JP7714976B2 - Photosensitive resin composition - Google Patents

Description

The present invention relates to a photosensitive resin composition, as well as a photosensitive film, circuit board, and semiconductor device that use the same.

A well-known manufacturing technique for printed wiring boards, which are widely used in various electronic devices, is the build-up method, in which insulating layers and conductor layers are alternately stacked. In build-up manufacturing methods, a thermosetting resin composition is generally used for the insulating layers, and a photosensitive resin composition is used for the solder resist layers (Patent Document 1). Furthermore, in recent years, photosensitive resin compositions have also been used to form insulating layers (Patent Document 2).

Japanese Patent Application Laid-Open No. 2018-155938 Japanese Patent Application Laid-Open No. 2018-173573

Openings such as holes and trenches may be formed in insulating layers by exposing and developing a photosensitive resin composition. With the recent trend toward finer wiring, these openings are required to be smaller. Therefore, photosensitive resin compositions are required to have a low limiting resolution. "Limiting resolution" refers to the limit of how small an opening can be formed in a photosensitive resin composition by exposure and development, and the smaller the better.

However, insulating layers formed using conventional photosensitive resin compositions with low limiting resolution tend to have poor adhesion to conductor layers. Therefore, there is a need for the development of photosensitive resin compositions that can form insulating layers with low limiting resolution and excellent adhesion to conductor layers.

The present invention was conceived in light of the above-mentioned problems, and aims to provide: a photosensitive resin composition capable of forming an insulating layer that has a small limiting resolution and excellent adhesion to a conductor layer; a photosensitive film having a photosensitive resin composition layer containing the photosensitive resin composition; a circuit board having an insulating layer containing a cured product of the photosensitive resin composition and a method for manufacturing the same; and a semiconductor device including the circuit board.

The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result, have found that the above-mentioned problems can be solved by a photosensitive resin composition containing (A) an alkali-soluble novolak resin, (B) a melamine resin containing one or more alkoxymethyl groups, (C) a photoacid generator, and (D) an alkoxy oligomer coupling agent, and have thus completed the present invention.
That is, the present invention includes the following.

[1] (A) an alkali-soluble novolak resin,
(B) a melamine resin containing one or more alkoxymethyl groups;
(C) a photoacid generator, and
(D) an alkoxy oligomer coupling agent,
A photosensitive resin composition comprising:
[2] The photosensitive resin composition according to [1], wherein the alkali-soluble novolak resin (A) contains a compound having a structure represented by formula (A-1).
(In formula (A-1),
R ¹ 's each independently represent a divalent group represented by the following formula (a):
^X1 's each independently represent an alkyl group which may have a substituent, an aryl group which may have a substituent, a halogen atom, or a monovalent heterocyclic group which may have a substituent;
n1 represents an integer of 0 to 4;
m1 represents an integer of 2 to 200. * represents a bond.
In formula (a), ^R11 and ^R12 each independently represent a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, a monovalent heterocyclic group which may have a substituent, an amino group, a carbonyl group, a carboxyl group, or a group consisting of a combination thereof, and ^R11 and ^R12 may be bonded to each other to form a ring. * represents a bond.
[3] The photosensitive resin composition according to [1] or [2], further comprising (E) an organic filler.
[4] The photosensitive resin composition according to [3], wherein the amount of the organic filler (E) is 7% by mass or more and 30% by mass or less, when the nonvolatile components of the photosensitive resin composition are 100% by mass.
[5] The photosensitive resin composition according to any one of [1] to [4], wherein the alkoxy oligomer coupling agent (D) contains a methoxy group.
[6] The photosensitive resin composition according to any one of [1] to [5], wherein the alkoxy oligomer coupling agent (D) contains at least one functional group selected from the group consisting of an epoxy group, an acryloyl group, and a methacryloyl group.
[7] A photosensitive film comprising a support and a photosensitive resin composition layer provided on the support, the photosensitive resin composition layer comprising the photosensitive resin composition according to any one of [1] to [6].
[8] A circuit board having an insulating layer containing a cured product of the photosensitive resin composition according to any one of [1] to [6].
[9] The circuit board according to [8], wherein the insulating layer is a solder resist.
[10] A semiconductor device comprising the circuit board according to [8] or [9].
[11] (I) forming a photosensitive resin composition layer containing the photosensitive resin composition according to any one of [1] to [6] on a base substrate;
(II) a step of exposing the photosensitive resin composition layer to light; and
(III) developing the photosensitive resin composition layer;
A method for manufacturing a circuit board, comprising the steps of:

The present invention provides a photosensitive resin composition capable of forming an insulating layer that has a small limiting resolution and excellent adhesion to a conductor layer; a photosensitive film having a photosensitive resin composition layer containing the photosensitive resin composition; a circuit board having an insulating layer containing a cured product of the photosensitive resin composition and a method for manufacturing the same; and a semiconductor device having the circuit board.

The present invention will be described in detail below, showing embodiments and examples. However, the present invention is not limited to the embodiments and examples listed below, and can be modified and implemented as desired within the scope of the claims and their equivalents.

[1. Overview of photosensitive resin composition]
A photosensitive resin composition according to one embodiment of the present invention comprises a combination of (A) an alkali-soluble novolak resin, (B) a melamine resin containing one or more alkoxymethyl groups, (C) a photoacid generator, and (D) an alkoxy oligomer coupling agent. In the following description, "(B) a melamine resin containing one or more alkoxymethyl groups" may be referred to as "(B) melamine resin."

This photosensitive resin composition can have a low limiting resolution. Furthermore, this photosensitive resin composition can form an insulating layer that has excellent adhesion to a conductor layer.

The photosensitive resin composition may contain further optional components in addition to components (A) to (D). A preferred optional component is, for example, (E) an organic filler.

[2. (A) Alkali-soluble novolak resin]
The photosensitive resin composition includes an alkali-soluble novolac resin (A) as component (A). The alkali-soluble novolac resin (A) is an alkali-soluble resin containing a structure in which benzene rings bonded to hydroxyl groups are linked by methylene groups which may have substituents. The hydroxyl groups of the alkali-soluble novolac resin (A) can undergo a crosslinking reaction with the melamine resin (B), so that a latent image can be formed in the photosensitive resin composition layer by exposure. Furthermore, the alkali-soluble novolac resin (A) can be dissolved in an alkaline developer, so that the latent image can be developed. The alkali-soluble novolac resin (A) may be used alone or in combination of two or more.

Preferred examples of the alkali-soluble novolak resin (A) include compounds containing a structure represented by the following formula (A-1). Therefore, the alkali-soluble novolak resin (A) preferably contains a compound containing a structure represented by the following formula (A-1). Hereinafter, the compound containing the structure represented by formula (A-1) may be referred to as the "component (A-1)."

(In formula (A-1), each R ¹ independently represents a divalent group represented by the following formula (a); each X ¹ independently represents an alkyl group which may have a substituent, an aryl group which may have a substituent, a halogen atom, or a monovalent heterocyclic group which may have a substituent; n1 represents an integer of 0 to 4; m1 represents an integer of 2 to 200; and * represents a bond.)

(In formula (a), R ¹¹ and R ¹² each independently represent a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, a monovalent heterocyclic group which may have a substituent, an amino group, a carbonyl group, a carboxyl group, or a group formed by a combination thereof, and R ¹¹ and R ¹² may be bonded to each other to form a ring. * represents a bond.)

In formula (A-1), ^X1s each independently represent an optionally substituted alkyl group, an optionally substituted aryl group, a halogen atom, or an optionally substituted monovalent heterocyclic group. Among these, ^X1 is preferably an optionally substituted alkyl group, an optionally substituted aryl group, or a halogen atom, more preferably an optionally substituted alkyl group or an optionally substituted aryl group, and still more preferably an optionally substituted alkyl group.

The alkyl group may be linear, branched, or cyclic. Cyclic alkyl groups may be monocyclic or polycyclic. The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, and even more preferably an alkyl group having 1 to 3 carbon atoms. Examples of alkyl groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, isopropyl, s-butyl, t-butyl, 2-methylpropyl, and 3-heptyl. Of these, methyl is particularly preferred.

The aryl group is preferably an aryl group having 6 to 30 carbon atoms, more preferably an aryl group having 6 to 20 carbon atoms, and even more preferably an aryl group having 6 to 10 carbon atoms. Examples of aryl groups include phenyl groups and naphthyl groups.

Halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc., with fluorine atoms being preferred.

As the monovalent heterocyclic group, a monovalent heterocyclic group having 3 to 21 carbon atoms is preferred, a monovalent heterocyclic group having 3 to 15 carbon atoms is more preferred, and a monovalent heterocyclic group having 3 to 9 carbon atoms is even more preferred. Monovalent heterocyclic groups also include monovalent aromatic heterocyclic groups (heteroaryl groups). Examples of monovalent heterocyclic groups include thienyl, pyrrolyl, furanyl, furyl, pyridyl, pyridazinyl, pyrimidyl, pyrazinyl, triazinyl, pyrrolidyl, piperidyl, quinolyl, and isoquinolyl groups. Of these, a pyrrolidyl group is preferred. A monovalent heterocyclic group refers to a group obtained by removing one hydrogen atom from the heterocycle of a heterocyclic compound.

The alkyl group, aryl group, and monovalent heterocyclic group represented by X ¹ may have a substituent. Examples of the substituent include a halogen atom, —OH, —O—C _1-6 alkyl group, —N(C _1-6 alkyl group) ₂ , a C _1-6 alkyl group, a C _6-10 aryl group, —NH ₂ , —NH(C _1-6 alkyl group), —CN, —C(O)O—C _1-6 alkyl group, —C(O)H, and —NO ₂ .

In this specification, the expression "optionally substituted" means unsubstituted or typically 1 to 5 (preferably 1, 2 or 3) substituents, unless otherwise specified. When a compound has multiple substituents, the substituents may be the same or different from each other. Furthermore, in this specification, the term "C _p-q " (p and q are positive integers, and p<q) indicates that the organic group described immediately after this term has p to q carbon atoms. For example, the expression "C _1-6 alkyl group" indicates an alkyl group having 1 to 6 carbon atoms.

