JP7557262B2 - Photosensitive resin composition - Google Patents

Description

The present invention relates to a photosensitive resin composition. It also relates to a photosensitive film, a photosensitive film with a support, a printed wiring board, and a semiconductor device obtained using the photosensitive resin composition.

In printed wiring boards, solder resist is sometimes provided as a permanent protective film to prevent solder from adhering to areas where solder is not required and to prevent the circuit board from corroding. For the solder resist, a photosensitive resin composition such as that described in Patent Document 1 is generally used.

JP 2014-115672 A

Photosensitive resin compositions for solder resists are generally required to have high resolution, insulating properties, etc. In recent years, the miniaturization of electronic devices has created a need for space saving, so printed wiring boards are required to be flexible (bendable). The solder resists used on these printed wiring boards are also required to be flexible.

However, as a result of extensive research, the inventors have found that attempts to improve flexibility can result in poorer insulating properties for the solder resist, and that there is a trade-off between flexibility and insulating properties in photosensitive resin compositions for solder resist.

The object of the present invention is to provide a photosensitive resin composition that can give a cured product with excellent flexibility and insulating properties and has excellent resolution; and to provide a photosensitive film, a photosensitive film with a support, a printed wiring board, and a semiconductor device obtained using the photosensitive resin composition.

As a result of intensive research, the inventors discovered that the resin containing an ethylenically unsaturated group and a carboxyl group, the epoxy resin, and the photopolymerizable monomer contained in the photosensitive resin composition contain an alkylene oxide chain, and that the alkylene oxide chain satisfies a specific relationship, thereby improving both the flexibility and the insulating properties, and thus completing the present invention.

式（１）中、Ｍ_ＡＯは、アルキレンオキシド鎖を含む成分が共重合体である場合は下記式（２）で示される値を表し、又はアルキレンオキシド鎖を含む成分が共重合体でない場合は、（（Ａ）～（Ｃ）成分に含まれる各化合物のアルキレンオキシド鎖の分子量）／（（Ａ）～（Ｃ）成分に含まれる各化合物の分子量）を表す。Ｎは、（Ａ）～（Ｃ）成分に含まれるすべての化合物の固形分含有量（質量部）を表し、ｎは、（Ａ）～（Ｃ）成分に含まれる各化合物の固形分含有量（質量部）を表す。

式（２）中、Ａ_ＡＯは、アルキレンオキシド鎖を含む各モノマーのアルキレンオキシド鎖の分子量を表し、Ａは、アルキレンオキシド鎖を含む各モノマーの分子量を表し、Ｂ_ＡＯは、アルキレンオキシド鎖を含む各モノマーのモル数を表し、Ｂは、共重合体に含まれる全モノマーの合計モル数を表す。
［２］ さらに、（Ｅ）無機充填材を含む、［１］に記載の感光性樹脂組成物。
［３］ アルキレンオキシド鎖は、（Ｂ）成分及び（Ｃ）成分のいずれかに含む、［１］又は［２］に記載の感光性樹脂組成物。
［４］ （Ａ）成分が、酸変性不飽和エポキシエステル樹脂を含む、［１］～［３］のいずれかに記載の感光性樹脂組成物。
［５］ （Ａ）成分が、酸変性エポキシ（メタ）アクリレートを含む、［１］～［４］のいずれかに記載の感光性樹脂組成物。
［６］ （Ａ）成分が、酸変性ナフタレン骨格含有エポキシ（メタ）アクリレート、及び酸変性ビスフェノール骨格含有エポキシ（メタ）アクリレートのいずれかを含む、［１］～［５］のいずれかに記載の感光性樹脂組成物。
［７］ 酸変性ビスフェノール骨格含有エポキシ（メタ）アクリレートが、ビスフェノールＡ骨格及びビスフェノールＦ骨格のいずれかを有する、［６］に記載の感光性樹脂組成物。
［８］ （Ｂ）成分が、ビフェニル骨格を有する、［１］～［７］のいずれかに記載の感光性樹脂組成物。
［９］ （Ｄ）成分が、オキシムエステル系光重合開始剤を含む、［１］～［８］のいずれかに記載の感光性樹脂組成物。
［１０］ ［１］～［９］のいずれかに記載の感光性樹脂組成物を含有する、感光性フィルム。
［１１］ 支持体と、該支持体上に設けられた、［１］～［９］のいずれかに記載の感光性樹脂組成物を含む感光性樹脂組成物層と、を有する支持体付き感光性フィルム。
［１２］ ［１］～［９］のいずれかに記載の感光性樹脂組成物の硬化物により形成された絶縁層を含むプリント配線板。
［１３］ 絶縁層が、ソルダーレジストである、［１２］に記載のプリント配線板。
［１４］ ［１２］又は［１３］に記載のプリント配線板を含む、半導体装置。 That is, the present invention includes the following.
[1] (A) a resin containing an ethylenically unsaturated group and a carboxyl group,
(B) an epoxy resin,
A photosensitive resin composition comprising: (C) a photopolymerizable monomer; and (D) a photopolymerization initiator,
A photosensitive resin composition, wherein any one of the components (A), (B), and (C) contains an alkylene oxide chain, and a parameter X represented by the following formula (1) is 4 or more and 25 or less:

In formula (1), M _AO represents a value shown by the following formula (2) when the component containing an alkylene oxide chain is a copolymer, or represents (molecular weight of alkylene oxide chain of each compound contained in components (A) to (C))/(molecular weight of each compound contained in components (A) to (C)) when the component containing an alkylene oxide chain is not a copolymer, N represents the solid content (parts by mass) of all compounds contained in components (A) to (C), and n represents the solid content (parts by mass) of each compound contained in components (A) to (C).

In formula (2), A _AO represents the molecular weight of the alkylene oxide chain of each monomer containing an alkylene oxide chain, A represents the molecular weight of each monomer containing an alkylene oxide chain, B _AO represents the number of moles of each monomer containing an alkylene oxide chain, and B represents the total number of moles of all monomers contained in the copolymer.
[2] The photosensitive resin composition according to [1], further comprising (E) an inorganic filler.
[3] The photosensitive resin composition according to [1] or [2], wherein the alkylene oxide chain is contained in either the component (B) or the component (C).
[4] The photosensitive resin composition according to any one of [1] to [3], wherein the component (A) contains an acid-modified unsaturated epoxy ester resin.
[5] The photosensitive resin composition according to any one of [1] to [4], wherein the component (A) contains an acid-modified epoxy (meth)acrylate.
[6] The photosensitive resin composition according to any one of [1] to [5], wherein the component (A) contains either an acid-modified naphthalene skeleton-containing epoxy(meth)acrylate or an acid-modified bisphenol skeleton-containing epoxy(meth)acrylate.
[7] The photosensitive resin composition according to [6], wherein the acid-modified bisphenol skeleton-containing epoxy (meth)acrylate has either a bisphenol A skeleton or a bisphenol F skeleton.
[8] The photosensitive resin composition according to any one of [1] to [7], wherein the component (B) has a biphenyl skeleton.
[9] The photosensitive resin composition according to any one of [1] to [8], wherein the component (D) contains an oxime ester-based photopolymerization initiator.
[10] A photosensitive film comprising the photosensitive resin composition according to any one of [1] to [9].
[11] A supported 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 [9].
[12] A printed wiring board comprising an insulating layer formed from a cured product of the photosensitive resin composition according to any one of [1] to [9].
[13] The printed wiring board according to [12], wherein the insulating layer is a solder resist.
[14] A semiconductor device comprising the printed wiring board according to [12] or [13].

According to the present invention, it is possible to provide a photosensitive resin composition that can obtain a cured product having excellent flexibility and insulating properties and excellent resolution; and a photosensitive film, a photosensitive film with a support, a printed wiring board, and a semiconductor device obtained using the photosensitive resin composition.

The photosensitive resin composition, photosensitive film, photosensitive film with support, printed wiring board, and semiconductor device of the present invention will be described in detail below.

