WO2016117243A1 - Method for producing resin sheet - Google Patents

Abstract

Provided is a method for producing a resin sheet in which it is possible to suppress delamination and actualize an insulating layer having high stability in terms of roughness and peel strength. A method for producing a resin sheet having a support, a first resin composition layer comprising a first resin composition provided on the support, and a second resin composition layer comprising a second resin composition provided on the first resin composition layer, the resin sheet also having a mixed layer that is a mixture of the first resin composition and second resin composition between the first resin composition layer and the second resin composition layer, wherein: the method for producing a resin sheet includes a step for applying a first resin varnish, obtained by dissolving the first resin composition, on the support, applying a second resin varnish, obtained by dissolving the second resin composition, on the first resin varnish, and drying; the viscosity of the first resin varnish is 100 mPa・s or higher; and the viscosity of the second resin varnish is 100 mPa・s or higher.

Description

Manufacturing method of resin sheet

The present invention relates to a method for producing a resin sheet. Furthermore, the present invention relates to a resin sheet, a printed wiring board manufacturing method, a printed wiring board, and a semiconductor device.

As a manufacturing technique of a printed wiring board, a build-up method in which circuit-formed conductor layers and insulating layers are alternately stacked is widely used. In the build-up method, the insulating layer is generally formed by laminating a resin sheet including a resin composition layer on an inner layer substrate and curing the resin composition layer.

In recent years, it has been known that the content of the inorganic filler in the resin composition layer is increased and the thermal expansion coefficient of the insulating layer is decreased, but when the content of the inorganic filler is large, the insulating layer obtained The adhesion strength (peel strength) between the conductor layer and the conductor layer tends to decrease. For this reason, for example, Patent Document 1 discloses a resin sheet including a plurality of resin composition layers and including a layer having a high ratio of resin components as the resin composition layer to be bonded to the conductor layer. Has been.

JP 2014-17301 A

In the insulating layer formed using a resin sheet including a plurality of resin composition layers, the present inventors have a case where delamination occurs when exposed to a high temperature environment such as during reflow. I found that there is. In addition, in the resin sheet containing a plurality of resin composition layers, the present inventors also find that it is difficult to control the thickness of each layer, which may result in an insulating layer having poor roughness and peel strength stability. I found it.

An object of the present invention is to provide a method for producing a resin sheet capable of suppressing the delamination and realizing an insulating layer having high stability of roughness and peel strength.

As a result of earnestly examining the above problems, the present inventors have mixed components of each resin composition layer in a region where the resin composition layers are in contact with each other when producing a resin sheet including a plurality of resin composition layers. The present inventors have found that the above-mentioned problems can be solved by newly providing a layer that has been completed, and have completed the present invention.

That is, the present invention includes the following contents.
[1] From a support, a first resin composition layer comprising a first resin composition provided on the support, and a second resin composition provided on the first resin composition layer A second resin composition layer, and the first resin composition and the second resin composition are mixed between the first resin composition layer and the second resin composition layer. A method for producing a resin sheet having a mixed layer,
A first resin varnish in which the first resin composition is dissolved is applied on the support, and a second resin varnish in which the second resin composition is dissolved is applied on the first resin varnish and dried. Including the steps of:
The viscosity of the first resin varnish is 100 mPa · s or more,
The manufacturing method of the resin sheet whose viscosity of a 2nd resin varnish is 100 mPa * s or more.
[2] The method includes the step of applying the first resin varnish on the support and simultaneously applying the second resin varnish on the first resin varnish and then drying, or
The resin according to [1], including a step of applying a first resin varnish on a support, preliminarily drying, then applying a second resin varnish on the first resin varnish, and then drying. Sheet manufacturing method.
[3] The residual solvent amount in the first resin varnish after the preliminary drying is 15% by mass to 70% by mass, where the total amount of nonvolatile components contained in the first resin varnish is 100% by mass. The manufacturing method of the resin sheet as described in [2].
[4] The method according to [1] or [2], which includes a step of applying the first resin varnish on the support and simultaneously applying the second resin varnish on the first resin varnish and then drying. Manufacturing method of resin sheet.
[5] The thickness of the first resin composition layer is 0.3 μm to 15 μm, the thickness of the second resin composition layer is 3 μm to 200 μm, and the thickness of the mixed layer is 0.4 μm or more. The method for producing a resin sheet according to any one of [1] to [4], which is not more than twice the thickness of the resin composition layer.
[6] The method for producing a resin sheet according to any one of [1] to [5], wherein the support is a support with a release layer.
[7] The minimum melt viscosity of the first resin composition layer is 3000 poise or more, and the minimum melt viscosity of the second resin composition layer is 10000 poise or less, according to any one of [1] to [6] Manufacturing method of resin sheet.
[8] The viscosity of the first resin varnish is 100 mPa · s to 3000 mPa · s, and the viscosity of the second resin varnish is 100 mPa · s to 6000 mPa · s. The manufacturing method of the resin sheet of description.
[9] The method for producing a resin sheet according to any one of [1] to [8], wherein the first resin varnish and the second resin varnish are applied on the same coating line.
[10] A method for producing a printed wiring board, wherein the resin sheet produced by the method according to any one of [1] to [9] is laminated on an inner substrate and thermally cured, and then the support is removed.
[11] From a support, a first resin composition layer comprising a first resin composition provided on the support, and a second resin composition provided on the first resin composition layer A second resin composition layer, and the first resin composition and the second resin composition are mixed between the first resin composition layer and the second resin composition layer. A resin sheet having a mixed layer having a thickness of 0.4 μm or more.
[12] The thickness of the first resin composition layer is 0.3 μm to 15 μm, the thickness of the second resin composition layer is 3 μm to 200 μm, and the thickness of the mixed layer is 0.4 μm or more. The resin sheet according to [11], which is not more than twice the thickness of the resin composition layer.
[13] The resin sheet according to [11] or [12], wherein the first resin composition layer has a minimum melt viscosity of 3000 poise or more.
[14] The resin sheet according to any one of [11] to [13], wherein the second resin composition layer has a minimum melt viscosity of 10,000 poise or less.
[15] A printed wiring board including an insulating layer formed using the resin sheet according to any one of [11] to [14].
[16] A semiconductor device including the printed wiring board according to [15].

According to the present invention, it is possible to provide a method for producing a resin sheet that can suppress delamination and realize an insulating layer having high stability of roughness and peel strength.

FIG. 1 is a schematic cross-sectional view showing an example of the resin sheet of the present invention. FIG. 2 is a schematic view showing an example of a method for producing a resin sheet of the present invention. FIG. 3 is a schematic view showing another example of the method for producing a resin sheet of the present invention.

Hereinafter, the present invention will be described in detail.
[Resin sheet]
The resin sheet of the present invention comprises a support, a first resin composition layer comprising the first resin composition provided on the support, and a second resin provided on the first resin composition layer. A second resin composition layer made of a resin composition, and the first resin composition and the second resin composition between the first resin composition layer and the second resin composition layer. And a thickness of the mixed layer is 0.4 μm or more.

As described above, in an insulating layer formed using a resin sheet including a plurality of resin composition layers, delamination may occur when exposed to a high temperature environment such as during reflow. The present inventors have found that. When an insulating layer is formed using a resin sheet including a plurality of resin composition layers, a plurality of cured product layers derived from each resin composition layer are formed in the obtained insulating layer. These cured product layers may exhibit different expansion rates under a high temperature environment due to the difference in composition. In such a case, since stress concentrates between the layers, it is assumed that delamination is likely to occur. In this regard, the resin sheet of the present invention has a mixed layer in which the respective resin compositions forming the first and second resin composition layers are mixed between the first and second resin composition layers. In the insulating layer formed using the resin sheet of the present invention, the first cured product layer derived from the first resin composition layer and the second cured product derived from the second resin composition layer A cured product layer derived from the mixed layer is formed between the layers. The cured product layer derived from the mixed layer relieves stress concentration caused by the difference in expansion coefficient between the first cured product layer and the second cured product layer, and therefore delamination in a high-temperature environment such as during reflow. Can be suppressed. Even when the insulating layer is formed using a conventional resin sheet including a plurality of resin composition layers, a stress relaxation layer may be formed depending on the composition of each resin composition layer and thermosetting conditions. . However, the thickness of the formed stress relaxation layer is not sufficient to solve the problem of delamination in a high temperature environment. On the other hand, by using the resin sheet of the present invention having a mixed layer of a predetermined thickness, an insulating layer in which delamination is suppressed can be easily performed regardless of the composition of each resin composition layer and thermosetting conditions. It is feasible.

FIG. 1 is a schematic cross-sectional view showing an example of the resin sheet of the present invention. In the resin sheet 1 shown in FIG. 1, the support body 11, the 1st resin composition layer 12, the mixed layer 13, and the 2nd resin composition layer 14 are laminated | stacked in order.
Hereinafter, each layer which comprises the resin sheet of this invention is demonstrated in detail.

<Support>
The resin sheet of the present invention has a support. Examples of the support in the present invention include a film made of a plastic material, a metal foil, and a release paper, and a film made of a plastic material and a metal foil are preferable.

When a film made of a plastic material is used as the support, examples of the plastic material include polyethylene terephthalate (hereinafter sometimes abbreviated as “PET”) and polyethylene naphthalate (hereinafter abbreviated as “PEN”). .) Polyester, polycarbonate (hereinafter sometimes abbreviated as “PC”), polymethyl methacrylate (PMMA) and other acrylics, cyclic polyolefin, triacetyl cellulose (TAC), polyether sulfide (PES), polyether Examples include ketones and polyimides. Among these, polyethylene terephthalate and polyethylene naphthalate are preferable, and inexpensive polyethylene terephthalate is particularly preferable.

When a metal foil is used as the support, examples of the metal foil include a copper foil and an aluminum foil, and a copper foil is preferable. As the copper foil, a foil made of a single metal of copper may be used, and a foil made of an alloy of copper and another metal (for example, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.). It may be used.

The support may be subjected to mat treatment or corona treatment on the surface to be bonded to the first resin composition layer.

Further, as the support, a support with a release layer having a release layer on the surface to be bonded to the first resin composition layer may be used. Examples of the release agent used for the release layer of the support with a release layer include one or more release agents selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins. . As the support with a release layer, a commercially available product may be used. For example, “SK-1” manufactured by Lintec Corporation, which is a PET film having a release layer mainly composed of an alkyd resin release agent. , “AL-5”, “AL-7”, “Lumirror T6AM” manufactured by Toray Industries, Inc., and the like.

The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, and more preferably in the range of 10 μm to 60 μm. In addition, when using a support body with a release layer, it is preferable that the thickness of the whole support body with a release layer is the said range.

<First resin composition layer>
The resin sheet of the present invention has a first resin composition layer made of the first resin composition. The first resin composition layer is bonded to the support, and when the printed wiring board is manufactured, a region in the vicinity of the surface of the insulating layer on which the conductor layer is provided is formed. The first resin composition is not particularly limited as long as the cured product has sufficient hardness and insulation. As such a resin composition, the composition containing curable resin and its hardening | curing agent is mentioned, for example. As curable resin, the conventionally well-known curable resin used when forming the insulating layer of a printed wiring board can be used, and an epoxy resin is especially preferable. Accordingly, in one embodiment, the first resin composition includes (a) an epoxy resin and (b) a curing agent. If necessary, the first resin composition may further contain (c) an inorganic filler, (d) a thermoplastic resin, (e) a curing accelerator, (f) a flame retardant, and (g) an organic filler. An agent may be included.

Hereinafter, an epoxy resin, a curing agent, and an additive that can be used as the material of the first resin composition will be described.

-(A) Epoxy resin-
Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol novolak type epoxy resin, Phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, glycidyl amine type epoxy resin, glycidyl ester type epoxy resin, cresol novolac type epoxy resin, biphenyl type Epoxy resin, linear aliphatic epoxy resin, epoxy resin having butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spiro ring-containing ester Carboxymethyl resins, cyclohexanedimethanol type epoxy resins, naphthylene ether type epoxy resins and trimethylol type epoxy resins. An epoxy resin may be used individually by 1 type, or may use 2 or more types together.

The epoxy resin preferably contains an epoxy resin having two or more epoxy groups in one molecule. When the nonvolatile component of the epoxy resin is 100% by mass, at least 50% by mass or more is preferably an epoxy resin having two or more epoxy groups in one molecule. Among them, it is preferable to contain an epoxy group having two or more (preferably three or more) epoxy groups in one molecule and a solid epoxy resin (hereinafter referred to as “solid epoxy resin”) at a temperature of 20 ° C. The epoxy resin may also contain an epoxy resin having two or more epoxy groups in one molecule and liquid at 20 ° C. (hereinafter referred to as “liquid epoxy resin”). In the first resin composition, the content of the solid epoxy resin in the epoxy resin is preferably 30% by mass or more, more preferably 40% by mass or more, when the nonvolatile component of the entire epoxy resin is 100% by mass. More preferably, they are 50 mass% or more, 60 mass% or more, 70 mass% or more, 80 mass% or more, or 90 mass% or more. The upper limit of the content of the solid epoxy resin is not particularly limited, and may be 100% by mass.