In formula (A-1), R ¹ each independently represents a divalent group represented by formula (a). The bond in formula (a) is preferably bonded to either the ortho-position, meta-position, or para-position relative to the OH group of the phenolic moiety in formula (A-1), more preferably bonded to either the meta-position or para-position, and even more preferably bonded to a mixture of meta- and para-positions. When the bond in formula (a) is a mixture of meta- and para-positions relative to the OH group of the phenolic moiety in formula (A-1), the mass of the bond in formula (a) bonded to the meta-position is m, and the mass of the bond in formula (a) bonded to the para-position is p. In this case, the mixing ratio (m:p) is preferably 1:0.1 to 1:10, more preferably 1:0.1 to 1:5, even more preferably 1:0.1 to 1:2, and particularly preferably 1:0.5 to 1:1.

In formula (a), ^R11 and ^R12 each independently represent a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted monovalent heterocyclic group, an amino group, a carbonyl group, a carboxyl group, or a group consisting of a combination thereof, and ^R11 and ^R12 may be bonded to each other to form a ring. Among these, ^R11 and ^R12 each independently preferably represent a hydrogen atom or an alkyl group.

The optionally substituted alkyl group, optionally substituted aryl group, and optionally substituted monovalent heterocyclic group represented by R ¹¹ and R ¹² may be the same as the optionally substituted alkyl group, optionally substituted aryl group, and optionally substituted monovalent heterocyclic group represented by X ¹ in formula (A-1).

Examples of groups formed from these combinations include groups formed from a combination of an alkyl group and a carbonyl group, groups formed from a combination of an aryl group and a carbonyl group, groups formed from a combination of an alkyl group, an amino group and a carbonyl group, and groups formed from a combination of an aryl group, an amino group and a carbonyl group.

R ¹¹ and R ¹² may be bonded to each other to form a ring. The ring structure that R ¹¹ and R ¹² may form also includes a spiro ring and a fused ring. In this case, R ¹¹ and R ¹² are preferably a group that forms a cyclopentane ring, a group that forms a cyclohexane ring, a group that forms a 2,2-dimethyl-4-methylcyclohexane ring, a group that forms a fluorene ring, a group that forms a pyrrolidine ring, or a group that forms a γ-lactam ring.

Specific examples of the divalent group represented by formula (a) include the following groups. In the formula, "*" represents a bond.

In formula (A-1), n1 represents an integer of 0 to 4, preferably an integer of 0 to 3, more preferably 0 or 1, and particularly preferably 1.

In formula (A-1), m1 represents an integer of 2 to 200, preferably an integer of 2 to 150, more preferably an integer of 2 to 100, and even more preferably an integer of 2 to 50.

A specific example of component (A-1) is a resin represented by the following formula (1). In this specific example, the OH groups in the phenol moiety are present in a ratio of 60% meta positions and 40% para positions. In formula (1), n represents an integer between 1 and 200.

(A) The alkali-soluble novolak resin may be a commercially available product. For example, commercially available (A-1) components include "TR4020G" (a resin represented by formula (1)) manufactured by Asahi Organic Chemicals Co., Ltd.; AV light series such as "TR4050G," "TR4080G," "TR5020G," "TR5050G," "TR6020G," "TR6050G," "TR6080G," "OC4500," "TRM30B20G," "TRM30B35G," "EP16F30G," "EP16F50G," "TR4000B," "EP0090G," "EP3010A," "PAPS-PN2," "PAPS-PN4," and "AYPN-3.5" manufactured by Asahi Organic Chemicals Co., Ltd.; Examples include the photoresist resin series manufactured by Tomo Bakelite Co., Ltd.; the Resitop series manufactured by Gun-ei Chemical Industry Co., Ltd.; the Phenolite series manufactured by DIC Corporation, such as "PR-30-40P," "PR-100L," "PR-100H," "PR-50," "PR-55," "PR-56-1," "PR-56-2," "WR-101," "WR-102," "WR-103," and "WR-104"; Lignite Corporation's "LF-100," "LF-110," "LF-120," "LF-200," "LF-400," and "LF-500"; and the photoresist base resin series manufactured by Meiwa Kasei Co., Ltd.

(A) The alkali-soluble novolak resin may be used alone or in combination of two or more types.

There are no particular limitations on the method for producing the alkali-soluble novolak resin (A). For example, component (A-1) can be obtained by polycondensation of phenol or a derivative thereof with an aldehyde and/or ketone. The polycondensation can be carried out in the presence of a catalyst such as an acid or base. For this reason, the terminals of component (A-1) are typically hydroxyphenyl groups or aldehyde groups which may have a substituent, and it is preferable that both terminals be hydroxyphenyl groups which may have a substituent.

The weight-average molecular weight of the alkali-soluble novolak resin (A) is preferably 500 or more, more preferably 700 or more, and even more preferably 1,000 or more, and is preferably 150,000 or less, more preferably 100,000 or less, and even more preferably 50,000 or less. The weight-average molecular weight can be measured as a polystyrene-equivalent value by gel permeation chromatography (GPC).

The amount of (A) alkali-soluble novolac resin is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, and is preferably 85% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less, based on 100% by mass of the non-volatile components of the photosensitive resin composition. When the amount of (A) alkali-soluble novolac resin is within the above range, both limiting resolution and adhesion can be effectively improved.

When the resin components of the photosensitive resin composition are taken as 100% by mass, the amount of (A) alkali-soluble novolac resin is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, and is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less. The resin components of the photosensitive resin composition refer to the non-volatile components of the photosensitive resin composition excluding fillers such as (E) organic fillers and inorganic fillers. When the amount of (A) alkali-soluble novolac resin is within the above range, both limiting resolution and adhesion can be effectively improved.

[3. (B) Melamine resin containing one or more alkoxymethyl groups]
The photosensitive resin composition includes, as component (B), a melamine resin (B) containing one or more alkoxymethyl groups. The alkoxymethyl groups contained in the melamine resin (B) can react with and bond to hydroxyl groups of the alkali-soluble novolak resin (A). The photosensitive resin composition layer can be made insoluble in a developer by exposure to light, or can be cured to form an insulating layer.

The alkoxymethyl group contained in (B) melamine resin is represented by the following formula (B-1). In formula (B-1), "*" represents a bond.

In formula (B-1), R ²¹ represents an alkyl group which may have a substituent. The alkyl group may be a linear, branched, or cyclic alkyl group. Furthermore, the cyclic alkyl group may be either a monocyclic or polycyclic alkyl group. As the alkyl group, an alkyl group having 1 to 10 carbon atoms is preferred, an alkyl group having 1 to 6 carbon atoms is more preferred, and an alkyl group having 1 to 4 carbon atoms is even more preferred. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an isopropyl group, a s-butyl group, and a t-butyl group. Among these, a methyl group and a butyl group are preferred, and a methyl group is more preferred.

The alkyl group represented by R ²¹ may have a substituent.

The alkoxymethyl group is preferably contained in an alkoxymethylamino group represented by the following formula (B-1'). Therefore, the (B) melamine resin preferably contains an alkoxymethylamino group represented by formula (B-1'). In the formula, "*" represents a bond.

In formula (B-1'), R ²² is the same as R ²¹ in formula (B-1), and R represents a hydrogen atom or an alkoxymethyl group.

The (B) melamine resin contained in the photosensitive resin composition according to this embodiment typically contains one or more of the above-described alkoxymethyl groups per molecule. From the viewpoint of obtaining a photosensitive resin composition with superior photosensitivity, the number of alkoxymethyl groups per molecule of the (B) melamine resin is preferably two or more.

The (B) melamine resin is preferably a melamine resin having a structure represented by the following formula (B-2):

(In formula (B-2), X ²¹ , X ²² , X ²³ and X ²⁴ each independently represent a hydrogen atom or an alkoxymethyl group. R ⁵⁰ represents a hydrogen atom, an amino group, an optionally substituted alkyl group, an optionally substituted aryl group, or an alkoxymethylamino group represented by formula (B-1′). However, when R ⁵⁰ represents a hydrogen atom, an optionally substituted alkyl group, or an optionally substituted aryl group, at least one of X ²¹ , X ²² , X ²³ and X ²⁴ is an alkoxymethyl group.)

In formula (B-2), X ²¹ , X ²² , X ²³ and X ²⁴ each independently represent a hydrogen atom or an alkoxymethyl group. The alkoxymethyl groups represented by X ²¹ to X ²⁴ may be the same as the groups represented by formula (B-1). When R ⁵⁰ represents a hydrogen atom, an optionally substituted alkyl group, or an optionally substituted aryl group, at least one of X ²¹ to X ²⁴ , preferably two or more, is an alkoxymethyl group. Preferably, when R ⁵⁰ represents a hydrogen atom, an amino group, an optionally substituted alkyl group, or an optionally substituted aryl group, at least one of X ²¹ to X ²⁴ , preferably two or more, is an alkoxymethyl group. It is more preferable that three or more of X ²¹ to X ²⁴ are alkoxymethyl groups, and particularly preferable that four or more of X ²¹ to X ²⁴ are alkoxymethyl groups.

In formula (B-2), R ⁵⁰ represents a hydrogen atom, an amino group, an optionally substituted alkyl group, an optionally substituted aryl group, or an alkoxymethylamino group represented by formula (B-1'). R ⁵⁰ is preferably an optionally substituted aryl group or an alkoxymethylamino group represented by formula (B-1'), and more preferably an alkoxymethylamino group represented by formula (B-1'). The optionally substituted alkyl group and optionally substituted aryl group represented by R ⁵⁰ may be the same as the optionally substituted alkyl group and optionally substituted aryl group represented by X ¹ in formula (A-1).

The melamine resin having the structure represented by formula (B-2) is preferably a melamine resin having the structure represented by formula (B-2').

(In formula (B-2'), X ²⁵ , X ²⁶ , X ²⁷ , X ²⁸ , X ²⁹ and X ³⁰ each independently represent a hydrogen atom or an alkoxymethyl group, provided that at least one of X ²⁵ , X ²⁶ , X ²⁷ , X ²⁸ , X ²⁹ and X ³⁰ is an alkoxymethyl group.)