式（１）中、Ｍ_ＡＯは、アルキレンオキシド鎖を含む成分が共重合体である場合は下記式（２）で示される値を表し、又はアルキレンオキシド鎖を含む成分が共重合体でない場合は、（（Ａ）～（Ｃ）成分に含まれる各化合物のアルキレンオキシド鎖の分子量）／（（Ａ）～（Ｃ）成分に含まれる各化合物の分子量）を表す。Ｎは、（Ａ）～（Ｃ）成分に含まれるすべての化合物の固形分含有量（質量部）を表し、ｎは、（Ａ）～（Ｃ）成分に含まれる各化合物の固形分含有量（質量部）を表す。

式（２）中、Ａ_ＡＯは、アルキレンオキシド鎖を含む各モノマーのアルキレンオキシド鎖の分子量を表し、Ａは、アルキレンオキシド鎖を含む各モノマーの分子量を表し、Ｂ_ＡＯは、アルキレンオキシド鎖を含む各モノマーのモル数を表し、Ｂは、共重合体に含まれる全モノマーの合計モル数を表す。 [Photosensitive resin composition]
The photosensitive resin composition of the present invention comprises: (A) a resin containing an ethylenically unsaturated group and a carboxyl group; (B) an epoxy resin; (C) a photopolymerizable monomer; and (D) a photopolymerization initiator. Any one of the components (A), (B), and (C) contains an alkylene oxide chain, and a parameter X represented by the following formula (1) is , 4 or greater and 25 or less.

In formula (1), M _AO represents a value shown in the following formula (2) when the component containing an alkylene oxide chain is a copolymer, or represents a value shown in the following formula (2) when the component containing an alkylene oxide chain is not a copolymer: , (the molecular weight of the alkylene oxide chain of each compound contained in components (A) to (C))/(the molecular weight of each compound contained in components (A) to (C)). N is represents the solid content (parts by mass) of all compounds contained in component (C), and n represents the solid content (parts by mass) of each of the compounds contained in components (A) to (C).

In formula (2), A _AO represents the molecular weight of the alkylene oxide chain of each monomer containing an alkylene oxide chain, A represents the molecular weight of each monomer containing an alkylene oxide chain, and B _AO represents the molecular weight of each monomer containing an alkylene oxide chain. represents the number of moles of each monomer, and B represents the total number of moles of all monomers contained in the copolymer.

In the present invention, by adjusting the content of the alkylene oxide chain contained in any one of the components (A), (B), and (C) relative to the entire components (A) to (C) that are curable resins, a cured product having excellent flexibility and insulation can be obtained, and a photosensitive resin composition having excellent resolution can be provided. In addition, a cured product having excellent adhesion can usually be obtained. The inventors have found that if a photosensitive resin composition is hydrophilic, it will have excellent flexibility but poor insulation. For this reason, they have focused on the content of the alkylene oxide chain that is involved in polymerization and has a hydrophobic structure in the components (A) to (C). As a result, by adjusting the content of the alkylene oxide chain contained in any one of the components (A), (B), and (C) relative to the entire components (A) to (C) so as to satisfy the above formula (1), the flexibility of the photosensitive resin composition can be increased, and both the flexibility and insulation can be improved. In addition, it is believed that the hydrophobic structure of the alkylene oxide chain also improves adhesion.

式（ａ）中、Ｒはそれぞれ独立に、置換基を有していてもよいアルキレン基を表し、ｑは１～１００の整数を表す。 The alkylene oxide chain has a structure represented by the following formula (a).

In formula (a), each R independently represents an alkylene group which may have a substituent, and q represents an integer of 1 to 100.

R represents an alkylene group which may have a substituent. The alkylene group is preferably an alkylene group having 1 to 10 carbon atoms, more preferably an alkylene group having 1 to 6 carbon atoms, and even more preferably an alkylene group having 1 to 5, 1 to 4, or 1 to 3 carbon atoms. Specific examples of the alkylene group include a methylene group, an ethylene group, a propylene group, an isopropylene group, an n-butylene group, a pentylene group, and a hexylene group.

The alkylene group may have a substituent. Examples of the substituent include an alkyl group having 1 to 3 carbon atoms and a halogen atom. The substituent may be contained alone or in combination of two or more kinds.

q represents an integer from 1 to 100, preferably an integer from 1 to 50, more preferably an integer from 1 to 10, and even more preferably an integer from 1 to 5.

Examples of alkylene oxide chains include methylene oxide, ethylene oxide (EO), propylene oxide (PO), isopropylene oxide, butylene oxide (BO), etc.

The alkylene oxide chain is preferably contained in component (A), preferably in component (B), and preferably in component (C). The alkylene oxide chain is preferably contained in components (A) and (B), preferably in components (A) and (C), preferably in components (B) and (C), and preferably in components (A) to (C). Of these, the alkylene oxide chain is more preferably contained in components (B) and (C).

Components (A) to (C) may each have one type of alkylene oxide chain in one molecule, or may each have multiple types of alkylene oxide chains.

The photosensitive resin composition may further contain optional components in combination with components (A) to (D). Examples of optional components include (E) inorganic filler, (F) solvent, and (G) other additives. Each component contained in the photosensitive resin composition is described in detail below.

<(A) Resin containing an ethylenically unsaturated group and a carboxyl group>
The photosensitive resin composition contains, as component (A), a resin containing an ethylenically unsaturated group and a carboxyl group. By including component (A) in the photosensitive resin composition, it is possible to improve developability.

Examples of ethylenically unsaturated groups include vinyl groups, allyl groups, propargyl groups, butenyl groups, ethynyl groups, phenylethynyl groups, maleimide groups, nadimide groups, and (meth)acryloyl groups. From the viewpoint of reactivity in photoradical polymerization, (meth)acryloyl groups are preferred. "(meth)acryloyl groups" refers to methacryloyl groups and acryloyl groups.

Component (A) has an ethylenically unsaturated group and a carboxyl group. Because of this structure, component (A) can be photoradical polymerized and can be developed in an alkaline environment. As component (A), for example, a resin having both a carboxyl group and two or more ethylenically unsaturated groups in one molecule is preferable.

One embodiment of the resin containing an ethylenically unsaturated group and a carboxyl group is an acid-modified unsaturated epoxy ester resin obtained by reacting an epoxy compound with an unsaturated carboxylic acid and then with an acid anhydride. In detail, an unsaturated epoxy ester resin is obtained by reacting an epoxy compound with an unsaturated carboxylic acid, and an acid-modified unsaturated epoxy ester resin is obtained by reacting the unsaturated epoxy ester resin with an acid anhydride. Any of the epoxy compound, the unsaturated carboxylic acid, and the acid anhydride may have an alkylene oxide chain.

As the epoxy compound, any compound having an epoxy group in the molecule can be used, and examples thereof include bisphenol-type epoxy resins such as epoxy group-containing copolymers, bisphenol A-type epoxy resins, hydrogenated bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, hydrogenated bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, and modified bisphenol F-type epoxy resins obtained by reacting bisphenol F-type epoxy resins with epichlorohydrin to modify them to have three or more functional groups; biphenol-type epoxy resins, such as biphenol-type epoxy resins and tetramethylbiphenol-type epoxy resins; novolac-type epoxy resins, such as phenol novolac-type epoxy resins, cresol novolac-type epoxy resins, bisphenol A-type novolac-type epoxy resins, and alkylphenol novolac-type epoxy resins; fluorine-containing epoxy resins, such as bisphenol AF-type epoxy resins and perfluoroalkyl-type epoxy resins; naphthalene-type epoxy resins, dihydroxynaphthalene-type epoxy resins, polyhydroxybinaphthalene-type epoxy resins, naphthol-type epoxy resins, and binaphthol-type epoxy resins. epoxy resins having a naphthalene skeleton such as naphthylene ether type epoxy resins, naphthol novolac type epoxy resins, and naphthalene type epoxy resins obtained by the condensation reaction of polyhydroxynaphthalene with aldehydes (epoxy resins containing a naphthalene skeleton); bixylenol type epoxy resins; dicyclopentadiene type epoxy resins; trisphenol type epoxy resins; tert-butyl-catechol type epoxy resins; epoxy resins containing a condensed ring skeleton such as anthracene type epoxy resins; glycidylamine type epoxy resins; glycidyl ester type epoxy resins; biphenyl type epoxy resins; linear aliphatic epoxy resins; epoxy resins having a butadiene structure; alicyclic epoxy resins; heterocyclic epoxy resins; spiro ring-containing epoxy resins; cyclohexanedimethanol type epoxy resins; trimethylol type epoxy resins; tetraphenylethane type epoxy resins; glycidyl group-containing acrylic resins such as polyglycidyl (meth)acrylate and copolymers of glycidyl methacrylate and acrylic acid esters; fluorene type epoxy resins; halogenated epoxy resins, etc.

