JP2024180657A - Photosensitive resin composition containing low dielectric tangent agent - Google Patents

Abstract

The present invention aims to provide a photosensitive resin composition that exhibits a low dielectric tangent, has excellent storage stability, and is capable of forming a cured relief pattern with high resolution, a method for producing a polyimide using the photosensitive resin composition, a method for producing a cured relief pattern, and a semiconductor device having the cured relief pattern.
[Solution] The photosensitive resin composition comprises (A) 100 parts by mass of a polyimide precursor, (B) 0.1 to 10 parts by mass of a photosensitizer, (C) 1 to 50 parts by mass of a dielectric loss tangent reducing agent, and (D) 50 to 300 parts by mass of a solvent, and the (C) dielectric loss tangent reducing agent has a molecular weight of 100 to 3,500.
[Selection diagram] None

Description

The present invention relates to a photosensitive resin composition containing a low dielectric tangent agent, such as an insulating material for electronic components, and a negative photosensitive resin composition used to form relief patterns for passivation films, buffer coat films, interlayer insulating films, and the like in semiconductor devices, a method for producing a polyimide using the same, a method for producing a cured relief pattern, and a semiconductor device.

Conventionally, polyimide resins, which have excellent heat resistance, electrical properties, and mechanical properties, have been used as insulating materials for electronic components, and passivation films, surface protective films, and interlayer insulating films for semiconductor devices. Among these polyimide resins, those provided in the form of photosensitive polyimide precursor compositions can easily form heat-resistant relief pattern films by applying the composition, exposing it to light, developing it, and subjecting it to a thermal imidization treatment by curing. Such photosensitive polyimide precursor compositions have the characteristic of enabling significant process shortening compared to conventional non-photosensitive polyimide materials.

Meanwhile, semiconductor devices (hereinafter also referred to as "elements") are mounted on printed circuit boards using various methods depending on the purpose. Conventional elements were generally produced using a wire bonding method in which thin wires connect the external terminals (pads) of the element to the lead frame. However, as elements have become faster and the operating frequencies have reached the GHz range, differences in the wiring length of each terminal during mounting have come to affect the operation of the element. As a result, when mounting elements for high-end applications, it has become necessary to precisely control the length of the mounting wiring, and it has become difficult to meet this requirement using wire bonding.

Therefore, flip-chip mounting has been proposed, in which a rewiring layer is formed on the surface of a semiconductor chip, bumps (electrodes) are formed on the rewiring layer, and then the chip is flipped over and mounted directly on a printed circuit board. This flip-chip mounting allows for precise control of the wiring distance, and is therefore used in high-end devices that handle high-speed signals, and in mobile phones and other devices due to the small mounting size, and demand is rapidly expanding. More recently, a semiconductor chip mounting technology called fan-out wafer-level packaging (FOWLP) has been proposed, in which individual chips are manufactured by dicing a wafer that has undergone pre-processing, the individual chips are reconstructed on a support, sealed with molding resin, and a rewiring layer is formed after the support is peeled off (for example, Patent Document 1). Fan-out wafer-level packaging has the advantage of being able to reduce the height of the package, as well as enabling high-speed transmission and low costs.

JP 2005-167191 A

In recent years, there has been an urgent need to develop packages for the fifth-generation mobile communication system (5G), a new communication standard. 5G uses the millimeter wave (10 GHz to 80 GHz) frequency band, which enables high speed and large capacity, low signal latency, and simultaneous connection of multiple terminals, which were not possible with conventional communications. However, it is known that the dielectric tangent (tan δ) of insulating materials is high in high frequency ranges such as millimeter waves, causing transmission loss. To reduce transmission loss, antenna-in-package (AiP) has been developed, in which the antenna is integrated with the front-end module (FEM) that transmits and receives radio waves. However, the dielectric tangent of insulating materials has a large impact on transmission loss, so materials with a low dielectric tangent are required.

The present invention therefore aims to provide a photosensitive resin composition that exhibits a low dielectric tangent, has excellent storage stability, and is capable of forming a cured relief pattern with high resolution, a method for producing a polyimide using the photosensitive resin composition, a method for producing a cured relief pattern, and a semiconductor device having the cured relief pattern.

The present inventors have found that the above object can be achieved by combining a polyimide precursor with an agent for reducing dielectric tangent, and have completed the present invention.
[1]
(A) Polyimide precursor: 100 parts by mass,
(B) photosensitizer: 0.1 to 10 parts by mass,
(C) a dielectric loss tangent reducing agent: 1 to 50 parts by mass; and (D) a solvent: 50 to 300 parts by mass, wherein the (C) dielectric loss tangent reducing agent has a molecular weight of 100 to 3,500.
[2]
The (C) dielectric loss tangent reducing agent is represented by the following formula (I):
In the formula, R ₁ , R _4, and R ₅ are each independently a hydrogen atom, a methyl group, or a t-butyl group; R ₂ and R ₃ are each independently a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms; and Z is an organic group having 7 to 80 carbon atoms and containing at least one heteroatom selected from the group consisting of sulfur, phosphorus, oxygen, and nitrogen, or an organic group having 2 to 15 carbon atoms and containing a carbonyl group.
2. The photosensitive resin composition according to item 1, having a structure represented by the following formula:
[3]
The (C) dielectric loss tangent reducing agent is represented by the following formula (II):
In the formula, R ₁ , R ₄ , R ₅ , R ₆ , R ₇ , and R ₁₀ are each independently a hydrogen atom, a methyl group, or a t-butyl group; R ₂ , R ₃ , R ₈ , and R ₉ are each independently a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms; and Z is a divalent organic group having 1 to 50 carbon atoms containing at least one heteroatom selected from the group consisting of sulfur, phosphorus, oxygen, and nitrogen, or a divalent organic group having 1 to 75 carbon atoms.
3. The photosensitive resin composition according to item 1 or 2, having a structure represented by the following formula:
[4]
The (C) dielectric loss tangent reducing agent is represented by the following formula (III):
In the formula, R ₁ , R ₄ , R ₅ , R ₆ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ , and R ₁₅ are each independently a hydrogen atom, a methyl group, or a t-butyl group; R ₂ , R ₃ , R ₈ , R ₇ , R ₁₃ , and R ₁₄ are each independently a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms; and Z is a trivalent organic group having 1 to 50 carbon atoms containing at least one heteroatom selected from the group consisting of sulfur, phosphorus, oxygen, and nitrogen, or a trivalent organic group having 1 to 50 carbon atoms.
3. The photosensitive resin composition according to item 1 or 2, having a structure represented by the following formula:
[5]
5. The photosensitive resin composition according to any one of items 2 to 4, wherein Z has at least one heteroatom selected from the group consisting of sulfur, phosphorus, oxygen, and nitrogen.
[6]
(C) The dielectric loss tangent reducing agent is represented by the following formula:
{In the formula, Z is an organic group containing a carbonyl group and having 2 to 15 carbon atoms.}
3. The photosensitive resin composition according to item 1 or 2, having at least one structure represented by the following formula:
[7]
The (C) dielectric loss tangent reducing agent is represented by the following formula (IV):
In the formula, R ₁ , R ₄ , R ₅ , R ₆ , R ₇ , R ₁₀ , R ₁₁ , R ₁₂ , R ₁₅ , R ₁₆ , R ₁₉ , and R ₂₀ are each independently a hydrogen atom, a methyl group, or a t-butyl group; R ₂ , R ₃ , R ₈ , R ₉ , R ₁₃ , R ₁₄ , R ₁₇ , and R ₁₈ are each independently a hydrogen atom, a hydroxyl group, or an organic group having 1 to 50 carbon atoms; and Z is a tetravalent organic group having 1 to 50 carbon atoms containing at least one heteroatom selected from the group consisting of sulfur, phosphorus, oxygen, and nitrogen, or a tetravalent organic group having 1 to 50 carbon atoms.
3. The photosensitive resin composition according to item 1 or 2, having a structure represented by the following formula:
[8]
The polyimide precursor (A) is represented by the following general formula (1):
In formula (1), _X1 is a tetravalent organic group having 6 to 40 carbon atoms, _Y1 is a divalent organic group having 6 to 40 carbon atoms, _n1 is an integer from 2 to 150, and _R1 and _R2 are each independently a hydrogen atom or a monovalent organic group having 1 to 40 carbon atoms. However, at least one of _R1 and _R2 is represented by the following general formula (2):
(In formula (2), R ₃ , R ₄ and R ₅ are each independently a hydrogen atom or a monovalent organic group having 1 to 3 carbon atoms, and m ₁ is an integer of 2 to 10.)
It is a group represented by the following formula:
8. The photosensitive resin composition according to any one of items 1 to 7, wherein
[9]
The _Y1 is represented by the following formula (Y1):
In the formula, each Rz independently represents a monovalent organic group having 1 to 10 carbon atoms which may contain a halogen atom, a represents an integer of 0 to 4, A represents an oxygen atom or a sulfur atom, and B represents a group represented by the following formula:
It is one of the following.
Item 9. The photosensitive resin composition according to item 8, wherein the photosensitive resin composition is represented by the formula:
[10]
The Y ₁ is represented by the following formula:
Or the following formula:
Or the following formula:
Item 10. The photosensitive resin composition according to item 9, wherein the structure is represented by the formula:
[11]
The _X1 is represented by the following formula (X1):
In the formula, each Ry independently represents a monovalent organic group having 1 to 10 carbon atoms which may contain a halogen atom, a represents an integer of 0 to 4, C represents an oxygen atom or a sulfur atom, and D represents a group represented by the following formula:
It is one of the following.
11. The photosensitive resin composition according to any one of items 8 to 10, wherein
[12]
The X ₁ is represented by the following formula:
Or the following formula:
Item 12. The photosensitive resin composition according to item 11, wherein the structure is represented by:
[13]
13. The photosensitive resin composition according to any one of items 1 to 12, wherein the (B) photosensitizer is a photoradical polymerization initiator.
[14]
14. The photosensitive resin composition according to any one of items 1 to 13, which is a negative photosensitive resin composition.
[15]
A method for producing a cured film obtained from a photosensitive resin composition comprising 100 parts by mass of a polyimide precursor, 0.1 to 10 parts by mass of a photosensitizer, and 50 to 300 parts by mass of a solvent, the cured film being represented by the following formula (i):
0.001<(tanδ ₄₀ -tanδ ₁₀ )/tanδ ₁₀ <0.2 (i)
{wherein tan δ ₄₀ represents a dielectric tangent at a frequency of 40 GHz as measured by a perturbation type split cylinder resonator method, and tan δ ₁₀ represents a dielectric tangent at a frequency of 10 GHz as measured by a perturbation type split cylinder resonator method}.
[16]
A method for producing a cured film obtained from a photosensitive resin composition comprising 100 parts by mass of a polyimide precursor, 0.1 to 10 parts by mass of a photosensitizer, and 50 to 300 parts by mass of a solvent, the cured film being represented by the following formula (ii):
0.001<(tanδ ₆₀ -tanδ ₁₀ )/tanδ ₁₀ <0.29 (ii)
{wherein tan δ ₆₀ represents a dielectric tangent at a frequency of 60 GHz as measured by a perturbation type split cylinder resonator method, and tan δ ₁₀ represents a dielectric tangent at a frequency of 10 GHz as measured by a perturbation type split cylinder resonator method}.
[17]
A method for producing a cured film obtained from a photosensitive resin composition comprising 100 parts by mass of a polyimide precursor, 0.1 to 10 parts by mass of a photosensitizer, and 50 to 300 parts by mass of a solvent, the cured film being represented by the following formulas (i) and (ii):
0.001<(tanδ ₄₀ -tanδ ₁₀ )/tanδ ₁₀ <0.2 (i)
0.001<(tanδ ₆₀ -tanδ ₁₀ )/tanδ ₁₀ <0.29 (ii)
{wherein tan δ ₄₀ represents the dielectric tangent at a frequency of 40 GHz measured by a perturbation type split cylinder resonator method, tan δ ₁₀ represents the dielectric tangent at a frequency of 10 GHz measured by a perturbation type split cylinder resonator method, and tan δ ₆₀ represents the dielectric tangent at a frequency of 60 GHz measured by a perturbation type split cylinder resonator method}.
[18]
Item 18. The method for producing a cured film according to any one of Items 15 to 17, wherein the photosensitizer contained in the photosensitive resin composition is a photoradical polymerization initiator.
[19]
Item 19. The method for producing a cured film according to any one of items 15 to 18, wherein the photosensitive resin composition is a negative photosensitive resin composition.
[20]
20. The method for producing a cured film according to any one of items 15 to 19, wherein the photosensitive resin composition contains a low dielectric tangent agent.