In formula (B-2'), X ²⁵ , X ²⁶ , X ²⁷ , X ²⁸ , X ²⁹ and X ³⁰ each independently represent a hydrogen atom or an alkoxymethyl group. The alkoxymethyl group represented by X ²⁵ to X ³⁰ may be the same as the group represented by formula (B-1). At least one of X ²⁵ to X ³⁰ , preferably two or more, is an alkoxymethyl group. It is more preferable that three or more of X ²⁵ to X ³⁰ are alkoxymethyl groups, even more preferable that four or more of X ²⁵ to X ³⁰ are alkoxymethyl groups, and particularly preferable that all of X ²⁵ to X ³⁰ are alkoxymethyl groups.

Specific examples of (B) melamine resin include the following melamine resins:

(B) Commercially available melamine resins may be used. Examples of commercially available products include "MW-390," "MW-100LM," and "MX-750LM" manufactured by Sanwa Chemical Co., Ltd.; and "Cymel-300," "Cymel-370N," and "Cymel-327" manufactured by Daicel Allnex Corporation.

(B) Melamine resin may be used alone or in combination of two or more types.

The amount of (B) melamine resin is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, and is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less, based on 100% by mass of the non-volatile components of the photosensitive resin composition. When the amount of (B) melamine resin is within this range, both limiting resolution and adhesion can be effectively improved.

When the resin component of the photosensitive resin composition is taken as 100% by mass, the amount of (B) melamine resin is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, and is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less. When the amount of (B) melamine resin is within this range, both limiting resolution and adhesion can be effectively improved.

The ratio of the mass of the (A) alkali-soluble novolac resin to the mass of the (B) melamine resin contained in the photosensitive resin composition ((B) melamine resin/(A) alkali-soluble novolac resin) is preferably 0.01 or more, more preferably 0.1 or more, and particularly preferably 0.2 or more, and is preferably 0.5 or less, more preferably 0.4 or less, and particularly preferably 0.3 or less.

[4. (C) Photoacid Generator]
The photosensitive resin composition contains a photoacid generator (C) as component (C). The photoacid generator (C) generates an acid upon irradiation with actinic rays such as ultraviolet light, and the generated acid can promote the reaction between the alkali-soluble novolak resin (A) and the melamine resin (B). Therefore, the solubility of the photosensitive resin composition in a developer can be effectively reduced by exposure, allowing the formation of a latent image by exposure to proceed smoothly. The photoacid generator (C) may be used alone or in combination of two or more.

(C) Photoacid generators that generate acid upon exposure to actinic rays can be used. Examples of (C) photoacid generators include halogen-containing compounds, onium salt compounds, diazoketone compounds, sulfone compounds, sulfonic acid compounds, sulfonimide compounds, diazomethane compounds, and oxime ester compounds. Among these, halogen-containing compounds are preferred.

(C) Examples of halogen-containing compounds that can be suitably used as a photoacid generator include haloalkyl group-containing hydrocarbon compounds and haloalkyl group-containing heterocyclic compounds. Specific examples of suitable halogen-containing compounds include 2-[2-(furan-2-yl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(5-methylfuran-2-yl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-(methoxyphenyl)-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(4-methoxyphenyl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 2-[2-(3,4-dimethoxyphenyl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, Examples of suitable halogen-containing compounds include s-triazine derivatives such as [4-(4-chlorophenyl)ethenyl]-4,6-bis(trichloromethyl)-s-triazine, 1,10-dibromo-n-decane, 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane, phenyl-bis(trichloromethyl)-s-triazine, 4-methoxyphenyl-bis(trichloromethyl)-s-triazine, styryl-bis(trichloromethyl)-s-triazine, and naphthyl-bis(trichloromethyl)-s-triazine. Commercially available halogen-containing compounds can be used, including, for example, "TFE-triazine," "TME-triazine," "MP-triazine," "MOP-triazine," and "dimethoxytriazine" (halogen-containing compound-based photoacid generators having a triazine skeleton) manufactured by Sanwa Chemical Co., Ltd.

(C) Examples of onium salt compounds that can be suitably used as photoacid generators include iodonium salts, sulfonium salts, phosphonium salts, diazonium salts, and pyridinium salts. Specific preferred examples of the onium salt compound include tris(4-methylphenyl)sulfonium trifluoromethanesulfonate, tris(4-methylphenyl)sulfonium hexafluorophosphonate, diphenyliodonium trifluoromethanesulfonate, diphenyliodonium p-toluenesulfonate, diphenyliodonium hexafluoroantimonate, diphenyliodonium hexafluorophosphate, diphenyliodonium tetrafluoroborate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium p-toluenesulfonate, triphenylsulfonium hexafluoroantimonate, 4-tert-butylphenyl.diphenylsulfonium trifluoromethanesulfonate, 4-tert-butylphenyl.diphenylsulfonium p-toluenesulfonate, and 4,7-di-n-butoxynaphthyltetrahydrothiophenium trifluoromethanesulfonate. Commercially available onium salt compounds can be used, including, for example, "TS-01" and "TS-91" manufactured by Sanwa Chemical Co., Ltd.; "CPI-110A," "CPI-210S," "HS-1," "LW-S1," "IK-1," and "CPI-310B" manufactured by San-Apro Co., Ltd.; and "SI-110L," "SI-180L," and "SI-100L" manufactured by Sanshin Chemical Industry Co., Ltd.

(C) Examples of diazoketone compounds that can be suitably used as a photoacid generator include 1,3-diketo-2-diazo compounds, diazobenzoquinone compounds, and diazonaphthoquinone compounds. Specific examples of suitable diazoketone compounds include 1,2-naphthoquinonediazide-4-sulfonic acid ester compounds of phenols.

(C) Examples of sulfone compounds that can be suitably used as a photoacid generator include β-ketosulfone compounds, β-sulfonylsulfone compounds, and α-diazo compounds of these compounds. Specific examples of suitable sulfone compounds include 4-trisphenacylsulfone, mesitylphenacylsulfone, and bis(phenacylsulfonyl)methane.

(C) Examples of sulfonic acid compounds that can be suitably used as photoacid generators include alkyl sulfonate esters, haloalkyl sulfonate esters, aryl sulfonate esters, and iminosulfonates. Specific examples of suitable sulfonic acid compounds include benzoin tosylate, pyrogallol tristrifluoromethanesulfonate, o-nitrobenzyl trifluoromethanesulfonate, and o-nitrobenzyl p-toluenesulfonate.

(C) Specific examples of sulfonimide compounds that can be suitably used as a photoacid generator include N-(trifluoromethylsulfonyloxy)succinimide, N-(trifluoromethylsulfonyloxy)phthalimide, N-(trifluoromethylsulfonyloxy)diphenylmaleimide, N-(trifluoromethylsulfonyloxy)bicyclo[2.2.1]hept-5-ene-2,3-dicarboximide, and N-(trifluoromethylsulfonyloxy)naphthylimide.

(C) Specific examples of diazomethane compounds that can be suitably used as a photoacid generator include bis(trifluoromethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, bis(phenylsulfonyl)diazomethane, etc. Commercially available diazomethane compounds can be used.

(C) Specific examples of oxime ester compounds that can be suitably used as a photoacid generator include benzeneacetonitrile, 2-methyl-α-[2-[[(propylsulfonyl)oxy]imino]-3(2H)-thienylidene], benzeneacetonitrile, 2-methyl-α-[2-[[[(4-methylphenyl)sulfonyl]oxy]imino]-3(2H)-thienylidene], and the like. Commercially available products include "PAG103," "PAG121," "PAG169," and "PAG203" manufactured by BASF.

The amount of (C) photoacid generator, based on 100% by mass of the non-volatile components in the photosensitive resin composition, is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, and is preferably 3% by mass or less, more preferably 2% by mass or less, and particularly preferably 1% by mass or less.

[5. (D) Alkoxy oligomer coupling agent]
The photosensitive resin composition includes an alkoxy oligomer coupling agent (D) as component (D). The alkoxy oligomer coupling agent (D) typically has multiple repeating units containing both an alkoxy group and a functional group in the molecule. When this alkoxy oligomer coupling agent (D) is used in combination with the above-described components (A) to (C), it is possible to improve both the limiting resolution and the adhesion to the conductor layer.

Examples of the alkoxy group contained in the (D) alkoxy oligomer coupling agent include a methoxy group, an ethoxy group, and a propoxy group, with a methoxy group and an ethoxy group being preferred. Among these, a methoxy group is more preferred from the viewpoint of improving adhesion between the insulating layer and the GaAs substrate. In particular, from the viewpoint of utilizing the high reactivity of a methoxy group to particularly effectively improve adhesion between the insulating layer and the GaAs substrate, it is particularly preferred that all of the alkoxy groups contained in the repeating units of the (D) alkoxy oligomer coupling agent are methoxy groups.

The functional groups contained in (D) the alkoxy oligomer coupling agent can typically react with an appropriate organic compound to form a chemical bond. Examples of such functional groups include epoxy groups, acryloyl groups, methacryloyl groups, vinyl groups, and mercapto groups. The functional groups may be of one type or two or more types. Among these, from the perspective of effectively enhancing adhesion, functional groups capable of reacting with (A) the alkali-soluble novolac resin are preferred. Specifically, at least one functional group selected from the group consisting of epoxy groups, acryloyl groups, and methacryloyl groups is preferred.

(D) Examples of alkoxy oligomer coupling agents include silane coupling agents, titanate coupling agents, aluminate coupling agents, and zirconate coupling agents, with silane coupling agents being preferred. Silane coupling agents typically contain repeating units containing a silicon atom, an alkoxy group bonded directly to the silicon atom, and a functional group bonded to the silicon atom directly or via a linking group. These repeating units are typically linked via bonds extending from the silicon atom. An example of a (D) alkoxy oligomer coupling agent is a silane coupling agent containing a repeating unit represented by the following formula (D-1):

(In formula (D-1), ^Xd represents a functional group, ^Ld represents a divalent linking group, nd represents 0 or 1, ^Rd represents an alkyl group, and ^Zd represents an oxygen atom or a divalent aliphatic hydrocarbon group.)

In formula (D-1), ^Xd represents a functional group. The functional group is as described above.