From the viewpoint of reducing the average linear thermal expansion coefficient, the epoxy compound is preferably an epoxy group-containing copolymer or an epoxy resin containing an aromatic skeleton. Here, the term "aromatic skeleton" includes polycyclic aromatics and aromatic heterocycles. The epoxy compound is preferably an epoxy resin containing a naphthalene skeleton; an epoxy resin containing a condensed ring skeleton; a biphenyl-type epoxy resin; a bisphenol-type epoxy resin such as a bisphenol F-type epoxy resin or a bisphenol A-type epoxy resin; a cresol novolac-type epoxy resin; or a glycidyl ester-type epoxy resin.

The epoxy group-containing copolymer can be obtained by polymerizing an epoxy group-containing monomer and, if necessary, any other monomer. Examples of the epoxy group-containing monomer include epoxy group-containing (meth)acrylate monomers such as glycidyl (meth)acrylate, 3,4-epoxybutyl (meth)acrylate, 2-methyl-3,4-epoxycyclohexyl (meth)acrylate, and allyl glycidyl ether, with glycidyl (meth)acrylate being preferred. The epoxy group-containing monomer may be used alone or in a mixture of two or more kinds.

Optional monomers include, for example, styrene, (meth)acrylic acid, methyl (meth)acrylate, ethyl methacrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl methacrylate, and nonyl (meth)acrylate. , decyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, behenyl (meth)acrylate, cyclohexyl (meth)acrylate, 4-tert-butylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, benzyl (meth)acrylate, acrylamide, N,N-dimethyl (meth)acrylamide, (meth)acrylonitrile, 3-(meth)acrylate, p) acryloylpropyltrimethoxysilane, N,N-dimethylaminoethyl (meth)acrylate, glycidyl (meth)acrylate, styrene, α-methylstyrene, p-methylstyrene, p-methoxystyrene, 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxy-n-butyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy-n-butyl (meth)acrylate, 3-hydroxy-n-butyl (meth)acrylate , 1,4-cyclohexanedimethanol mono(meth)acrylate, glycerin mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-(meth)acryloyloxyethyl-2-hydroxyethyl phthalate, lactone-modified (meth)acrylate having a hydroxyl group at the end, 1-adamantyl (meth)acrylate, etc. are included, and n-butyl (meth)acrylate is preferred. The optional monomers may be used alone or in a mixture of two or more. "(meth)acrylic acid" refers to acrylic acid and methacrylic acid. "(meth)acrylate" refers to acrylate and methacrylate.

Preferred naphthalene skeleton-containing epoxy resins are dihydroxynaphthalene type epoxy resins, polyhydroxybinaphthalene type epoxy resins, and naphthalene type epoxy resins obtained by condensation reaction of polyhydroxynaphthalene with aldehydes. Examples of dihydroxynaphthalene type epoxy resins include 1,3-diglycidyloxynaphthalene, 1,4-diglycidyloxynaphthalene, 1,5-diglycidyloxynaphthalene, 1,6-diglycidyloxynaphthalene, 2,3-diglycidyloxynaphthalene, 2,6-diglycidyloxynaphthalene, and 2,7-diglycidyloxynaphthalene. Examples of polyhydroxybinaphthalene type epoxy resins include 1,1'-bi-(2-glycidyloxy)naphthyl, 1-(2,7-diglycidyloxy)-1'-(2'-glycidyloxy)binaphthyl, 1,1'-bi-(2,7-diglycidyloxy)naphthyl, etc. Examples of naphthalene type epoxy resins obtained by condensation reaction of polyhydroxynaphthalene with aldehydes include 1,1'-bis(2,7-diglycidyloxynaphthyl)methane, 1-(2,7-diglycidyloxynaphthyl)-1'-(2'-glycidyloxynaphthyl)methane, 1,1'-bis(2-glycidyloxynaphthyl)methane.

Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, cinnamic acid, crotonic acid, glycidyl methacrylate, and glycidyl acrylate, and these may be used alone or in combination of two or more. Among these, acrylic acid and methacrylic acid are preferred from the viewpoint of improving the photocurability of the photosensitive resin composition. In this specification, the epoxy ester resin, which is the reaction product of the above epoxy compound and (meth)acrylic acid, may be referred to as "epoxy (meth)acrylate", and here the epoxy group of the epoxy compound is substantially eliminated by the reaction with (meth)acrylic acid.

Examples of acid anhydrides include maleic anhydride, succinic anhydride, itaconic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and benzophenonetetracarboxylic dianhydride. Any one of these may be used alone, or two or more may be used in combination. Among these, succinic anhydride and tetrahydrophthalic anhydride are preferred from the viewpoint of improving the resolution and insulation reliability of the cured product.

When obtaining the acid-modified unsaturated epoxy ester resin, a catalyst, a solvent, a polymerization inhibitor, etc. may be used as necessary.

As the acid-modified unsaturated epoxy ester resin, an acid-modified epoxy (meth)acrylate is preferred, and it is more preferred to include either an acid-modified naphthalene skeleton-containing epoxy (meth)acrylate or an acid-modified bisphenol skeleton-containing epoxy (meth)acrylate. The "epoxy" in the acid-modified unsaturated epoxy ester resin represents the structure derived from the above-mentioned epoxy compound. For example, "acid-modified bisphenol-type epoxy (meth)acrylate" refers to an acid-modified unsaturated epoxy ester resin obtained by using a bisphenol-type epoxy resin as the epoxy compound and (meth)acrylic acid as the unsaturated carboxylic acid.

The acid-modified unsaturated epoxy ester resin is preferably a (meth)acrylic polymer having a glass transition temperature of -20°C or lower. A (meth)acrylic polymer is a polymer containing structural units having a structure formed by polymerizing a (meth)acrylic monomer. Examples of such a (meth)acrylic polymer include a polymer obtained by polymerizing a (meth)acrylic monomer, or a polymer obtained by copolymerizing a (meth)acrylic monomer and a monomer that can be copolymerized with the (meth)acrylic monomer.

Examples of (meth)acrylic polymers with a glass transition temperature of -20°C or less include acid-modified unsaturated epoxy (meth)acrylic copolymers obtained by reacting an epoxy group-containing copolymer with (meth)acrylic acid and then with an acid anhydride. In more detail, an unsaturated epoxy (meth)acrylic copolymer can be obtained by reacting an epoxy group-containing copolymer with (meth)acrylic acid, and then an acid-modified unsaturated epoxy (meth)acrylic copolymer can be obtained by reacting the unsaturated epoxy (meth)acrylic copolymer with an acid anhydride.

Preferred embodiments of the (meth)acrylic polymer with a glass transition temperature of -20°C or less include an epoxy group-containing copolymer obtained by polymerizing an epoxy group-containing monomer and an arbitrary monomer, and a compound obtained by reacting (meth)acrylic acid with an acid anhydride, in which the epoxy group-containing monomer is glycidyl methacrylate, the arbitrary monomer is butyl acrylate, and the acid anhydride is tetrahydrophthalic anhydride.