According to the present invention, it is possible to provide a photosensitive resin composition that has good storage stability and a low dielectric loss tangent while maintaining the resolution of the relief pattern formed. In one embodiment, the dielectric loss tangent can be reduced by reducing the polarity of the cured film. In another embodiment, by mixing resins with good compatibility with each other, the composition can be stored without phase separation, and the resolution when the relief pattern is formed can be maintained.

The following provides a detailed description of the form for carrying out the present invention (hereinafter, abbreviated as "embodiment"). Note that the present invention is not limited to the following embodiment, and can be carried out in various modifications within the scope of the gist. Throughout this specification, when a plurality of structures represented by the same symbol in a general formula are present in a molecule, they are each independently selected and may be the same or different from each other, unless otherwise specified. Furthermore, structures represented by a common symbol in different general formulas are also each independently selected and may be the same or different from each other, unless otherwise specified.

[Photosensitive resin composition]
The photosensitive resin composition of the present embodiment contains (A) a polyimide precursor, (B) a photosensitizer, (C) a dielectric loss tangent reducing agent, and (D) a solvent. The composition includes other ingredients, each of which is described in turn below.

The photosensitive resin composition may be either negative or positive depending on the desired application, and is preferably negative from the viewpoint of the physical properties of the polyimide precursor (A) described below.

(A) Polyimide Precursor In the present embodiment, (A) a polyimide precursor is a resin component contained in the photosensitive resin composition, and is represented by the following general formula (1):
In formula (1), _X1 is a tetravalent organic group having 6 to 40 carbon atoms, _Y1 is a divalent organic group having 6 to 40 carbon atoms, _n1 is an integer from 2 to 150, and _R1 and _R2 are each independently a hydrogen atom or a monovalent organic group having 1 to 40 carbon atoms. However, at least one of _R1 and _R2 is represented by the following general formula (2):
(In formula (2), R ₃ , R ₄ and R ₅ are each independently a hydrogen atom or a monovalent organic group having 1 to 3 carbon atoms, and m ₁ is an integer of 2 to 10.)
It is a group represented by the following formula:
It is preferable that the polyamide has a structural unit represented by the following formula (1):

The ratio of the monovalent organic group represented by the above general formula (2) to all of R ₁ and R ₂ of the precursor represented by the above general formula (1) contained in the polyimide precursor (A) is preferably 50 mol % to 100 mol % from the viewpoint of high resolution, and more preferably 75 mol % to 100 mol % from the viewpoints of high chemical resistance and sensitivity.

In the above general formula (1), _n1 is preferably an integer from 3 to 100, and more preferably an integer from 5 to 70, from the viewpoint of the photosensitive properties and mechanical properties of the photosensitive resin composition.

In the above general formula (1), the tetravalent organic group represented by _X1 is preferably an organic group having 6 to 40 carbon atoms, from the viewpoint of achieving both heat resistance and photosensitive properties, and more preferably an aromatic group in which the _-COOR1 group, the _-COOR2 group, and the -CONH- group are in the ortho position relative to each other, or an alicyclic aliphatic group. Specific examples of the tetravalent organic group represented by _X1 include organic groups having 6 to 40 carbon atoms containing an aromatic ring, such as the following general formula (20):
{In formula (20), R6 is a monovalent group selected from the group consisting of a hydrogen atom, a fluorine atom, a C1-C10 hydrocarbon group, and a C1-C10 fluorine-containing hydrocarbon group, l is an integer selected from 0 to 2, m is an integer selected from 0 to 3, and n is an integer selected from 0 to 4.}
Examples of the structure represented by the formula (20) include, but are not limited to, a group having a structure represented by the formula (20). The structure represented by the formula (20 ₎ may be a single type or a combination of two or more types. The group represented by the formula ( ₂₀ ) is particularly preferred in that it has both heat resistance and photosensitive properties.

In addition, in the above general formula (1), the tetravalent organic group represented by _X1 is preferably represented by the following formula (X1):
In the formula, each Ry independently represents a monovalent organic group having 1 to 10 carbon atoms which may contain a halogen atom, a represents an integer of 0 to 4, C represents an oxygen atom or a sulfur atom, and D represents a group represented by the following formula:
It is one of the following.
It is preferably represented by the following formula:
Or the following formula:
It is more preferable that the structure is represented by the following formula:

In the above general formula (1), the divalent organic group represented by _Y1 is preferably an aromatic group having 6 to 40 carbon atoms in terms of achieving both heat resistance and photosensitive properties, and is, for example, a group represented by the following formula (21):
In formula (21), R6 is a monovalent group selected from the group consisting of a hydrogen atom, a fluorine atom, a C1 to C10 hydrocarbon group, and a C1 to C10 fluorine-containing hydrocarbon group, and n is an integer selected from 0 to 4.
Examples of the structure represented by the formula ( ₂₁ ) include, but are not limited to, the structure represented by the formula (21). The structure represented by the formula (21) may be a single type or a combination of two or more types. The structure represented by the formula ( ₂₁ ) is particularly preferred in that it provides both heat resistance and photosensitive properties.

As the _Y1 group, among the structures represented by the above formula (21), the following formula:
The structure represented by the following formula is preferred from the viewpoints of the imidization rate during low-temperature heating, degassing properties, copper adhesion, and chemical resistance.
The structure represented by the formula (1) is preferable from the viewpoint of low dielectric tangent.

In addition, in the above general formula (1), the divalent organic group represented by _Y1 is preferably represented by the following formula (Y1):
In the formula, each Rz independently represents a monovalent organic group having 1 to 10 carbon atoms which may contain a halogen atom, a represents an integer of 0 to 4, A represents an oxygen atom or a sulfur atom, and B represents a group represented by the following formula:
It is one of the following.
It is preferably represented by the following formula:
Or the following formula:
Or the following formula:
It is more preferable that the structure is represented by the following formula:

In the above general formula (2), _R3 is preferably a hydrogen atom or a methyl group, and _R4 and _R5 are preferably hydrogen atoms from the viewpoint of photosensitive properties. Also, _m1 is an integer of 2 to 10, preferably an integer of 2 to 4, from the viewpoint of photosensitive properties.

(A) Method for Preparing Polyimide Precursor The polyimide precursor containing the structure represented by the above general formula (1) in this embodiment can be obtained, for example, by a method comprising reacting a tetracarboxylic dianhydride containing a tetravalent organic group _X1 having 6 to 40 carbon atoms with (a) an alcohol having a structure in which a monovalent organic group represented by the above general formula (2) and a hydroxyl group are bonded, and, if desired, with (b) an alcohol having a structure other than the group represented by the above general formula (2) to prepare a partially esterified tetracarboxylic acid (hereinafter also referred to as an acid/ester body); and subsequently polycondensing the obtained acid/ester body with a diamine containing a divalent organic group _Y1 having 6 to 40 carbon atoms.

(Preparation of Acid/Ester Forms)
In this embodiment, examples of tetracarboxylic dianhydrides containing a tetravalent organic group X ₁ having 6 to 40 carbon atoms include pyromellitic anhydride, diphenylether-3,3',4,4'-tetracarboxylic dianhydride, benzophenone-3,3',4,4'-tetracarboxylic dianhydride, biphenyl-3,3',4,4'-tetracarboxylic dianhydride, diphenylsulfone-3,3',4,4'-tetracarboxylic dianhydride, diphenylmethane-3,3',4,4'-tetracarboxylic dianhydride, 2,2-bis(3,4-phthalic anhydride)propane, 2,2-bis(3,4-phthalic anhydride)-1,1,1,3,3,3-hexafluoropropane, etc. In addition, these can be used alone or in combination of two or more.

(b) Examples of alcohols having a structure other than the group represented by the general formula (2) above include aliphatic alcohols having 5 to 30 carbon atoms or aromatic alcohols having 6 to 30 carbon atoms, such as 1-pentanol, 2-pentanol, 3-pentanol, neopentyl alcohol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, 2-octanol, 3-octanol, 1-nonanol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, and benzyl alcohol.

The content of the organic group of general formula (2) in the polyimide precursor is preferably 50 mol % or more relative to the total content of R ₁ , R ₂ , R ₆ , and R _7. When the content of the organic group of general formula (2) exceeds 50 mol %, it is preferable since desired photosensitive characteristics can be obtained.
The content of the organic group of general formula (2) in the photosensitive resin composition is preferably 75 mol % or more based on the total content of R ₁ , R ₂ , R ₆ , and R ₇ .

By dissolving and mixing the above tetracarboxylic dianhydride and the above alcohol (a) in a reaction solvent in the presence of a basic catalyst such as pyridine, the half-esterification reaction of the acid dianhydride proceeds, and the desired acid/ester body can be obtained. The reaction conditions are preferably a reaction temperature of 20 to 50°C and stirring for 4 to 10 hours.

The reaction solvent is preferably one that dissolves the acid/ester and the polyimide precursor, which is a polycondensation product of the acid/ester and diamines. Examples of reaction solvents include N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, tetramethylurea, gamma butyrolactone, ketones, esters, lactones, ethers, halogenated hydrocarbons, hydrocarbons, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl acetate, ethyl acetate, butyl acetate, diethyl oxalate, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, dichloromethane, 1,2-dichloroethane, 1,4-dichlorobutane, chlorobenzene, o-dichlorobenzene, hexane, heptane, benzene, toluene, and xylene. These may be used alone or in combination as needed.

(Preparation of polyimide precursor)
A known dehydration condensation agent is mixed with the acid/ester (typically a solution in the reaction solvent) under ice cooling to convert the acid/ester into a polyacid anhydride, and then a diamine containing a divalent organic group _Y1 having 6 to 40 carbon atoms dissolved or dispersed in a separate solvent is added dropwise to the acid/ester to polycondense it, thereby obtaining a polyimide precursor. Examples of the dehydration condensation agent include dicyclohexylcarbodiimide, 1-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline, 1,1-carbonyldioxy-di-1,2,3-benzotriazole, N,N'-disuccinimidyl carbonate, and the like.