In formula (D-1), ^Ld represents a divalent linking group. Examples of the divalent linking group include alkylene groups such as a methylene group, a propylene group, and a hexylene group; and alkyleneoxyalkylene groups such as a methyleneoxymethylene group, a propyleneoxymethylene group, and an octyleneoxymethylene group. Ld has usually 1 or more, preferably 2 or more, and preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. ^Ld is preferably an alkylene group, ^and more preferably a propylene group.

In formula (D-1), nd represents 0 or 1.

In formula (D-1), ^Rd represents an alkyl group. ^Rd has usually 1 to 10 carbon atoms, preferably 1 to 5, more preferably 1 to 2, and particularly preferably 1. Examples of ^Rd include a methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group. A methyl group and an ethyl group are preferred, and a methyl group is more preferred.

In formula (D-1), ^Zd represents an oxygen atom or a divalent aliphatic hydrocarbon group. The divalent aliphatic hydrocarbon group may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group, with a saturated aliphatic hydrocarbon group being preferred. The divalent aliphatic hydrocarbon group has usually 1 or more, preferably 2 or more, more preferably 3 or more, and preferably 6 or less, more preferably 5 or less, and particularly preferably 4 or less. Examples of divalent aliphatic hydrocarbon groups include alkylene groups such as a methylene group, an ethylene group, and a propylene group. Of these, ^Zd is preferably an oxygen atom.

The number of repeating units per molecule of (D) the alkoxy oligomer coupling agent is typically 3 or more, preferably 4 or more, and preferably 20 or less, more preferably 10 or less.

The weight average molecular weight of the (D) alkoxy oligomer coupling agent is preferably 800 to 30,000, and more preferably 800 to 10,000.

The viscosity of the (D) alkoxy oligomer coupling agent at 25°C is preferably 5 mm ² /s or more, more preferably 10 mm ² /s or more, and particularly preferably 15 mm ² /s or more, and is preferably 2000 mm ² /s or less, more preferably 1000 mm ² /s or less, and particularly preferably 100 mm ² /s or less. The viscosity can be measured using an E-type viscometer (RE-80, manufactured by Toki Sangyo Co., Ltd.) at a rotation speed set to 5 to 20 rpm by measuring out about 0.2 ml of a sample using a syringe into an apparatus adjusted to 25°C.

The functional group equivalent of the (D) alkoxy oligomer coupling agent is preferably 100 g/mol or more, more preferably 150 g/mol or more, even more preferably 200 g/mol or more, and preferably 2000 g/mol or less, more preferably 1500 g/mol or less, even more preferably 1000 g/mol or less. The functional group equivalent of the (D) alkoxy oligomer coupling agent represents the mass of the (D) alkoxy oligomer coupling agent having 1 mol of functional groups.

(D) Commercially available alkoxy oligomer coupling agents may be used. Commercially available products include, for example, Shin-Etsu Chemical Co., Ltd.'s "KR-513" (an oligomeric silane coupling agent containing a methoxy group as an alkoxy group and an acryloyl group as a functional group), "KR-516" (an oligomeric silane coupling agent containing a methoxy group as an alkoxy group and an epoxy group as a functional group), "KR-517" (an oligomeric silane coupling agent containing a methoxy group and an ethoxy group as an alkoxy group and an epoxy group as a functional group), "X-40-9296" (an oligomeric silane coupling agent containing a methoxy group as an alkoxy group and a methacryloyl group as a functional group), "KR-511" (an oligomeric silane coupling agent containing a methoxy group as an alkoxy group and a vinyl group as a functional group), "KR-518" (an oligomeric silane coupling agent containing a methoxy group and an ethoxy group as an alkoxy group and a mercapto group as a functional group), and "KR-519" (an oligomeric silane coupling agent containing a methoxy group as an alkoxy group). , an oligomeric silane coupling agent containing a mercapto group as a functional group), "X-40-9318" (an oligomeric silane coupling agent containing a methoxy group as an alkoxy group and an isocyanate group as a functional group), "X-12-981S" (an oligomeric silane coupling agent containing an ethoxy group as an alkoxy group and an epoxy group as a functional group), "X-12-984S" (an oligomeric silane coupling agent containing an ethoxy group as an alkoxy group and an epoxy group as a functional group), "X-12-1048" (an oligomeric silane coupling agent containing a methoxy group as an alkoxy group and an acryloyl group as a functional group), "X-12-1050" (an oligomeric silane coupling agent containing a methoxy group as an alkoxy group and an acryloyl group as a functional group), and "X-12-1159L" (an oligomeric silane coupling agent containing a methoxy group as an alkoxy group and an acryloyl group as a functional group). (D) The alkoxy oligomer coupling agent may be used alone or in combination of two or more types.

The amount of (D) alkoxy oligomer coupling agent is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 1.5% by mass or more, and preferably 20% by mass or less, more preferably 18% by mass or less, even more preferably 15% by mass or less, based on 100% by mass of the non-volatile components of the photosensitive resin composition. When the amount of (D) alkoxy oligomer coupling agent is within the above range, both limiting resolution and adhesion can be effectively improved.

The amount of (D) alkoxy oligomer coupling agent is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 1.5% by mass or more, and preferably 20% by mass or less, more preferably 18% by mass or less, even more preferably 15% by mass or less, based on 100% by mass of the resin component of the photosensitive resin composition. When the amount of (D) alkoxy oligomer coupling agent is within the above range, both limiting resolution and adhesion can be effectively improved.

The ratio (W _D /W A ) of the mass W _D of the alkoxy oligomer coupling agent (D) to the mass W _A of the alkali-soluble novolak resin ( _A ) is preferably 0.01 or more, more preferably 0.015 or more, even more preferably 0.02 or more, and is preferably 0.5 or less, more preferably 0.3 or less, and particularly preferably 0.2 or less.

[6. (E) Organic filler]
The photosensitive resin composition may further contain a filler as an optional component in addition to the above-described components (A) to (D). The filler is usually incompatible with the resin components and may exist as particles in the photosensitive resin composition and its cured product. The photosensitive resin composition preferably contains an organic filler (E) as this filler.

(E) Organic fillers are generally flexible because they are made from organic materials. Therefore, when (E) Organic fillers are used, it is possible to distribute stress in the insulating layer, improving the crack resistance and insulating properties of the insulating layer. Examples of (E) Organic fillers include urethane particles, rubber particles, polyamide particles, and silicone particles.

Commercially available urethane particles may be used, such as "MM-101SW," "MM-101SWA," "MM-101SM," "MM-101SMA," and "MM-110SMA" manufactured by Negami Chemical Industrial Co., Ltd.; and the RKB series manufactured by Resinous Chemical Co., Ltd.

The rubber particles can be made from resin that exhibits rubber elasticity and is chemically crosslinked to make it insoluble and infusible in organic solvents. Examples of rubber particles include acrylonitrile butadiene rubber particles, butadiene rubber particles, acrylic rubber particles, and methyl methacrylate-butadiene-styrene copolymer particles. Commercially available rubber particles may be used, such as "EXL-2655" manufactured by Dow Chemical Japan; "AC3816N," "AC3355," "AC3816," "AC3832," "AC4030," "AC3364," and "IM101" manufactured by Ganz Chemical Industry Co., Ltd.; "Paraloid EXL2655" and "EXL2602" manufactured by Kureha Chemical Industry Co., Ltd.; "B-11A," "B513," "B22," "B-521," "B-561," "B-564," "FM-21," "FM-40," "FM-50," "M-701," "M-711," "M-732," "M-300," "FM-40," "M-570," and "M-210" manufactured by Kaneka Corporation; and the RKB series manufactured by Resinous Chemical Industry Co., Ltd.

The polyamide particles may be particles of a resin having an amide bond. Examples of polyamide particles include particles of aliphatic polyamides such as nylon, particles of aromatic polyamides such as Kevlar, and polyamide-imide particles. Commercially available polyamide particles may also be used, such as "VESTOSINT 2070" manufactured by Daicel-Huls Ltd. and "SP500" manufactured by Toray Industries, Inc.

(E) The organic filler may be used alone or in combination of two or more types.

(E) The average particle size of the organic filler is preferably 0.005 μm or more, more preferably 0.01 μm or more, even more preferably 0.05 μm or more, and preferably 5 μm or less, more preferably 2 μm or less, even more preferably 1 μm or less, and particularly preferably 0.5 μm or less. The average particle size of the organic filler can be measured using dynamic light scattering. Specifically, the average particle size of the organic filler can be measured by uniformly dispersing the organic filler in an appropriate organic solvent using ultrasound, creating a particle size distribution of the organic filler on a mass basis using a concentrated particle size analyzer (e.g., the "FPAR-1000" manufactured by Otsuka Electronics Co., Ltd.), and taking the median diameter as the average particle size.

The amount of (E) organic filler may be 0% by mass or more, but is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 7% by mass or more, and is preferably 40% by mass or less, more preferably 35% by mass or less, and even more preferably 30% by mass or less, when the non-volatile components of the photosensitive resin composition are taken as 100% by mass. When the amount of (E) organic filler is within the above range, both limiting resolution and adhesion can be effectively improved.

7. (F) Optional Additives
The photosensitive resin composition may further contain an optional additive (F) as an optional non-volatile component in addition to the non-volatile components (A) to (E) described above. Examples of the additive (F) as component (F) include thermoplastic resins; inorganic fillers such as silica particles and alumina particles; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium oxide, carbon black, and naphthalene black; polymerization inhibitors such as hydroquinone, phenothiazine, methylhydroquinone, hydroquinone monomethyl ether, catechol, and pyrogallol; thickeners such as bentone and montmorillonite; silicone-based, fluorine-based, and vinyl resin-based defoamers; flame retardants such as epoxy resins, antimony compounds, phosphorus-based compounds, aromatic condensed phosphate esters, and halogen-containing condensed phosphate esters; and thermosetting resins such as phenolic curing agents and cyanate ester-based curing agents. The additive (F) may be used alone or in combination of two or more.

[8. (G) Solvent]
The photosensitive resin composition may contain a (G) solvent as a volatile component in addition to the non-volatile components (A) to (F) described above. The (G) solvent as the (G) component can adjust the viscosity of the photosensitive resin composition. Examples of the (G) solvent include organic solvents.