Such acid-modified unsaturated epoxy ester resins can be commercially available products, and specific examples include "ZAR-2000" (a reaction product of bisphenol A type epoxy resin, acrylic acid, and succinic anhydride), "ZFR-1491H", and "ZFR-1533H" (a reaction product of bisphenol F type epoxy resin, acrylic acid, and tetrahydrophthalic anhydride (a bisphenol F type backbone-containing acid-modified epoxy acrylate)) manufactured by Nippon Kayaku Co., Ltd., and "PR-300CP" (a reaction product of cresol novolac type epoxy resin, acrylic acid, and acid anhydride) manufactured by Showa Denko KK. These may be used alone or in combination of two or more types.

Other examples of resins containing ethylenically unsaturated groups and carboxyl groups include unsaturated modified (meth)acrylic resins in which ethylenically unsaturated groups are introduced by reacting an ethylenically unsaturated group-containing epoxy compound with a (meth)acrylic resin having structural units obtained by polymerizing (meth)acrylic acid. Examples of ethylenically unsaturated group-containing epoxy compounds include glycidyl methacrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, and 3,4-epoxycyclohexylmethyl (meth)acrylate. It is also possible to react an acid anhydride with the hydroxyl group generated during the introduction of the unsaturated group. The acid anhydride may be the same as the acid anhydride described above, and the preferred range is also the same.

Such unsaturated modified (meth)acrylic resins can be commercially available products, and specific examples include "SPC-1000" and "SPC-3000" manufactured by Showa Denko K.K., and "Cyclomer P(ACA)Z-250", "Cyclomer P(ACA)Z-251", "Cyclomer P(ACA)Z-254", "Cyclomer P(ACA)Z-300", and "Cyclomer P(ACA)Z-320" manufactured by Daicel Allnex Co., Ltd.

The weight average molecular weight of component (A) is preferably 1000 or more, more preferably 1500 or more, and even more preferably 2000 or more, from the viewpoint of film-forming properties. The upper limit is preferably 50000 or less, more preferably 30000 or less, and even more preferably 25000 or less, from the viewpoint of developability. The weight average molecular weight is the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

The acid value of the (A) component is preferably 0.1 mgKOH/g or more, more preferably 0.5 mgKOH/g or more, and even more preferably 1 mgKOH/g or more, from the viewpoint of improving the alkaline developability of the photosensitive resin composition. On the other hand, from the viewpoint of suppressing the fine pattern of the cured product from dissolving due to development and improving the insulation reliability, the acid value is preferably 150 mgKOH/g or less, more preferably 120 mgKOH/g or less, and even more preferably 100 mgKOH/g or less. Here, the acid value refers to the residual acid value of the carboxyl group present in the (A) component, and the acid value can be measured by the following method. First, after weighing out about 1 g of the resin solution to be measured, 30 g of acetone is added to the resin solution to dissolve the resin solution uniformly. Next, an appropriate amount of phenolphthalein, which is an indicator, is added to the solution, and titration is performed using a 0.1 N KOH aqueous solution. Then, the acid value is calculated by the following formula.
Formula: A(b)=10×Vf×56.1/(Wp×I)

In the above formula, A(b) represents the acid value (mgKOH/g), Vf represents the titration amount of KOH (mL), Wp represents the mass of the measured resin solution (g), and I represents the proportion of non-volatile matter in the measured resin solution (mass%).

In the production of component (A), from the viewpoint of improving storage stability, the ratio of the number of moles of epoxy groups in the epoxy resin to the number of moles of carboxyl groups in the total of the unsaturated carboxylic acid and acid anhydride is preferably in the range of 1:0.8-1.3, and more preferably in the range of 1:0.9-1.2.

From the viewpoint of improving flexibility, the glass transition temperature (Tg) of the component (A) is preferably −300° C. or higher, more preferably −200° C. or higher, and even more preferably −80° C. or higher, and is preferably −20° C. or lower, more preferably −23° C. or lower, and even more preferably −25° C. or lower. Here, the glass transition temperature of the component (A) is the theoretical glass transition temperature of the main chain of the component (A), and this theoretical glass transition temperature can be calculated by the FOX formula shown below. The glass transition temperature calculated by the FOX formula is almost the same as the glass transition temperature measured by differential scanning calorimetry (TMA, DSC, DTA), so the glass transition temperature of the main chain of the component (A) may be measured by differential scanning calorimetry.
1/Tg=(W1/Tg1)+(W2/Tg2)+...+(Wm/Tgm)
W1+W2+...+Wm=1
Wm represents the content (mass%) of each monomer constituting component (A), and Tgm represents the glass transition temperature (K) of each monomer constituting component (A).

From the viewpoint of improving alkaline developability, the (A) component is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, when the non-volatile components in the photosensitive resin composition are taken as 100% by mass. From the viewpoint of improving heat resistance and average linear expansion coefficient, the upper limit is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less. In the present invention, the content of each component in the photosensitive resin composition is the value when the non-volatile components in the photosensitive resin composition are taken as 100% by mass, unless otherwise specified.

<(B) Epoxy Resin>
The photosensitive resin composition contains an epoxy resin as component (B). By containing component (B), the insulation reliability can be improved. However, component (B) does not include epoxy resins containing ethylenically unsaturated groups and carboxyl groups.

Examples of component (B) include bixylenol type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol AF type epoxy resins, dicyclopentadiene type epoxy resins, trisphenol type epoxy resins, naphthol novolac type epoxy resins, phenol novolac type epoxy resins, tert-butyl-catechol type epoxy resins, naphthalene type epoxy resins, naphthol type epoxy resins, anthracene type epoxy resins, glycidylamine type epoxy resins, glycidyl ester type epoxy resins, cresol novolac type epoxy resins, biphenyl type epoxy resins, linear aliphatic epoxy resins, alkylene oxide chain-containing aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexane type epoxy resins, cyclohexane dimethanol type epoxy resins, naphthylene ether type epoxy resins, trimethylol type epoxy resins, tetraphenylethane type epoxy resins, etc. Among them, the (B) epoxy resin is preferably a biphenyl type epoxy resin or a linear aliphatic epoxy resin, and more preferably a biphenyl type epoxy resin. The (B) epoxy resin may be used alone or in combination of two or more types. Examples of the alkylene oxide chain-containing aliphatic epoxy resin include an alkylene oxide chain-containing linear aliphatic epoxy resin, an alkylene oxide chain-containing branched aliphatic epoxy resin, and an alkylene oxide chain-containing cyclic aliphatic epoxy resin.

The photosensitive resin composition preferably contains, as component (B), an epoxy resin having two or more epoxy groups in one molecule. From the viewpoint of obtaining the desired effect of the present invention significantly, the ratio of the epoxy resin having two or more epoxy groups in one molecule to 100% by mass of the non-volatile components of component (B) is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more.

Component (B) includes epoxy resins that are liquid at a temperature of 20°C (hereinafter sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at a temperature of 20°C (hereinafter sometimes referred to as "solid epoxy resins"). The resin composition may contain only liquid epoxy resins as component (B), only solid epoxy resins, or a combination of liquid and solid epoxy resins.

As the solid epoxy resin, a solid epoxy resin having three or more epoxy groups in one molecule is preferable, and an aromatic solid epoxy resin having three or more epoxy groups in one molecule is more preferable.

As solid epoxy resins, bixylenol type epoxy resins, naphthalene type epoxy resins, naphthalene type tetrafunctional epoxy resins, cresol novolac type epoxy resins, dicyclopentadiene type epoxy resins, trisphenol type epoxy resins, naphthol type epoxy resins, biphenyl type epoxy resins, naphthylene ether type epoxy resins, anthracene type epoxy resins, bisphenol A type epoxy resins, bisphenol AF type epoxy resins, and tetraphenylethane type epoxy resins are preferred, with naphthalene type epoxy resins being more preferred.