Liquid epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, cycloaliphatic epoxy resin having ester skeleton, cyclohexanedimethanol type Epoxy resin, glycidylamine type epoxy resin, epoxy resin having butadiene structure, phenol novolac type epoxy resin, and naphthalene type epoxy resin are preferable, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, and naphthalene Type epoxy resin is more preferable, and bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol AF type epoxy resin are more preferable. Arbitrariness. Specific examples of the liquid epoxy resin include “HP4032”, “HP4032D”, “HP4032SS” (naphthalene type epoxy resin) manufactured by DIC Corporation, and “jER828EL” (bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Corporation. "JER807" (bisphenol F type epoxy resin), "YL7223", "YL7723" (bisphenol AF type epoxy resin), "jER152" (phenol novolac type epoxy resin), "ZX1059" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. ( Bisphenol A type epoxy resin and bisphenol F type epoxy resin), “EX-721” (glycidyl ester type epoxy resin) manufactured by Nagase ChemteX Corporation. These may be used individually by 1 type, or may use 2 or more types together.

Solid epoxy resins include naphthalene type tetrafunctional epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol type epoxy resin, biphenyl type epoxy resin, naphthol novolak type epoxy resin, biphenyl. Type epoxy resin, naphthylene ether type epoxy resin, anthracene type epoxy resin, bisphenol A type epoxy resin, and tetraphenylethane type epoxy resin are preferable, naphthalene type tetrafunctional epoxy resin, biphenyl type epoxy resin, or naphthylene ether type epoxy Resins are more preferable, and naphthalene type tetrafunctional epoxy resins and biphenyl type epoxy resins are more preferable. Specific examples of the solid epoxy resin include “HP-4700”, “HP-4710” (naphthalene type tetrafunctional epoxy resin), “N-690” (cresol novolac type epoxy resin) manufactured by DIC Corporation, “ N-695 ”(cresol novolac type epoxy resin),“ HP-7200 ”(dicyclopentadiene type epoxy resin),“ EXA7311 ”,“ EXA7311-G3 ”,“ EXA7311-G4 ”,“ EXA7311-G4S ”,“ HP6000 ” ”(Naphthylene ether type epoxy resin),“ EPPN-502H ”(trisphenol epoxy resin) manufactured by Nippon Kayaku Co., Ltd.,“ NC7000L ”(naphthol novolac epoxy resin),“ NC3000H ”,“ NC3000 ”,“ NC3000L ” ”,“ NC3100 ”(biphenyl type XES resin), “ESN475V” (naphthol novolac type epoxy resin) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., “ESN485V” (naphthol novolac type epoxy resin), “YX4000H”, “YL6121” (biphenyl) manufactured by Mitsubishi Chemical Corporation Type epoxy resin), “YX4000HK” (bixylenol type epoxy resin), “PG-100”, “CG-500” manufactured by Osaka Gas Chemical Co., Ltd., “YL7800” (fluorene type epoxy manufactured by Mitsubishi Chemical Co., Ltd.) Resin), “YL7760” (bisphenol AF type epoxy resin), and the like.

The content of the epoxy resin in the first resin composition is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 20% by mass or more or 30% by mass or more. Although the upper limit of content of an epoxy resin is not specifically limited, Preferably it is 50 mass% or less, More preferably, it is 45 mass% or less, More preferably, it is 40 mass% or less.
In addition, in this invention, content of each component which comprises a resin composition is a value when the sum total of the non-volatile component in a resin composition is 100 mass% unless there is separate description.

The epoxy equivalent of the epoxy resin is preferably 50 to 3000, more preferably 80 to 2000, and still more preferably 110 to 1000. By becoming this range, the crosslinked density of hardened | cured material becomes sufficient and it can bring about an insulating layer with small surface roughness. The epoxy equivalent can be measured according to JIS K7236, and is the mass of a resin containing 1 equivalent of an epoxy group.

The weight average molecular weight of the epoxy resin is preferably 100 to 5000, more preferably 250 to 3000, and still more preferably 400 to 1500. Here, the weight average molecular weight of the epoxy resin is a weight average molecular weight in terms of polystyrene measured by a gel permeation chromatography (GPC) method.

-(B) Curing agent-
The curing agent is not particularly limited as long as it has a function of curing the epoxy resin. For example, a phenolic curing agent, a naphthol curing agent, an active ester curing agent, a benzoxazine curing agent, a cyanate ester curing agent, and Examples thereof include carbodiimide curing agents. A hardening | curing agent may be used individually by 1 type, or may use 2 or more types together.

As the phenol-based curing agent and the naphthol-based curing agent, a phenol-based curing agent having a novolak structure or a naphthol-based curing agent having a novolak structure is preferable from the viewpoint of heat resistance and water resistance. Moreover, from a viewpoint of adhesiveness with a conductor layer, a nitrogen-containing phenol type hardening | curing agent is preferable and a triazine frame | skeleton containing phenol type hardening | curing agent is more preferable. Among these, a triazine skeleton-containing phenol novolac curing agent is preferable from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion to the conductor layer (peel strength).

Specific examples of the phenol-based curing agent and the naphthol-based curing agent include, for example, “MEH-7700”, “MEH-7810”, “MEH-7785” manufactured by Meiwa Kasei Co., Ltd., and Nippon Kayaku Co., Ltd. “NHN”, “CBN”, “GPH”, “SN170”, “SN180”, “SN190”, “SN475”, “SN485”, “SN495”, “SN375”, “SN395” manufactured by Nippon Steel & Sumikin Co., Ltd. And “LA-7052,” “LA-7054,” “LA-3018,” “EXB-9500” manufactured by DIC Corporation.
Specific examples of the triazine skeleton-containing phenol novolak curing agent include “LA-3018-50P” and the like.

From the viewpoint of obtaining an insulating layer having a small surface roughness after the roughening treatment, an active ester curing agent is also preferable. The active ester curing agent is not particularly limited, but generally one molecule of ester group having high reaction activity, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and heterocyclic hydroxy compound esters. A compound having two or more thereof is preferably used. The active ester curing agent is preferably obtained by a condensation reaction between a carboxylic acid compound and / or a thiocarboxylic acid compound and a hydroxy compound and / or a thiol compound. In particular, from the viewpoint of improving heat resistance, an active ester curing agent obtained from a carboxylic acid compound and a hydroxy compound is preferable, and an active ester curing agent obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound is more preferable. Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of the phenol compound or naphthol compound include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol S, phenolphthaline, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m- Cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, Benzenetriol, dicyclopentadiene type diphenol compound, phenol novolac and the like can be mentioned. Here, the “dicyclopentadiene type diphenol compound” refers to a diphenol compound obtained by condensing two molecules of phenol with one molecule of dicyclopentadiene.

Specifically, an active ester compound containing a dicyclopentadiene-type diphenol structure, an active ester compound containing a naphthalene structure, an active ester compound containing an acetylated product of a phenol novolac, and an active ester compound containing a benzoylated product of a phenol novolac are preferred, Of these, active ester compounds having a naphthalene structure and active ester compounds having a dicyclopentadiene type diphenol structure are more preferred. The “dicyclopentadiene type diphenol structure” represents a divalent structural unit composed of phenylene-dicyclopentylene-phenylene.

Commercially available active ester curing agents include “EXB9451”, “EXB9460”, “EXB9460S”, “HPC-8000-65T” (made by DIC Corporation) as active ester compounds containing a dicyclopentadiene type diphenol structure. ), “EXB9416-70BK” (manufactured by DIC Corporation) as an active ester compound containing a naphthalene structure, “DC808” (manufactured by Mitsubishi Chemical Corporation) as an active ester compound containing an acetylated product of phenol novolac, and benzoyl of phenol novolac Examples of the active ester compound containing a compound include “YLH1026” (manufactured by Mitsubishi Chemical Corporation).

Specific examples of the benzoxazine-based curing agent include “HFB2006M” manufactured by Showa Polymer Co., Ltd. and “Pd” and “Fa” manufactured by Shikoku Kasei Kogyo Co., Ltd.

Examples of the cyanate ester curing agent include bisphenol A dicyanate, polyphenol cyanate, oligo (3-methylene-1,5-phenylene cyanate), 4,4′-methylenebis (2,6-dimethylphenyl cyanate), 4,4 '-Ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis (4-cyanate) phenylpropane, 1,1-bis (4-cyanatephenylmethane), bis (4-cyanate-3,5-dimethyl) Bifunctional cyanate resins such as phenyl) methane, 1,3-bis (4-cyanatephenyl-1- (methylethylidene)) benzene, bis (4-cyanatephenyl) thioether, and bis (4-cyanatephenyl) ether, phenol Novolac and Polyfunctional cyanate resin derived from resol novolac, these cyanate resins and partially triazine of prepolymer. Specific examples of the cyanate ester curing agent include “PT30” and “PT60” (both phenol novolak polyfunctional cyanate ester resins) and “BA230” (part or all of bisphenol A dicyanate) manufactured by Lonza Japan Co., Ltd. And the like, and the like, and the like.

Specific examples of the carbodiimide curing agent include “V-03” and “V-07” manufactured by Nisshinbo Chemical Co., Ltd.

The amount ratio of the epoxy resin and the curing agent is preferably a ratio of [total number of epoxy groups of the epoxy resin]: [total number of reactive groups of the curing agent] in the range of 1: 0.2 to 1: 2. The ratio is more preferably 1: 0.3 to 1: 1.5, and further preferably 1: 0.4 to 1: 1.2. Here, the reactive group of the curing agent is an active hydroxyl group, an active ester group or the like, and varies depending on the type of the curing agent. Moreover, the total number of epoxy groups of the epoxy resin is a value obtained by dividing the value obtained by dividing the solid mass of each epoxy resin by the epoxy equivalent for all epoxy resins, and the total number of reactive groups of the curing agent is: The value obtained by dividing the solid mass of each curing agent by the reactive group equivalent is the total value for all curing agents. By setting the amount ratio of the epoxy resin and the curing agent in such a range, the heat resistance of the cured product of the resin composition is further improved.

In one embodiment, the first resin composition includes the above-described (a) epoxy resin and (b) a curing agent. The first resin composition is (a) an epoxy resin containing a solid epoxy resin as an epoxy resin (the content of the solid epoxy resin in the epoxy resin is preferably 30% by mass or more, more preferably 40% by mass or more, More preferably 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more) (b) a phenol-based curing agent, a naphthol-based curing agent, an active ester type as a curing agent One or more selected from the group consisting of curing agents and cyanate ester curing agents (preferably one or more selected from the group consisting of phenolic curing agents, naphthol curing agents and active ester curing agents), respectively It is preferable to include.

The content of the curing agent in the first resin composition is not particularly limited, but is preferably 30% by mass or less, more preferably 25% by mass or less, still more preferably 20% by mass or less, and even more preferably 15% by mass or less. It is. The lower limit is not particularly limited but is preferably 3% by mass or more.

-(C) Inorganic filler-
The first resin composition may further contain an inorganic filler. The material of the inorganic filler is not particularly limited. For example, silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, water Aluminum oxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide , Zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica such as amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica is particularly suitable. Moreover, spherical silica is preferable as the silica. An inorganic filler may be used individually by 1 type, and may be used in combination of 2 or more type.

The average particle diameter of the inorganic filler used in the first resin composition is not particularly limited, but is preferably 600 nm or less, more preferably 300 nm or less, and even more preferably 200 nm, from the viewpoint of obtaining an insulating layer having a small surface roughness. Hereinafter, it is 150 nm or less, 100 nm or less, 90 nm or less, 80 nm or less, 70 nm or less, 60 nm or less, or 50 nm or less. Although the minimum of this average particle diameter is not specifically limited, Usually, it is 5 nm or more. Examples of commercially available inorganic fillers having such an average particle diameter include “YC100C”, “YA050C”, “YA050C-MJE”, “YA010C” manufactured by Admatechs Co., Ltd., “UFP-” manufactured by Denki Kagaku Kogyo. 30 ”,“ Sylfil NSS-3N ”,“ Silfil NSS-4N ”, and“ Sylfil NSS-5N ”manufactured by Tokuyama.
The average particle diameter of the inorganic filler can be measured by a laser diffraction / scattering method based on Mie scattering theory. Specifically, the particle size distribution of the inorganic filler can be prepared on a volume basis by a laser diffraction / scattering particle size distribution measuring apparatus, and the median diameter can be measured as the average particle diameter. As the measurement sample, an inorganic filler dispersed in water by ultrasonic waves can be preferably used. As a laser diffraction / scattering particle size distribution measuring apparatus, “LA-500” manufactured by Horiba, Ltd. or the like can be used.

Inorganic fillers are aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, silane coupling agents, organosilazane compounds, titanate coupling agents from the viewpoint of improving moisture resistance and dispersibility. It is preferable that it is processed with 1 or more types of surface treating agents. Examples of commercially available surface treatment agents include “KBM403” (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. and “KBM803” (3-mercaptopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. Silane), Shin-Etsu Chemical "KBE903" (3-aminopropyltriethoxysilane), Shin-Etsu Chemical "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical “SZ-31” (Hexamethyldisilazane) manufactured by Co., Ltd., “KBM103” (phenyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., and the like.

The degree of surface treatment with the surface treatment agent can be evaluated by the amount of carbon per unit surface area of the inorganic filler. Carbon content per unit surface area of the inorganic filler, from the viewpoint of improving dispersibility of the inorganic filler is preferably 0.02 mg / ^{m 2} or more, 0.1 mg / ^{m 2} or more preferably, 0.2 mg / ^{m 2} The above is more preferable. On the other hand, 1 mg / m ² or less is preferable, 0.8 mg / m ² or less is more preferable, and 0.5 mg / m ² or less is more preferable from the viewpoint of preventing an increase in the melt viscosity of the resin varnish or the sheet form. preferable.

The amount of carbon per unit surface area of the inorganic filler can be measured after the surface-treated inorganic filler is washed with a solvent (for example, methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler surface-treated with the surface treatment agent and ultrasonically cleaned at 25 ° C. for 5 minutes. After removing the supernatant and drying the solid, the carbon amount per unit surface area of the inorganic filler can be measured using a carbon analyzer. As the carbon analyzer, “EMIA-320V” manufactured by Horiba, Ltd. can be used.

The content of the inorganic filler in the first resin composition is not particularly limited, but is preferably 60% by mass or less, more preferably 55% by mass or less, still more preferably 50% by mass or less, and even more preferably 48% by mass. Hereinafter, it is 46 mass% or less, 44 mass% or less, 42 mass% or less, or 40 mass% or less. The lower limit of the content of the inorganic filler in the first resin composition is not particularly limited, and may be 0% by mass.

-(D) Thermoplastic resin-
The first resin composition may further contain a thermoplastic resin. Examples of the thermoplastic resin include phenoxy resin, polyvinyl acetal resin, acrylic resin, polyolefin resin, polybutadiene resin, polyimide resin, polyamideimide resin, polyethersulfone resin, polyetherimide resin, polycarbonate resin, polyetheretherketone resin, Examples include polyester resins, polyphenylene ether resins, and polysulfone resins. A thermoplastic resin may be used individually by 1 type, or may use 2 or more types together.

The weight average molecular weight in terms of polystyrene of the thermoplastic resin is preferably in the range of 8,000 to 70,000, more preferably in the range of 10,000 to 60,000, and still more preferably in the range of 20,000 to 60,000. The weight average molecular weight in terms of polystyrene of the thermoplastic resin is measured by a gel permeation chromatography (GPC) method. Specifically, the polystyrene-converted weight average molecular weight of the thermoplastic resin is LC-9A / RID-6A manufactured by Shimadzu Corporation as a measuring device, and Shodex K-800P / K- manufactured by Showa Denko KK as a column. 804L / K-804L can be measured using chloroform or the like as a mobile phase at a column temperature of 40 ° C. and calculated using a standard polystyrene calibration curve.

Examples of the phenoxy resin include bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenolacetophenone skeleton, novolac skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene Examples thereof include phenoxy resins having a skeleton and one or more skeletons selected from the group consisting of a trimethylcyclohexane skeleton. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. A phenoxy resin may be used individually by 1 type, or may use 2 or more types together. Specific examples of the phenoxy resin include “1256” and “4250” (both bisphenol A skeleton-containing phenoxy resin), “YX8100” (bisphenol S skeleton-containing phenoxy resin), and “YX6954” (manufactured by Mitsubishi Chemical Corporation). In addition, “FX280” and “FX293” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., “YX7553BH30”, “YL7769BH30”, “YL6794” manufactured by Mitsubishi Chemical Corporation, "YL7213", "YL7290", "YL7482", etc. are mentioned.

The acrylic resin is preferably a functional group-containing acrylic resin, more preferably an epoxy group-containing acrylic resin, and still more preferably an epoxy group-containing acrylic ester copolymer resin. When a functional group-containing acrylic resin is used as the acrylic resin, the functional group equivalent is preferably 1000 to 50000, more preferably 2500 to 30000.

Specific examples of the acrylic resin include “SG-80H” and “SG-P3” (epoxy group-containing acrylic ester copolymer resin) manufactured by Nagase ChemteX Corporation.

Examples of the polyvinyl acetal resin include polyvinyl formal resin and polyvinyl butyral resin, and polyvinyl butyral resin is preferable. Specific examples of the polyvinyl acetal resin include electrified butyral 4000-2, 5000-A, 6000-C, and 6000-EP manufactured by Denki Kagaku Kogyo Co., Ltd., and the ESREC BH series and BX series manufactured by Sekisui Chemical Co., Ltd. Examples include the KS series (specifically “KS-1”, etc.), the BL series, the BM series, and the like.

Specific examples of polyimide resins include “Rika Coat SN20” and “Rika Coat PN20” manufactured by Shin Nippon Rika Co., Ltd. Specific examples of the polyimide resin include linear polyimide obtained by reacting a bifunctional hydroxyl group-terminated polybutadiene, a diisocyanate compound and a tetrabasic acid anhydride (Japanese Patent Laid-Open No. 2006-37083), a polysiloxane skeleton-containing polyimide. Examples thereof include modified polyimides such as JP-A Nos. 2002-12667 and 2000-319386.

Specific examples of the polyamide-imide resin include “Bilomax HR11NN” and “Bilomax HR16NN” manufactured by Toyobo Co., Ltd. Specific examples of the polyamideimide resin also include modified polyamideimides such as polysiloxane skeleton-containing polyamideimides “KS9100” and “KS9300” manufactured by Hitachi Chemical Co., Ltd.

Specific examples of the polyethersulfone resin include “PES5003P” manufactured by Sumitomo Chemical Co., Ltd.

Specific examples of the polysulfone resin include polysulfone “P1700” and “P3500” manufactured by Solvay Advanced Polymers Co., Ltd.

The content of the thermoplastic resin in the first resin composition is not particularly limited, but is preferably 0.1% by mass or more, more preferably 1% by mass or more, further preferably 3% by mass or more, 5% by mass or more or 7% by mass or more. Although the upper limit of content of a thermoplastic resin is not specifically limited, Preferably it is 30 mass% or less, More preferably, it is 20 mass% or less, More preferably, it is 10 mass% or less.

-(E) Curing accelerator-
The first resin composition may further contain a curing accelerator. Examples of the curing accelerator include a phosphorus-based curing accelerator, an amine-based curing accelerator, an imidazole-based curing accelerator, a guanidine-based curing accelerator, a metal-based curing accelerator, and the like. A curing accelerator and an imidazole curing accelerator are preferable, and an amine curing accelerator and an imidazole curing accelerator are more preferable. A hardening accelerator may be used individually by 1 type, and may be used in combination of 2 or more type.

Examples of phosphorus curing accelerators include triphenylphosphine, phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, and (4-methylphenyl) triphenylphosphonium thiocyanate. , Tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate and the like, and triphenylphosphine and tetrabutylphosphonium decanoate are preferable.

Examples of amine curing accelerators include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6, -tris (dimethylaminomethyl) phenol, 1,8-diazabicyclo. (5,4,0) -undecene and the like, and 4-dimethylaminopyridine and 1,8-diazabicyclo (5,4,0) -undecene are preferable.

Examples of the imidazole curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl- 2 Phenylimidazolium trimellitate, 2,4-diamino-6- [2'-methylimidazolyl- (1 ')]-ethyl-s-triazine, 2,4-diamino-6- [2'-undecylimidazolyl- (1 ′)]-Ethyl-s-triazine, 2,4-diamino-6- [2′-ethyl-4′-methylimidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino- 6- [2′-Methylimidazolyl- (1 ′)]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl- 4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo [1,2-a] benzimidazole, 1-dodecyl-2-methyl-3-ben Examples thereof include imidazole compounds such as loumidazolium chloride, 2-methylimidazoline, 2-phenylimidazoline, and adducts of imidazole compounds and epoxy resins, and 2-ethyl-4-methylimidazole and 1-benzyl-2-phenylimidazole are preferable.
Commercially available products may be used as the imidazole curing accelerator, and examples thereof include “P200-H50” manufactured by Mitsubishi Chemical Corporation.

Examples of the guanidine curing accelerator include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1- (o-tolyl) guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, Tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo [4.4.0] dec-5-ene, 7-methyl-1,5,7-triazabicyclo [4.4.0] Deca-5-ene, 1-methyl biguanide, 1-ethyl biguanide, 1-n-butyl biguanide, 1-n-octadecyl biguanide, 1,1-dimethyl biguanide, 1,1-diethyl biguanide, 1-cyclohexyl biguanide, 1 -Allyl biguanide, 1-phenyl biguanide, 1- ( - tolyl) biguanide, and the like, dicyandiamide, 1,5,7-triazabicyclo [4.4.0] dec-5-ene are preferred.
Moreover, as a metal type hardening accelerator, the organometallic complex or organometallic salt of metals, such as cobalt, copper, zinc, iron, nickel, manganese, tin, is mentioned, for example. Specific examples of the organometallic complex include organic cobalt complexes such as cobalt (II) acetylacetonate and cobalt (III) acetylacetonate, organic copper complexes such as copper (II) acetylacetonate, and zinc (II) acetylacetonate. Organic zinc complexes such as iron (III) acetylacetonate, organic nickel complexes such as nickel (II) acetylacetonate, and organic manganese complexes such as manganese (II) acetylacetonate. Examples of the organic metal salt include zinc octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

The content of the curing accelerator in the first resin composition is not particularly limited, but in the range of 0.05% by mass to 3% by mass when the total amount of the nonvolatile components of the epoxy resin and the curing agent is 100% by mass. It is preferable to use it.

-(F) Flame retardant-
The first resin composition may further contain a flame retardant. Examples of the flame retardant include an organic phosphorus flame retardant, an organic nitrogen-containing phosphorus compound, a nitrogen compound, a silicone flame retardant, and a metal hydroxide. A flame retardant may be used individually by 1 type, or may use 2 or more types together.
Commercially available products may be used as the flame retardant, and examples thereof include “HCA-HQ” manufactured by Sanko Co., Ltd.
The content of the flame retardant in the first resin composition layer is not particularly limited, but is preferably 0.5% by mass to 20% by mass, more preferably 1% by mass to 15% by mass, and still more preferably 1.5% by mass. % To 10% by mass is more preferable.

-(G) Organic filler-
The first resin composition may further contain an organic filler. As the organic filler, any organic filler that can be used for forming an insulating layer of a printed wiring board may be used. Examples thereof include rubber particles, polyamide fine particles, and silicone particles, and rubber particles are preferable. A commercially available product may be used as the rubber particles, and examples thereof include “AC3816N” manufactured by Aika Industry Co., Ltd.
The content of the organic filler in the first resin composition is preferably 1% by mass to 20% by mass, more preferably 2% by mass to 10% by mass.

-Other ingredients-
The first resin composition may contain other additives as necessary. Examples of such other additives include organic metals such as organic copper compounds, organic zinc compounds, and organic cobalt compounds. Examples include compounds and resin additives such as organic fillers, thickeners, antifoaming agents, leveling agents, adhesion-imparting agents, and coloring agents.

The thickness of the first resin composition layer is preferably 0.3 μm to 15 μm from the viewpoint of obtaining an insulating layer having high stability of roughness and peel strength. The lower limit of the thickness of the first resin composition layer is more preferably 0.5 μm or more, further preferably 1 μm or more, 1.5 μm or more, 2 μm or more, 2.5 μm or more, or 3 μm or more. In particular, when the thickness of the first resin composition layer is 1 μm or more, the stability of roughness and peel strength can be further improved. The upper limit of the thickness of the first resin composition layer is more preferably 12 μm or less, still more preferably 10 μm or less, 9 μm or less, or 8 μm or less. In addition, it is preferable that the thickness of the 1st resin composition layer is thinner than the thickness of the 2nd resin composition layer.
The thickness of the first resin composition layer can be measured according to the procedure described later (measurement of the thickness of each layer of the resin sheet).

The minimum melt viscosity of the first resin composition layer is 3000 poise from the viewpoint that it is easy to maintain the desired thickness when laminated on the inner layer substrate, and that an insulating layer having high stability of roughness and peel strength can be achieved. (300 Pa · s) or more is preferable, 5000 poise (500 Pa · s) or more is more preferable, and 10,000 poise (1000 Pa · s) or more is more preferable. In particular, when the minimum melt viscosity is 5000 poise or more, an insulating layer exhibiting particularly good reflow resistance can be obtained. The upper limit of the minimum melt viscosity of the first resin composition layer is not particularly limited, but is preferably 100000 poise (10000 Pa · s) or less, more preferably 80000 poise (8000 Pa · s) or less, and 50000 poise (5000 Pa · s) or less. Further preferred.

The minimum melt viscosity of the first resin composition layer refers to the minimum viscosity exhibited by the resin composition layer when the resin of the first resin composition layer is melted. Specifically, when the first resin composition layer is heated at a constant rate of temperature to melt the resin, the initial stage of the melt viscosity decreases as the temperature rises, and then melts as the temperature increases beyond a certain level. Viscosity increases. The minimum melt viscosity refers to the melt viscosity at such a minimum point. The minimum melt viscosity of the first resin composition layer is, for example, a dynamic viscoelasticity measuring apparatus (“Rheosol-G3000” manufactured by UBM Co., Ltd.). The temperature is increased from a starting temperature of 60 ° C. to 200 ° C. at a rate of temperature increase of 5 ° C./min, and measured under measurement conditions of a measurement temperature interval of 2.5 ° C., a frequency of 1 Hz, and a strain of 1 deg. be able to. The definition and measurement method of the minimum melt viscosity of the second resin composition layer are the same.

<Second resin composition layer>
The resin sheet of the present invention has a second resin composition layer made of the second resin composition. The second resin composition layer affects the bulk properties of the resulting insulating layer.

From the viewpoint of reducing the thermal expansion coefficient of the obtained insulating layer and preventing the occurrence of cracks and circuit distortion due to the difference in thermal expansion between the insulating layer and the conductor layer, the second resin composition contains an inorganic filler. It is preferable. The content of the inorganic filler in the second resin composition is preferably 50% by mass or more, more preferably 55% by mass or more, and further preferably 60% by mass from the viewpoint of reducing the thermal expansion coefficient of the obtained insulating layer. % Or more, 62 mass% or more, 64 mass% or more, 66 mass% or more, 68 mass% or more, or 70 mass% or more. The upper limit of the content of the inorganic filler in the second resin composition is preferably 96% by mass or less, more preferably 95% by mass or less, and still more preferably 90% by mass from the viewpoint of mechanical strength of the obtained insulating layer. Or 85% by mass or less.

In a preferred embodiment, the content of the inorganic filler in the second resin composition is higher than the content of the inorganic filler in the first resin composition. When the content of the inorganic filler in the first resin composition is A1 (mass%) and the content of the inorganic filler in the second resin composition is A2 (mass%), the difference between A1 and A2 ( A2-A1) is preferably 10% by mass or more, more preferably 15% by mass or more, still more preferably 20% by mass or more, 25% by mass or more, or 30% by mass or more. The upper limit of the difference (A2−A1) is not particularly limited, but can usually be 90% by mass or less, 80% by mass or less. Regarding the conventional resin sheet, the present inventors have found that when the difference (A2-A1) is increased, delamination tends to occur in the insulating layer when exposed to a high temperature environment such as during reflow. In contrast, an insulating layer formed using the resin sheet of the present invention having a mixed layer can suppress delamination even when the difference (A2-A1) is large. Therefore, in the present invention, the degree of freedom in designing the composition of each layer is high, and the desired function can be advantageously imparted to each layer. In addition, when A1 and A2 are different from each other in this way, it becomes easier to grasp the mixed layer described later.

Examples of the inorganic filler include, for example, the inorganic filler described for the first resin composition. Among them, silica is preferable, and spherical silica is more preferable. The average particle diameter of the inorganic filler contained in the second resin composition is in the range of 0.01 μm to 5 μm from the viewpoint of improving the fluidity of the second resin composition layer and realizing sufficient circuit embedding properties. The range of 0.05 μm to 2 μm is more preferable, the range of 0.1 μm to 1 μm is more preferable, and the range of 0.2 μm to 0.8 μm is even more preferable. Examples of commercially available inorganic fillers having such an average particle diameter include “SOC4”, “SOC2”, and “SOC1” manufactured by Admatechs Co., Ltd.

The inorganic filler contained in the second resin composition is preferably treated with a surface treatment agent. The kind of surface treating agent and the degree of surface treatment are as described in the section <First resin composition layer>.

Other materials included in the second resin composition include, for example, (a) a curable resin including an epoxy resin, and (b) a curing agent described in the section <First resin composition layer>. Is mentioned. Accordingly, in one embodiment, the second resin composition includes (a) an epoxy resin, (b) a curing agent, and (c) an inorganic filler. Suitable examples of each component are as described in the <First resin composition layer> column. Among them, the second resin composition includes (a) a liquid epoxy resin and a solid epoxy resin as an epoxy resin. (The mass ratio of liquid epoxy resin: solid epoxy resin is preferably in the range of 1: 0.1 to 1: 4, more preferably in the range of 1: 0.3 to 1: 3.5, and 1: 0. (B) a phenolic curing agent, a naphthol curing agent, an active ester type as a curing agent. One or more selected from the group consisting of curing agents and cyanate ester curing agents (preferably one or more selected from the group consisting of phenolic curing agents, naphthol curing agents and active ester curing agents), c) As an inorganic filler Preferably contains silica, respectively.

The content of the (a) epoxy resin in the second resin composition is not particularly limited, but is preferably 3% by mass to 50% by mass, more preferably 5% by mass to 45% by mass, and still more preferably 5% by mass to It is 40% by mass, and more preferably 7% by mass to 35% by mass.

The amount ratio of (a) epoxy resin and (b) curing agent in the second resin composition may be the same as that described in the section <First resin composition layer>.
Although content of (b) hardening | curing agent in 2nd resin composition is not specifically limited, Preferably it is 30 mass% or less, More preferably, it is 25 mass% or less, More preferably, it is 20 mass% or less, More preferably, it is 15 It is 10 mass% or less. The lower limit is not particularly limited but is preferably 3% by mass or more.

The second resin composition may further contain one or more components selected from the group consisting of (d) a thermoplastic resin, (e) a curing accelerator, (f) a flame retardant, and (g) an organic filler. Good. Suitable examples of these components (d) to (g) are as described in the section <First resin composition layer>.
The content of the thermoplastic resin (d) in the second resin composition is not particularly limited, but is preferably 0.1% by mass to 20% by mass, more preferably 0.5% by mass to 10% by mass.
The content of (e) the curing accelerator in the second resin composition is preferably 0.05% by mass when the total amount of nonvolatile components of (a) the epoxy resin and (b) the curing agent is 100% by mass. To 3% by mass.
The content of the flame retardant (f) in the second resin composition is not particularly limited, but is preferably 0.5% by mass to 10% by mass, more preferably 1% by mass to 9% by mass, and even more preferably 1%. .5 mass% to 8 mass%.
The content of the organic filler (g) in the second resin composition is not particularly limited, but is preferably 1% by mass to 10% by mass, more preferably 2% by mass to 5% by mass.

The second resin composition may contain other additives as necessary. Examples of such other additives include organic metals such as organic copper compounds, organic zinc compounds, and organic cobalt compounds. Examples include compounds and resin additives such as organic fillers, thickeners, antifoaming agents, leveling agents, adhesion-imparting agents, and coloring agents.

The thickness of the second resin composition layer is not particularly limited as long as an insulating layer having a desired thickness can be obtained, but is preferably 3 μm to 200 μm. The lower limit of the thickness of the second resin composition layer is more preferably 5 μm or more, further preferably 10 μm or more, or 15 μm or more. The upper limit of the thickness of the second resin composition layer is more preferably 180 μm or less, still more preferably 160 μm or less, 150 μm or less, 140 μm or less, 120 μm or less, or 100 μm or less.
The thickness of the second resin composition layer can be measured according to the procedure described later (measurement of the thickness of each layer of the resin sheet).

The minimum melt viscosity of the second resin composition layer is preferably 10,000 poise (1000 Pa · s) or less, more preferably 8000 poise (800 Pa · s) or less, and 5000 poise (500 Pa · s) from the viewpoint of obtaining good circuit embedding properties. The following is more preferable. The lower limit is not particularly limited, but is preferably 500 poise (50 Pa · s) or more, more preferably 800 poise (80 Pa · s) or more, and further preferably 1000 poise (100 Pa · s) or more.

<Mixed layer>
The resin sheet of the present invention has a mixed layer in which the first resin composition and the second resin composition are mixed between the first resin composition layer and the second resin composition layer.

The thickness of the mixed layer is 0.4 μm or more, preferably 0.5 μm or more, and more preferably 1.0 μm or more from the viewpoint of obtaining an insulating layer in which delamination is suppressed in a high temperature environment such as during reflow. Although there is no restriction | limiting in particular about the upper limit of the thickness of a mixed layer, 2 times or less of the thickness of a 1st resin composition layer is preferable. For example, when the thickness of the first resin composition layer is t (μm), the thickness of the mixed layer is preferably 2 t or less, more preferably 1.5 t or less, further preferably t or less, 0.9 t or less, 0 0.8 t or less, or 0.7 t or less. As long as the thickness of the mixed layer is 2 t or less, it is more preferably 10 μm or less, further preferably 5 μm or less, and particularly preferably 3 μm or less.
The thickness of the mixed layer can be measured according to the procedure described later (measurement of the thickness of each layer of the resin sheet). In addition, a mixed layer can be grasped | ascertained as an area | region which has a different composition from a 1st resin composition layer or a 2nd resin composition layer. For example, when the content A1 of the inorganic filler in the first resin composition layer and the content A2 of the inorganic filler in the second resin composition layer satisfy the relationship of A1 <A2, the cross section of the resin sheet In SEM observation, the mixed layer can be grasped as follows. That is, in the cross section of the resin sheet, the ratio of the inorganic filler / resin component is constant in the region where the distance from the bonding interface with the support is from 0 to t1, and the distance from the bonding interface with the support is from t1 to t2. In the region up to, the inorganic filler / resin component ratio gradually increases, and in the region where the distance from the bonding interface with the support is from t2 to t3, the inorganic filler / resin component ratio is constant. The position of the distance t3 from the bonding interface with the support is the surface position of the resin composition layer on the side opposite to the support. In such a case, the region where the distance from the bonding interface with the support is 0 to t1 is the first resin composition layer, the region where the distance is from t1 to t2 is the mixed layer, and the distance is t2 To t3 is the second resin composition layer. Alternatively, when the particle size of the inorganic filler in the first resin composition layer is different from the particle size of the inorganic filler in the second resin composition layer, the change in the particle size of the inorganic filler It is also possible to grasp the mixed layer from the point of view.

The resin sheet of the present invention may further include a protective film on the surface of the second resin composition layer. The protective film contributes to the prevention of adhesion and scratches of dust and the like on the surface of the second resin composition layer. As the material for the protective film, the same materials as described for the support may be used. The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. The resin sheet with a support can be used by peeling off the protective film when producing a printed wiring board.

The resin sheet of the present invention is used to form an insulating layer of a metal-clad laminate (for an insulating layer of a metal-clad laminate) and to form an insulating layer of a printed wiring board (for an insulating layer of a printed wiring board) can do. In particular, in the production of printed wiring boards by the build-up method, it can be suitably used for forming an insulating layer (for build-up insulating layers of printed wiring boards), and for forming a conductor layer by plating (by plating) It can be more suitably used for a build-up insulating layer of a printed wiring board for forming a conductor layer.

-Other embodiments-
In the present invention, in a resin sheet including a plurality of resin composition layers, a layer in which the components of each resin composition layer are mixed is provided in a region where the resin composition layers are in contact with each other. Thus, the present invention realizes an insulating layer in which delamination is suppressed in a high temperature environment. In the above, although embodiment containing two resin composition layers was described, you may obtain the resin sheet containing a multilayer resin composition layer using the concept of such this invention. For example, a resin sheet including three resin composition layers, that is, a first resin composition layer, a second resin composition layer, and an additional resin composition layer (third resin composition layer) can be obtained. In such a case, a mixed layer may be provided between the first resin composition layer and the third resin composition layer and between the second resin composition layer and the third resin composition layer. Also in the resin sheet including three or more resin composition layers, the preferred composition and thickness of the first resin composition layer to be bonded to the support are as described in the above <First resin composition layer>. is there. The preferred composition of the resin composition layer to be bonded to the inner layer substrate is as described in the above <Second resin composition layer>. Specifically, the support, the first resin composition layer, the first mixed layer, the additional resin composition layer (third resin composition layer), the second mixed layer, and the second resin composition layer. A resin sheet having the following layer structure can be obtained. In such a resin sheet, the composition and thickness of the additional resin composition layer may be appropriately determined according to the design of the desired printed wiring board. According to the present invention in which a mixed layer is provided even when an additional resin composition layer exhibiting expansion characteristics greatly different from those of the first and second resin composition layers is provided, the insulating layer having an intended function is provided. Can be advantageously achieved without delamination in high temperature environments. As an additional resin composition layer, in order to provide a new function to a resin sheet, the resin composition layer containing glass fiber etc. may be sufficient, for example.

[Production method of resin sheet]
As described above, the resin sheet of the present invention is formed on a support, a first resin composition layer made of the first resin composition formed on the support, and a first resin composition layer. A second resin composition layer made of the second resin composition, and the first resin composition and the second resin composition layer between the first resin composition layer and the second resin composition layer. A mixed layer in which the resin composition is mixed. In the method for producing such a resin sheet, the first resin varnish in which the first resin composition is dissolved is applied on a support, and the second resin composition is dissolved on the first resin varnish. And a step of applying and drying the second resin varnish, wherein the viscosity of the first resin varnish is 100 mPa · s or more and the viscosity of the second resin varnish is 100 mPa · s or more.

Conventionally, for example, in a resin sheet described in JP-A-2014-17301, a first resin varnish in which a first resin composition is dissolved is applied onto a support to form a first resin composition layer. Later, a second resin varnish in which the second resin composition was dissolved was applied on the first resin composition layer to form a second resin composition layer (hereinafter referred to as “twice coating method”). Also called).
In the present invention, the first resin varnish and the second resin varnish are applied on the same coating line. Specifically, the second resin varnish is applied not on the first resin composition layer but on the first resin varnish. That is, the second resin varnish is applied before forming the first resin composition layer. Thereby, between the 1st resin composition layer and the 2nd resin composition layer, the 1st resin composition contained in the 1st resin varnish and the 2nd contained in the 2nd resin varnish A mixed layer in which the resin composition is mixed can be formed.

The method for producing the resin sheet of the present invention is not particularly limited as long as the desired mixed layer can be formed by applying the second resin varnish on the first resin varnish. In a preferred embodiment, the method for producing the resin sheet of the present invention comprises:
The process includes the step of applying the first resin varnish on the support and simultaneously applying the second resin varnish on the first resin varnish and then drying, or applying the first resin varnish on the support Then, after the preliminary drying, the second resin varnish is applied on the first resin varnish and then dried.
Hereinafter, the method including the former step is also referred to as “simultaneous coating method”, and the method including the latter step is also referred to as “tandem coating method”. Note that the simultaneous coating method and the tandem coating method are different from the conventional two-time coating method in that the first resin varnish and the second resin varnish are applied on the same coating line.

Hereinafter, a simultaneous coating method and a tandem coating method, which are preferred embodiments of the method for producing a resin sheet of the present invention, will be described with reference to FIGS.

<Simultaneous coating method>
In FIG. 2, an example of the manufacturing apparatus of the resin sheet in a simultaneous coating method is shown. A resin sheet manufacturing apparatus 100 illustrated in FIG. 2 includes a coating apparatus 101 and a drying apparatus 102. In the apparatus 100, the support 11 is supplied to the coating apparatus 101. The coating device 101 applies the first resin varnish on the support 11 and simultaneously applies the second resin varnish on the first resin varnish. The support on which the first and second resin varnishes are applied is supplied to the drying device 102. The drying device 102 dries the first and second resin varnishes applied on the support. If necessary, the resin sheet is wound into a roll. As a result, a first resin composition layer derived from the first resin varnish and a second resin composition layer derived from the second resin varnish are formed on the support, and the first resin composition layer and the first resin composition layer A mixed layer obtained by mixing the first resin varnish and the second resin varnish is formed between the two resin composition layers.

In the simultaneous coating method, the thermal history in the production of the resin sheet can be suppressed, and the thermal contraction of the support can be suppressed. Thereby, the resin sheet formed by the simultaneous coating method can provide an insulating layer excellent in stability of roughness and peel strength. In the simultaneous coating method, since the first and second resin varnishes are applied simultaneously, it is easy to form a thick mixed layer. Therefore, the resin sheet manufactured by the simultaneous coating method can provide an insulating layer that is superior in reflow resistance.

In the simultaneous coating method, the first and second resin varnishes are applied using a known coating apparatus that can apply the first resin varnish and simultaneously apply the second resin varnish onto the first resin varnish. Can do. For example, it can apply | coat using well-known multilayer coating systems, such as a multi slit type | mold die coater provided with the slit for apply | coating a 1st resin varnish, and the slit for apply | coating a 2nd resin varnish.

The first and second resin varnishes can be prepared by dissolving the first and second resin compositions in a solvent, respectively. Although there is no restriction | limiting in particular as a solvent used for preparation of a resin varnish, An organic solvent is preferable. Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone and cyclohexanone, acetates such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate and carbitol acetate, and carbitols such as cellosolve and butyl carbitol. , Aromatic hydrocarbons such as toluene and xylene, amide solvents such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone, and solvent naphtha. An organic solvent may be used individually by 1 type, or may use 2 or more types together.
The solvent that dissolves the first resin composition and the solvent that dissolves the second resin composition may be the same or different.
The solvent contained in the first and second resin varnishes is preferably 75% by mass or less, more preferably 65% by mass or less, further preferably 100% by mass when the total of non-volatile components contained in the resin varnish is 100% by mass. Is adjusted to 55% by mass or less, particularly preferably 45% by mass or less. From the viewpoint of promoting the formation of the mixed layer, the lower limit is preferably 15% by mass or more, and more preferably 20% by mass or more.

The viscosity of the first resin varnish improves the affinity with the support from the viewpoint that the thickness of the first resin composition layer can be easily controlled, and the first resin varnish can be applied without the occurrence of cissing or streaks. In view of the possibility, it is 100 mPa · s or more, preferably 200 mPa · s or more, and more preferably 300 mPa · s or more. Although there is no restriction | limiting in particular about the upper limit of the viscosity of a 1st resin varnish, 3000 mPa * s or less is preferable from a viewpoint that the thickness of a 1st resin composition layer is easy to control and thin film formation is easy, and 2000 mPa * s or less Is more preferable, and 1000 mPa · s or less is more preferable.

From the viewpoint of easily controlling the thickness of the second resin composition layer, the viscosity of the second resin varnish is 100 mPa · s or more, preferably 200 mPa · s or more, and more preferably 300 mPa · s or more. Although there is no restriction | limiting in particular about the upper limit of the viscosity of a 2nd resin varnish, 6000 mPa * s or less is preferable from a viewpoint that the thickness of a 2nd resin composition layer is easy to control and thin film formation is easy, and 3000 mPa * s or less is preferable. Is more preferable, and 1000 mPa · s or less is more preferable.
The viscosity of the first and second resin varnishes can be measured using, for example, a rotary (E type) viscometer. Examples of the rotary (E type) viscometer include “RE-80U” manufactured by Toki Sangyo Co., Ltd.

The drying of the first and second resin varnishes may be performed by a known drying method such as heating or hot air blowing. The drying conditions are not particularly limited, but the residual solvent amount in the resin sheet after drying is 100% by mass of the total of the non-volatile components contained in the first resin composition layer, the mixed layer, and the second resin composition layer. , It is preferably dried so as to be 10% by mass or less, more preferably 5% by mass or less. The lower limit of the residual solvent amount is not particularly limited, but can usually be 0.1% by mass or more, 0.5% by mass or more. Depending on the boiling point of the organic solvent in the first and second resin varnishes, for example, when using the first and second resin varnishes containing 30% by mass to 60% by mass of the organic solvent, the temperature is 50 ° C. to 150 ° C. The resin sheet of the present invention can be produced by drying for 3 to 10 minutes.

<Tandem coating method>
In FIG. 3, an example of the manufacturing apparatus of the resin sheet in a tandem coating method is shown. A resin sheet manufacturing apparatus 200 shown in FIG. 3 includes a first coating apparatus 201, a preliminary drying apparatus 202, a second coating apparatus 203, and a drying apparatus 204. In the manufacturing apparatus 200, the support 11 is supplied to the first coating apparatus 201. The first coating apparatus 201 applies a first resin varnish on the support 11. The support on which the first resin varnish is applied is supplied to the preliminary drying device 202. The predrying device 202 predrys the first resin varnish. After preliminary drying of the first resin varnish, the support is supplied to the second coating device 203. The second coating device 203 applies the second resin varnish onto the first resin varnish. Thereafter, the support on which the first and second resin varnishes are applied is supplied to the drying device 204. The drying device 204 dries the first and second resin varnishes applied on the support. If necessary, the resin sheet is wound into a roll. As a result, a first resin composition layer derived from the first resin varnish and a second resin composition layer derived from the second resin varnish are formed on the support, and the first resin composition layer and the first resin composition layer A mixed layer obtained by mixing the first resin varnish and the second resin varnish is formed between the two resin composition layers.

In the tandem coating method, since the first resin varnish is preliminarily dried, the accuracy of the thickness of the first resin composition layer can be improved.

In the tandem coating method, the preliminary drying is not particularly limited as long as it does not hinder the formation of the mixed layer by mixing the first resin varnish and the second resin varnish, and is performed by a known drying method such as heating or hot air blowing. May be implemented. Preliminary drying conditions are not particularly limited, but the residual solvent amount in the first resin varnish after drying is preferably 70% by mass when the total of the non-volatile components contained in the first resin varnish is 100% by mass. Hereinafter, it is preliminarily dried so as to be 60% by mass or less, more preferably 50% by mass or less, and particularly preferably 40% by mass or less. From the viewpoint of promoting the formation of the mixed layer, the lower limit of the residual solvent amount is preferably 15% by mass or more, more preferably 20% by mass or more, and further preferably 25% by mass or more. Depending on the boiling point of the organic solvent in the first resin varnish, for example, when the first resin varnish containing 30% by mass to 60% by mass of the organic solvent is used, the temperature is from 50 ° C. to 150 ° C. for 0.1 minute to 3%. It is preferable to dry for a minute (more preferably at 60 ° C. to 130 ° C. for 0.2 minute to 2 minutes, more preferably at 70 ° C. to 120 ° C. for 0.3 minute to 1.5 minutes).

The first and second resin varnishes (viscosity, solvent type, etc.) are as described for the simultaneous coating method. Moreover, you may implement the drying after apply | coating a 2nd resin varnish on the conditions similar to the drying in a simultaneous coating method.

The method for producing a resin sheet of the present invention may further include a step of laminating a protective film on the surface of the second resin composition layer (surface opposite to the support side). The details of the protective film are as described above.

[Printed wiring board and manufacturing method thereof]
A printed wiring board can be manufactured using the resin sheet manufactured by the method of the present invention. For example, a printed wiring board can be produced by laminating a resin sheet produced by the method of the present invention on an inner layer substrate and thermally curing it, and then removing the support. Therefore, the printed wiring board of the present invention is characterized by including an insulating layer formed using the resin sheet of the present invention.

Specifically, the printed wiring board of the present invention can be produced by a method including the following steps (I) to (III) using the resin sheet of the present invention.
(I) The step of laminating the resin sheet of the present invention on the inner layer substrate so that the second resin composition layer is joined to the inner layer substrate (II) The step of thermosetting the resin sheet to form the insulating layer (III) ) The step of removing the support

In step (I), the resin sheet of the present invention is laminated on the inner layer substrate such that the second resin composition layer is bonded to the inner layer substrate.

The “inner layer substrate” used in the step (I) is mainly a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, a thermosetting polyphenylene ether substrate, or one or both sides of the substrate. A circuit board on which a conductor layer (circuit) patterned is formed. Further, when the printed wiring board is manufactured, an inner layer circuit board of an intermediate product in which an insulating layer and / or a conductor layer is further formed is also included in the “inner layer board” in the present invention.

Lamination of the resin sheet and the inner layer substrate in step (I) may be performed by any conventionally known method, but the second resin composition layer is bonded to the inner layer substrate by roll crimping or press crimping. It is preferable to laminate.

The laminating process is preferably performed by roll pressing or press pressing. Among these, a vacuum laminating method of laminating under reduced pressure is more preferable. The laminating method may be a batch type or a continuous type.

Lamination generally crimping pressure of ^{1kgf / cm 2 ~ 11kgf / cm} 2 (9.8 × 10 4 N / m 2 ~ 107.9 × 10 4 N / m 2) range, 70 ° C. The bonding temperature It is preferable that the temperature is in the range of ˜120 ° C., the pressure bonding time is in the range of 5 seconds to 180 seconds, and the air pressure is 20 mmHg (26.7 hPa) or less under reduced pressure.

Lamination can be performed using a commercially available vacuum laminator. Examples of the commercially available vacuum laminator include a vacuum pressure laminator manufactured by Meiki Seisakusho, a vacuum applicator manufactured by Nichigo Morton, and the like.
In addition, it is preferable to laminate through an elastic material such as heat-resistant rubber so that the resin sheet sufficiently follows the surface unevenness of the inner layer substrate (for example, the unevenness of the surface circuit of the inner layer circuit substrate).

In step (I), the resin sheet may be laminated on one side of the inner layer substrate or may be laminated on both sides of the inner layer substrate.

After the step (I), the resin sheet laminated on the inner layer substrate may be subjected to a treatment for smoothing by heating and pressing. The smoothing treatment is generally carried out by heating and pressurizing the resin sheet with a heated metal plate or metal roll under normal pressure (atmospheric pressure). The heating and pressurizing conditions can be the same conditions as the laminating conditions. The laminating process and the smoothing process may be continuously performed using a commercially available vacuum laminator.

In step (II), the resin sheet is thermoset to form an insulating layer. Specifically, the first resin composition layer, the mixed layer, and the second resin composition layer of the laminated resin sheet are thermoset to form an insulating layer.

The conditions for thermosetting are not particularly limited, and the conditions normally employed when forming the insulating layer of the printed wiring board may be used.

For example, although the thermosetting conditions of the resin sheet vary depending on the composition of the resin composition constituting the first and second resin composition layers, the curing temperature is in the range of 120 ° C. to 240 ° C. (preferably 150 ° C. to 210 ° C. The curing time can be in the range of 5 minutes to 90 minutes (preferably 10 minutes to 75 minutes, more preferably 15 minutes to 60 minutes).

Before the resin sheet is thermally cured, each resin composition layer may be preheated at a temperature lower than the curing temperature. For example, prior to thermosetting the resin sheet, each resin composition layer is heated to 5 ° C. or more and less than 120 ° C. (preferably 60 ° C. or more and 110 ° C. or less, more preferably 70 ° C. or more and 100 ° C. or less) Preheating may be performed for more than a minute (preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes).

In step (III), the support is removed. Thereby, the surface of the insulating layer is exposed. The support may be removed manually or mechanically using an automatic peeling device or the like. Further, when a metal foil is used as the support, it may be removed using a chemical.

When manufacturing a printed wiring board, (IV) a step of drilling an insulating layer, (V) a step of roughening the insulating layer, (VI) a step of forming a conductor layer on the surface of the insulating layer Good. These steps (IV) to (VI) may be carried out according to various methods known to those skilled in the art used for the production of printed wiring boards. Note that the support is removed between step (II) and step (IV), between step (IV) and step (V), or between step (V) and step (VI). Good.

Step (IV) is a step of making a hole in the insulating layer, whereby a hole such as a via hole or a through hole can be formed in the insulating layer. For example, a hole can be formed in the insulating layer using a drill, a laser (a carbon dioxide laser, a YAG laser, or the like), plasma, or the like.

Step (V) is a step of roughening the insulating layer. The procedure and conditions for the roughening treatment are not particularly limited, and known procedures and conditions that are usually used when forming an insulating layer of a printed wiring board can be employed. For example, the insulating layer can be roughened by performing a swelling treatment with a swelling liquid, a roughening treatment with an oxidizing agent, and a neutralization treatment with a neutralizing liquid in this order. Although it does not specifically limit as a swelling liquid, An alkaline solution, surfactant solution, etc. are mentioned, Preferably it is an alkaline solution, As this alkaline solution, a sodium hydroxide solution and a potassium hydroxide solution are more preferable. Examples of commercially available swelling liquids include Swelling Dip Securigans P and Swelling Dip Securigans SBU manufactured by Atotech Japan. The swelling treatment with the swelling liquid is not particularly limited, and can be performed, for example, by immersing the insulating layer in a swelling liquid at 30 ° C. to 90 ° C. for 1 minute to 20 minutes. Although it does not specifically limit as an oxidizing agent, For example, the alkaline permanganate solution which melt | dissolved potassium permanganate and sodium permanganate in the aqueous solution of sodium hydroxide is mentioned. The roughening treatment with an oxidizing agent such as an alkaline permanganic acid solution is preferably performed by immersing the insulating layer in an oxidizing agent solution heated to 60 to 80 ° C. for 10 to 30 minutes. The concentration of permanganate in the alkaline permanganate solution is preferably 5% by mass to 10% by mass. Examples of commercially available oxidizing agents include alkaline permanganate solutions such as concentrate compact CP and dosing solution securigans P manufactured by Atotech Japan. Moreover, as a neutralization liquid, acidic aqueous solution is preferable, As a commercial item, the reduction solution securigant P by Atotech Japan Co., Ltd. is mentioned, for example. The treatment with the neutralizing solution can be performed by immersing the treated surface, which has been subjected to the roughening treatment with the oxidizing agent solution, in a neutralizing solution at 30 to 80 ° C. for 5 to 30 minutes.

In one embodiment, the arithmetic average roughness Ra of the surface of the insulating layer after the roughening treatment is preferably 400 nm or less, more preferably 350 nm or less, further preferably 300 nm or less, 250 nm or less, 200 nm or less, 150 nm or less, or 100 nm or less. It is. The insulating layer formed using the resin sheet of the present invention exhibits excellent peel strength with respect to the conductor layer even when Ra is small as described above. The lower limit of the Ra value is not particularly limited, but can usually be 0.5 nm or more, 1 nm or more, and the like. When there is a variation in Ra on the surface of the insulating layer after the roughening treatment, it is preferable that the maximum value of Ra (Ra _max ) be in the above range.

In the present invention, an insulating layer with little variation in surface roughness after the roughening treatment and high roughness stability can be formed. In one embodiment, the difference Ra _max −Ra _min between the maximum value (Ra _max ) and the minimum value (Ra _min ) of the arithmetic average roughness of the insulating layer surface after the roughening treatment is preferably 150 nm or less, more preferably 100 nm. Hereinafter, it is more preferably 80 nm or less, 60 nm or less, 40 nm or less, or 30 nm or less. The lower limit of the difference Ra _max -Ra _min is preferably low and may be 0 nm, but can usually be 0.1 nm or more, 0.5 nm or more, and the like.

The arithmetic average roughness Ra of the insulating layer surface can be measured using a non-contact type surface roughness meter. As a specific example of the non-contact type surface roughness meter, “WYKO NT3300” manufactured by Beecoin Instruments can be cited.

Step (VI) is a step of forming a conductor layer on the surface of the insulating layer.

The conductor material used for the conductor layer is not particularly limited. In a preferred embodiment, the conductor layer is one or more selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin and indium. Contains metal. The conductor layer may be a single metal layer or an alloy layer. As the alloy layer, for example, an alloy of two or more metals selected from the above group (for example, nickel-chromium alloy, copper- A layer formed from a nickel alloy and a copper / titanium alloy). Among them, from the viewpoint of versatility of conductor layer formation, cost, ease of patterning, etc., single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or nickel / chromium alloy, copper / An alloy layer of nickel alloy or copper / titanium alloy is preferable, and a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or an alloy layer of nickel / chromium alloy is more preferable, and a single layer of copper is preferable. A metal layer is more preferred.

The conductor layer may have a single-layer structure or a multi-layer structure in which two or more single metal layers or alloy layers made of different types of metals or alloys are laminated. When the conductor layer has a multilayer structure, the layer in contact with the insulating layer is preferably a single metal layer of chromium, zinc or titanium, or an alloy layer of nickel / chromium alloy.

The thickness of the conductor layer is generally 3 μm to 35 μm, preferably 5 μm to 30 μm, although it depends on the desired printed wiring board design.

The conductor layer may be formed by plating. For example, the surface of the insulating layer can be plated by a conventionally known technique such as a semi-additive method or a full additive method to form a conductor layer having a desired wiring pattern. Hereinafter, an example in which the conductor layer is formed by a semi-additive method will be described.

First, a plating seed layer is formed on the surface of the insulating layer by electroless plating. Next, a mask pattern that exposes a part of the plating seed layer corresponding to a desired wiring pattern is formed on the formed plating seed layer. A metal layer is formed by electrolytic plating on the exposed plating seed layer, and then the mask pattern is removed. Thereafter, an unnecessary plating seed layer can be removed by etching or the like to form a conductor layer having a desired wiring pattern.

In one embodiment, the peel strength between the insulating layer and the conductor layer after the roughening treatment is preferably 0.4 kgf / cm or more, more preferably 0.45 kgf / cm or more, and further preferably 0.50 kgf / cm or more. is there. On the other hand, the upper limit value of the peel strength is not particularly limited, but is 1.2 kgf / cm or less, 0.9 kgf / cm or less, and the like. In the present invention, although the surface roughness Ra of the insulating layer after the roughening treatment is small, an insulating layer exhibiting such a high peel strength can be formed. It contributes. In addition, when the peeling strength of an insulating layer and a conductor layer has dispersion | variation, it is preferable that the minimum value ( _Smin ) of a peeling strength exists in said range.

Further, in the present invention, it is possible to form an insulating layer having little peel strength variation between the insulating layer and the conductor layer and having high peel strength stability. In one embodiment, the difference S _max −S _min between the maximum value (S _max ) and the minimum value (S _min ) of the peel strength between the insulating layer and the conductor layer is preferably 0.15 kgf / cm or less, more preferably 0. .1 kgf / cm or less. The lower limit of the difference S _max -S _min is preferably low and may be 0 kgf / cm, but can usually be 0.01 kgf / cm or more, 0.05 kgf / cm or more, and the like.

In the present invention, the peel strength between the insulating layer and the conductor layer refers to the peel strength (90-degree peel strength) when the conductor layer is peeled in the direction perpendicular to the insulating layer (90-degree direction), The peel strength when the conductor layer is peeled in the direction perpendicular to the insulating layer (90-degree direction) can be determined by measuring with a tensile tester. Examples of the tensile tester include “AC-50C-SL” manufactured by TSE Corporation.

[Semiconductor device]
The semiconductor device of the present invention includes the printed wiring board of the present invention, and the semiconductor device can be manufactured using the printed wiring board of the present invention. By using the printed wiring board of the present invention, the delamination of the insulating layer can be advantageously suppressed even in a mounting process employing a high solder reflow temperature, and the peel strength stability between the insulating layer and the conductor layer can be suppressed. Combined with the height, high reflow reliability can be realized.

Examples of such semiconductor devices include various semiconductor devices used for electrical products (for example, computers, mobile phones, digital cameras, and televisions) and vehicles (for example, motorcycles, automobiles, trains, ships, and aircrafts). .

The semiconductor device of the present invention can be manufactured by mounting a component (semiconductor chip) on a conductive portion of a printed wiring board. The “conduction location” is a “location where an electrical signal is transmitted on a printed wiring board”, and the location may be a surface or an embedded location. The semiconductor chip is not particularly limited as long as it is an electric circuit element made of a semiconductor.

The semiconductor chip mounting method for manufacturing the semiconductor device of the present invention is not particularly limited as long as the semiconductor chip functions effectively, but specifically, a wire bonding mounting method, a flip chip mounting method, and no bumps. Examples include a mounting method using a build-up layer (BBUL), a mounting method using an anisotropic conductive film (ACF), and a mounting method using a non-conductive film (NCF). Here, “a mounting method using a build-up layer without a bump (BBUL)” means “a mounting method in which a semiconductor chip is directly embedded in a recess of a printed wiring board and the semiconductor chip and wiring on the printed wiring board are connected”. It is.

Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to these examples. In the following description, “parts” and “%” mean “parts by mass” and “% by mass”, respectively, unless otherwise specified.

(Preparation of resin varnish 1)
10 parts of naphthylene ether type epoxy resin (DIC Corporation "EXA-7311-G4S", epoxy equivalent 186), bixylenol type epoxy resin (Mitsubishi Chemical Corporation "YX4000HK", epoxy equivalent of about 185) , 20 parts of biphenyl type epoxy resin (“NC3000H” manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 288), and phenoxy resin (“YX7553BH30” manufactured by Mitsubishi Chemical Corporation), cyclohexanone: methyl ethyl ketone (MEK) with a solid content of 30% by mass 1 part solution) was dissolved by heating in a mixed solvent of 15 parts of solvent naphtha and 5 parts of cyclohexanone with stirring. After cooling to room temperature, there were added 12 parts of a triazine skeleton-containing phenol novolac curing agent (hydroxyl equivalent 125, “LA-7054” manufactured by DIC Corporation, MEK solution with a solid content of 60%), naphthol curing agent ( 15 parts of "SN485" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., MEK solution having a hydroxyl equivalent of 215 and a solid content of 60%, polyvinyl butyral resin (glass transition temperature of 105 ° C, "KS-1" manufactured by Sekisui Chemical Co., Ltd.) 10 parts of a 1: 1 mixed solution of ethanol and toluene with a solid content of 15%, 1 part of an amine curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution with a solid content of 5% by mass), an imidazole curing accelerator (Mitsubishi Chemical Corporation “P200-H50”, propylene glycol monomethyl ether solution having a solid content of 50% by mass), 2 parts, rubber particles (Aika Industry ( ), AC3816N) 4 parts of MEK 20 parts swollen at room temperature for 12 hours, spherical silica surface-treated with an aminosilane coupling agent (“KBM573” manufactured by Shin-Etsu Chemical Co., Ltd.) After mixing 50 parts of Admatechs “SOC2”, average particle size 0.5 μm, carbon amount per unit surface area 0.38 mg / m ² , and uniformly dispersing with a high-speed rotary mixer, cartridge filter (“SHP050 made by ROKITECHNO”) )) To prepare a resin varnish 1.

(Preparation of resin varnish 2)
10 parts of bisphenol AF type epoxy resin ("YL7760" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 238), 6 parts of bixylenol type epoxy resin ("YX4000HK" manufactured by Mitsubishi Chemical Corporation, about 185 epoxy equivalent), biphenyl type epoxy Resin (Nippon Kayaku Co., Ltd. "NC3000H", epoxy equivalent 288) 30 parts, and phenoxy resin (Mitsubishi Chemical Corporation "YX7553BH30", solid content 30 mass% cyclohexanone: methyl ethyl ketone (MEK) 1: 1. Solution) 5 parts, 20 parts of phenoxy resin (“YL7769BH30” manufactured by Mitsubishi Chemical Corporation, 1: 1 solution of cyclohexanone: methyl ethyl ketone (MEK) having a solid content of 30% by mass) in a mixed solvent of 20 parts of MEK and 5 parts of cyclohexanone It was dissolved by heating with stirring. After cooling to room temperature, 20 parts of an active ester curing agent (“HPC8000-65T” manufactured by DIC Corporation, a toluene solution having an active group equivalent of about 223 and a nonvolatile component of 65% by mass), an amine curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution having a solid content of 5% by mass) 4 parts, imidazole curing accelerator (1-benzyl-2-phenylimidazole (1B2PZ), MEK solution having a solid content of 5% by mass) 3 Part, spherical silica surface treated with phenyltrimethoxysilane (“KBM103” manufactured by Shin-Etsu Chemical Co., Ltd.) (“UFP-30” manufactured by Denki Kagaku Kogyo Co., Ltd.), average particle size of 0.1 μm, per unit surface area After mixing 45 parts of carbon (0.22 mg / m ² ) and uniformly dispersing with a high-speed rotary mixer, cartridge filter (manufactured by ROKITECHNO) The resin varnish 2 was prepared by filtration through “SHP030”).

(Preparation of resin varnish 3)
In the preparation of the resin varnish 2, the compounding amount of the amine curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution having a solid content of 5% by mass) was changed from 4 parts to 2 parts to obtain an imidazole curing accelerator ( Resin varnish 3 was prepared in the same manner as resin varnish 2, except that the amount of 1-benzyl-2-phenylimidazole (1B2PZ) and MEK solution having a solid content of 5% by mass was changed from 3 parts to 1 part.

(Preparation of resin varnish 4)
Bisphenol type epoxy resin (“ZX1059” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., epoxy equivalent of about 169, 1: 1 mixture of bisphenol A type and bisphenol F type) 5 parts, naphthalene type epoxy resin (“HP4032SS” manufactured by DIC Corporation) ”, Epoxy equivalent of about 144), 5 parts, naphthalene type epoxy resin (DIC-4,“ HP-4710 ”, epoxy equivalent of about 170), xylenol type epoxy resin (Mitsubishi Chemical Corporation“ YX4000HK ”, 5 parts of epoxy equivalent (185), 12 parts of biphenyl type epoxy resin (“NC3000H” manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 288), and phenoxy resin (“YX7553BH30” manufactured by Mitsubishi Chemical Corporation), solid content: 30% by mass 10 parts of cyclohexanone: methyl ethyl ketone (MEK) It was dissolved by heating with stirring in a mixed solvent of Rubentonafusa 20 parts of cyclohexanone 10 parts. After cooling to room temperature, 12 parts of a triazine skeleton-containing phenol novolac curing agent (hydroxyl equivalent: 125, “LA7054” manufactured by DIC Corporation, MEK solution with a solid content of 60%), naphthol curing agent (DIC ( "EXB-9500" manufactured by Co., Ltd., 12 parts of MEK solution having a hydroxyl equivalent weight of 190 and a solid content of 50%, 1 part of an amine curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution having a solid content of 5% by mass) 1 part A flame retardant (“HCA-HQ” manufactured by Sanko Co., Ltd., 10- (2,5-dihydroxyphenyl) -10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide, average particle size 2 μm ) 2 parts, 2 parts of rubber particles (“AC3816N” manufactured by Aika Kogyo Co., Ltd.) were swollen in 10 parts of MEK at room temperature for 12 hours, aminosilane-based coupling Grayed agent (Shin-Etsu Chemical Co., Ltd., "KBM573") surface-treated with spherical silica (Co. Admatechs Co. "SOC4", average particle size 1 [mu] m, the carbon amount 0.31 mg ^{/ m} 2 per unit surface area) After mixing 200 parts and uniformly dispersing with a high-speed rotary mixer, the resin varnish 4 was prepared by filtering with a cartridge filter (“SHP050” manufactured by ROKITECHNO).

(Preparation of resin varnish 5)
Bisphenol type epoxy resin (“ZX1059” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., epoxy equivalent of about 169, 1: 1 mixture of bisphenol A type and bisphenol F type) 5 parts, bisphenol AF type epoxy resin (manufactured by Mitsubishi Chemical Corporation) "YL7760", 10 parts of epoxy equivalent 238), 5 parts of bixylenol type epoxy resin ("YX4000HK" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent of about 185), naphthalene type epoxy resin ("ESN475V" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) , Epoxy equivalent 330) 20 parts, and phenoxy resin ("YX7553BH30" manufactured by Mitsubishi Chemical Corporation, 10 parts of a cyclohexanone: methyl ethyl ketone (MEK) 1: 1 solution having a solid content of 30% by mass), 30 parts of solvent naphtha and cyclohexanone 5 Part of the mixed solvent with heating and stirring It was. After cooling to room temperature, 12 parts of a triazine skeleton-containing cresol novolac curing agent (hydroxyl equivalent: 151, “LA-3018-50P” manufactured by DIC Corporation, 2-methoxypropanol solution with a solid content of 50%), Active ester-based curing agent (“HPC-8000-65T” manufactured by DIC Corporation, active group equivalent of about 223, non-volatile component 65% by weight toluene solution) 12 parts, amine-based curing accelerator (4-dimethylaminopyridine (DMAP) ), 1.5 parts of MEK solution with a solid content of 5% by weight, 1 part of an imidazole curing accelerator (1-benzyl-2-phenylimidazole (1B2PZ), MEK solution with a solid content of 5% by weight), flame retardant (Sanko) "HCA-HQ", 10- (2,5-dihydroxyphenyl) -10-hydro-9-oxa-10-phosphaphenanthrene manufactured by KK 2 parts of 10-oxide, average particle size 2 μm), spherical silica surface-treated with an aminosilane coupling agent (“KBM573” manufactured by Shin-Etsu Chemical Co., Ltd.) (“SOC1” manufactured by Admatechs Co., Ltd.), average particle size After mixing 160 parts of 0.25 μm and carbon amount per unit surface area 0.36 mg / m ² ) and uniformly dispersing with a high-speed rotary mixer, it is filtered with a cartridge filter (“SHP030” manufactured by ROKITECHNO), and resin varnish 5 Was prepared.

(Preparation of resin varnish 6)
Resin varnish 1 was prepared in the same manner as resin varnish 1 except that a mixed solvent of 15 parts of solvent naphtha, 15 parts of MEK and 15 parts of cyclohexanone was used instead of a mixed solvent of 15 parts of solvent naphtha and 5 parts of cyclohexanone. Resin varnish 6 was prepared.

(Measurement of viscosity of resin varnish)
The viscosity was measured using a rotary (E type) viscometer (Toki Sangyo Co., Ltd. “RE-80U”) equipped with a cone plate having a radius of 24 mm and an angle of 1.34 °. Sample resin composition varnish 1.2g was collected on a sample stage with 25 ° C temperature-controlled water circulated in the jacket so that no bubbles would enter it, left to stand for 2 minutes, and then temperature-controlled, then rotated for 2 minutes at 20 rpm. The value at the time of letting it be made into the viscosity.

(Example 1: Production of resin sheet 1)
As a support, a PET film (“Lumirror T6AM” manufactured by Toray Industries, Inc., having a thickness of 38 μm, a softening point of 130 ° C.) subjected to release treatment with an alkyd resin mold release agent (“AL-5” manufactured by Lintec Co., Ltd.) Prepared.
The resin sheet 1 was produced by the following procedure by the simultaneous coating method. A roll-shaped PET film is placed on a coating machine and unwound, and a resin varnish 1 is applied onto the release surface of the support using a two-layer slit die coater. 4 was applied. The resin varnish 1 was applied (applied) so that the target thickness after drying was 5 μm, and the resin varnish 4 was applied so that the target thickness after drying was 20 μm. Each resin composition layer was formed by drying at 70 ° C. to 110 ° C. (average 95 ° C.) for 4.5 minutes. Next, a polypropylene film (“Alphan MA-411” manufactured by Oji Specialty Paper Co., Ltd., thickness 15 μm) is used as a protective film on the surface of the resin composition layer not bonded to the support, and the rough surface of the protective film. Were laminated so as to be bonded to the second resin composition layer. Thereby, the resin sheet 1 which consists of a support body, the 1st resin composition layer (resin varnish 1 origin), a mixed layer, the 2nd resin composition layer (resin varnish 4 origin), and a protective film was obtained. . The target thickness after application and drying of the resin varnish refers to the thickness when the resin varnish is applied and dried as it is.

(Example 2: Production of resin sheet 2)
Resin sheet 2 was produced in the same manner as in Example 1 except that the tandem coating method was used instead of the simultaneous coating method. Specifically, the resin varnish 1 was applied to a thickness of 3 μm using a die coater, applied to the desired thickness after drying, and pre-dried at 90 ° C. for 0.8 minutes (residual solvent amount of about 30% by mass). The resin varnish 4 was applied to the resin varnish 1 using a die coater to a thickness of 22 μm, and dried to a target thickness after drying, and dried at 80 ° C. to 110 ° C. (average 100 ° C.) for 4 minutes. Obtained the resin sheet 2 like Example 1. FIG.

(Example 3: Production of resin sheet 3)
In Example 1, resin sheet 3 was obtained in the same manner as in Example 1 except that resin varnish 2 was used instead of resin varnish 1 and resin varnish 5 was used instead of resin varnish 4.

(Example 4: Production of resin sheet 4)
In Example 1, 1) The resin varnish 3 was used instead of the resin varnish 1, the target thickness after application and drying of the resin varnish was changed from 5 μm to 8 μm, and 2) the resin varnish 5 instead of the resin varnish 4 The resin sheet 4 was obtained in the same manner as in Example 1 except that the target thickness after application and drying of the resin varnish was changed from 20 μm to 17 μm.

(Comparative Example 1: Production of resin sheet 5)
As a support, a PET film (“Lumirror T6AM” manufactured by Toray Industries, Inc., having a thickness of 38 μm, a softening point of 130 ° C.) subjected to release treatment with an alkyd resin mold release agent (“AL-5” manufactured by Lintec Co., Ltd.) Prepared.
The resin sheet 5 was produced by the following procedure by a twice coating method. On the support, using a die coater, the resin varnish 1 was applied, applied so that the target thickness after drying was 3 μm, and dried at 70 ° C. to 110 ° C. (average 95 ° C.) for 4.5 minutes. A first resin composition layer was formed. Next, the resin varnish 4 is applied onto the first resin composition layer using a die coater, and is applied so that the target thickness after drying is 22 μm, and the temperature is 70 ° C. to 110 ° C. (average 95 ° C.). It dried for 4.5 minutes, the 2nd resin composition layer was formed, and the resin sheet 5 was obtained.

(Comparative Example 2: Production of resin sheet 6)
In Example 1, 1) The resin varnish 6 was used in place of the resin varnish 1, and the target thickness after application of the resin varnish and drying was changed from 5 μm to 3 μm. 2) Application of the resin varnish 4 and after drying A resin sheet 6 was obtained in the same manner as in Example 1 except that the target thickness was changed from 20 μm to 22 μm.

(Measurement of minimum melt viscosity)
A first or second resin composition layer was applied as a single layer on a PET film under the same conditions as in each example and each comparative example, and a measurement sample was prepared. Using a dynamic viscoelasticity measuring apparatus (“Rheosol-G3000” manufactured by UBM Co., Ltd.), using a parallel plate with a diameter of 18 mm, 1 g of the sample resin composition, a starting temperature of 60 ° C. to 200 ° C. The temperature is raised at a rate of 5 ° C./minute until the measurement temperature interval is 2.5 ° C., the vibration frequency is 1 Hz, the strain is 1 deg, the dynamic viscoelastic modulus is measured, and the minimum melt viscosity (poise) is measured. did.

(Measurement of thickness of each layer of resin sheet)
The protective film was peeled off from the resin sheet (200 mm square) produced in each Example and each Comparative Example. With the second resin composition layer as the top surface, the resin sheet is placed on a glass cloth base epoxy resin double-sided copper-clad laminate (0.7 mm thickness, “R5715ES” manufactured by Matsushita Electric Works Co., Ltd.) having a size of 255 mm × 255 mm. The four sides of the resin sheet were fixed with polyimide adhesive tape (width 10 mm), 30 minutes at 100 ° C. (after being put into an oven at 100 ° C.), and then 30 minutes at 175 ° C. (after being transferred to an oven at 175 ° C.). And heat cured. Thereafter, the substrate was taken out in a room temperature atmosphere.

The cross section of the heat-cured resin sheet was observed using a FIB-SEM composite apparatus (“SMI3050SE” manufactured by SII Nanotechnology Co., Ltd.). Specifically, the cross section in the direction perpendicular to the surface of the resin sheet was cut out by FIB (focused ion beam), and a cross-sectional SEM image (observation width 30 μm, observation magnification 9,000 times) was obtained. For each sample, five cross-sectional SEM images selected at random were obtained, the thickness of each layer was shown as an average value, and this value was taken as the thickness of each layer.

(Production and evaluation of printed wiring boards)
Using the resin sheets of each Example and each Comparative Example, printed wiring boards were produced according to the following procedure.

<Production of printed wiring board>
(1) Substrate treatment of circuit board IPC MULTI-PURPOSE TEST on glass cloth base epoxy resin double-sided copper-clad laminate (copper foil thickness 18μm, substrate thickness 0.3mm, "679FGR" manufactured by Hitachi Chemical Co., Ltd.) BOARD NO. A pattern of IPC B-25 (line / space = 175/175 μm comb tooth pattern (residual copper ratio 50%)) is formed, and both sides are etched by 1 μm with a microetching agent (“CZ8100” manufactured by Mec Co., Ltd.). The copper surface was roughened.

(2) Lamination | stacking of resin sheet The protective film was peeled from the resin sheet produced by the Example and the comparative example. Using a batch type vacuum pressure laminator (2-stage build-up laminator “CVP700” manufactured by Nichigo Morton Co., Ltd.), the resin sheet is bonded to the circuit board so that the second resin composition layer is bonded to the circuit board. Laminated on both sides. Lamination was performed by reducing the pressure for 30 seconds to a pressure of 13 hPa or less, and then pressure bonding at 110 ° C. and a pressure of 0.74 MPa for 30 seconds. Next, the laminated resin sheets were smoothed by hot pressing at 110 ° C. and a pressure of 0.5 MPa for 60 seconds under atmospheric pressure.

(3) Curing of resin composition layer After laminating resin sheets, with support attached, transfer to 100 ° C for 30 minutes (after putting into 100 ° C oven), then at 175 ° C (transfer to 175 ° C oven) After) thermosetting under conditions of 30 minutes, insulating layers were formed on both sides of the circuit board. Thereafter, the substrate was taken out in a room temperature atmosphere.

(4) Roughening treatment The substrate from which the support was peeled was placed in a swelling liquid (an aqueous solution containing “Swelling Dip Securigant P” manufactured by Atotech Japan Co., Ltd., diethylene glycol monobutyl ether and sodium hydroxide) at 60 ° C. for 5 minutes. (Examples 1 and 2 and Comparative Examples 1 and 2) or 10 minutes (Examples 3 and 4), oxidizing agent ("Concentrate Compact CP" manufactured by Atotech Japan Co., Ltd.), KMnO ₄ : 60 g / L, NaOH: (40 g / L aqueous solution) at 80 ° C. for 20 minutes, and finally immersed in a neutralizing solution (“Reduction Solution Securigant P” manufactured by Atotech Japan Co., Ltd., sulfuric acid aqueous solution) at 40 ° C. for 5 minutes, then at 80 ° C. Dry for 30 minutes. The obtained substrate is referred to as “evaluation substrate A”.

(5) Formation of conductor layer by semi-additive method Evaluation substrate A was immersed in an electroless plating solution containing PdCl ₂ at 40 ° C. for 5 minutes and then in an electroless copper plating solution at 25 ° C. for 20 minutes. The obtained substrate was heated at 150 ° C. for 30 minutes for annealing treatment, and then copper sulfate electrolytic plating was performed to form a conductor layer having a thickness of 30 μm on the entire surface. Next, annealing was performed by heating at 190 ° C. for 60 minutes. The obtained substrate is referred to as “evaluation substrate B”.

<Evaluation>
(1) Arithmetic mean roughness (Ra)
The arithmetic average roughness (Ra) of the insulating layer surface was measured and evaluated by the following procedure. For each evaluation substrate A, the surface of the insulating layer on the comb / tooth pattern (remaining copper ratio 50%) of line / space = 175/175 μm was subjected to a non-contact type surface roughness meter (“WYKO NT3300” manufactured by Beeco Instruments). Using the VSI contact mode, a measurement range of 121 μm × 92 μm was measured with a 50 × lens, and the Ra value was obtained from the obtained numerical value. Ra values were determined for 10 randomly selected points. Then, the difference between the maximum value and the minimum value of Ra value (maximum value−minimum value) was evaluated according to the following criteria.
[Evaluation criteria]
○: Difference is 150 nm or less ×: Difference exceeds 150 nm

(2) Peel strength The peel strength between the insulating layer and the conductor layer was measured and evaluated by the following procedure. For each evaluation board B, a conductor layer on a comb / tooth pattern (remaining copper ratio 50%) of line / space = 175/175 μm is cut into a portion having a width of 10 mm and a length of 100 mm. (TSE Co., Ltd., Autocom type testing machine “AC-50C-SL”) and the load when peeling 35 mm vertically at a speed of 50 mm / min at room temperature (kgf / cm). Then, the difference between the maximum value and the minimum value of peel strength (maximum value−minimum value) was evaluated according to the following criteria.
[Evaluation criteria]
○: Difference is 0.15 kgf / cm or less ×: Difference exceeds 0.15 kgf / cm

(3) Reflow resistance The evaluation substrate B was cut into 45 mm square pieces (n = 3) and then left for 48 hours in an atmosphere of 60 ° C. and 60% relative humidity. Thereafter, the sample was passed through a reflow apparatus (“HAS-6116” manufactured by Nippon Antom Co., Ltd.) that reproduces a solder reflow temperature having a peak temperature of 260 ° C. (reflow temperature profile conforms to IPC / JEDEC J-STD-020C). The reflow process was performed up to 13 times, and the presence or absence of peeling abnormality such as delamination in the insulating layer or peeling between the insulating layer and the conductor layer and the timing at which the peeling abnormality occurred were evaluated according to the following criteria.
[Evaluation criteria]
◎: No peeling abnormality up to 13 times ○: Even one piece has a peeling abnormality in 7 to 12 times ×: One piece has a peeling abnormality by the 6th time

From the above table, it can be seen that Examples 1 to 4 have high stability of roughness and peel strength, and are excellent in reflow resistance because delamination is suppressed even when exposed to a high temperature environment during reflow. The resin sheet of Example 1 and Example 3 in which the thickness of the mixed layer is 1.0 μm or more is more excellent in reflow resistance than the resin sheet of Example 2 in which the thickness of the mixed layer is 0.7 μm. It turns out that it brings. Further, the resin sheets of Example 1 and Example 3 in which the minimum melt viscosity of the first resin composition layer is 5000 poise or more are the resins of Example 4 in which the minimum melt viscosity of the first resin composition layer is 3900 poise. It can be seen that compared to the sheet, it provides an insulating layer with better reflow resistance.
On the other hand, the resin sheet of Comparative Example 1 produced by the twice coating method has a thin mixed layer, and the insulating layer formed using the resin sheet is delaminated in a high temperature environment during reflow. It is easy to see that it is inferior in reflow resistance.
Further, in Comparative Example 2 in which the first resin composition layer was prepared using a resin varnish having a viscosity of 80 mPa · s, the surface of the insulating layer obtained due to the repellency of the resin varnish on the support. It turns out that there are many defects and the stability of roughness and peel strength is poor. In Comparative Example 2, the stability of the roughness and peel strength is also due to the excessive mixing of the resin varnishes due to the low viscosity resin varnish and the thin thickness of the first resin composition layer. Will be inferior. At locations where the peel strength is low, the insulation layer and the conductor layer are also peeled off, so that the reflow resistance is extremely inferior.

DESCRIPTION OF SYMBOLS 1 Resin sheet 11 Support body 12 1st resin composition layer 13 Mixed layer 14 2nd resin composition layer 100 Resin sheet manufacturing apparatus 101 Coating apparatus 102 Drying apparatus 200 Resin sheet manufacturing apparatus 201 1st coating apparatus 202 Pre-drying device 203 Second coating device 204 Drying device

Claims (16)

A first resin composition layer comprising a support, a first resin composition provided on the support, and a second resin composition comprising a second resin composition provided on the first resin composition layer. A mixed layer in which the first resin composition and the second resin composition are mixed between the first resin composition layer and the second resin composition layer. A method for producing a resin sheet having
A first resin varnish in which the first resin composition is dissolved is applied on the support, and a second resin varnish in which the second resin composition is dissolved is applied on the first resin varnish and dried. Including the steps of:
The viscosity of the first resin varnish is 100 mPa · s or more,
The manufacturing method of the resin sheet whose viscosity of a 2nd resin varnish is 100 mPa * s or more. A step of applying the first resin varnish on the support and simultaneously applying the second resin varnish on the first resin varnish and then drying, or
2. The resin according to claim 1, comprising a step of applying a first resin varnish on a support, preliminarily drying, then applying a second resin varnish on the first resin varnish, and then drying. Sheet manufacturing method. The amount of residual solvent in the first resin varnish after the preliminary drying is 15% by mass to 70% by mass when the total amount of non-volatile components contained in the first resin varnish is 100% by mass. Item 3. A method for producing a resin sheet according to Item 2. The manufacturing method of the resin sheet of Claim 1 or 2 including the process of apply | coating a 2nd resin varnish on a 1st resin varnish simultaneously with apply | coating a 1st resin varnish on a support body, and drying after that. . The first resin composition layer has a thickness of 0.3 μm to 15 μm, a second resin composition layer has a thickness of 3 μm to 200 μm, and a mixed layer has a thickness of 0.4 μm or more. The method for producing a resin sheet according to any one of claims 1 to 4, wherein the thickness is 2 times or less the thickness of the layer. The method for producing a resin sheet according to any one of claims 1 to 5, wherein the support is a support with a release layer. The resin sheet according to any one of claims 1 to 6, wherein the minimum melt viscosity of the first resin composition layer is 3000 poise or more and the minimum melt viscosity of the second resin composition layer is 10000 poise or less. Production method. The resin according to any one of claims 1 to 7, wherein the viscosity of the first resin varnish is 100 mPa · s to 3000 mPa · s, and the viscosity of the second resin varnish is 100 mPa · s to 6000 mPa · s. Sheet manufacturing method. The method for producing a resin sheet according to any one of claims 1 to 8, wherein the first resin varnish and the second resin varnish are applied on the same coating line. A method for producing a printed wiring board, wherein the resin sheet produced by the method according to any one of claims 1 to 9 is laminated on an inner substrate and thermally cured, and then the support is removed. A first resin composition layer comprising a support, a first resin composition provided on the support, and a second resin composition comprising a second resin composition provided on the first resin composition layer. A mixed layer in which the first resin composition and the second resin composition are mixed between the first resin composition layer and the second resin composition layer. And a thickness of the mixed layer is 0.4 μm or more. The first resin composition layer has a thickness of 0.3 μm to 15 μm, a second resin composition layer has a thickness of 3 μm to 200 μm, and a mixed layer has a thickness of 0.4 μm or more. The resin sheet according to claim 11, wherein the resin sheet is twice or less the thickness of the layer. The resin sheet according to claim 11 or 12, wherein the minimum melt viscosity of the first resin composition layer is 3000 poise or more. The resin sheet according to any one of claims 11 to 13, wherein the minimum melt viscosity of the second resin composition layer is 10,000 poise or less. A printed wiring board including an insulating layer formed using the resin sheet according to any one of claims 11 to 14. A semiconductor device comprising the printed wiring board according to claim 15.

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