(G) Examples of solvents include ketone solvents such as ethyl methyl ketone and cyclohexanone; aromatic hydrocarbon solvents such as toluene, xylene, and tetramethylbenzene; glycol ether solvents such as methyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether; ester solvents such as ethyl acetate, butyl acetate, butyl cellosolve acetate, carbitol acetate, and ethyl diglycol acetate; aliphatic hydrocarbon solvents such as octane and decane; and petroleum-based solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha. These solvents may be used alone or in combination.

The amount of (G) solvent may be 0% by mass or more, and is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less, when the entire photosensitive resin composition including (G) solvent is taken as 100% by mass. The content of (G) solvent in the photosensitive resin composition layer of the photosensitive film is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, and is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, when the entire photosensitive resin composition including (G) solvent is taken as 100% by mass.

[9. Method for producing photosensitive resin composition]
The method for producing the photosensitive resin composition is not particularly limited. The photosensitive resin composition can be produced, for example, by mixing components (A) to (D) and, if necessary, components (E) to (G). During mixing, if necessary, kneading may be performed using a kneading device such as a triple roll mill, ball mill, bead mill, or sand mill, or stirring may be performed using a stirring device such as a super mixer or planetary mixer. There is no limitation on the order in which the components are mixed. Furthermore, cooling or heating may be performed during the process of mixing the components.

[10. Characteristics and Uses of Photosensitive Resin Composition]
The photosensitive resin composition according to this embodiment can have a small limiting resolution. Therefore, by using this photosensitive resin composition, an insulating layer having small openings can be formed. In one example, a photosensitive resin composition layer having a dry thickness of 20 μm is formed using the photosensitive resin composition, and an insulating layer having via holes is formed from this photosensitive resin composition layer by the method described in the examples. In this case, the minimum opening diameter of the via holes that can be properly formed in the insulating layer can be reduced. Specifically, the opening diameter can be preferably 30 μm or less, more preferably 25 μm or less, and even more preferably 20 μm or less.

The photosensitive resin composition according to this embodiment can produce a cured product that can adhere highly to a conductor layer such as copper foil. Therefore, by using this photosensitive resin composition, an insulating layer that can adhere highly to a conductor layer can be formed. In one example, a photosensitive resin composition layer is formed on copper foil using the method described in the examples, and then cured to form an insulating layer. In this case, the load required to peel the copper foil from the insulating layer (peel strength) can be 0.4 kgf or more per 10 mm width.

The photosensitive resin composition according to this embodiment preferably produces a cured product that exhibits high adhesion to GaAs substrates (gallium arsenide substrates), such as gallium arsenide wafers containing gallium arsenide. Therefore, by using this photosensitive resin composition, an insulating layer that exhibits high adhesion to GaAs substrates can be formed. In one example, a photosensitive resin composition layer is formed on a GaAs substrate using the method described in the Examples and then cured to form an insulating layer. When this insulating layer is subjected to a cross-cut tape peel test in accordance with JIS K5600-5-6:1999 (ISO2409:1992), it preferably achieves a result of classifications "0" to "2" in Table 1 of JIS K5600-5-6:1999 8.3, more preferably a result of classifications "0" to "1," and most preferably a result of classification "0." In the above classifications, a smaller number indicates better adhesion. Specifically, a rating of "0" indicates that the edges of the cuts are completely smooth and there is no peeling at any of the grid squares. A rating of "1" indicates that there is minor peeling of the coating at the intersections of the cuts, but no more than 5% of the cross-cut area is significantly affected. A rating of "2" indicates that the coating has peeled along the edges and/or at the intersections of the cuts, but no more than 5% of the cross-cut area is significantly affected, but no more than 15%.

The uses of the above-mentioned photosensitive resin composition are not particularly limited, and it can be used in a wide range of applications, including, for example, photosensitive films, insulating resin sheets such as prepregs, materials for forming insulating layers on circuit boards, solder resists, buffer coating films, underfill materials, die bonding materials, semiconductor encapsulants, hole-filling resins, and component-embedding resins.

Examples of circuit boards include semiconductor chip packages such as multi-chip packages, package-on-packages, wafer-level packages, panel-level packages, and system-in-packages; package substrates equipped with the aforementioned semiconductor chip packages; and printed wiring boards such as rigid substrates, flexible substrates, single-area layer substrates, thin substrates, and component-embedded substrates. Among these, photosensitive resin compositions are suitable for semiconductor chip packages, and are particularly suitable for wafer-level packages. Examples of wafer-level packages include fan-in wafer-level packages and fan-out wafer-level packages, and either type may be used.

In a circuit board, an insulating layer formed from a photosensitive resin composition may be an insulating layer for forming a wiring layer on the insulating layer. Furthermore, an insulating layer formed from a photosensitive resin composition may be an interlayer insulating layer. Furthermore, an insulating layer formed from a photosensitive resin composition may be a solder resist. Furthermore, an insulating layer formed from a photosensitive resin composition may be a buffer coat film.

[11. Photosensitive Film]
A photosensitive film according to one embodiment of the present invention includes a support and a photosensitive resin composition layer formed on the support. The photosensitive resin composition layer is formed from a photosensitive resin composition and therefore contains, and typically contains only, a photosensitive resin composition.

Examples of the support include polyethylene terephthalate film, polyethylene naphthalate film, polypropylene film, polyethylene film, polyvinyl alcohol film, and triacetyl acetate film, with polyethylene terephthalate film being particularly preferred.

Commercially available supports include, for example, Oji Paper Co., Ltd. products under the names "Alphan MA-410" and "E-200C," polypropylene films manufactured by Shin-Etsu Film Co., Ltd., and polyethylene terephthalate films such as the PS series manufactured by Teijin Limited under the name "PS-25." To facilitate release of the support, the surface of the support may be coated with a release agent such as a silicone coating. An example of a support whose surface has been treated with a release agent is Lintec Corporation's "AL-5." The thickness of the support is preferably in the range of 5 μm to 100 μm, and more preferably in the range of 10 μm to 50 μm.

There are no particular restrictions on the thickness of the photosensitive resin composition layer, and it can be, for example, from 1 μm to 100 μm. Of these, it is preferably 2 μm or more, more preferably 4 μm or more, and preferably 50 μm or less, more preferably 30 μm or less.

The photosensitive film may be provided with a protective film that protects the photosensitive resin composition layer. Typically, the protective film is provided on the side of the photosensitive resin composition layer opposite the support. The protective film may be, for example, a film made of the same material as the support. The adhesion between the protective film and the photosensitive resin composition layer is preferably smaller than the adhesion between the support and the photosensitive resin composition layer. Typically, the photosensitive film is used after the protective film is peeled off.

A photosensitive film can be produced, for example, by coating a photosensitive resin composition on a support. To facilitate smooth coating, a solvent-containing photosensitive resin composition in varnish form may be prepared and then coated. When a solvent-containing photosensitive resin composition is applied, drying may be performed after coating, if necessary.

The photosensitive resin composition layer provided in the photosensitive film may or may not contain a solvent, but it is preferable that the amount of solvent is small. The preferred range of the amount of solvent in the photosensitive resin composition layer is as described above.

12. Circuit Board
A circuit board according to one embodiment of the present invention includes an insulating layer containing a cured product of the above-described photosensitive resin composition. This insulating layer preferably contains only a cured product of the photosensitive resin composition. The insulating layer may be provided on a GaAs substrate, preferably because it can adhere to the GaAs substrate with high adhesion. Therefore, the circuit board may include a GaAs substrate and an insulating layer formed on the GaAs substrate. Furthermore, from the viewpoint of utilizing the advantage of a small limiting resolution, it is preferable that openings are formed in the insulating layer by exposure and development.

The above-mentioned photosensitive resin composition can be used as a negative photosensitive resin composition.
(I) forming a photosensitive resin composition layer on a base substrate;
(II) a step of exposing the photosensitive resin composition layer to light; and
(III) developing the photosensitive resin composition layer;
It can be produced by a production method including the steps of:

The manufacturing method may further include any optional steps. For example, the manufacturing method may include step (IV) of heating the photosensitive resin composition layer between step (II) and step (III). The manufacturing method may also include step (V) of further exposing the photosensitive resin composition layer to light after step (III). The manufacturing method may also include step (VI) of subjecting the photosensitive resin composition layer to a heat treatment after step (III). The manufacturing method may also include step (VII) of forming a conductor layer on the insulating layer. This manufacturing method will be described in detail below.

[12.1. Process (I)]
The method for producing a circuit board according to this embodiment includes a step (I) of forming a photosensitive resin composition layer on a base substrate. The photosensitive resin composition layer is formed from a photosensitive resin composition, and therefore contains a photosensitive resin composition, and typically contains only a photosensitive resin composition.

The base substrate may be any suitable member to be provided on the circuit board.
For example, when manufacturing a printed wiring board as a circuit board, an inner layer substrate that can be provided in the printed wiring board can be used as the base substrate. The inner layer substrate is a component that serves as the base material of the printed wiring board, and examples thereof include glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates. The inner layer substrate may also have a conductor layer on one or both sides, and this conductor layer may be patterned. The inner layer substrate also includes intermediate products on which an insulating layer and/or a conductor layer is to be further formed when manufacturing a printed wiring board. An inner layer substrate with built-in components may also be used.

For example, a wafer may be used as the base substrate. When a wafer is used as the base substrate, a wafer-level package can be manufactured as the circuit substrate. The wafer may be a semiconductor wafer or a pseudo wafer. Examples of semiconductor wafers include silicon wafers, gallium arsenide (GaAs) wafers, indium phosphide (InP) wafers, gallium phosphide (GaP) wafers, gallium nitride (GaN) wafers, gallium telluride (GaTe) wafers, zinc selenium (ZnSe) wafers, and silicon carbide (SiC) wafers. Furthermore, the pseudo wafer may be, for example, a plate-shaped member comprising a molding resin and electronic components embedded in the molding resin. The pseudo wafer may be manufactured, for example, by a method including placing electronic components in a circular mold, filling the mold with molding resin, and curing the molding resin. Typically, wafers are prepared as discs containing semiconductors, but the shape of the wafer is not limited to a disc shape. The wafer may also have a conductive layer on its surface or inside, and this conductive layer may be patterned.