Specific examples of solid epoxy resins include DIC's "HP4032H" (naphthalene type epoxy resin); DIC's "HP-4700" and "HP-4710" (naphthalene type tetrafunctional epoxy resin); DIC's "N-690" (cresol novolac type epoxy resin); DIC's "N-695" (cresol novolac type epoxy resin); DIC's "HP-7200", "HP-7200HH", and "HP-7200H" (dicyclopenta diene type epoxy resin); "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", and "HP6000" (naphthylene ether type epoxy resin) manufactured by DIC Corporation; "EPPN-502H" (trisphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC7000L" (naphthol novolac type epoxy resin) manufactured by Nippon Kayaku Co., Ltd.; "NC3000H", "NC3000", and "NC3000" manufactured by Nippon Kayaku Co., Ltd. "L", "NC3100" (biphenyl type epoxy resin); "ESN475V" (naphthol type epoxy resin) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; "ESN485" (naphthol novolac type epoxy resin) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; "YX4000H", "YX4000", "YL6121" (biphenyl type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX4000HK" (bixylenol type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX8800" ( anthracene type epoxy resin); "PG-100" and "CG-500" manufactured by Osaka Gas Chemicals; "YL7760" (bisphenol AF type epoxy resin) manufactured by Mitsubishi Chemical; "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical; "jER1010" (solid bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical; "jER1031S" (tetrakishydroxyphenylethane type epoxy resin) manufactured by Mitsubishi Chemical. These may be used alone or in combination of two or more types.

Preferably, the liquid epoxy resin has two or more epoxy groups in one molecule.

Preferred liquid epoxy resins are bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins, alicyclic epoxy resins having an ester skeleton, cyclohexane type epoxy resins, cyclohexane dimethanol type epoxy resins, glycidyl amine type epoxy resins, and epoxy resins having a butadiene structure, with bisphenol A type epoxy resins and bisphenol F type epoxy resins being more preferable.

Specific examples of liquid epoxy resins include DIC's "HP4032", "HP4032D", and "HP4032SS" (naphthalene type epoxy resins); Mitsubishi Chemical's "828US", "jER828EL", "825", and "Epicoat 828EL" (bisphenol A type epoxy resins); Mitsubishi Chemical's "jER807" and "1750" (bisphenol F type epoxy resins); Mitsubishi Chemical's "jER152" (phenol novolac type epoxy resin); Mitsubishi Chemical's "630" and "630LSD" (glycidylamine type epoxy resins); and Nippon Steel & Sumitomo Metal Chemical's "ZX1059" (bisphenol A type epoxy resins). Examples of such epoxy resins include mixtures of bisphenol A type epoxy resins and bisphenol F type epoxy resins; Nagase ChemteX's "EX-721" (glycidyl ester type epoxy resin); Nagase ChemteX's "EX-821" and "EX-920" (linear aliphatic epoxy resins containing alkylene oxide chains); Daicel's "Celloxide 2021P" (alicyclic epoxy resin having an ester skeleton); Daicel's "PB-3600" (epoxy resin having a butadiene structure); and Nippon Steel & Sumikin Chemical's "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resins). These may be used alone or in combination of two or more.

When a liquid epoxy resin and a solid epoxy resin are used in combination as component (B), the ratio by mass (liquid epoxy resin:solid epoxy resin) is preferably 1:1 to 1:20, more preferably 1:1.5 to 1:15, and particularly preferably 1:2 to 1:10. By keeping the ratio by mass of the liquid epoxy resin to the solid epoxy resin within this range, the desired effects of the present invention can be significantly obtained.

The epoxy equivalent of component (B) is preferably 50 g/eq. to 5000 g/eq., more preferably 50 g/eq. to 3000 g/eq., even more preferably 80 g/eq. to 2000 g/eq., and even more preferably 110 g/eq. to 1000 g/eq. Within this range, the crosslink density of the cured product of the resin composition layer is sufficient, resulting in an insulating layer with small surface roughness. The epoxy equivalent is the mass of an epoxy resin containing one equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

The weight average molecular weight (Mw) of the component (B) is preferably 100 to 5,000, more preferably 250 to 3,000, and even more preferably 400 to 1,500, from the viewpoint of significantly achieving the desired effects of the present invention.
The weight average molecular weight of the resin can be measured by gel permeation chromatography (GPC) as a polystyrene equivalent value.

The content of component (B) is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more, based on 100% by mass of the non-volatile components in the resin composition, from the viewpoint of obtaining an insulating layer that exhibits good tensile mechanical strength and insulating reliability. The upper limit of the content of component (C) is preferably 20% by mass or less, more preferably 15% by mass or less, and particularly preferably 10% by mass or less, based on 100% by mass of the non-volatile components in the resin composition.

<(C) Photopolymerizable Monomer>
The photosensitive resin composition contains a photopolymerizable monomer as component (C). However, component (C) does not include components (A) and (B). By including the photopolymerizable monomer (C) in the photosensitive resin composition, the photoreactivity can be improved. As component (C), for example, a photosensitive (meth)acrylate compound that has one or more (meth)acryloyl groups in one molecule and is liquid, solid or semi-solid at room temperature can be used. Room temperature refers to about 25°C.

Examples of photosensitive (meth)acrylate compounds include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl acrylate and 2-hydroxybutyl acrylate; mono- or di(meth)acrylates of glycols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene glycol; acrylamides such as N,N-dimethylacrylamide and N-methylolacrylamide; aminoalkyl (meth)acrylates such as N,N-dimethylaminoethyl acrylate; trimethylolpropane, pentaerythritol, dipentaerythritol, and the like. Examples of the acrylates include polyhydric (meth)acrylates of polyhydric alcohols such as taerythritol or their adducts with ethylene oxide, propylene oxide or ε-caprolactone; (meth)acrylates of phenols such as phenoxy acrylate and phenoxyethyl acrylate or their ethylene oxide or propylene oxide adducts; epoxy acrylates derived from glycidyl ethers such as trimethylolpropane triglycidyl ether, modified epoxy acrylates, melamine acrylates, and/or methacrylates corresponding to the above acrylates. (Meth)acrylate refers to acrylate and methacrylate.

Among these, (meth)acrylates and polyhydric (meth)acrylates such as mono- or di(meth)acrylates of glycols, phenols such as phenoxy acrylate and phenoxyethyl acrylate, or their ethylene oxide or propylene oxide adducts are preferred.

Examples of glycol mono- or di(meth)acrylates include polytetramethylene glycol diacrylate.

Examples of phenols such as phenoxy acrylate and phenoxyethyl acrylate, or (meth)acrylates such as their ethylene oxide or propylene oxide adducts include EO-modified bisphenol A acrylate.

As polyvalent (meth)acrylates, for example, trivalent acrylates or methacrylates are preferred. Examples of trivalent acrylates or methacrylates include 1,9-nonanediol diacrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolpropane EO-added tri(meth)acrylate, glycerin PO-added tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, tetrafurfuryl alcohol oligo(meth)acrylate, ethyl carbitol oligo(meth)acrylate, 1,4-butanediol oligo(meth)acrylate, 1,6-hexanediol oligo(meth)acrylate, trimethylolpropane oligo(meth)acrylate, pentaerythritol oligo(meth)acrylate, and tetramethylolmethane tetra(meth)acrylate. Examples of the trivalent or higher acrylates or methacrylates include phosphate triester (meth)acrylates such as tri(2-(meth)acryloyloxyethyl)phosphate, tri(2-(meth)acryloyloxypropyl)phosphate, tri(3-(meth)acryloyloxypropyl)phosphate, tri(3-(meth)acryloyl-2-hydroxyloxypropyl)phosphate, di(3-(meth)acryloyl-2-hydroxyloxypropyl)(2-(meth)acryloyloxyethyl)phosphate, and (3-(meth)acryloyl-2-hydroxyloxypropyl)di(2-(meth)acryloyloxyethyl)phosphate. These photosensitive (meth)acrylate compounds may be used alone or in combination of two or more.