Examples of diamines containing a divalent organic group Y ₁ having 6 to 40 carbon atoms include p-phenylenediamine, m-phenylenediamine, 4,4-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminobiphenyl, 3,4'-diaminobiphenyl, 3,3'-diaminobiphenyl, 4,4'-diaminobenzophenone, 3,4' -diaminobenzophenone, 3,3'-diaminobenzophenone, 4,4'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 3,3'-diaminodiphenylmethane, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]sulfone, 4,4-bis(4-aminophenoxy)biphenyl, 4,4-bis(3-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]ether , bis[4-(3-aminophenoxy)phenyl]ether, 1,4-bis(4-aminophenyl)benzene, 1,3-bis(4-aminophenyl)benzene, 9,10-bis(4-aminophenyl)anthracene, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-aminophenyl)hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane, 1,4-bis(3-aminopropyldimethylsilyl)benzene, ortho-tolidine sulfone, 9,9-bis(4-aminophenyl)fluorene , 2,2-bis{3-methyl-4-(4-aminophenoxy)phenyl}propane, and those in which some of the hydrogen atoms on the benzene ring are substituted with a methyl group, an ethyl group, a hydroxymethyl group, a hydroxyethyl group, a halogen, or the like, such as 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 2,2'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dimethytoxy-4,4'-diaminobiphenyl, 3,3'-dichloro-4,4'-diaminobiphenyl, and mixtures thereof. However, the diamines are not limited to these.

In order to improve the adhesion between the photosensitive resin layer formed on a substrate by applying the photosensitive resin composition of this embodiment onto the substrate and various substrates, diaminosiloxanes such as 1,3-bis(3-aminopropyl)tetramethyldisiloxane and 1,3-bis(3-aminopropyl)tetraphenyldisiloxane can also be copolymerized during preparation of the polyimide precursor (A).

After the polycondensation reaction is completed, the water-absorbing by-product of the dehydrating condensing agent coexisting in the reaction solution may be filtered off as necessary, and then a poor solvent such as water, aliphatic lower alcohol, or a mixture thereof may be added to the reaction solution to precipitate the polymer component. The polymer may be purified by repeating the above-mentioned redissolution and reprecipitation operations. The polymer may then be vacuum-dried to isolate the polyimide precursor. To improve the degree of purification, the polymer solution may be passed through a column packed with an anion and/or cation exchange resin swollen with an appropriate organic solvent to remove ionic impurities.

The molecular weight of the polyimide precursor (A), as measured by gel permeation chromatography in terms of polystyrene equivalent weight average molecular weight, is preferably 8,000 to 150,000, more preferably 9,000 to 50,000, and particularly preferably 18,000 to 40,000. A weight average molecular weight of 8,000 or more is preferable because of good mechanical properties, while a weight average molecular weight of 150,000 or less is preferable because of good dispersibility in the developer and resolution performance of the relief pattern. Tetrahydrofuran and N-methyl-2-pyrrolidone are recommended as developing solvents for gel permeation chromatography. The molecular weight is determined from a calibration curve prepared using standard monodisperse polystyrene. It is recommended to select the standard monodisperse polystyrene from among the organic solvent-based standard samples STANDARD SM-105 manufactured by Showa Denko KK.

(B) Photosensitizer The photosensitive resin composition of the present embodiment contains a photosensitizer. In one embodiment, the photosensitizer may be a photopolymerization initiator. The photopolymerization initiator is preferable because it promotes curing of the relief pattern by light irradiation. The photopolymerization initiator is preferably a photoradical polymerization initiator, and examples of the photopolymerization initiator include benzophenone, o-benzoyl methyl benzoate, 4-benzoyl-4'-methyldiphenyl ketone, dibenzyl ketone, fluorenone and other benzophenone derivatives, 2,2'-diethoxyacetophenone, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone and other acetophenone derivatives, thioxanthone, 2-methylthioxanthone, 2-isopropylthioxanthone, diethylthioxanthone and other thioxanthone derivatives, benzyl derivatives, benzil, benzil dimethyl ketal, benzyl-β-methoxyethyl acetal and other benzyl derivatives, benzoin, benzoin methyl ether and other benzoin derivatives, 1-phenyl-1,2-butanedione-2-(o-methoxy Preferred examples of the photopolymerization initiator include, but are not limited to, oximes such as 1-phenyl-1,2-propanedione-2-(o-methoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-ethoxycarbonyl)oxime, 1-phenyl-1,2-propanedione-2-(o-benzoyl)oxime, 1,3-diphenylpropanetrione-2-(o-ethoxycarbonyl)oxime, and 1-phenyl-3-ethoxypropanetrione-2-(o-benzoyl)oxime, N-arylglycines such as N-phenylglycine, peroxides such as benzoyl perchloride, aromatic biimidazoles, titanocenes, and photoacid generators such as α-(n-octanesulfonyloxyimino)-4-methoxybenzyl cyanide. Of the above photopolymerization initiators, oximes are more preferred, particularly in terms of photosensitivity.

The amount of the photopolymerization initiator is preferably 0.1 parts by mass or more and 10 parts by mass or less, and more preferably 1 part by mass or more and 8 parts by mass or less, relative to 100 parts by mass of the polyimide precursor (A). The amount is preferably 0.1 parts by mass or more from the viewpoint of photosensitivity or patterning property, and 10 parts by mass or less from the viewpoint of the physical properties of the photosensitive resin layer after curing of the photosensitive resin composition.

(C) Dielectric Loss Tangent Reduction Agent The photosensitive resin composition of this embodiment contains a dielectric loss tangent reduction agent. The (C) dielectric loss tangent reduction agent is a compound that, when used as an additive in a resin composition, gives a cured film obtained from a composition of the (C) dielectric loss tangent reduction agent and a resin a dielectric loss tangent at 40 GHz that is 5 to 80% lower than the dielectric loss tangent of a resin composition that does not contain the (C) dielectric loss tangent reduction agent.

The molecular weight of the low dielectric tangent agent is preferably 5,000 or less, more preferably 3,500 or less, from the viewpoint of solubility, and is preferably 100 or more, from the viewpoint of low dielectric tangent.

(C) The structure of the low dielectric tangent agent is not limited as long as it reduces the dielectric tangent, but from the viewpoint of the thermal properties of the cured film, a substituted benzene structure is preferred. The substituent structure in the substituted benzene structure is not limited, but examples include alkyl groups, ester groups, ether groups, phenyl groups, hydroxy groups, ketone groups, carboxy groups, peroxide groups, amino groups, imino groups, imide groups, amide groups, isocyanate groups, sulfo groups, epoxy groups, fluoro groups, nitro groups, thiol groups, phosphonyl groups, and isocyanuric groups. From the viewpoint of low dielectric tangent, alkyl groups, ester groups, ether groups, amide groups, phenyl groups, and phosphonyl groups are preferred. Among these, from the viewpoint of low dielectric tangent, it is more preferred to have an alkyl group.

(C) The dielectric loss tangent reducing agent may have one, two or more, or three or more benzene structures in the same molecule. When the dielectric loss tangent reducing agent has one benzene structure, the compound represented by the following formula (I) may have one benzene structure in the same molecule.
In the formula, R ₁ , R _4, and R ₅ are each independently a hydrogen atom, a methyl group, or a t-butyl group; R ₂ and R ₃ are each independently a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms; and Z is an organic group having 7 to 80 carbon atoms and containing at least one heteroatom selected from the group consisting of sulfur, phosphorus, oxygen, and nitrogen, or an organic group having 2 to 15 carbon atoms and containing a carbonyl group.
A compound having a structure represented by the following formula is preferred.

In the case where there is one benzene structure, the (C) dielectric loss tangent reducing agent preferably has an organic group having 2 to 15 carbon atoms and containing a carbonyl group, and a benzene ring which may have a substituent, from the viewpoints of storage stability, relief pattern resolution, low dielectric tangent, low polarity, compatibility with resins, and the like, and is represented by the following formula:
{In the formula, Z is an organic group containing a carbonyl group and having 2 to 15 carbon atoms.}
It is more preferable that the compound has a structure represented by at least one of the following:

More specifically, examples of the (C) low dielectric tangent agent having one benzene structure include, but are not limited to, the following compound groups:

(C) In the case where the dielectric loss tangent reducing agent has two benzene structures in the same molecule, the compound represented by the following formula (II):
In the formula, R ₁ , R ₄ , R ₅ , R ₆ , R ₇ , and R ₁₀ are each independently a hydrogen atom, a methyl group, or a t-butyl group; R ₂ , R ₃ , R ₈ , and R ₉ are each independently a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms; and Z is a divalent organic group having 1 to 50 carbon atoms and containing at least one heteroatom selected from the group consisting of sulfur, phosphorus, oxygen, and nitrogen, or a divalent organic group having 1 to 75 carbon atoms.
The structure represented by the following formula is preferred.

More specifically, examples of the (C) low dielectric tangent agent having two benzene structures include, but are not limited to, the following compound groups:

(C) In the case where the dielectric loss tangent reducing agent has three benzene structures in one molecule, the dielectric loss tangent reducing agent has the following formula (III):
{In the formula, R ₁ , R ₄ , R ₅ , R ₆ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ , and R ₁₅ are each independently a hydrogen atom, a methyl group, or a t-butyl group; R ₂ , R ₃ , R ₈ , R ₇ , R ₁₃ , and R ₁₄ are each independently a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms; and Z is a trivalent organic group having 1 to 50 carbon atoms containing at least one heteroatom selected from the group consisting of sulfur, phosphorus, oxygen, and nitrogen, or a trivalent organic group having 1 to 50 carbon atoms.}
It is preferable that the compound has a structure represented by the following formula:

More specifically, examples of the (C) low dielectric tangent agent having three benzene structures include, but are not limited to, the following compound groups:

(C) In the case where the dielectric loss tangent reducing agent has four or more benzene structures in one molecule, the dielectric loss tangent reducing agent is represented by the following general formula (IV):
In the formula, R ₁ and R ₄ and R ₅ and R ₆ and R ₇ and R ₁₀ and R ₁₁ and R ₁₂ and R ₁₅ and R ₁₆ and R ₁₉ and R ₂₀ are each independently a hydrogen atom, a methyl group or a t-butyl group, R ₂ and R ₃ and R ₈ and R ₉ and R ₁₃ and R ₁₄ and R ₁₇ and R ₁₈ are each independently a hydrogen atom, a hydroxyl group or an organic group having 1 to 50 carbon atoms, and Z is a tetravalent organic group having 1 to 50 carbon atoms containing at least one heteroatom selected from sulfur, phosphorus, oxygen and nitrogen, or a tetravalent organic group having 1 to 50 carbon atoms. ), or the following general formula (V):
{In the formula, R ₁ , R ₂ , R ₄ , R ₅ , R ₆ , R ₇ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ , R ₁₄ , and R ₁₅ are each independently a hydrogen atom, a methyl group, or a t-butyl group; R ₃ , R _8, and R ₁₃ are each independently a hydrogen atom or an organic group having 1 to 10 carbon atoms; X is an organic group having 1 to 5 carbon atoms which may contain an oxygen atom; and Z is a hydrogen atom, or a trivalent organic group containing at least one heteroatom selected from sulfur, phosphorus, oxygen, and nitrogen, or a trivalent organic group having 1 to 50 carbon atoms.}, or the following general formula (VI):
{In the formula, R ₁ , R ₃ , R ₄ , R ₅ , R ₆ , R ₈ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ , and R ₁₅ are each independently a hydrogen atom, a methyl group, or a t-butyl group; R ₂ , R _7, and R ₁₄ are each independently a hydrogen atom or an organic group having 1 to 10 carbon atoms; X is an organic group having 1 to 5 carbon atoms which may contain an oxygen atom; and Z is a hydrogen atom, or a trivalent organic group containing at least one heteroatom selected from sulfur, phosphorus, oxygen, and nitrogen, or a trivalent organic group having 1 to 50 carbon atoms.}, or the following general formula (VII):
{In the formula, R ₁ , R ₂ , R ₄ , R ₅ , R ₆ , R ₇ , R ₉ , and R ₁₀ are each independently a hydrogen atom, a methyl group, or a t-butyl group, R ₃ and R ₈ are each independently a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms, R ₄ , R ₇ , and R ₁₂ are each independently a hydrogen atom or an organic group having 1 to 10 carbon atoms, X is an organic group having 1 to 5 carbon atoms which may contain an oxygen atom, and Z is a hydrogen atom, or a divalent organic group containing at least one heteroatom selected from sulfur, phosphorus, oxygen, and nitrogen, or a divalent organic group having 1 to 50 carbon atoms.} is preferable.

(C) In the case where the dielectric loss tangent reducing agent has four or more benzene structures in one molecule, examples of the compound include, but are not limited to, the following compounds:

The (C) low dielectric tangent agent can be obtained, for example, as a reaction product of a phenol compound and an acid chloride compound, although the synthesis method is not limited. Preferably, the (C) low dielectric tangent agent can be produced by obtaining a solution by adding and mixing a basic catalyst and a solvent to a phenol compound, and then adding an acid chloride compound to the solution and reacting it. The reaction is not particularly limited as long as the peak derived from the reaction residue disappears in liquid chromatography, but for example, the reaction temperature may be heated to 30°C after adding the acid chloride at -10°C to 0°C, or may be kept constant at -10°C to 0°C. After synthesis, the basic catalyst is removed through a column filled with a cation exchange resin, and the mixture is diluted with a solvent, separated and purified with a basic solution and water, and the solvent is distilled off with an evaporator to obtain the (C) low dielectric tangent agent. The cation exchange resin is not particularly limited, but it is preferable to use a weakly acidic ion exchange resin. Solvents used for separation include, but are not limited to, toluene, ethyl acetate, diethyl ether, dichloromethane, benzene, and hexane.

(C) Phenol compounds used in the synthesis reaction of the low dielectric tangent agent include, but are not limited to, structures represented by the following general formula:

(C) The acid chloride compound used in the synthesis reaction of the dielectric loss tangent enhancer includes, but is not limited to, structures represented by the following general formula:

The amount of the low dielectric tangent agent is preferably 0.1 parts by mass or more and 100 parts by mass or less, more preferably 1 part by mass or more and 60 parts by mass or less, more preferably 2 parts by mass or more and 50 parts by mass or less, and more preferably 5 parts by mass or more and 32 parts by mass or less, relative to 100 parts by mass of the polyimide precursor (A). The amount is preferably 0.1 parts by mass or more from the viewpoint of low dielectric tangent of the cured film, and 32 parts by mass or less from the viewpoint of photosensitivity or patterning property.

The photosensitive resin composition of the present embodiment contains the low dielectric tangent agent, and thus can provide a resin film with low dielectric tangent in the high frequency range (10 to 80 GHz) and low frequency dependency while maintaining resolution and storage stability. Although not bound by theory, the reason for the decrease in dielectric tangent is believed to be that the dipole moment of the low dielectric tangent agent (C) itself is small, which reduces the ratio of polar functional groups such as imide groups and amide groups in the entire film. Also, although not bound by theory, the reason for the low frequency dependency is believed to be that the polarity of the entire film is reduced, which reduces the water absorption rate during film formation. Also, although not bound by theory, the reason for maintaining resolution and storage stability is believed to be that the molecular weight is 100 to 3,500, and polyimide precursors with different polarities are mixed in the resin composition and in the cured film without phase separation.

(D) Solvent The photosensitive resin composition of this embodiment contains a solvent. As the solvent, it is preferable to use a polar organic solvent from the viewpoint of solubility in the polyimide precursor (A). Specific examples of the solvent include N,N-dimethylformamide, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N,N-dimethylacetamide, dimethylsulfoxide, diethylene glycol dimethyl ether, cyclopentanone, γ-butyrolactone, α-acetyl-γ-butyrolactone, tetramethylurea, 1,3-dimethyl-2-imidazolinone, N-cyclohexyl-2-pyrrolidone, and 2-octanone, which can be used alone or in combination of two or more.

The above solvent can be used in an amount ranging from, for example, 30 parts by mass to 1500 parts by mass, preferably 100 parts by mass to 1000 parts by mass, and more preferably 100 parts by mass to 860 parts by mass, per 100 parts by mass of the polyimide precursor (A), depending on the desired coating thickness and viscosity of the photosensitive resin composition.

From the viewpoint of improving the storage stability of the photosensitive resin composition, a solvent containing an alcohol is preferred. The alcohol that can be suitably used is typically an alcohol that has an alcoholic hydroxyl group in the molecule and does not have an olefinic double bond. Specific examples include alkyl alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, and tert-butyl alcohol; lactate esters such as ethyl lactate; propylene glycol monoalkyl ethers such as propylene glycol-1-methyl ether, propylene glycol-2-methyl ether, propylene glycol-1-ethyl ether, propylene glycol-2-ethyl ether, propylene glycol-1-(n-propyl) ether, and propylene glycol-2-(n-propyl) ether; monoalcohols such as ethylene glycol methyl ether, ethylene glycol ethyl ether, and ethylene glycol-n-propyl ether; 2-hydroxyisobutyric acid esters; and dialcohols such as ethylene glycol and propylene glycol. Of these, lactate esters, propylene glycol monoalkyl ethers, 2-hydroxyisobutyrate esters, and ethyl alcohol are preferred, with ethyl lactate, propylene glycol-1-methyl ether, propylene glycol-1-ethyl ether, and propylene glycol-1-(n-propyl) ether being particularly preferred.

When the solvent contains an alcohol that does not have an olefinic double bond, the content of the alcohol that does not have an olefinic double bond in the total solvent is preferably 5% by mass to 50% by mass, and more preferably 10% by mass to 30% by mass, based on the mass of the total solvent. When the content of the alcohol that does not have an olefinic double bond is 5% by mass or more, the storage stability of the photosensitive resin composition is good, while when it is 50% by mass or less, the solubility of the (A) polyimide precursor is good, which is preferable.

In one embodiment, in order to improve the resolution of the relief pattern, the photosensitive resin composition may optionally contain a monomer having a photopolymerizable unsaturated bond. As such a monomer, a (meth)acrylic compound that undergoes a radical polymerization reaction with a photopolymerization initiator is preferable, and examples thereof include, but are not limited to, mono- or diacrylates and methacrylates of ethylene glycol or polyethylene glycol, including diethylene glycol dimethacrylate and tetraethylene glycol dimethacrylate, mono- or diacrylates and methacrylates of propylene glycol or polypropylene glycol, mono-, di- or triacrylates and methacrylates of glycerol, cyclohexane diacrylate and dimethacrylate, diacrylates and dimethacrylates of 1,4-butanediol, 1,6-hexafluoropropanediol, and 1,6-hexafluoropropanediol. Examples of such compounds include diacrylate and dimethacrylate of Sandiol, diacrylate and dimethacrylate of neopentyl glycol, mono- or diacrylate and methacrylate of bisphenol A, benzene trimethacrylate, isobornyl acrylate and methacrylate, acrylamide and its derivatives, methacrylamide and its derivatives, trimethylolpropane triacrylate and methacrylate, di- or triacrylate and methacrylate of glycerol, di-, tri-, or tetraacrylate and methacrylate of pentaerythritol, and ethylene oxide or propylene oxide adducts of these compounds.

The amount of the monomer having a photopolymerizable unsaturated bond is preferably 1 to 50 parts by mass per 100 parts by mass of the polyimide precursor (A).

In one embodiment, the photosensitive resin composition may optionally contain an adhesion aid to improve adhesion between the film formed using the photosensitive resin composition and the substrate. Examples of the adhesion aid include γ-aminopropyldimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, 3-methacryloxypropyldimethoxymethylsilane, 3-methacryloxypropyltrimethoxysilane, dimethoxymethyl-3-piperidinopropylsilane, diethoxy-3-glycidoxypropylmethylsilane, N-(3-diethoxymethylsilylpropyl)succinimide, N-[3-(triethoxysilyl)propyl]phthalamine, and the like. Examples of such additives include silane coupling agents such as benzophenone-3,3'-bis(N-[3-triethoxysilyl]propylamide)-4,4'-dicarboxylic acid, benzene-1,4-bis(N-[3-triethoxysilyl]propylamide)-2,5-dicarboxylic acid, 3-(triethoxysilyl)propyl succinic anhydride, and N-phenylaminopropyl trimethoxysilane, as well as aluminum-based adhesion promoters such as aluminum tris(ethylacetoacetate), aluminum tris(acetylacetonate), and ethylacetoacetate aluminum diisopropylate.

Among these adhesive aids, it is more preferable to use a silane coupling agent in terms of adhesive strength. The amount of adhesive aid to be added is preferably in the range of 0.5 to 25 parts by mass per 100 parts by mass of (A) polyimide precursor.

In one embodiment, the photosensitive resin composition may optionally contain a thermal polymerization inhibitor in order to improve the stability of the viscosity and photosensitivity of the photosensitive resin composition during storage, particularly in the form of a solution containing a solvent. Examples of the thermal polymerization inhibitor include hydroquinone, N-nitrosodiphenylamine, p-tert-butylcatechol, 4-methoxyphenol, phenothiazine, N-phenylnaphthylamine, ethylenediaminetetraacetic acid, 1,2-cyclohexanediaminetetraacetic acid, glycol ether diaminetetraacetic acid, 2,6-di-tert-butyl-p-methylphenol, 5-nitroso-8-hydroxyquinoline, 1-nitroso-2-naphthol, 2-nitroso-1-naphthol, 2-nitroso-5-(N-ethyl-N-sulfopropylamino)phenol, N-nitroso-N-phenylhydroxylamine ammonium salt, and N-nitroso-N(1-naphthyl)hydroxylamine ammonium salt.

The amount of thermal polymerization inhibitor to be added is preferably in the range of 0.005 parts by mass to 12 parts by mass per 100 parts by mass of (A) polyimide precursor.