There are no particular limitations on the method for forming the photosensitive resin composition layer. For example, the photosensitive resin composition layer may be formed by applying the photosensitive resin composition to a base substrate. To facilitate smooth application, a varnish-like photosensitive resin composition containing a solvent may be prepared, and the varnish-like photosensitive resin composition may be applied.

Examples of coating methods include gravure coating, microgravure coating, reverse coating, kiss reverse coating, die coating, slot die coating, lip coating, comma coating, blade coating, roll coating, knife coating, curtain coating, chamber gravure coating, slot orifice coating, spin coating, slit coating, spray coating, dip coating, hot melt coating, bar coating, applicator coating, air knife coating, curtain flow coating, offset printing, brush coating, and screen printing.

The photosensitive resin composition may be applied in one step or in multiple steps. It may also be applied using a combination of different application methods. To avoid contamination, it is preferable to apply the composition in an environment where foreign matter is unlikely to be generated, such as a clean room.

After application of the photosensitive resin composition, the photosensitive resin composition layer may be dried, if necessary. Drying can be carried out using a drying device such as a hot air oven or far-infrared oven. It is preferable to set drying conditions appropriately depending on the composition of the photosensitive resin composition. Specific examples include a drying temperature of preferably 50°C or higher, more preferably 70°C or higher, and particularly preferably 80°C or higher, and preferably 150°C or lower, more preferably 130°C or lower, and particularly preferably 120°C or lower. Furthermore, the drying time is preferably 30 seconds or higher, more preferably 60 seconds or higher, and particularly preferably 120 seconds or higher, and preferably 60 minutes or lower, more preferably 20 minutes or lower, and particularly preferably 5 minutes or lower.

The photosensitive resin composition layer may be formed using, for example, a photosensitive film. Specifically, the photosensitive resin composition layer of the photosensitive film can be formed on the base substrate by laminating the photosensitive resin composition layer on the base substrate. Lamination is typically performed by pressing the photosensitive resin composition layer of the photosensitive film onto the base substrate while heating it. This lamination is preferably performed under reduced pressure by vacuum lamination. Furthermore, prior to lamination, a preheating treatment may be performed, in which the photosensitive film and base substrate are heated, if necessary.

The lamination conditions can be, for example, a pressure bonding temperature (lamination temperature) of 70°C to 140°C, a pressure bonding pressure of 1 kgf/ ^cm2 to 11 kgf/ ^cm2 (9.8 x ¹⁰⁴ N/ ^m2 to 107.9 x ¹⁰⁴ N/ ^m2 ), and a pressure bonding time of 5 to 300 seconds. Furthermore, lamination is preferably carried out under reduced pressure with an air pressure of 20 mmHg (26.7 hPa) or less. Lamination may be carried out batchwise or continuously using a roll.

Vacuum lamination can be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include the vacuum applicator manufactured by Nikko Materials Co., Ltd., the vacuum pressure laminator manufactured by Meiki Seisakusho Co., Ltd., the roll-type dry coater manufactured by Hitachi Industries, Ltd., and the vacuum laminator manufactured by Hitachi AIC Corporation.

When a photosensitive resin composition layer is formed using a photosensitive film, the support is usually peeled off at an appropriate time before step (III).

[12.2. Process (II)]
The method for manufacturing a circuit board according to this embodiment includes, after step (I), step (II) of exposing the photosensitive resin composition layer. In this step (II), the photosensitive resin composition layer is typically irradiated with actinic rays to form a latent image in the photosensitive resin composition layer. Specifically, in step (II), actinic rays are selectively irradiated to specific portions of the photosensitive resin composition layer. Thus, exposed portions irradiated with actinic rays and unexposed portions not irradiated with actinic rays are formed in the photosensitive resin composition layer. Then, a latent image corresponding to the opening is formed in the unexposed portions.

It is preferable to use an appropriate actinic ray depending on the composition of the photosensitive resin composition. The wavelength of the actinic ray is usually 190 nm to 1000 nm, preferably 240 nm to 550 nm, but light of other wavelengths may also be used. Specific examples of actinic light sources include ultraviolet light, visible light, electron beams, and X-rays, with ultraviolet light being particularly preferred.

The exposure dose of actinic rays is preferably set so as to form desired openings after development. In one example, the specific exposure dose range is preferably 10 mJ/ ^cm2 or more, more preferably 50 mJ/ ^cm2 or more, particularly preferably 200 mJ/cm2 or more, and preferably 10,000 mJ/ ^cm2 or less, more preferably 8,000 mJ/ ^cm2 or ^less , particularly preferably 1,000 mJ/ ^cm2 or less.

Irradiation with actinic rays is usually carried out using a mask. Specifically, actinic rays are irradiated onto the photosensitive resin composition layer through a mask having light-transmitting and light-shielding areas. The actinic rays pass through the light-transmitting areas and enter the exposed areas, but cannot pass through the light-shielding areas and therefore cannot enter the non-exposed areas. Therefore, exposed and non-exposed areas corresponding to the light-transmitting and light-shielding areas can be provided in the photosensitive resin composition layer. The mask may be in close contact with the photosensitive resin composition layer (contact exposure method), or exposure may be carried out using parallel light without contact (non-contact exposure method).

Generally, the light-shielding portion of the mask is formed to have a planar shape corresponding to the opening to be formed in the insulating layer. Unless otherwise specified, "planar shape" refers to the shape when viewed from the thickness direction. Furthermore, a light-shielding portion having a planar shape corresponding to the opening in the insulating layer may be referred to as a "mask pattern" hereinafter. In one example, a via pattern such as a round hole pattern may be used as the mask pattern. The via diameter (opening diameter) is preferably 100 μm or less, more preferably 50 μm or less, and even more preferably 30 μm or less. There is no particular lower limit, but it can be 0.1 μm or more, 0.5 μm or more, etc.

If a support is present on the photosensitive resin composition layer, exposure may be performed through the support, or after peeling off the support.

[12.3. Process (IV)]
The method for producing a circuit board according to this embodiment may include a step (IV) of heating the photosensitive resin composition layer after the step (II) and before the step (III). The heating in the step (IV) can promote the crosslinking reaction between the alkali-soluble novolac resin (A) and the melamine resin (B), thereby quickly reducing the solubility of the exposed area in a developer.

The heating temperature in step (IV) may be a hot plate or an oven, and may be, for example, 40° C. to 115° C. The heating time may be, for example, 30 seconds to 60 minutes.
In particular, when heating is performed on a hot plate, the heating temperature is preferably 50° C. or higher, more preferably 60° C. or higher, and particularly preferably 70° C. or higher, and preferably 115° C. or lower, more preferably 110° C. or lower, and particularly preferably 105° C. or lower. The heating time is preferably 30 seconds or longer, more preferably 60 seconds or longer, and particularly preferably 120 seconds or longer, and preferably 30 minutes or shorter, more preferably 20 minutes or shorter, and particularly preferably 10 minutes or shorter.
When heating is performed in an oven, the heating temperature is preferably 40° C. or higher, more preferably 50° C. or higher, and preferably 100° C. or lower, more preferably 90° C. or lower. The heating time is preferably 3 minutes or longer, more preferably 10 minutes or longer, particularly preferably 15 minutes or longer, and preferably 60 minutes or shorter, more preferably 50 minutes or shorter, particularly preferably 40 minutes or shorter.

[12.4. Process (III)]
The method for producing a circuit board according to this embodiment includes a step (III) of developing the photosensitive resin composition layer after the step (II). The development removes the unexposed portions that were not exposed in the step (II) to form openings. The development is typically performed by a wet development method in which the photosensitive resin composition layer is brought into contact with a developer. Examples of the developer include an alkaline aqueous solution, a water-based developer, and an organic solvent.

Examples of alkaline aqueous solutions used as developers include aqueous solutions of alkali metal compounds. Examples of alkaline metal compounds include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; alkali metal carbonates or bicarbonates such as sodium carbonate and sodium bicarbonate; alkali metal phosphates such as sodium phosphate and potassium phosphate; and alkali metal pyrophosphates such as sodium pyrophosphate and potassium pyrophosphate. Examples of alkaline aqueous solutions include aqueous solutions of metal-ion-free organic bases such as tetraalkylammonium hydroxide. These alkaline aqueous solutions may be used alone or in combination. Among these, an aqueous solution of tetramethylammonium hydroxide (TMAH) is preferred because it contains no metal ions and has minimal effect on semiconductor chips. The pH of the alkaline aqueous solution is preferably in the range of 8 to 14. The base concentration of the alkaline aqueous solution is preferably 0.1% to 10% by weight.

Examples of organic solvents used as developers include acetone, ethyl acetate, alkoxyethanols having an alkoxy group with 1 to 4 carbon atoms, ethyl alcohol, isopropyl alcohol, butyl alcohol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether. One organic solvent may be used alone, or two or more may be used in combination. The concentration of the organic solvent is typically 2% by weight or more, preferably 50% by weight or more, more preferably 70% by weight or more, and particularly preferably 90% by weight or more, based on the total amount of the developer. The developer may be 100% by weight organic solvent. Examples of organic solvent-based developers that can be used alone include 1,1,1-trichloroethane, N-methylpyrrolidone, N,N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone.

If necessary, the developer may contain additives such as surfactants and antifoaming agents to improve the developing action.

The development time is preferably 10 seconds to 5 minutes. The temperature of the developer during development is not particularly specified, but is preferably 20°C or higher, and preferably 50°C or lower, and more preferably 40°C or lower.

Examples of development methods include the puddle method, spray method, immersion method, brushing method, slapping method, and ultrasonic method.

After development using the developer, the photosensitive resin composition layer may be further rinsed. Rinsing is preferably performed with a solvent different from the developer. For example, rinsing may be performed using the same type of solvent as that contained in the photosensitive resin composition. The rinsing time is preferably 5 seconds to 1 minute.

[12.5. Process (V)]
The above-described steps may result in curing of the photosensitive resin composition layer to obtain an insulating layer. However, from the viewpoint of further promoting the curing of the photosensitive resin composition layer to obtain an insulating layer having excellent mechanical strength, the method for producing a circuit board according to this embodiment may further include a step (V) of exposing the photosensitive resin composition layer after the step (III). In this step (V), the photosensitive resin composition layer is irradiated with actinic rays. The actinic rays used for exposure in the step (V) may be the same as those used for exposure in the step (II).