(C) Photopolymerizable monomers may be commercially available products. Examples of commercially available products include "DPHA" manufactured by Nippon Kayaku Co., Ltd., "EBECRYL3708" manufactured by Daicel Allnex Co., Ltd., "R-551" manufactured by Nippon Kayaku Co., Ltd., "A-PTMG-65" manufactured by Shin-Nakamura Chemical Co., Ltd., and "1.9ND" manufactured by Kyoeisha Chemical Co., Ltd.

The content of (C) photopolymerizable monomer is, from the viewpoint of promoting photocuring, preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 1.5% by mass or more, and is preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, when the total solid content of the photosensitive resin composition is taken as 100% by mass.

<(D) Photopolymerization initiator>
The photosensitive resin composition contains a photopolymerization initiator as component (D). By including the photopolymerization initiator (D) in the photosensitive resin composition, the photosensitive resin composition can be efficiently photocured. These may be used alone or in combination of two or more.

(D) Any compound can be used as the photopolymerization initiator, for example, acylphosphine oxide-based photopolymerization initiators such as bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide) and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide; oxime ester-based photopolymerization initiators such as 1,2-octanedione, 1-4-(phenylthio)-2-(O-benzoyloxime), ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, and 1-(O-acetyloxime); 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-[4-(4-morpholinyl)phenyl]-1-butanone, and 2-methyl-1-[4-(methylthio)phenyl]-2-mol Examples of the photopolymerization initiator include α-aminoalkylphenone-based photopolymerization initiators such as holinopropan-1-one; benzophenone, methylbenzophenone, o-benzoylbenzoic acid, benzoyl ethyl ether, 2,2-diethoxyacetophenone, 2,4-diethylthioxanthone, diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl-(2,4,6-trimethylbenzoyl)phenylphosphinate, 4,4'-bis(diethylamino)benzophenone, 1-hydroxy-cyclohexyl-phenyl ketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxand; and sulfonium salt-based photopolymerization initiators. These may be used alone or in combination of two or more. Among these, from the viewpoint of more efficiently photocuring the photosensitive resin composition, either an acylphosphine oxide-based photopolymerization initiator or an oxime ester-based photopolymerization initiator is preferred, and an oxime ester-based photopolymerization initiator is more preferred.

(D) Specific examples of photopolymerization initiators include "Omnirad 907", "Omnirad 369", "Omnirad 379", "Omnirad 819", and "Omnirad TPO" manufactured by IGM, "Irgacure OXE-01", "Irgacure OXE-02", "Irgacure TPO", and "Irgacure 819" manufactured by BASF, and "N-1919" and "NCI-831" manufactured by ADEKA.

Furthermore, the photosensitive resin composition may contain, in combination with the (D) photopolymerization initiator, tertiary amines such as N,N-dimethylaminobenzoic acid ethyl ester, N,N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine, triethanolamine, etc., as a photopolymerization initiation assistant, or may contain photosensitizers such as pyrazonides, anthracenes, coumarins, xanthones, thioxanthones, etc. These may be used alone or in combination of two or more.

The content of the photopolymerization initiator (D) is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, and even more preferably 0.01% by mass or more, when the non-volatile components of the photosensitive resin composition are taken as 100% by mass, from the viewpoint of sufficiently photocuring the photosensitive resin composition and improving insulation reliability. On the other hand, from the viewpoint of suppressing a decrease in resolution due to excessive sensitivity, the upper limit is preferably 3% by mass or less, more preferably 1% by mass or less, and even more preferably 0.5% by mass or less. In addition, when the photosensitive resin composition contains a photopolymerization initiator assistant, it is preferable that the total content of the photopolymerization initiator (D) and the photopolymerization initiator assistant is within the above range.

<(E) Inorganic filler>
In addition to the above-mentioned components, the photosensitive resin composition may further contain an inorganic filler as an optional component (E).

(E) An inorganic compound is used as the material of the inorganic filler. Examples of the material of the inorganic filler include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, silica and magnesium hydroxide are preferred, and magnesium hydroxide is particularly preferred. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. In addition, spherical silica is preferred as the silica. (F) The inorganic filler may be used alone or in combination of two or more types.

Commercially available products of component (E) include, for example, "UFP-20" and "UFP-30" manufactured by Denka; "SP60-05" and "SP507-05" manufactured by Nippon Steel & Sumitomo Metal Materials; "SC2050", "YC100C", "YA050C", "YA050C-MJE", "YA010C", "SC2500SQ", "SO-C4", "SO-C2", and "SO-C1" manufactured by Admatechs; "Silfil NSS-3N", "Silfil NSS-4N", and "Silfil NSS-5N" manufactured by Tokuyama Corporation; and "EP4-A" manufactured by Konoshima Chemical Co., Ltd.

The specific surface area of component (E) is preferably 1 m ² /g or more, more preferably 2 m ² /g or more, and particularly preferably 3 m ² /g or more. There is no particular upper limit, but it is preferably 60 m ² /g or less, 50 m ² /g or less, or 40 m ² /g or less. The specific surface area is obtained according to the BET method by adsorbing nitrogen gas onto the surface of a sample using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountech Co., Ltd.) and calculating the specific surface area using the BET multipoint method.

From the viewpoint of significantly obtaining the desired effects of the present invention, the average particle size of component (E) is preferably 0.01 μm or more, more preferably 0.05 μm or more, and particularly preferably 0.1 μm or more, and is preferably 5 μm or less, more preferably 2 μm or less, and even more preferably 1 μm or less.

The average particle size of component (E) can be measured by a laser diffraction/scattering method based on the Mie scattering theory. Specifically, a particle size distribution of the inorganic filler is created on a volume basis using a laser diffraction/scattering particle size distribution measuring device, and the median diameter is used as the average particle size. The measurement sample can be prepared by weighing 100 mg of inorganic filler and 10 g of methyl ethyl ketone into a vial and dispersing the mixture ultrasonically for 10 minutes. The measurement sample is measured using a laser diffraction particle size distribution measuring device with blue and red light wavelengths as the light source, and the volume-based particle size distribution of component (E) is measured using a flow cell method, and the average particle size can be calculated as the median diameter from the particle size distribution obtained. An example of a laser diffraction particle size distribution measuring device is the "LA-960" manufactured by Horiba, Ltd.

From the viewpoint of improving moisture resistance and dispersibility, it is preferable that the (E) component is treated with a surface treatment agent. Examples of the surface treatment agent include vinylsilane coupling agents, (meth)acrylic coupling agents, fluorine-containing silane coupling agents, aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, silane coupling agents, alkoxysilanes, organosilazane compounds, and titanate coupling agents. Among them, from the viewpoint of obtaining the effects of the present invention significantly, vinylsilane coupling agents, (meth)acrylic coupling agents, and aminosilane coupling agents are preferred. Moreover, the surface treatment agent may be used alone or in any combination of two or more types.

Commercially available surface treatment agents include, for example, Shin-Etsu Chemical Co., Ltd.'s "KBM1003" (vinyltriethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM503" (3-methacryloxypropyltriethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM403" (3-glycidoxypropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM803" (3-mercaptopropyltrimethoxysilane), and Shin-Etsu Chemical Co., Ltd.'s "KBE903" (3-aminopropyltriethoxy silane), Shin-Etsu Chemical Co., Ltd.'s "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "SZ-31" (hexamethyldisilazane), Shin-Etsu Chemical Co., Ltd.'s "KBM103" (phenyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd.'s "KBM-4803" (long-chain epoxy-type silane coupling agent), Shin-Etsu Chemical Co., Ltd.'s "KBM-7103" (3,3,3-trifluoropropyltrimethoxysilane), etc.

From the viewpoint of improving the dispersibility of the inorganic filler, it is preferable that the degree of surface treatment with the surface treatment agent falls within a specified range. Specifically, 100 parts by mass of the inorganic filler is preferably surface-treated with 0.2 parts by mass to 5 parts by mass of the surface treatment agent, more preferably with 0.2 parts by mass to 3 parts by mass, and more preferably with 0.3 parts by mass to 2 parts by mass.