For example, when a substrate made of copper or a copper alloy is used, the photosensitive resin composition may optionally contain an azole compound in order to suppress discoloration of the substrate. Examples of the azole compound include 1H-triazole, 5-methyl-1H-triazole, 5-ethyl-1H-triazole, 4,5-dimethyl-1H-triazole, 5-phenyl-1H-triazole, 4-t-butyl-5-phenyl-1H-triazole, 5-hydroxyphenyl-1H-triazole, phenyltriazole, p-ethoxyphenyltriazole, 5-phenyl-1-(2-dimethylaminoethyl)triazole, 5-benzyl-1H-triazole, hydroxyphenyltriazole, 1,5-dimethyltriazole, 4,5-diethyl-1H-triazole, 1H-benzotriazole, 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-benzotriazole, and the like. benzotriazole, 2-(3,5-di-t-butyl-2-hydroxyphenyl)benzotriazole, 2-(3-t-butyl-5-methyl-2-hydroxyphenyl)-benzotriazole, 2-(3,5-di-t-amyl-2-hydroxyphenyl)benzotriazole, 2-(2'-hydroxy-5'-t-octylphenyl)benzotriazole, hydroxyphenylbenzotriazole, tolyltriazole, 5-methyl-1H-benzotriazole, 4-methyl-1H-benzotriazole, 4-carboxy-1H-benzotriazole, 5-carboxy-1H-benzotriazole, 1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 5-amino-1H-tetrazole, 1-methyl-1H-tetrazole, etc. Particularly preferred are tolyltriazole, 5-methyl-1H-benzotriazole, and 4-methyl-1H-benzotriazole. These azole compounds may be used alone or in a mixture of two or more.

The amount of the azole compound is preferably 0.1 to 20 parts by mass per 100 parts by mass of the polyimide precursor (A), and more preferably 0.5 to 5 parts by mass from the viewpoint of photosensitivity characteristics. When the amount of the azole compound per 100 parts by mass of the polyimide precursor (A) is 0.1 part by mass or more, discoloration of the copper or copper alloy surface is suppressed when the photosensitive resin composition is formed on copper or a copper alloy, while when the amount is 20 parts by mass or less, photosensitivity is excellent, which is preferable.

In this embodiment, in order to suppress discoloration on copper, the photosensitive resin composition may contain a hindered phenol compound. Examples of the hindered phenol compound include 2,6-di-t-butyl-4-methylphenol, 2,5-di-t-butyl-hydroquinone, octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 4,4'-methylenebis(2,6-di-t-butylphenol), 4,4'-thio-bis(3-methyl-6-t-butylphenol), 4,4'-butylyl 1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], N,N'-hexamethylenebis(3,5-di-t-butyl-4-hydroxy-hydrogen) rosinamide), 2,2'-methylene-bis(4-methyl-6-t-butylphenol), 2,2'-methylene-bis(4-ethyl-6-t-butylphenol), pentaerythrityl-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], tris-(3,5-di-t-butyl-4-hydroxybenzyl)-isocyanurate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene, 1 ,3,5-tris(3-hydroxy-2,6-dimethyl-4-isopropylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-s-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-t lion, 1,3,5-tris[4-(1-ethylpropyl)-3-hydroxy-2,6-dimethylbenzyl]-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris[4-triethylmethyl-3-hydroxy-2,6-dimethylbenzyl]-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(3-hydroxy-2,6-dimethyl-4-phenylbenzyl)-1,3,5-triazine-2,4,6- (1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-3-hydroxy-2,5,6-trimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-5-ethyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-6-ethyl-3-hydroxy-2-methylbenzyl)-1, 3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-6-ethyl-3-hydroxy-2,5-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-5,6-diethyl-3-hydroxy-2-methylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-3-hydroxy- 2-methylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-3-hydroxy-2,5-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, 1,3,5-tris(4-t-butyl-5-ethyl-3-hydroxy-2-methylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione, etc., but are not limited thereto. Among these, 1,3,5-tris(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6-(1H,3H,5H)-trione is particularly preferred.

The amount of the hindered phenol compound is preferably 0.1 to 20 parts by mass per 100 parts by mass of the polyimide precursor (A), and more preferably 0.5 to 10 parts by mass from the viewpoint of photosensitivity characteristics. When the amount of the hindered phenol compound per 100 parts by mass of the polyimide precursor (A) is 0.1 part by mass or more, for example, when the photosensitive resin composition is formed on copper or a copper alloy, discoloration and corrosion of the copper or copper alloy is prevented, while when the amount is 20 parts by mass or less, photosensitivity is excellent, which is preferable.

In one embodiment, the photosensitive resin composition may contain an organotitanium compound. By containing an organotitanium compound, a photosensitive resin layer having excellent chemical resistance can be formed even when cured at a low temperature of about 250°C.

Examples of organotitanium compounds that can be used include those in which an organic chemical is bonded to a titanium atom via a covalent or ionic bond.

Specific examples of the organotitanium compound are shown below in I) to VII):
I) As the titanium chelate compound, a titanium chelate having two or more alkoxy groups is more preferable because it provides storage stability of the photosensitive resin composition and a good pattern. Specific examples of the titanium chelate compound include titanium bis(triethanolamine)diisopropoxide, titanium di(n-butoxide)bis(2,4-pentanedionate), titanium diisopropoxide bis(2,4-pentanedionate), titanium diisopropoxide bis(tetramethylheptanedionate), titanium diisopropoxide bis(ethylacetoacetate), etc.

II) Examples of tetraalkoxytitanium compounds include titanium tetra(n-butoxide), titanium tetraethoxide, titanium tetra(2-ethylhexoxide), titanium tetraisobutoxide, titanium tetraisopropoxide, titanium tetramethoxide, titanium tetramethoxypropoxide, titanium tetramethylphenoxide, titanium tetra(n-nonyloxide), titanium tetra(n-propoxide), titanium tetrastearyloxide, and titanium tetrakis[bis{2,2-(allyloxymethyl)butoxide}].

III) Examples of titanocene compounds include pentamethylcyclopentadienyltitanium trimethoxide, bis(η ⁵ -2,4-cyclopentadiene-1-yl)bis(2,6-difluorophenyl)titanium, and bis(η ⁵ -2,4-cyclopentadiene-1-yl)bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium.

IV) Examples of monoalkoxytitanium compounds include titanium tris(dioctylphosphate) isopropoxide, titanium tris(dodecylbenzenesulfonate) isopropoxide, etc.

V) Examples of titanium oxide compounds include titanium oxide bis(pentanedionate), titanium oxide bis(tetramethylheptanedionate), phthalocyanine titanium oxide, etc.

VI) Examples of titanium tetraacetylacetonate compounds include titanium tetraacetylacetonate.

VII) Examples of titanate coupling agents include isopropyl tridodecylbenzenesulfonyl titanate, etc.

Among the above I) to VII), the organic titanium compound is preferably at least one compound selected from the group consisting of the above I) titanium chelate compounds, II) tetraalkoxytitanium compounds, and III) titanocene compounds, from the viewpoint of exhibiting better chemical resistance. In particular, titanium diisopropoxide bis(ethylacetoacetate), titanium tetra(n-butoxide), and bis(η ⁵ -2,4-cyclopentadiene-1-yl)bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium are preferred.

When an organic titanium compound is blended, the blending amount is preferably 0.05 parts by mass to 10 parts by mass, and more preferably 0.1 parts by mass to 2 parts by mass, per 100 parts by mass of the (A) resin. When the blending amount is 0.05 parts by mass or more, good heat resistance and chemical resistance are exhibited, while when the blending amount is 10 parts by mass or less, excellent storage stability is obtained, which is preferable.

[Polyimide]
The structure of the polyimide contained in the cured relief pattern formed from the polyimide precursor composition is preferably represented by the following general formula (11).
{In general formula (11), ^X1 and ^Y1 are the same as _X1 and _Y1 in general formula (1), and m is a positive integer.}
For the same reason, the preferred _X1 and _Y1 in the general formula (1) are also preferred in the polyimide of the general formula (11). The number m of repeating units in the general formula (11) is not particularly limited, but may be an integer of 2 to 150.
According to the present invention, there can also be provided a method for producing a polyimide, which includes a step of converting the above-described photosensitive resin composition into a polyimide.

[Cured film and method for producing same]
In another embodiment of the present invention, there is provided a cured film obtained from the above-described photosensitive resin composition and a method for producing the same, wherein the cured film has a structure represented by the following formula (i) and/or (ii):
0.001<(tanδ ₄₀ -tanδ ₁₀ )/tanδ ₁₀ <0.2 (i)
{wherein tan δ ₄₀ represents the dielectric tangent at a frequency of 40 GHz as measured by the perturbation type split cylinder resonator method, and tan δ ₁₀ represents the dielectric tangent at a frequency of 10 GHz as measured by the perturbation type split cylinder resonator method}
0.001<(tanδ ₆₀ -tanδ ₁₀ )/tanδ ₁₀ <0.29 (ii)
{wherein tan δ ₆₀ represents the dielectric tangent at a frequency of 60 GHz as measured by a perturbation type split cylinder resonator method, and tan δ ₁₀ represents the dielectric tangent at a frequency of 10 GHz as measured by a perturbation type split cylinder resonator method}
The relationship expressed as:

When the above formula (1) and/or (ii) is satisfied, the polarity of the cured film can be reduced, thereby reducing the dielectric loss tangent, and by mixing the resins with good compatibility with each other, the resins can be stored without phase separation, and the resolution during the formation of a relief pattern tends to be maintained.
0.002<(tan δ ₄₀ -tan _{δ 10} )/tan δ ₁₀ <0.1909; and/or 0.002<(tan δ ₆₀ -tan δ ₁₀ )/tan δ ₁₀ <0.2789
It is preferable that the dielectric loss tangent satisfies the following: The dielectric loss tangent can be measured by a perturbation type split cylinder resonator method shown in the examples described later.

From the viewpoint of satisfying the above formula (1) and/or (ii), the photosensitive resin composition used in the method for producing a cured film preferably contains 100 parts by mass of a polyimide precursor, 0.1 to 10 parts by mass of a photosensitizer, and 50 to 300 parts by mass of a solvent, more preferably contains a photoradical polymerization initiator as a photosensitizer and/or contains a low dielectric tangent agent, and further preferably the photosensitive resin composition is negative type.

The specific steps in the method for producing a cured film can be performed according to steps (1) to (4) of the method for producing a cured relief pattern described below.

[Cured relief pattern]
According to the present invention, it is possible to provide a cured relief pattern using the above-described photosensitive resin composition, and a method for producing the same. In one embodiment, the method for producing the cured relief pattern includes the following steps (1) to (4):
(1) applying the photosensitive resin composition according to the present embodiment onto a substrate to form a photosensitive resin layer on the substrate;
(2) a step of exposing the photosensitive resin layer to light;
(3) developing the exposed photosensitive resin layer to form a relief pattern; and (4) heat-treating the relief pattern to form a hardened relief pattern.

Each step will be described below.
(1) Step of applying the photosensitive resin composition of the present embodiment onto a substrate to form a photosensitive resin layer on the substrate In this step, the photosensitive resin composition of the present embodiment is applied onto a substrate, and then dried as necessary to form a photosensitive resin layer. As the application method, a method that has been conventionally used for applying a photosensitive resin composition, such as a method of applying with a spin coater, a bar coater, a blade coater, a curtain coater, a screen printer, etc., or a method of spray application with a spray coater, etc., can be used.