The exposure dose of actinic rays in step (V) is preferably set so as to form desired openings after development. In one example, the specific exposure dose range is preferably 500 mJ/ ^cm2 or more, more preferably 800 mJ/ ^cm2 or more, particularly preferably 1000 mJ/ ^cm2 or more, and preferably 10,000 mJ/cm2 or ^less , more preferably 8,000 mJ/ ^cm2 or less, particularly preferably 6,000 mJ/ ^cm2 or less.

[12.6. Process (VI)]
Although the photosensitive resin composition layer may be cured by the above-described steps to obtain an insulating layer, from the viewpoint of further promoting the curing of the photosensitive resin composition layer to obtain an insulating layer excellent in mechanical strength, the method for producing a circuit board according to this embodiment preferably includes, after step (III), step (VI) of subjecting the photosensitive resin composition layer to a heat treatment. When the method for producing a circuit board includes step (V), step (VI) is preferably performed after step (V).

The heat treatment can be carried out using a heating device such as a clean oven. The heat treatment atmosphere can be air or an inert gas atmosphere such as nitrogen. The heat treatment conditions can be selected depending on the type and amount of resin components in the photosensitive resin composition, and are preferably in the range of 150°C to 250°C for 20 to 180 minutes, and more preferably in the range of 160°C to 230°C for 30 to 120 minutes.

[12.7. Process (VII)]
The method for manufacturing a circuit board according to this embodiment may include a step (VII) of forming a conductor layer on the insulating layer. The conductor material used for the conductor layer is not particularly limited. For example, the conductor layer may contain one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. The conductor layer may be a single metal layer or an alloy layer. Examples of alloy layers include layers formed from alloys of two or more metals selected from the above group (e.g., nickel-chromium alloys, copper-nickel alloys, and copper-titanium alloys). Among these, from the viewpoints of versatility in forming the conductor layer, cost, and ease of patterning, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of a nickel-chromium alloy, a copper-nickel alloy, or a copper-titanium alloy is preferred, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or an alloy layer of a nickel-chromium alloy is more preferred, and a single metal layer of copper is even more preferred.

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

The thickness of the conductor layer depends on the circuit board design, but is typically 3 μm to 35 μm, preferably 5 μm to 30 μm.

There are no limitations on the method for forming the conductor layer. The conductor layer may be formed, for example, by sputtering. Alternatively, the conductor layer may be formed by combining electroless plating and electrolytic plating. Furthermore, the conductor layer may be formed by forming a plating resist with a reverse pattern to the conductor layer and then using only electroless plating.

Among these, the conductor layer is preferably formed by a sputtering method. When forming a conductor layer by a sputtering method, a conductor seed layer is typically formed on an insulating layer by sputtering, and then a conductor sputtered layer is further formed on the conductor seed layer by sputtering. Furthermore, before forming the conductor seed layer by sputtering, the surface of the insulating layer may be cleaned by reverse sputtering. Gases used for reverse sputtering are preferably Ar gas, _O2 gas, or _N2 gas. Sputtering can be performed using various sputtering devices such as magnetron sputtering and mirror tron sputtering. Examples of metals that form the conductor seed layer include Cr, Ni, Ti, and nichrome. Cr and Ti are particularly preferred. The thickness of the conductor seed layer is preferably 5 nm or more, more preferably 10 nm or more, and preferably 1000 nm or less, more preferably 500 nm or less. Examples of metals that form the conductor sputtered layer include Cu, Pt, Au, and Pd. Cu is particularly preferred. The thickness of the sputtered conductor layer is preferably 50 nm or more, more preferably 100 nm or more, and is preferably 3000 nm or less, more preferably 1000 nm or less.

A copper plating layer may be further formed on the layer formed by sputtering by electrolytic copper plating. The thickness of the copper plating layer is preferably 5 μm or more, more preferably 8 μm or more, and is preferably formed to be 75 μm or less, more preferably 35 μm or less.

The conductor layer may be patterned. Methods that can be used for patterning include, for example, subtractive and semi-additive processes.

12.8. Optional Steps
The method for manufacturing a circuit board according to this embodiment may further include any optional steps in combination with the steps described above.
For example, a method for manufacturing a circuit board may include a step of drilling holes in an insulating layer. The holes may be trenches that do not penetrate the insulating layer, via holes that penetrate only the insulating layer, or through holes that penetrate the entire circuit board. The holes may be drilled using, for example, a drill, a laser, or plasma.

The method for manufacturing a circuit board may also include a step of desmearing the insulating layer. When holes are drilled in the insulating layer, resin residue (smear) may adhere to the formed holes. The desmearing removes this smear. The desmearing may be performed by dry desmearing, wet desmearing, or a combination of these.

Furthermore, the method for manufacturing a circuit board may include a step of dicing the manufactured circuit board.

The method for manufacturing a circuit board may involve repeating the steps described above. For example, steps (I) to (VII) may be repeated to manufacture a multi-layer circuit board having alternating insulating layers and conductor layers.

[13. Semiconductor Device]
The circuit board can be used to manufacture semiconductor devices, including various semiconductor devices provided with a circuit board, such as those used in electrical appliances (e.g., computers, mobile phones, digital cameras, and televisions) and vehicles (e.g., motorcycles, automobiles, trains, ships, and aircraft).

The present invention will be explained in more detail below using examples, but the present invention is not limited to these examples. In the following description, the terms "parts" and "%" used to express amounts refer to "parts by mass" and "% by mass," respectively, unless otherwise specified. Furthermore, the operations described below were carried out in air at room temperature and normal pressure (23°C, 1 atmosphere) unless otherwise specified.

[Examples 1 to 9 and Comparative Examples 1 to 5]
Photosensitive resin compositions were prepared by mixing the amounts (parts by mass) of reagents (component (A), component (A′), component (B), component (B′), component (C), component (D), and component (E)) and 2-butanone (MEK) shown in Tables 1 and 2 below.
In the table below, the abbreviations of the reagents have the following meanings:

Component (A):
- TR4020G: Cresol novolac resin "TR4020G" manufactured by Asahi Organic Materials Co., Ltd.

Component (A'):
・BisA: "BisA" manufactured by Mitsui Fine Chemicals Co., Ltd.

(B) Component:
Cymel-300: "Cymel-300" manufactured by Daicel Allnex Co., Ltd. A compound represented by the following formula (B-X), in which R represents a methyl group.
Cymel-370N: "Cymel-370N" manufactured by Daicel Allnex Co., Ltd. A compound represented by the following formula (B-X), in which R represents a methyl group or a hydrogen atom.
Cymel-327: "Cymel-327" manufactured by Daicel Allnex Co., Ltd. A compound in which R represents a methyl group and some of the -CH ₂ OR groups are replaced with hydrogen atoms in the following formula (B-X). Therefore, some of the -N(CH ₂ OR) _{2 groups} bonded to the triazine ring are replaced with groups represented by the following formula (b-1). In formula (b-1), * represents a bond.

(B') Component:
MX-270: Sanwa Chemical's "Nicalac MX-270"
TML-BPA: "TML-BPA" manufactured by Honshu Chemical Co., Ltd.

(C) Component:
MP-triazine: "MP-triazine" manufactured by Sanwa Chemical Co., Ltd.

(D) Component:
KR-513: Acrylic-containing oligomeric silane coupling agent "KR-513" manufactured by Shin-Etsu Chemical Co., Ltd. Contains a methoxysilyl group as the alkoxysilyl group and an acryloyl group as the functional group. Acryloyl group equivalent: 210 g/mol, viscosity at 25°C: 35 mm ² /s.
KR-516: Epoxy-containing oligomeric silane coupling agent "KR-516" manufactured by Shin-Etsu Chemical Co., Ltd. Contains a methoxysilyl group as the alkoxysilyl group and an epoxy group as the functional group. Methyl groups are bonded to some of the silicon atoms. Epoxy group equivalent: 280 g/mol, viscosity at 25°C: 50 mm ² /s.
X-40-9296: Methacrylic-containing oligomeric silane coupling agent "X-40-9296" manufactured by Shin-Etsu Chemical Co., Ltd. Contains a methoxysilyl group as the alkoxysilyl group and a methacryloyl group as the functional group. Methacryloyl group equivalent: 230 g/mol, viscosity at 25°C: 20 mm ² /s.
KR-517: Epoxy-containing oligomeric silane coupling agent "KR-517" manufactured by Shin-Etsu Chemical Co., Ltd. Contains methoxysilyl and ethoxysilyl groups as alkoxysilyl groups and epoxy groups as functional groups. Epoxy equivalent: 830 g/mol, viscosity at 25°C: 12 mm ² /s.

(E) Component:
MM-101SM: Urethane fine particles "MM-101SM" manufactured by Negami Chemical Industrial Co., Ltd. Average particle size: 0.07 to 0.1 μm.

[Production of photosensitive film]
A polyethylene terephthalate film ("Lumirror T60" manufactured by Toray Industries, Inc., thickness 38 μm) with a release-treated surface was prepared as a support. The photosensitive resin compositions prepared in each Example and Comparative Example were uniformly applied to the support using a die coater so that the thickness of the photosensitive resin composition layer after drying would be 20 μm, and the resulting film was dried at 80°C to 110°C for 6 minutes to obtain a photosensitive film. This photosensitive film had a support and a photosensitive resin composition layer formed on the support.

[Evaluation of limiting resolution]
A copper-clad laminate was prepared by copper plating a silicon wafer to form a copper layer with a thickness of 5 μm and then roughening the copper layer with a 1% hydrochloric acid aqueous solution for 60 seconds. A photosensitive film was placed on this copper needle laminate so that the photosensitive resin composition layer was in contact with the surface of the copper layer, and the laminate was laminated using a vacuum laminator (VP160, manufactured by Nikko Materials Co., Ltd.). The lamination conditions were a vacuum time of 30 seconds, a pressure bonding temperature of 80 ° C, a pressure bonding pressure of 0.7 MPa, and a pressure time of 30 seconds. After leaving the laminate at room temperature for 10 minutes, the support was peeled off to obtain an intermediate laminate comprising a copper-clad laminate and a photosensitive resin composition layer.