The degree of surface treatment by the surface treatment agent can be evaluated by the amount of carbon per unit surface area of the inorganic filler. From the viewpoint of improving the dispersibility of the inorganic filler, the amount of carbon per unit surface area of the inorganic filler is preferably 0.02 mg/m ² or more, more preferably 0.1 mg/m ² or more, and even more preferably 0.2 mg/m ² or more. On the other hand, from the viewpoint of suppressing the increase in the melt viscosity of the resin varnish and the melt viscosity in the film form, it is preferably 1 mg/m ² or less, more preferably 0.8 mg/m ² or less, and even more preferably 0.5 mg/m ² or less.

The amount of carbon per unit surface area of the inorganic filler can be measured after the surface-treated inorganic filler is washed with a solvent (e.g., methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler that has been surface-treated with a surface treatment agent, and ultrasonic cleaning is performed at 25°C for 5 minutes. After removing the supernatant and drying the solids, the amount of carbon per unit surface area of the inorganic filler can be measured using a carbon analyzer. An example of a carbon analyzer that can be used is the "EMIA-320V" manufactured by Horiba, Ltd.

From the viewpoint of obtaining a significant effect of the present invention, the content of component (E) is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, 30% by mass or more, 40% by mass or more, 50% by mass or more, and is preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 70% by mass or less, 60% by mass or less, 50% by mass or less, 40% by mass or less, when the non-volatile components in the photosensitive resin composition are taken as 100% by mass.

<(F) Solvent>
The photosensitive resin composition may further contain a solvent (F) as an optional component in addition to the above-mentioned components. The viscosity of the varnish can be adjusted by adding the solvent (F). Examples of the solvent (F) include organic solvents.

(F) Examples of the solvent include ketones such as ethyl methyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers 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; esters such as ethyl acetate, butyl acetate, butyl cellosolve acetate, carbitol acetate, and ethyl diglycol acetate; aliphatic hydrocarbons such as octane and decane; and petroleum-based solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha. These may be used alone or in combination of two or more. When a solvent is used, the content can be appropriately adjusted from the viewpoint of the coatability of the resin composition.

<(G) Other Additives>
The photosensitive resin composition may further contain (G) other additives to the extent that the object of the present invention is not hindered. (G) Other additives include, for example, thermoplastic resins, organic fillers, fine particles such as melamine and organic bentonite, 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 brominated epoxy compounds, acid-modified brominated epoxy compounds, antimony compounds, phosphorus-based compounds, aromatic condensed phosphate esters, and halogen-containing condensed phosphate esters, and thermosetting resins such as phenol-based curing agents and cyanate ester-based curing agents.

The photosensitive resin composition can be produced by mixing the above essential components (A) to (D) and the above optional components (E) to (G), and kneading or stirring the mixture as necessary using a kneading device such as a triple roll mill, ball mill, bead mill, or sand mill, or a stirring device such as a super mixer or planetary mixer.

式（１）中、Ｍ_ＡＯは、アルキレンオキシド鎖を含む成分が共重合体である場合は下記式（２）で示される値を表す。また、Ｍ_ＡＯは、アルキレンオキシド鎖を含む成分が共重合体でない場合は、（（Ａ）～（Ｃ）成分に含まれる各化合物のアルキレンオキシド鎖の分子量）／（（Ａ）～（Ｃ）成分に含まれる各化合物の分子量）を表す。よって、アルキレンオキシド鎖を含む成分が共重合体でない場合、Ｍ_ＡＯは、それら各成分に占めるアルキレンオキシド鎖の質量比率を表す。Ｎは、（Ａ）～（Ｃ）成分に含まれるすべての化合物の固形分含有量（質量部）を表し、ｎは、（Ａ）～（Ｃ）成分に含まれる各化合物の固形分含有量（質量部）を表す。よって、Ｘは、Ｍ_ＡＯとｎとの積を、樹脂組成物中のすべての（Ａ）～（Ｃ）成分のそれぞれについて計算し、そうして得たすべての積の和を求め、この和をＮで割って百分率で表した値である。

式（２）中、Ａ_ＡＯは、アルキレンオキシド鎖を含む各モノマーのアルキレンオキシド鎖の分子量を表し、Ａは、アルキレンオキシド鎖を含む各モノマーの分子量を表し、Ｂ_ＡＯは、アルキレンオキシド鎖を含む各モノマーのモル数を表し、Ｂは、共重合体に含まれる全モノマーの合計モル数を表す。 <Properties and Applications of Photosensitive Resin Composition>
The photosensitive resin composition contains an alkylene oxide chain in any one of the components (A), (B), and (C), and the parameter X shown in the following formula (1) is 4 or more and 25 or less. By satisfying formula (1), it is possible to obtain a cured product having excellent flexibility and insulating properties.

In formula (1), M _AO represents the value shown in formula (2) below when the component containing an alkylene oxide chain is a copolymer. When the component containing an alkylene oxide chain is not a copolymer, M _AO represents (the molecular weight of the alkylene oxide chain of each compound contained in components (A) to (C))/(the molecular weight of each compound contained in components (A) to (C)). Thus, when the component containing an alkylene oxide chain is not a copolymer, M _AO represents the mass ratio of the alkylene oxide chain in each of these components. N represents the solid content (parts by mass) of all compounds contained in components (A) to (C), and n represents the solid content (parts by mass) of each compound contained in components (A) to (C). Thus, X is a value obtained by calculating the product of M _AO and n for each of components (A) to (C) in the resin composition, finding the sum of all the products thus obtained, and dividing this sum by N to express it as a percentage.

In formula (2), A _AO represents the molecular weight of the alkylene oxide chain of each monomer containing an alkylene oxide chain, A represents the molecular weight of each monomer containing an alkylene oxide chain, B _AO represents the number of moles of each monomer containing an alkylene oxide chain, and B represents the total number of moles of all monomers contained in the copolymer.

The term "copolymer" refers to a polymer obtained by polymerization of two or more monomers and having a weight average molecular weight of 10,000 or more. The copolymer may be a random copolymer, a block copolymer, an alternating copolymer, or a graft copolymer.

As described above, the copolymer may be a random copolymer, and it may be difficult to calculate the value of M _AO from the molecular weight. Since the copolymer usually has additivity, when it is difficult to calculate the value of M _AO from the molecular weight, the M _AO can be calculated using formula (2). The molecular weight per unit of the alkylene oxide chain is calculated by A _AO /A in formula (2), and the value of M _AO in the copolymer can be calculated by multiplying it by the molar ratio of the monomer containing the alkylene oxide chain represented by B _AO /B in formula (2). The "monomer" described in the definition in formula (2) represents a compound corresponding to the monomer unit contained in the copolymer. The "monomer unit" represents a partial structure in the copolymer formed by polymerizing a certain compound.

In order to obtain a cured product having excellent flexibility and insulating properties and to improve resolution, X in formula (1) is 25 or less, preferably 23 or less, more preferably 20 or less, and even more preferably 18 or less. In order to obtain the effects of the present invention significantly, the lower limit of X in formula (1) is 4 or more, preferably 5 or more, and more preferably 6 or more.

The cured product obtained by photocuring the photosensitive resin composition of the present invention exhibits excellent resolution. Therefore, when a round hole (via) with an opening diameter of 100 μm is formed using the cured product, the formation of residue at the bottom of the round hole can be suppressed. The via bottom residue can be evaluated according to the method described below in <Evaluation of via bottom residue>.

The photocured product obtained by photocuring the photosensitive resin composition of the present invention exhibits excellent flexibility. A specific example of measuring flexibility is to use a photosensitive film in which the photosensitive resin composition layer has been subjected to full-surface exposure, development, and heat treatment, and to evaluate the flexibility using an MIT folding fatigue tester in accordance with JIS P8115. At this time, the average number of flexures is usually 100 or more, and preferably 300 or more. Details of the evaluation of flexibility can be measured according to the method described in the examples below.