If necessary, the coating film made of the photosensitive resin composition can be dried, and examples of the drying method include air drying, heat drying in an oven or on a hot plate, and vacuum drying. It is desirable to dry the coating film under conditions that do not cause imidization of the (A) polyimide precursor in the photosensitive resin composition. Specifically, when air drying or heat drying is performed, drying can be performed at 20°C to 140°C for 1 minute to 1 hour. In this manner, a photosensitive resin layer can be formed on the substrate.

(2) Step of Exposing the Photosensitive Resin Layer In this step, the photosensitive resin layer formed in the above step (1) is exposed to an ultraviolet light source or the like through a photomask or reticle having a pattern, or directly, using an exposure device such as a contact aligner, a mirror projection, or a stepper.

After this, for the purpose of improving the photosensitivity, etc., a post-exposure bake (PEB) and/or a pre-development bake may be performed at any combination of temperature and time as necessary. The range of baking conditions is preferably a temperature of 40°C to 120°C and a time of 10 seconds to 240 seconds, but is not limited to this range as long as it does not impair the various properties of the negative photosensitive resin composition.

(3) Step of developing the exposed photosensitive resin layer to form a relief pattern In this step, when the photosensitive resin composition is a negative type, the unexposed portion of the exposed photosensitive resin layer is developed and removed. As a development method for developing the exposed (irradiated) photosensitive resin layer, any method can be selected from conventionally known photoresist development methods, such as a rotary spray method, a paddle method, and a dipping method accompanied by ultrasonic treatment. After development, for the purpose of adjusting the shape of the relief pattern, post-development baking may be performed at any combination of temperature and time, as necessary. As a developer used for development, for example, a good solvent for the negative photosensitive resin composition, or a combination of the good solvent and a poor solvent is preferable. As a good solvent, for example, N-methyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, N,N-dimethylacetamide, cyclopentanone, cyclohexanone, γ-butyrolactone, α-acetyl-γ-butyrolactone, etc. are preferable. As the poor solvent, for example, toluene, xylene, methanol, ethanol, isopropyl alcohol, ethyl lactate, propylene glycol methyl ether acetate, water, etc. are preferable. When a good solvent and a poor solvent are used in combination, it is preferable to adjust the ratio of the poor solvent to the good solvent depending on the solubility of the polymer in the negative photosensitive resin composition. In addition, two or more kinds of each solvent, for example, several kinds, can be used in combination.

(4) Step of Heating the Relief Pattern to Form a Cured Relief Pattern In this step, the relief pattern obtained by the above development is heated to disperse the photosensitive component and also imidize the polyimide precursor (A) to convert it into a cured relief pattern made of polyimide. As a method of heat curing, various methods can be selected, such as a method using a hot plate, an oven, or a method using a temperature-programmable heating oven. Heating can be performed, for example, under conditions of 150°C to 400°C for 30 minutes to 5 hours. Air may be used as the atmospheric gas during heat curing, or an inert gas such as nitrogen or argon may also be used.

[Semiconductor device]
The photosensitive resin composition of the present embodiment can also provide a semiconductor device having a cured relief pattern obtained by the above-mentioned method for producing a cured relief pattern. Thus, a semiconductor device can be provided having a substrate that is a semiconductor element and a cured relief pattern of polyimide formed on the substrate by the above-mentioned method for producing a cured relief pattern. The present invention can also be applied to a method for producing a semiconductor device that uses a semiconductor element as the substrate and includes the above-mentioned method for producing a cured relief pattern as part of the process. The semiconductor device of the present invention can be produced by forming the cured relief pattern formed by the above-mentioned method for producing a cured relief pattern as a surface protective film, an interlayer insulating film, an insulating film for rewiring, a protective film for a flip chip device, or a protective film for a semiconductor device having a bump structure, and combining the method with a known method for producing a semiconductor device.

[Display device]
The photosensitive resin composition of the present embodiment can also provide a display device comprising a display element and a cured film provided on the upper portion of the display element, the cured film being the above-mentioned cured relief pattern. Here, the cured relief pattern may be laminated in direct contact with the display element, or may be laminated with another layer sandwiched therebetween. For example, the cured film can be a surface protective film, an insulating film, and a planarizing film for a TFT liquid crystal display element and a color filter element, a protrusion for an MVA type liquid crystal display device, and a partition wall for a cathode of an organic EL element.

In addition to being applicable to the semiconductor devices described above, the photosensitive resin composition of the present invention is also useful for applications such as interlayer insulation in multilayer circuits, cover coats for flexible copper-clad boards, solder resist films, and liquid crystal alignment films.

The present embodiment will be described in detail below with reference to examples, but the present embodiment is not limited thereto. In the examples, comparative examples, and production examples, the physical properties of the photosensitive resin composition were measured and evaluated according to the following methods.

[Measurement and evaluation methods]
(1) Weight-average molecular weight The weight-average molecular weight (Mw) of each resin was measured by gel permeation chromatography (standard polystyrene equivalent). The column used in the measurement was a "Shodex 805M/806M series" manufactured by Showa Denko K.K., the standard monodisperse polystyrene was "Shodex STANDARD SM-105" manufactured by Showa Denko K.K., the developing solvent was N-methyl-2-pyrrolidone, and the detector was "Shodex RI-930" manufactured by Showa Denko K.K.

(2) Esterification rate The progress of the reaction between the phenol compound and the acid chloride was measured by gel permeation chromatography. The column used in the measurement was "Shodex 802/801/801 in series" manufactured by Showa Denko K.K. The developing solvent was tetrahydrofuran, and the detector was "Shodex RI-930" manufactured by Showa Denko K.K. The reaction was considered to be complete when the integral ratio of the peak derived from the acid chloride became 1% or less of the total peak integral ratio.

(3) Resolution of the cured relief pattern on Cu A 6-inch silicon wafer (manufactured by Fujimi Electronics Co., Ltd., thickness 625±25 μm) was sputtered with a 200 nm thick Ti film and a 400 nm thick Cu film in this order using a sputtering device (L-440S-FHL type, manufactured by Canon Anelva Corporation). Next, a photosensitive resin composition prepared by the method described below was spin-coated on this wafer using a coater developer (D-Spin 60A type, manufactured by SOKUDO Co., Ltd.), and dried to form a coating film with a thickness of 10 μm. This coating film was irradiated with energy of 250 mJ/cm ² using a test pattern mask and a Prisma GHI (manufactured by Ultratech Co., Ltd.) equipped with an i-line filter. The coating was then spray-developed with a coater developer (D-Spin 60A type, manufactured by Sokudo Co., Ltd.) using cyclopentanone as a developer, and rinsed with propylene glycol methyl ether acetate to obtain a relief pattern on Cu.
The wafer on which the relief pattern was formed on Cu was subjected to a heat treatment in a temperature-rising programmable curing furnace (VF-2000 type, manufactured by Koyo Lindberg) at 230° C. for 2 hours in a nitrogen atmosphere to obtain a cured relief pattern made of resin having a thickness of approximately 6 to 7 μm on Cu.
The relief pattern thus produced was observed under an optical microscope to determine the size of the minimum opening pattern. If the area of the opening of the obtained pattern was 1/2 or more of the area of the corresponding opening in the pattern mask, the pattern was deemed resolved, and the length of the side of the mask opening corresponding to the opening having the smallest area among the resolved openings was taken as the resolution.
"Excellent": The minimum opening pattern size is less than 10 μm. "Good": The minimum opening pattern size is 10 μm or more and less than 14 μm. "Fair": The minimum opening pattern size is 14 μm or more and less than 18 μm. "Unfair": The minimum opening pattern size is 18 μm or more.

(4) Storage stability evaluation After preparing the photosensitive resin composition, the composition was stirred for 3 days at room temperature (23.0°C ± 0.5°C, relative humidity 50% ± 10%) and then the state was evaluated. As a result of the evaluation, a state in which the whole was mixed was rated as "good", and a state in which phase separation occurred in the resin composition was rated as "poor".

(5) Measurement of Dielectric Constant and Dielectric Loss Tangent A 100 nm-thick aluminum (Al) was sputtered onto a 6-inch silicon wafer (manufactured by Fujimi Electronics Co., Ltd., thickness 625±25 μm) using a sputtering device (L-440S-FHL type, manufactured by Canon Anelva Corporation) to prepare a sputtered Al wafer substrate.
The negative photosensitive resin composition was spin-coated on the sputtered Al wafer substrate using a spin coater (D-spin 60A type, manufactured by SOKUDO Co., Ltd.), and dried by heating at 110 ° C. for 180 seconds to prepare a spin-coated film. Thereafter, the entire surface was exposed to ghi rays at an exposure dose of 600 mJ / cm ² using an aligner (PLA-501F, manufactured by Canon Co., Ltd.), and a cured film was prepared by subjecting the substrate to a heat curing treatment at 230 ° C. for 2 hours under a nitrogen atmosphere using a vertical curing furnace (manufactured by Koyo Lindberg, model name VF-2000B). The thickness of the cured film was measured by the method described below. This cured film was cut into a length of 80 mm, a width of 60 mm, or a length of 40 mm, a width of 30 mm using a dicing saw (manufactured by Disco, model name DAD-2H / 6T), and immersed in a 10% hydrochloric acid aqueous solution to peeling from the silicon wafer to prepare a film sample.

The relative dielectric constant and dielectric loss tangent of the film sample were calculated at 10, 28, 40, and 60 GHz by a resonator perturbation method. The details of the measurement method are as follows.
(Measurement method)
Perturbation split cylinder resonator method (device configuration)
Network analyzer: PNA Network analyzer E5224B
(Agilent Technologies)
Split cylinder resonator: CR-710 (manufactured by Kanto Electronics Application Development Co., Ltd., measurement frequency: about 10 GHz), CR-728 (manufactured by Kanto Electronics Application Development Co., Ltd., measurement frequency: about 28 GHz), CR-740 (manufactured by Kanto Electronics Application Development Co., Ltd., measurement frequency: about 40 GHz), CR-760 (manufactured by Kanto Electronics Application Development Co., Ltd., measurement frequency: about 60 GHz)

(6) Film Thickness Measurement A 100 nm-thick aluminum (Al) was sputtered onto a 6-inch silicon wafer (manufactured by Fujimi Electronics Co., Ltd., thickness 625±25 μm) using a sputtering device (L-440S-FHL type, manufactured by Canon Anelva Corporation) to prepare a sputtered Al wafer substrate.
The negative photosensitive resin composition was spin-coated on the sputtered Al wafer substrate using a spin coater (D-spin 60A type, manufactured by SOKUDO Corporation), and dried by heating at 110 ° C. for 180 seconds to produce a spin-coated film. Thereafter, the entire surface was exposed to ghi rays at an exposure dose of 600 mJ / cm ² using an aligner (PLA-501F, manufactured by Canon Corporation), and a heat curing treatment was performed at 230 ° C. for 2 hours under a nitrogen atmosphere using a vertical curing furnace (manufactured by Koyo Lindberg, model name VF-2000B) to produce a cured film. The film thickness of the cured film was measured using a step gauge (P-15, manufactured by KLA-Tenchore Corporation).

<Production Example 1> (A) Synthesis of polyimide precursor (polymer A-1)
155.1 g of 4,4'-oxydiphthalic dianhydride (ODPA) was placed in a 2-liter separable flask, 134.0 g of 2-hydroxyethyl methacrylate (HEMA) and 400 ml of γ-butyrolactone were added, and 79.1 g of pyridine was added while stirring at room temperature to obtain a reaction mixture. After the heat generation due to the reaction had ceased, the mixture was allowed to cool to room temperature and then left to stand for another 16 hours.

Next, under ice cooling, a solution of 206.3 g of dicyclohexylcarbodiimide (DCC) dissolved in 180 ml of γ-butyrolactone was added to the reaction mixture over 40 minutes while stirring, followed by a suspension of 93.0 g of 4,4'-oxydianiline (ODA) suspended in 350 ml of γ-butyrolactone, which was added over 60 minutes while stirring. After further stirring at room temperature for 2 hours, 30 ml of ethyl alcohol was added and stirred for 1 hour, after which 400 ml of γ-butyrolactone was added. The precipitate formed in the reaction mixture was removed by filtration to obtain a reaction liquid.

The obtained reaction solution was added to 3 liters of ethyl alcohol to produce a precipitate consisting of a crude polymer. The produced crude polymer was filtered and dissolved in 1.5 liters of tetrahydrofuran to obtain a crude polymer solution. The obtained crude polymer solution was purified using an anion exchange resin ("Amberlyst ^TM 15" manufactured by Organo Corporation) to obtain a polymer solution. The obtained polymer solution was dropped into 28 liters of water to precipitate the polymer, and the obtained precipitate was filtered and then vacuum dried to obtain a powdered polymer A-1.
The weight average molecular weight (Mw) of this polymer A-1 was measured and found to be 22,000.

<Production Example 2> (Synthesis of polyimide precursor (polymer A-2))
Polymer A-2 was obtained by carrying out the reaction in the same manner as in Production Example 1, except that 175.9 g of 2,2-bis{4-(4-aminophenoxy)phenyl}propane (BAPP) was used instead of 93.0 g of ODA in Production Example 1.
The weight average molecular weight (Mw) of this polymer A-2 was measured and found to be 24,000.

<Production Example 3> (Synthesis of polyimide precursor (polymer A-3))
Polymer A-3 was obtained by carrying out the reaction in the same manner as in Production Example 1, except that 169.9 g of bis{4-(4-aminophenoxy)phenyl}ketone was used instead of 93.0 g of ODA in Production Example 1.
The weight average molecular weight (Mw) of this polymer A-3 was measured and found to be 21,000.

<Production Example 4> (Synthesis of polyimide precursor (polymer A-4))
Polymer A-4 was obtained by carrying out the reaction in the same manner as in Production Example 1, except that 260.2 g of 4,4'-(4,4'-isopropylidenediphenoxy) acid dianhydride was used instead of 155.1 g of ODPA, and 175.9 g of BAPP was used instead of 93.0 g of ODA in Production Example 1.
The weight average molecular weight (Mw) of this polymer A-4 was measured and found to be 29,000.

<Production Example 5> (Synthesis of polyimide precursor (polymer A-5))
Polymer A-5 was obtained by carrying out a reaction in the same manner as in Production Example 1, except that in Production Example 2, 260.2 g of 4,4'-(4,4'-isopropylidenediphenoxy) acid dianhydride was used instead of 155.1 g of ODPA, and 169.9 g of bis{4-(4-aminophenoxy)phenyl}ketone was used instead of 93.0 g of ODA.
The weight average molecular weight (Mw) of this polymer A-5 was measured and found to be 28,000.

<Production Example 6> (Synthesis of polyimide precursor (polymer A-6))
Polymer A-6 was obtained by carrying out the reaction in the same manner as in Production Example 1, except that 77.6 g of ODPA and 130.1 g of 4,4'-(4,4'-isopropylidenediphenoxy) acid dianhydride were used instead of 155.1 g of ODPA, and 175.9 g of BAPP were used instead of 93.0 g of ODA in Production Example 1. The weight average molecular weight (Mw) of this polymer A-6 was measured and found to be 24,000.

<Production Example 7> (Synthesis of polyimide precursor (polymer A-7))
Polymer A-7 was obtained by carrying out the reaction in the same manner as in Production Example 1, except that 73.6 g of BPDA and 130.1 g of 4,4'-(4,4'-isopropylidenediphenoxy) acid dianhydride were used instead of 155.1 g of ODPA, and 175.9 g of BAPP were used instead of 93.0 g of ODA in Production Example 1.
The weight average molecular weight (Mw) of this polymer A-7 was measured and found to be 24,000.

<Production Example 8> (Synthesis of polyimide precursor (polymer A-8))
Polymer A-8 was obtained by carrying out a reaction in the same manner as in Production Example 1, except that 219.3 g of 2,2-bis{3-methyl-4-(4-aminophenoxy)phenyl}propane (MBAPP) was used instead of 93.0 g of ODA in Production Example 1.
The weight average molecular weight (Mw) of this polymer A-8 was measured and found to be 25,000.

<Production Example 9> (Synthesis of low dielectric tangent agent C-1)
38.3 g of Adeka STAB AO-40 (manufactured by ADEKA) was placed in a 1 L separable flask under a nitrogen atmosphere, and 383 g of toluene and 60.7 g of triethylamine (TEA) were added and dissolved at room temperature. Next, 29.6 g of 3,3-dimethylbutyryl chloride was added under ice cooling, and after confirming that the temperature did not rise any more, the mixture was heated to 30°C and reacted for 1 hour. After confirming the completion of the reaction by GPC, the resulting reaction solution was purified using an anion exchange resin ("Amberlyst ^TM 15" manufactured by Organo Corporation). 300 mL of ethyl acetate was added to the purified reaction solution, which was then transferred to a separatory funnel and purified three times with a saturated aqueous sodium bicarbonate solution and ten times with water. The solvent was removed from the resulting organic layer using an evaporator, and a low dielectric loss agent C-1 was obtained, which is mainly composed of the following compound.

<Production Example 10> (Synthesis of low dielectric tangent agent C-2)
A reaction was carried out in the same manner as in Production Example 9, except that 74.1 g of AO-80 (manufactured by ADEKA) was used instead of 38.3 g of Adeka STAB AO-40 (ADEKA), to obtain a low dielectric tangent agent C-2 containing the following compound as a main component.

<Production Example 11> (Synthesis of low dielectric tangent agent C-3)
54.5 g of Adeka STAB AO-30 (manufactured by ADEKA) was placed in a 1 L separable flask under a nitrogen atmosphere, and 545 g of toluene and 91.1 g of triethylamine (TEA) were added and dissolved at room temperature. Next, 44.4 g of 3,3-dimethylbutyryl chloride was added under ice cooling, and after confirming that the temperature did not rise any more, the mixture was heated to 30°C and reacted for 1 hour. After confirming the completion of the reaction by GPC, the resulting reaction solution was purified using an anion exchange resin ("Amberlyst ^TM 15" manufactured by Organo Corporation). 300 mL of ethyl acetate was added to the purified reaction solution, which was then transferred to a separatory funnel and purified three times with a saturated aqueous sodium bicarbonate solution and ten times with water. The solvent was removed from the resulting organic layer using an evaporator, and a low dielectric loss agent C-3 was obtained, which is mainly composed of the following compound.

<Production Example 12> (Synthesis of low dielectric tangent agent C-4)
A reaction was carried out in the same manner as in Production Example 11, except that 69.9 g of cyanox 1790 was used instead of 54.5 g of Adeka STAB AO-30 (manufactured by ADEKA Corporation), to obtain a low dielectric tangent agent C-4 containing the following compound as a main component.

<Production Example 13> (Synthesis of low dielectric tangent agent C-5)
A reaction was carried out in the same manner as in Production Example 11, except that 69.9 g of cyanox 1790 was used instead of 54.5 g of Adeka STAB AO-30 (manufactured by ADEKA Corporation), and 49.0 g of heptanoyl chloride was used instead of 44.4 g of 3,3-dimethylbutyryl chloride, to obtain a low dielectric tangent agent C-5 containing the following compound as a main component.

<Production Example 14> (Synthesis of low dielectric tangent agent C-6)
A reaction was carried out in the same manner as in Production Example 11, except that 69.9 g of cyanox 1790 was used instead of 54.5 g of Adeka STAB AO-30 (manufactured by ADEKA Corporation), and 34.5 g of methacryloyl chloride was used instead of 44.4 g of 3,3-dimethylbutyryl chloride, to obtain a low dielectric tangent agent C-6 containing the following compound as a main component.

<Production Example 15> (Synthesis of low dielectric tangent agent C-7)
A reaction was carried out in the same manner as in Production Example 11, except that 69.9 g of cyanox 1790 was used instead of 54.5 g of Adeka STAB AO-30 (manufactured by ADEKA Corporation), and 46.4 g of benzoyl chloride was used instead of 44.4 g of 3,3-dimethylbutyryl chloride, to obtain a low dielectric tangent agent C-7 containing the following compound as a main component.

<Production Example 16> (Synthesis of low dielectric tangent agent C-8)
63.3 g of 4,4',4'',4''-[(1-methylethylidene)-1-ylidene]tetrakis[2-methylphenol] (Honshu Chemical Industry Co., Ltd.) was placed in a 1 L separable flask under a nitrogen atmosphere, and 63.3 g of toluene and 121.4 g of triethylamine (TEA) were added and dissolved at room temperature. Next, 44.4 g of 3,3-dimethylbutyryl chloride was added under ice cooling, and after it was confirmed that the temperature did not rise any more, the mixture was heated to 30°C and reacted for 1 hour. After confirming the completion of the reaction by GPC, the resulting reaction solution was purified using an anion exchange resin ("Amberlyst ^TM 15" manufactured by Organo Corporation). 300 mL of ethyl acetate was added to the purified reaction solution, which was then transferred to a separatory funnel and separated and purified three times with a saturated aqueous sodium bicarbonate solution and ten times with water. The solvent was removed from the obtained organic layer using an evaporator, to obtain a low dielectric tangent agent C-8 containing the following compound as a main component.

As the (C) dielectric loss tangent reducing agent, the following compounds were used as provided.
C-9: SR-3000 (manufactured by Daihachi Chemical Industry Co., Ltd.)
C-10: PX-200 (manufactured by Daihachi Chemical Industry Co., Ltd.)

The following compounds were used in the examples and comparative examples.
Photopolymerization initiator B-1: PBG-304 (manufactured by Changzhou Strong Electronics Co., Ltd.)
Photopolymerization initiator B-2: PBG-305 (manufactured by Changzhou Strong Electronics Co., Ltd.)
Photopolymerization initiator B-3: PBG-3057 (manufactured by Changzhou Strong Electronics Co., Ltd.)
Solvent D-1: γ-butyrolactone Solvent D-2: dimethyl sulfoxide (DMSO)
Solvent D-3: N-methyl-2-pyrrolidone Polymer E-1: Polystyrene (weight average molecular weight: 20,000)

Example 1
100 g of polymer A-1 as component (A), 5 g of photopolymerization initiator B-1 as component (B), and 15 g of C-1 as a dielectric loss tangent reducing agent (C) were dissolved in γ-butyrolactone (200 g) to prepare a photosensitive resin composition solution.
This composition was evaluated by the above-mentioned methods, and the evaluation results are shown in Table 1.

<Examples 2 to 24 and Comparative Examples 1 to 3>
The evaluation was carried out in the same manner as in Example 1, except that the resin composition solutions were prepared in the proportions shown in Tables 1 and 2. The evaluation results are shown in Tables 1 and 2.

As is clear from Tables 1 and 2, the dielectric tangent of the examples was lower than that of Comparative Example 1, regardless of the measurement frequency. In Comparative Example 2, the polyimide resin and polystyrene were phase-separated, and the pattern after development had an opening of 40 μm or more. In Comparative Example 3, the (C) low dielectric tangent agent was phase-separated from the polyimide resin, and the pattern after development had an opening of 30 μm or more.

In Tables 1 and 2, the dielectric tangent values obtained at 40 GHz and 10 GHz for Examples 1 to 24 were calculated using the following formula (i):
x=(tanδ ₄₀ - tanδ ₁₀ )/tanδ ₁₀ (i)
(where tan δ ₄₀ indicates the dielectric tangent at a frequency of 40 GHz as measured by a perturbation type split cylinder resonator method, and tan δ ₁₀ indicates the dielectric tangent at a frequency of 10 GHz as measured by a perturbation type split cylinder resonator method) the value of x given by this formula was 0.14 to 0.19, and was 0.25 for Comparative Example 1. As is clear from the results of Examples 1 and 24, the same results were obtained when cured films of different thicknesses were used.
In Tables 1 and 2, the dielectric tangent values obtained at 60 GHz and 10 GHz for the cured films formed to a thickness of 10 μm in Examples 1 to 23 are calculated using the following formula (ii):
x=(tanδ ₆₀ - tanδ ₁₀ )/tanδ ₁₀ (ii)
(where tan δ ₆₀ indicates the dielectric tangent at a frequency of 60 GHz as measured by a perturbation type split cylinder resonator method, and tan δ ₁₀ indicates the dielectric tangent at a frequency of 10 GHz as measured by a perturbation type split cylinder resonator method) the value of x given was 0.25 to 0.28, and was 0.34 in Comparative Example 1. As is clear from the results of Examples 1 and 24, the same results were obtained when cured films of different thicknesses were used.

The above describes an embodiment of the present invention, but the present invention is not limited to this and can be modified as appropriate without departing from the spirit of the invention.

The photosensitive resin composition of the present invention can be suitably used in the field of photosensitive materials that are useful for manufacturing electrical and electronic materials, such as semiconductor devices and multilayer wiring boards.

Claims (20)

(A) Polyimide precursor: 100 parts by mass,
(B) photosensitizer: 0.1 to 10 parts by mass,
(C) a dielectric loss tangent reducing agent: 1 to 50 parts by mass; and (D) a solvent: 50 to 300 parts by mass. The photosensitive resin composition comprises the (C) dielectric loss tangent reducing agent, and the (C) dielectric loss tangent reducing agent has a molecular weight of 100 to 3,500. The (C) dielectric loss tangent reducing agent is represented by the following formula (I):
In the formula, R ₁ , R _4, and R ₅ are each independently a hydrogen atom, a methyl group, or a t-butyl group; R ₂ and R ₃ are each independently a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms; and Z is an organic group having 7 to 80 carbon atoms and containing at least one heteroatom selected from the group consisting of sulfur, phosphorus, oxygen, and nitrogen, or an organic group having 2 to 15 carbon atoms and containing a carbonyl group.
The photosensitive resin composition according to claim 1 , having a structure represented by the following formula: The (C) dielectric loss tangent reducing agent is represented by the following formula (II):
In the formula, R ₁ , R ₄ , R ₅ , R ₆ , R ₇ , and R ₁₀ are each independently a hydrogen atom, a methyl group, or a t-butyl group; R ₂ , R ₃ , R ₈ , and R ₉ are each independently a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms; and Z is a divalent organic group having 1 to 50 carbon atoms and containing at least one heteroatom selected from the group consisting of sulfur, phosphorus, oxygen, and nitrogen, or a divalent organic group having 1 to 75 carbon atoms.
The photosensitive resin composition according to claim 1 or 2, having a structure represented by the following formula: The (C) dielectric loss tangent reducing agent is represented by the following formula (III):
In the formula, R ₁ , R ₄ , R ₅ , R ₆ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ , and R ₁₅ are each independently a hydrogen atom, a methyl group, or a t-butyl group; R ₂ , R ₃ , R ₈ , R ₇ , R ₁₃ , and R ₁₄ are each independently a hydrogen atom, a hydroxyl group, or an organic group having 1 to 30 carbon atoms; and Z is a trivalent organic group having 1 to 50 carbon atoms containing at least one heteroatom selected from the group consisting of sulfur, phosphorus, oxygen, and nitrogen, or a trivalent organic group having 1 to 50 carbon atoms.
The photosensitive resin composition according to claim 1 or 2, having a structure represented by the following formula: The photosensitive resin composition according to any one of claims 2 to 4, wherein Z has at least one heteroatom selected from the group consisting of sulfur, phosphorus, oxygen, and nitrogen. (C) The dielectric loss tangent reducing agent is represented by the following formula:
{In the formula, Z is an organic group containing a carbonyl group and having 2 to 15 carbon atoms.}
The photosensitive resin composition according to claim 1 or 2, having at least one structure represented by the following formula: The (C) dielectric loss tangent reducing agent is represented by the following formula (IV):
In the formula, R ₁ , R ₄ , R ₅ , R ₆ , R ₇ , R ₁₀ , R ₁₁ , R ₁₂ , R ₁₅ , R ₁₆ , R ₁₉ , and R ₂₀ are each independently a hydrogen atom, a methyl group, or a t-butyl group; R ₂ , R ₃ , R ₈ , R ₉ , R ₁₃ , R ₁₄ , R ₁₇ , and R ₁₈ are each independently a hydrogen atom, a hydroxyl group, or an organic group having 1 to 50 carbon atoms; and Z is a tetravalent organic group having 1 to 50 carbon atoms containing at least one heteroatom selected from the group consisting of sulfur, phosphorus, oxygen, and nitrogen, or a tetravalent organic group having 1 to 50 carbon atoms.
The photosensitive resin composition according to claim 1 or 2, having a structure represented by the following formula: The polyimide precursor (A) is represented by the following general formula (1):
In formula (1), _X1 is a tetravalent organic group having 6 to 40 carbon atoms, _Y1 is a divalent organic group having 6 to 40 carbon atoms, _n1 is an integer from 2 to 150, and _R1 and _R2 are each independently a hydrogen atom or a monovalent organic group having 1 to 40 carbon atoms. However, at least one of _R1 and _R2 is represented by the following general formula (2):
(In formula (2), R ₃ , R ₄ and R ₅ are each independently a hydrogen atom or a monovalent organic group having 1 to 3 carbon atoms, and m ₁ is an integer of 2 to 10.)
It is a group represented by the following formula:
The photosensitive resin composition according to any one of claims 1 to 7, wherein The _Y1 is represented by the following formula (Y1):
In the formula, each Rz independently represents a monovalent organic group having 1 to 10 carbon atoms which may contain a halogen atom, a represents an integer of 0 to 4, A represents an oxygen atom or a sulfur atom, and B represents a group represented by the following formula:
It is one of the following.
The photosensitive resin composition according to claim 8 , wherein the photosensitive resin composition is represented by the formula: The Y ₁ is represented by the following formula:
Or the following formula:
Or the following formula:
The photosensitive resin composition according to claim 9 , wherein the structure is represented by the following formula: The _X1 is represented by the following formula (X1):
In the formula, each Ry independently represents a monovalent organic group having 1 to 10 carbon atoms which may contain a halogen atom, a represents an integer of 0 to 4, C represents an oxygen atom or a sulfur atom, and D represents a group represented by the following formula:
It is one of the following.
The photosensitive resin composition according to any one of claims 8 to 10, wherein The X ₁ is represented by the following formula:
Or the following formula:
The photosensitive resin composition according to claim 11, wherein the structure is represented by the following formula: The photosensitive resin composition according to any one of claims 1 to 12, wherein the photosensitizer (B) is a photoradical polymerization initiator. The photosensitive resin composition according to any one of claims 1 to 13, which is a negative type photosensitive resin composition. A method for producing a cured film obtained from a photosensitive resin composition comprising 100 parts by mass of a polyimide precursor, 0.1 to 10 parts by mass of a photosensitizer, and 50 to 300 parts by mass of a solvent, the cured film being represented by the following formula (i):
0.001<(tanδ ₄₀ -tanδ ₁₀ )/tanδ ₁₀ <0.2 (i)
{wherein tan δ ₄₀ represents a dielectric tangent at a frequency of 40 GHz as measured by a perturbation type split cylinder resonator method, and tan δ ₁₀ represents a dielectric tangent at a frequency of 10 GHz as measured by a perturbation type split cylinder resonator method}. A method for producing a cured film obtained from a photosensitive resin composition comprising 100 parts by mass of a polyimide precursor, 0.1 to 10 parts by mass of a photosensitizer, and 50 to 300 parts by mass of a solvent, the cured film being represented by the following formula (ii):
0.001<(tanδ ₆₀ -tanδ ₁₀ )/tanδ ₁₀ <0.29 (ii)
{wherein tan δ ₆₀ represents a dielectric tangent at a frequency of 60 GHz as measured by a perturbation type split cylinder resonator method, and tan δ ₁₀ represents a dielectric tangent at a frequency of 10 GHz as measured by a perturbation type split cylinder resonator method}. A method for producing a cured film obtained from a photosensitive resin composition comprising 100 parts by mass of a polyimide precursor, 0.1 to 10 parts by mass of a photosensitizer, and 50 to 300 parts by mass of a solvent, the cured film being represented by the following formulas (i) and (ii):
0.001<(tanδ ₄₀ -tanδ ₁₀ )/tanδ ₁₀ <0.2 (i)
0.001<(tanδ ₆₀ -tanδ ₁₀ )/tanδ ₁₀ <0.29 (ii)
{wherein tan δ ₄₀ represents a dielectric tangent at a frequency of 40 GHz measured by a perturbation type split cylinder resonator method, tan δ ₁₀ represents a dielectric tangent at a frequency of 10 GHz measured by a perturbation type split cylinder resonator method, and tan δ ₆₀ represents a dielectric tangent at a frequency of 60 GHz measured by a perturbation type split cylinder resonator method}. The method for producing a cured film according to any one of claims 15 to 17, wherein the photosensitizer contained in the photosensitive resin composition is a photoradical polymerization initiator. The method for producing a cured film according to any one of claims 15 to 18, wherein the photosensitive resin composition is a negative-type photosensitive resin composition. The method for producing a cured film according to any one of claims 15 to 19, wherein the photosensitive resin composition contains a low dielectric tangent agent.