This intermediate laminate was subjected to a heat treatment at 100°C for 3 minutes. Thereafter, the photosensitive resin composition layer of the intermediate laminate was exposed to ultraviolet light (wavelength 365 nm, intensity 40 mW/ ^cm2 ) through a quartz glass mask. The exposure dose was set to an optimum value in the range of 50 mJ/ ^cm2 to 1000 mJ/ ^cm2 . Here, the optimum value refers to the value that minimizes the limiting resolution. Furthermore, a glass mask having multiple mask patterns with different dimensions was used so that multiple round holes (via holes) with different design opening diameters could be drawn. After leaving the product at room temperature for 5 minutes, a heat treatment at 100°C for 3 minutes was performed. A 2.38% by mass aqueous solution of tetramethylammonium hydroxide at 23°C was sprayed onto the entire surface of the photosensitive resin composition layer of the intermediate laminate at a spray pressure of 0.1 MPa for 1 minute to perform spray development. After the spray development, the photosensitive resin composition layer was cured by irradiating it with ultraviolet light at 1 J/ ^cm² and then by heating it at 190°C for 60 minutes. Through these operations, an insulating layer was formed on the copper-clad laminate using the cured product of the photosensitive resin composition.

The diameter of the bottom of the via holes formed in the insulating layer was observed and measured using a scanning electron microscope (SEM) (magnification 1000x). If the diameter of the bottom of the via hole was between 60% and 120% of the design value of the via hole, the via hole was determined to have been properly formed. Of the properly formed via holes, the via hole with the smallest design value was selected, and the design value of that selected via hole was taken as the limiting resolution.

[Evaluation of GaAs Adhesion]
A photosensitive film was placed on a 6-inch gallium arsenide wafer as a GaAs substrate, with the photosensitive resin composition layer in contact with the gallium arsenide wafer. Lamination was performed using a vacuum laminator (VP160, manufactured by Nikko Materials Co., Ltd.) to obtain a laminate comprising a gallium arsenide wafer, a photosensitive resin composition layer, and a support, in that order. The lamination conditions were a vacuum time of 30 seconds, a pressure bonding temperature of 80°C, a pressure bonding pressure of 0.7 MPa, and a pressure time of 30 seconds. The laminate was left at room temperature for 30 minutes or more, and the entire surface of the photosensitive resin composition layer was exposed to ultraviolet light through the support. The exposure dose was set to the optimum value described above. The laminate was left at room temperature for 5 minutes, and then the support was peeled off. Next, a heat treatment was performed at 80°C for 10 minutes. A 2.38% by mass aqueous solution of tetramethylammonium hydroxide at 23°C was sprayed onto the entire surface of the photosensitive resin composition layer as a developer at a spray pressure of 0.1 MPa for 1 minute to perform spray development. After spray development, the photosensitive resin composition layer was cured by irradiating it with ultraviolet light at 1 J/ ^cm2 and then heating it at 190°C for 60 minutes. Through the above operations, a sample substrate was obtained that included a gallium arsenide wafer and an insulating layer formed from the cured product of the photosensitive resin composition.

The insulating layer of the obtained sample substrate was subjected to a cross-cut tape peel test in accordance with JIS K5600-5-6:1999 (ISO2409:1992), and the adhesion to the gallium arsenide wafer was evaluated according to the following evaluation criteria.
"A": Corresponds to classification 0 in Table 1 of JIS K5600-5-6:1999 8.3.
"B": Corresponds to Classification 1 in Table 1 of JIS K5600-5-6:1999 8.3.
"C": Corresponds to Classification 2 in Table 1 of JIS K5600-5-6:1999 8.3.
"D": Corresponds to Classification 3 in Table 1 of JIS K5600-5-6:1999 8.3.
"E": Corresponds to category 4 or 5 in Table 1 of JIS K5600-5-6:1999 8.3.

[Measurement of Cu Adhesion]
A rolled copper foil (JX Nippon Mining & Metals Corporation, "BHY-22B-T," thickness 18 μm) was prepared, which had been washed with 10% sulfuric acid and dried. A photosensitive film was placed on the shiny side of the rolled copper foil, with the photosensitive resin composition layer in contact with the surface of the copper layer. Lamination was performed using a vacuum laminator (Nikko Materials Co., Ltd., VP160), to obtain a laminate comprising, in this order, the rolled copper foil, the photosensitive resin composition layer, and the support. The lamination conditions were a vacuum time of 30 seconds, a pressure bonding temperature of 80°C, a pressure bonding pressure of 0.7 MPa, and a pressure time of 30 seconds. The laminate was allowed to stand at room temperature for 30 minutes or more, and the entire surface of the photosensitive resin composition layer was exposed to ultraviolet light through the support. The exposure dose was set to the optimum value described above. The laminate was allowed to stand at room temperature for 5 minutes, and then the support was peeled off. Next, a heat treatment was performed at 80°C for 10 minutes. A 2.38% by mass aqueous solution of tetramethylammonium hydroxide at 23°C was sprayed onto the entire surface of the photosensitive resin composition layer as a developer at a spray pressure of 0.1 MPa for 1 minute to perform spray development. After spray development, the photosensitive resin composition layer was cured by irradiating it with ultraviolet light at 1 J/ ^cm2 and then heat-treating it at 190°C for 60 minutes. Through these operations, a sample substrate was obtained that included a rolled copper foil and an insulating layer formed from the cured product of the photosensitive resin composition.

The insulating layer side of the obtained sample substrate was bonded to a glass epoxy substrate, and the peel strength of the copper foil was measured using a tensile tester ("AC-50C-SL" manufactured by TSE Corporation) conforming to Japanese Industrial Standards (JIS C6481). Specifically, a slit was made in the rolled copper foil of the sample substrate, surrounding a section 10 mm wide and 100 mm long, and one end of this section was peeled off and gripped with the gripping tools of the tensile tester. The load required to peel 35 mm in the vertical direction at a rate of 50 mm/min was measured as the peel strength. Based on the measured peel strength, the adhesion to the copper foil was evaluated according to the following criteria.
"◯": Peel strength is 0.4 kgf or more.
"X": Peel strength is less than 0.4 kgf.

[result]
The compositions and evaluation results of the photosensitive resin compositions of the above-mentioned Examples and Comparative Examples are shown in the following table. In the table, the numerical values in the reagent column represent parts by mass. In addition, the meanings of the abbreviations in the table are as follows.
Concentration of component (E): The proportion of component (E) relative to 100% by mass of the nonvolatile components of the photosensitive resin composition.
Alkoxy group type: The type of alkoxy group contained in the alkoxysilyl group of the silane coupling agent.
"M" in the "Type of alkoxy group" column: methoxy group.
In the "Type of alkoxy group" column, "E: Ethoxy group."
"NG" in the "Limiting resolution" column: Via holes with an opening diameter of 100 μm or less could not be formed.
GaAs adhesion: Adhesion to GaAs substrate.
Cu adhesion: Adhesion to copper foil.

Claims (12)

(A) an alkali-soluble novolak resin,
(B) a melamine resin containing one or more alkoxymethyl groups;
(C) a photoacid generator, and
(D) an alkoxy oligomer coupling agent,
Including ,
(D) A photosensitive resin composition, wherein the alkoxy oligomer coupling agent is a silane coupling agent having, in the molecule, a plurality of repeating units each containing both an alkoxy group and at least one functional group selected from the group consisting of an epoxy group, an acryloyl group, a methacryloyl group, a vinyl group, and a mercapto group. 2. The photosensitive resin composition according to claim 1, wherein the alkali-soluble novolak resin (A) comprises a compound having a structure represented by formula (A-1):
(In formula (A-1),
R ¹ 's each independently represent a divalent group represented by the following formula (a):
^X1 's each independently represent an alkyl group which may have a substituent, an aryl group which may have a substituent, a halogen atom, or a monovalent heterocyclic group which may have a substituent;
n1 represents an integer of 0 to 4;
m1 represents an integer of 2 to 200. * represents a bond.
In formula (a), ^R11 and ^R12 each independently represent a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, a monovalent heterocyclic group which may have a substituent, an amino group, a carbonyl group, a carboxyl group, or a group consisting of a combination thereof, and ^R11 and ^R12 may be bonded to each other to form a ring. * represents a bond. The photosensitive resin composition according to claim 1 or 2, further comprising (E) an organic filler. The photosensitive resin composition according to claim 3, wherein the amount of (E) organic filler is 7% by mass or more and 30% by mass or less, when the non-volatile components of the photosensitive resin composition are taken as 100% by mass. The photosensitive resin composition according to any one of claims 1 to 4, wherein (D) the alkoxy oligomer coupling agent contains a methoxy group. The photosensitive resin composition according to any one of claims 1 to 5, wherein (D) the alkoxy oligomer coupling agent contains at least one functional group selected from the group consisting of an epoxy group, an acryloyl group, and a methacryloyl group. The photosensitive resin composition according to any one of claims 1 to 6, wherein the repeating unit contained in the alkoxy oligomer coupling agent (D) is represented by the following formula (D-1):
(In formula (D-1), X ^d represents at least one functional group selected from the group consisting of an epoxy group, an acryloyl group, a methacryloyl group, a vinyl group, and a mercapto group; L ^d represents a divalent linking group, nd represents 0 or 1, R ^d represents an alkyl group, Z ^d represents an oxygen atom or a divalent aliphatic hydrocarbon group. A photosensitive film comprising: a support; and a photosensitive resin composition layer provided on the support, the photosensitive resin composition layer comprising the photosensitive resin composition according to any one of claims 1 to 7 . A circuit board comprising an insulating layer containing a cured product of the photosensitive resin composition according to any one of claims 1 to 7 . The circuit board according to claim 9 , wherein the insulating layer is a solder resist. A semiconductor device comprising the circuit board according to claim 9 or 10 . (I) forming a photosensitive resin composition layer containing the photosensitive resin composition according to any one of claims 1 to 7 on a base substrate;
(II) a step of exposing the photosensitive resin composition layer to light; and
(III) developing the photosensitive resin composition layer;
A method for manufacturing a circuit board, comprising the steps of: