other hand, the solder resist films of Examples A-3 and A-4 demonstrate superior thermal resistance and hardness. (Example B-I) [Preparation of Photosensitive Film for Permanent Pattern]

To polyethylene terephthalate (PET) film of 20 μm thick as a support, an emulsion of olef in-acrylic acid (Chemi-Pearl S-IOO₇ solid content: 27 %, by Mitsui Chemical Co.) was coated using a wire bar and dried, thereby to form a cushion layer of 20 μm thick.

Then, the liquid of the barrier layer composition, having the following formula, was coated on the cushion layer described above, thereby to form a barrier layer of 1.5 μm thick. [Formula of Barrier Layer Composition]

Polyvinyl alcohol PVA 205 (by Kuraray Co.)¹*⁾ 130 parts

Polyvinyl pyrrolidone PVP K-90 (by GAF Co.) 60 parts Surflon S-131 (by Asahi Glass Co.) ²*⁾ 10 parts

Methanol 1675 parts

Distilled Water 1675 parts

^!*) saponification rate: 80 %, ²*) fluorine-containing surfactant Then, the liquid of the photosensitive composition, having the following formula, was coated on the barrier layer and dried to form a photosensitive layer of 10 μm thick on the barrier layer. Then, a polypropylene film of 12 μm thick was laminated on the photosensitive layer as a protective film, thereby to prepare a photosensitive film for forming a permanent pattern.

[Formula of Photosensitive Composition]

Dispersion of barium sulfate 24.75 parts

Addition reaction product dissolved in MEK **⁾ 13.36 parts

R712 (bifunctional acrylic monomer, by Nippon Kayaku Co.) 3.06 parts Dipentaerithritol hexaacrylate 4.59 parts Irgacure 819 (by Ciba Specialty Chemicals Co.) 1.98 parts

F780F ²*) dissolved in MEK at 30 % concentration 0.066 part

Hydroquinone monomethylether 0.024 part

Methylethylketone (MEK) 8.60 parts ^!*⁾ concentration: 35 %, MEK: methylethylketone addition reaction product of between copolymer of styrene/maleic anhydride/ butylacrylate (mole ratio: 40/32/28) and benzylamine; the benzylamine corresponds to 1.0 equivalence to anhydride group of the copolymer ²*⁾ by Dainippon Ink and Chemicals, Inc.

< Laminating Step >

A laminated body was prepared in the same manner as Example A-I. Then, the support and the cushion layer were properly peeled away from the barrier layer. The peeling could be carried out easily. < Exposing Step >

A pattern was irradiated through the barrier layer onto the photosensitive layer of the laminated body without the support and the cushion layer, using a laser beam having a wavelength of 405 to 415 nm, thereby a part of the photosensitive layer was hardened in the same manner as Example A-I.

< Pattern Forming Apparatus >

The same pattern forming apparatus as that utilized in Example A-I was employed.

< Developing Step > Following the exposing, developing was carried out in the same manner as Example A-I to form a solder resist film. From visual inspection, no peeling, swelling, or discoloring was observed for the solder resist film. [Evaluation]

The photosensitive film and the laminated body obtained in Example B-I were evaluated with respect to laminating property, sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in substantially the same way as Example A-I as briefly explained below. The results are shown in Table 5.

< Evaluation of Laminating Property > The laminated body prepared in Example B-I was evaluated in the same way as Example A-I. The results are shown in Table 5.

< Resolution >

The evaluation of the resolution was carried out in the same way as Example A-I. The results are shown in Table 5. < Shelf Stability >

The evaluation of the shelf stability was carried out in the same way as Example A-I. The results are shown in Table 5.

< Thermal Resistance >

The evaluation of the thermal resistance was carried out in the same way as Example A-I. The results are shown in Table 5.

< Surface Hardness >

The evaluation of the surface hardness was carried out in the same way as Example A-I. The results are shown in Table 5. (Example B-2) A photosensitive film and a laminated body were prepared in the same manner as Example B-I, except that 5 parts of methoxymethylol melamine was incorporated into the photosensitive composition as a thermal crosslinker.

The resulting photosensitive film and the laminated body were evaluated with respect to laminating property, sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example B-I. The results are shown in Table 5. (Example B-3)

A photosensitive film and a laminated body were prepared in the same manner as Example B-I, except that the formula of the photosensitive composition was that of Example A-3.

The resulting photosensitive film and the laminated body were evaluated with respect to laminating property, sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example B-I. The results are shown in Table 5. (Example B-4)

A photosensitive film and a laminated body were prepared in the same manner as Example B-I, except that the formula of the photosensitive composition was that of Example A-4.

The resulting photosensitive film and the laminated body were evaluated with respect to laminating property, sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example B-I. The results are shown in Table 5. (Example B-5)

A photosensitive film and a laminated body were prepared in the same manner as Example B-I, except that a liquid of ethylene-vinyl acetate copolymer (mixture of 17 parts of Evaflex™ 45X (content of vinyl acetate: 46 %, by Mitsui DuPont Chemical Co.) and 83 parts of toluene) was coated on the support and dried, thereby to form a cushion layer.

The resulting photosensitive film and the laminated body were evaluated with respect to laminating property, sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example B-I. The results are shown in Table 5. (Comparative Example B-I)

A photosensitive film and a laminated body were prepared in the same manner as Example B-I, except that no cushion layer was formed on the support.

The resulting photosensitive film and the laminated body were evaluated with respect to laminating property, sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example B-I. The results are shown in Table 5. - (Reference Example B-2)

A photosensitive film and a laminated body were prepared in the same manner as Example B-3, except that no barrier layer was formed on the cushion layer. The resulting photosensitive film and the laminated body were evaluated with respect to laminating property, sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example B-I. The results are shown in Table 5. (Reference Example B-3) A photosensitive film and a laminated body were prepared in the same manner as Example B-4^ except that no barrier layer was formed on the cushion layer.

The resulting photosensitive film and the laminated body were evaluated with respect to laminating property, sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example B-I. The results are shown in Table 5. (Reference Example B-4)

A photosensitive film and a laminated body were prepared in the same manner as Example B-I, except that the coating liquid for cushion layer was the same as that of Reference Example A-2.

The resulting photosensitive film and the laminated body were evaluated with respect to laminating property, sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example B-I. The results are shown in Table 5. (Comparative Example B-5)

A photosensitive film and a laminated body were prepared in the same manner as Example B-I, except that no dispersion of barium sulfate was added to the photosensitive composition.

The resulting photosensitive film and the laminated body were evaluated with respect to laminating property, sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example B-I. The results are shown in Table 5. Table 5

O3 K)

The results of Table 5 demonstrate that the permanent patterns of Examples B-I, B -2, and B-5 exhibit higher sensitivity and resolution, prolonged shelf stability, and superior thermal resistance and hardness of the solder resist film compared to those of Comparative or Reference Examples B-I to B-5. The permanent patterns of Examples B-3 and B-4 represent somewhat insufficient sensitivity and resolution, which is believed due to the epoxyacrylate resin for the binder. On the other hand, the solder resist films of Examples B-3 and B-4 demonstrate superior thermal resistance and hardness.

(Example C-I)

[Preparation of Photosensitive Film for Permanent Pattern]

To polyethylene terephthalate (PET) film of 20 μm thick as a support, the liquid for cushion layer composition, having the following formula, was coated using a wire bar and dried, thereby to form a cushion layer of 20 μm thick. The liquid for cushion layer composition contained an alkali-soluble thermoplastic resin having a Tg of 60 °C. [Formula for Cushion Layer] Copolymer of methylmethacrylate/2-ethylhexylacrylate/ 15.0 parts benzylmethacrylate/methacrylic acid ^α*)

Multifunctional aery late ²*⁾ 7.0 parts

Fluorine-containing surfactant ³*⁾ 0.3 part

Methanol 30.0 parts

Methylethylketone 19.0 parts l-methoxy-2-propanol 10.0 parts

^!*⁾ mole ratio of monomers: 55/11.7/4.5/28.8, mass-averaged molecular mass: 80,000 2*) BPE-500, by Shin-Nakamura Chemical Co. 3*) pi77p_r by Dainippon Ink and Chemicals, Inc.

Then, the liquid for the barrier layer composition, having the following formula, was coated and dried on the cushion layer described above, thereby to form a barrier layer of 1.5 μm thick. [Formula of Barrier Layer Composition]

Polyvinyl alcohol PVA 205 (by Kuraray Co.)¹*) 130 parts

Polyvinyl pyrrolidone PVP K-90 (by GAF Co.) 60 parts Surflon S-131 (by Asahi Glass Co.) ²*) 10 parts

Methanol 1675 parts

Distilled Water 1675 parts

!*) saponification rate: 80 %, ²*) fluorine-containing surfactant Then, the liquid of the photosensitive composition, having the following formula, was coated on the barrier layer and dried to form a photosensitive layer of 10 μm thick on the barrier layer. Then, a polypropylene film of 12 μm thick was laminated on the photosensitive layer as a protective film, thereby to prepare a photosensitive film for forming a permanent pattern.

[Formula of Photosensitive Composition]

Dispersion of barium sulfate 24.75 parts

Addition reaction product dissolved in MEK ^α*) 13.36 parts

F780F ²*⁾ dissolved in MEK at 30 % concentration 0.066 part

Hydroquinone monomethylether 0.024 part

Methylethylketone (MEK) 8.60 parts ^α*⁾ concentration: 35 %, MEK: methylethylketone addition reaction product of between copolymer of styrene/maleic anhydride/ butylacrylate (mole ratio: 40/32/28) and benzylamine; the benzylamine corresponds to 1.0 equivalence to anhydride group of the copolymer ²*⁾ by Dainippon Ink and Chemicals, Inc.

< Laminating Step >

A laminated body was prepared in the same manner as Example A-I. Then, the support was peeled away from the cushion layer. The peeling could be carried out easily, and the adhesions between other than the support and the cushion layer were maintained properly after the peeling. - < Exposing Step >

A pattern was irradiated through the barrier layer onto the photosensitive layer of the laminated body without the support and the cushion layer, using a laser beam having a wavelength of 405 to 415 run, thereby a part of the photosensitive layer was hardened.

< Pattern Forming Apparatus >

The photosensitive film and the laminated body obtained in Example C-I were evaluated with respect to laminating property, sensitivity, resolution, shelf stability, bleeding at cushion layer, thermal resistance, and surface hardness in substantially the same way as Example A-I as briefly explained below. The results are shown in Table 6.

< Evaluation of Laminating Property > The laminated body prepared in Example C-I was evaluated in the same way as Example A-I. The results are shown in Table 6.

< Resolution >

The evaluation of the resolution was carried out in the same way as Example A-I. The results are shown in Table 6. < Shelf Stability >

The evaluation of the shelf stability was carried out in the same way as Example A-I. The results are shown in Table 6.

< Bleeding at Cushion Layer >

The existence of bleeding was evaluated by visually observing the substrate surface after the developing step.

< Thermal Resistance >

The evaluation of the thermal resistance was carried out in the same way as Example A-I. The results are shown in Table 6.

< Surface Hardness > The evaluation of the surface hardness was carried out in the same way as Example A-I. The results are shown in Table 6. (Example C-2)

A photosensitive film and a laminated body were prepared in the same manner as Example C-I, except that 5 parts of methoxymethylol melamine was incorporated into the photosensitive composition as a thermal crosslinker.

The peeling of the support from the cushion layer could be carried out easily at the laminating step.

The resulting photosensitive film and the laminated body were evaluated with respect to laminating property, sensitivity, resolution, shelf stability, bleeding at cushion layer, thermal resistance, and surface hardness in the same manner as Example C-I. The results are shown in Table 6. (Example C-3)

A photosensitive film and a laminated body were prepared in the same manner as Example C-I, except that the formula of the photosensitive composition was that of Example A-3. The peeling of the support from the - cushion layer could be carried out easily at the laminating step.

The resulting photosensitive film and the laminated body were evaluated with respect to laminating property, sensitivity, resolution, shelf stability, bleeding at cushion layer, thermal resistance, and surface hardness in the same manner as Example C-I. The results are shown in Table 6. (Example C-4)

A photosensitive film and a laminated body were prepared in the same manner as Example C-I, except that the formula of the photosensitive composition was that of Example A-4. The peeling of the support from the cushion layer could be carried out easily at the laminating step. The resulting photosensitive film and the laminated body were evaluated with respect to laminating property, sensitivity, resolution, shelf stability, bleeding at cushion layer, thermal resistance, and surface hardness in the same manner as Example C-I. The results are shown in Table 6. (Reference Example C-I)

A photosensitive film and a laminated body were prepared in the same manner as Example C-I, except that no barrier layer was formed on the cushion layer.

The resulting photosensitive film and the laminated body were evaluated with respect to laminating property, sensitivity, resolution, shelf stability, thermal resistance, and surface hardness in the same manner as Example C-I. The results are shown in Table 6. (Reference Example C-2)

A photosensitive film and a laminated body were prepared in the same manner as Example C-3, except that no barrier layer was formed on the cushion layer. The peeling of the support from the cushion layer could be carried out easily at the laminating step.

The resulting photosensitive film and the laminated body were evaluated with respect to laminating property, sensitivity, resolution, shelf stability, bleeding at cushion layer, thermal resistance, and surface hardness in the same manner as Example C-3. The results are shown in Table 6. (Reference Example C-3)

A photosensitive film and a laminated body were prepared in the same manner as Example C-4, except that no barrier layer was formed on the cushion layer. The resulting photosensitive film and the laminated body were evaluated with respect to laminating property, sensitivity, resolution, shelf stability, bleeding at cushion layer, thermal resistance, and surface hardness in the same manner as Example C-I. The results are shown in Table 6. (Reference Example C-4)

A photosensitive film and a laminated body were prepared in the same manner as Example C-I, except that the coating liquid for cushion layer, having the formula as follows, was coated on the support and dried, thereby to form a cushion layer. The resulting photosensitive film and the laminated body were evaluated with respect to laminating property, sensitivity, resolution, shelf stability, bleeding at cushion layer, thermal resistance, and surface hardness in the same manner as Example C-I. The results are shown in Table 6. [Formula for Cushion Layer] Copolymer of methylmethacrylate/2-ethylhexylacrylate ^α*⁾ 15.0 parts Multifunctional acrylate ²*⁾ 7.0 parts

Fluorine-containing surfactant ³*⁾ 0.3 part

Methylethylketone 49.0 parts l-methoxy-2-propanol 10.0 parts ^!*⁾ mole ratio of monomers: 76/24, mass-averaged molecular mass: 92,000 ²*⁾ BPE-500, by Shin-Nakamura Chemical Co. 3*) pi77p^ by Dainippon Ink and Chemicals, Inc.

(Comparative Example C-5) A photosensitive film and a laminated body were prepared in the same manner as Example C-I, except that no dispersion of barium sulfate was added to the photosensitive composition.

The resulting photosensitive film and the laminated body were evaluated with respect to laminating property, sensitivity, resolution, shelf stability, bleeding at cushion layer, thermal resistance, and surface hardness in the same manner as Example C-I. The results are shown in Table 6.

Table 6

^

The results of Table 6 demonstrate that the permanent patterns of Examples C-I and C-2 exhibit higher sensitivity and resolution, prolonged shelf stability, and superior thermal resistance and hardness of the solder resist film compared to those of Comparative or Reference Examples C-I to C-5. The permanent patterns of Examples C-3 and C-4 represent somewhat insufficient sensitivity, resolution, and shelf stability, which is believed due to the epoxyacrylate resin for the binder. On the other hand, the solder resist films of Examples C-3 and C-4 demonstrate superior thermal resistance and hardness. Further, it is demonstrated that the photosensitive films of Examples

C-I to C-4 can lead to solder resist with superior thermal resistance, higher surface hardness, and lower thermal expansion, as well as to permanent patterns with excellent conformability to irregularities of substrate surface and without inferior adhesion; and also can bring about efficient formation of solder resist with higher exposure sensitivity. Industrial Applicability

The present invention provides photosensitive films for forming permanent patterns that may exhibit higher thermal resistance, higher surface hardness, and lower thermal expansion, may represent superior conformability to irregularities of substrate surface and less possibility of inferior adhesion of solder resist, are less likely to degrade the exposure sensitivity; may afford proper working properties at forming solder resist, namely release characteristics from supports and cleaning properties of substrates surface are appropriate; may represent prolonged shelf stability, and also may exhibit appropriate sensitivity to LDIs.

Claims

1. A photosensitive film comprising: a support, 5 a cushion layer, and a photosensitive layer, in this order, wherein the photosensitive layer is formed of a photosensitive composition which comprises (A) a binder, (B) a polymerizable compound, (C) a photopolymerization initiator, and (D) a filler, and the photosensitive film is 0 utilized for forming a permanent pattern.

2. The photosensitive film according to claim 1, further comprising a barrier layer, wherein the barrier layer capable of suppressing substance mobility is disposed between the cushion layer and the photosensitive layer. 5 3. The photosensitive film according to claim 2, wherein the barrier

. layer contains at least one polymer selected from the group consisting of vinyl polymers and vinyl copolymers.

4. The photosensitive film according to one of claims 1 to 3, wherein the peel strength between the cushion layer and the photosensitive layer is o lower than the peel strength between the cushion layer and the support.

5. The photosensitive film according to one of claims 1 to 4, wherein the adhesive strength between the cushion layer and the photosensitive layer exhibits the minimum level among the adhesive strengths between two materials within the photosensitive film. 5

6. The photosensitive film according to one of claims 1 to 4, wherein the adhesive strength between the support and the cushion layer exhibits the minimum level among the adhesive strengths between two materials within the photosensitive film.

7. The photosensitive film according to one of claims 2 to 4, wherein the adhesive strength between the cushion layer and the barrier layer exhibits the minimum level among the adhesive strengths between two materials within the photosensitive film.

8. The photosensitive film according to one of claims 1 to 7, wherein the content of the (D) filler is 10 % by mass to 60 % by mass on the base of the photosensitive layer.

9. The photosensitive film according to one of claims 1 to 8, wherein the thickness of the photosensitive layer is 10 μm to 100 μm, and the thickness of the cushion layer is 5 μm to 100 μm.

10. The photosensitive film according to one of claims 1 to 9, wherein the cushion layer is hardly soluble in alkaline liquids, and contains a

- thermoplastic resin of which the glass transition temperature is 80 ⁰C or less.

11. The photosensitive film according to one of claims 1 to 9, wherein the cushion layer is soluble in alkaline liquids, and contains a thermoplastic resin of which the glass transition temperature is 80 °C or less.

12. The photosensitive film according to claim 10, wherein the thermoplastic resin contains a copolymer of an olefin and (meth) aery late.

13. The photosensitive film according to one of claims 1 to 12, wherein the (A) binder contains a copolymer synthesized by reaction of anhydride group of a precursor copolymer with a primary amine compound in an equivalent ratio of 1 : 0.1 to 1, in which the precursor copolymers are formed from (a) maleic anhydride, (b) aromatic vinyl monomers, and (c) vinyl monomers of which the homopolymer represents a glass transition temperature of less than 80 °C.

14. The photosensitive film according to one of claims 1 to 13,

5 wherein the (B) polymerizable compound contains a monomer unit having a (meth) acrylic group.

15. The photosensitive film according to one of claims 1 to 14, wherein the (C) photopolymerization initiator comprises a compound selected from the group consisting of halogenated hydrocarbon derivatives, phosphine 0 oxides, hexaaryl-biimidazoles, oxime derivatives, organic peroxides, thio compounds, ketone compounds, aromatic onium salts, and ketoxime ethers.

16. The photosensitive film according to one of claims 1 to 15, wherein the sensitivity fluctuation of the photosensitive film is - 2 points to + 2 points after subjecting to the condition of 40 ⁰C and 65 % relative humidity 5 for three days.

17. A process for producing a photosensitive film, comprising: forming a cushion layer, and forming a photosensitive layer, wherein the cushion layer is formed by way of coating an aqueous o emulsion containing a thermoplastic resin, and drying the coated emulsion, the photosensitive layer is formed by way of coating a liquid for a photosensitive composition which comprises (A) a binder, (B) a polymerizable compound, (C) a photopolymerization initiator, and (D) a filler, and drying the coated liquid. 5

18. The process for producing a photosensitive film according to claim 17, further comprising forming a barrier layer, wherein the barrier layer is formed, after the cushion layer being formed, by way of coating a liquid for barrier layer composition on the cushion layer and drying the coated liquid. 5

19. A process for forming a permanent pattern, comprising: laminating a photosensitive film on a front side of a substrate through at least one of heating and pressuring, irradiating a laser beam from a laser source onto a photosensitive layer, and developing the irradiated photosensitive layer, 0 wherein the photosensitive film is one according to claims 1 to 16.

20. The process for forming a permanent pattern according to claim 19, wherein the support and the cushion layer are simultaneously separated from the photosensitive layer by peeling between the cushion layer and the photosensitive layer after irradiating the laser beam, then the photosensitive 5 layer is developed.

21. The process for forming a permanent pattern according to claim 19, wherein the support and the cushion layer are simultaneously separated from the photosensitive layer by peeling between the cushion layer and the photosensitive layer after laminating the photosensitive film, then the o photosensitive layer is irradiated.

22. The process for forming a permanent pattern according to one of claims 19 to 21, wherein at least one of a protective film and an interlayer insulating film is provided into the photosensitive film.

23. The process for forming a permanent pattern according to one of 5 claims 19 to 22, wherein the laser beam from the laser source is modulated by means of a laser modulator which comprises plural imaging portions each capable of receiving the laser beam and outputting the modulated laser beam, the modulated laser beam is compensated by transmitting through plural microlenses, being arranged into a microlens array, each having a non-spherical surface capable of compensating the aberration due to distortion of the output surface of the imaging portions, and the photosensitive layer is irradiated by the modulated and transmitted laser beam.

24. The process for forming a permanent pattern according to one of claims 19 to 23, wherein the laser beam from the laser source is modulated by means of a laser modulator, the modulated later beam is transmitted through a microlens array which has an aperture configuration of the plural microlenses capable of - substantially shielding incident light other than the modulated laser beam from the laser modulator.

25. The process for forming a permanent pattern according to one of claims 23 and 24, wherein each of the microlenses has a non-spherical surface capable of compensating the aberration due to distortion of the output surface of the imaging portions.

26. The process for forming a permanent pattern according to claim 25, wherein the non-spherical surface is a toric surface.

27. The process for forming a permanent pattern according to one of claims 23 to 26, wherein each of the microlenses has a circular aperture configuration.

28. The process for forming a permanent pattern according to one of claims 23 to 27, wherein the aperture configuration of the plural microlenses is defined by light shielding portion provided on the microlens surface.

29. The process for forming a permanent pattern according to one of claims 23 to 28, wherein the laser modulator is capable of controlling a part of the plural imaging portions depending on pattern information.

30. The process for forming a permanent pattern according to one of claims 23 to 29, wherein the laser modulator is a spatial light modulator.

31. The process for forming a permanent pattern according to claim 30, wherein the spatial light modulator is a digital micromirror device (DMD).

32. The process for forming a permanent pattern according to one of claims 19 to 31, wherein the exposing is performed by a laser beam transmitted through an aperture array.

33. The process for forming a permanent pattern according to one of

- claims 19 to 32, wherein the exposing is performed while moving relatively the laser beam and the photosensitive layer.

34. The process for forming a permanent pattern according to one of claims 19 to 33, wherein the laser source is capable of irradiating two or more types of laser beams together with.

35. The process for forming a permanent pattern according to one of claims 19 to 34, wherein the laser source comprises plural lasers, a multimode optical fiber, and a collective optical system that collects the laser beams from the plural lasers into the multimode optical fiber.

36. The process for forming a permanent pattern according to claim 35, wherein the wavelength of the laser beam is 395 run to 415 nm.

37. The process for forming a permanent pattern according to one of claims 19 to 36, wherein the photosensitive layer is hardened after the developing.

38. The process for forming a permanent pattern according to claim 37, wherein the photosensitive layer is hardened by at least one of irradiating onto the entire surface of the photosensitive layer and heating the entire surface of the photosensitive layer to 120 ⁰C to 200 °C.