The cured product obtained by photocuring the photosensitive resin composition of the present invention exhibits excellent insulating properties. A specific example of evaluation of insulating properties is to expose, develop, and heat-treat the photosensitive resin film on the comb-shaped wiring pattern. Copper wires are soldered as electrodes on both sides of the comb-shaped pattern, a predetermined voltage is applied, and the resistance values of seven points after 500 hours are measured. At this time, the resistance value is preferably 10 ⁸ Ω or more. Details of the evaluation of insulating properties can be measured according to the method described in the examples below.

The photocured product of the photosensitive resin composition of the present invention usually exhibits excellent adhesive strength with copper foil. A specific example of evaluating adhesive strength is to laminate a photosensitive resin composition layer with a glass epoxy substrate laminated to rolled copper foil, and then expose the entire surface to light, develop, and heat treatment. The copper foil is peeled off using a tensile tester (TSE's "AC-50C-SL") that complies with the Japanese Industrial Standards (JIS C6481). At this time, the adhesive strength with the copper foil is usually 0.5 kgf or more. Details of the adhesive strength evaluation can be measured according to the method described in the examples below.

The photosensitive resin composition of the present invention can be used in a wide range of applications requiring a photosensitive resin composition, including, but not limited to, photosensitive films, photosensitive films with supports, insulating resin films such as prepregs, circuit boards (for laminates, multilayer printed wiring boards, etc.), solder resists, underfill materials, die bonding materials, semiconductor encapsulants, hole-filling resins, and component-embedding resins. In particular, it can be suitably used as a photosensitive resin composition for insulating layers of printed wiring boards (printed wiring boards in which the cured product of the photosensitive resin composition is the insulating layer), a photosensitive resin composition for interlayer insulating layers (printed wiring boards in which the cured product of the photosensitive resin composition is the interlayer insulating layer), a photosensitive resin composition for plating (printed wiring boards in which plating is formed on the cured product of the photosensitive resin composition), and a photosensitive resin composition for solder resist (printed wiring boards in which the cured product of the photosensitive resin composition is the solder resist).

[Photosensitive film]
The photosensitive resin composition of the present invention can be applied in a resin varnish state onto a supporting substrate, and the organic solvent can be dried to form a photosensitive resin composition layer, which can be used as a photosensitive film. Also, a photosensitive film formed in advance on a support can be laminated onto the supporting substrate. The photosensitive film can be laminated onto various supporting substrates. The supporting substrate can mainly be a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, a thermosetting polyphenylene ether substrate, or the like.

[Photosensitive film with support]
The photosensitive resin composition of the present invention can be suitably used in the form of a supported photosensitive film in which a photosensitive resin composition layer is formed on a support. That is, the supported photosensitive film includes a support and a photosensitive resin composition layer formed of the photosensitive resin composition of the present invention provided on the support.

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

Examples of commercially available supports include, but are not limited to, polyethylene terephthalate films such as those manufactured by Oji Paper under the product names "Alphan MA-410" and "E-200C," polypropylene films manufactured by Shin-Etsu Film Co., Ltd., and those manufactured by Teijin under the product name "PS-25" and other PS series. These supports are preferably coated with a release agent such as a silicone coating agent on the surface in order to facilitate removal of the photosensitive resin composition layer. The thickness of the support is preferably in the range of 5 μm to 50 μm, and more preferably in the range of 10 μm to 25 μm. By making the thickness 5 μm or more, it is possible to prevent the support from breaking when peeling off the support before development, and by making the thickness 50 μm or less, it is possible to improve the resolution when exposing from above the support. In addition, supports with low fisheyes are preferred. Here, fisheyes are foreign matter, undissolved matter, oxidized deterioration products, etc. of the material that are incorporated into the film when the material is thermally melted and then kneaded, extruded, biaxially stretched, cast, etc. to produce a film.

In order to reduce light scattering during exposure to active energy rays such as ultraviolet rays, the support is preferably one with excellent transparency. Specifically, the support is preferably one with a turbidity (haze standardized by JIS-K6714), which is an index of transparency, of 0.1 to 5. Furthermore, the photosensitive resin composition layer may be protected by a protective film.

By protecting the photosensitive resin composition layer side of the photosensitive film with a support with a protective film, it is possible to prevent the adhesion of dirt and the like to the surface of the photosensitive resin composition layer and scratches. As the protective film, a film made of the same material as the support can be used. The thickness of the protective film is not particularly limited, but is preferably in the range of 1 μm to 40 μm, more preferably in the range of 5 μm to 30 μm, and even more preferably in the range of 10 μm to 30 μm. By making the thickness 1 μm or more, the handleability of the protective film can be improved, and by making the thickness 40 μm or less, the cost tends to be improved. In addition, it is preferable that the adhesive strength between the photosensitive resin composition layer and the protective film is smaller than the adhesive strength between the photosensitive resin composition layer and the support.

The photosensitive film with a support of the present invention can be produced according to a method known to those skilled in the art, for example, by preparing a resin varnish by dissolving the photosensitive resin composition of the present invention in an organic solvent, applying this resin varnish to a support, and drying the organic solvent by heating or blowing hot air to form a photosensitive resin composition layer. Specifically, first, bubbles in the photosensitive resin composition are completely removed by a vacuum degassing method or the like, and then the photosensitive resin composition is applied to a support, the solvent is removed by a hot air oven or far-infrared oven, the support is dried, and then a protective film is laminated on the obtained photosensitive resin composition layer as necessary to produce a photosensitive film with a support. Specific drying conditions vary depending on the curability of the photosensitive resin composition and the amount of organic solvent in the resin varnish, but in a resin varnish containing 30% by mass to 60% by mass of organic solvent, drying can be performed at 80°C to 120°C for 3 to 13 minutes. The amount of the remaining organic solvent in the photosensitive resin composition layer is preferably 5% by mass or less, more preferably 2% by mass or less, based on the total amount of the photosensitive resin composition layer, from the viewpoint of preventing the diffusion of the organic solvent in the subsequent process. A person skilled in the art can appropriately set suitable drying conditions through simple experiments. The thickness of the photosensitive resin composition layer is preferably in the range of 5 μm to 500 μm, more preferably in the range of 10 μm to 200 μm, even more preferably in the range of 15 μm to 150 μm, even more preferably in the range of 20 μm to 100 μm, and especially preferably in the range of 20 μm to 60 μm, from the viewpoint of improving the handleability and suppressing the decrease in the sensitivity and resolution inside the photosensitive resin composition layer.

Examples of methods for applying the photosensitive resin composition include gravure coating, microgravure coating, reverse coating, kiss reverse coating, die coating, slot die, lip coating, comma coating, blade coating, roll coating, knife coating, curtain coating, chamber gravure coating, slot orifice, spray coating, and dip coating.
The photosensitive resin composition may be applied in several separate applications, or in one application, or by combining different methods. Among these, the die coating method is preferred because of its excellent uniformity. In addition, in order to avoid contamination by foreign matter, it is preferred to carry out the application process in an environment where foreign matter is unlikely to be generated, such as a clean room.

[Printed wiring board]
The printed wiring board of the present invention includes an insulating layer formed from a cured product of the photosensitive resin composition of the present invention. The insulating layer is preferably used as a solder resist.

In detail, the printed wiring board of the present invention can be manufactured using the above-mentioned photosensitive film or a photosensitive film with a support. Below, we will explain the case where the insulating layer is a solder resist.

<Coating and drying process>
The photosensitive resin composition is applied directly onto the circuit board in the form of a resin varnish, and the organic solvent is dried to form a photosensitive film on the circuit board.

Examples of circuit boards include glass epoxy boards, metal boards, polyester boards, polyimide boards, BT resin boards, and thermosetting polyphenylene ether boards. Here, the circuit board refers to a board such as the above boards on which a patterned conductor layer (circuit) is formed on one or both sides. In addition, in a multilayer printed wiring board formed by alternately laminating conductor layers and insulating layers, a board in which one or both sides of the outermost layer of the multilayer printed wiring board are patterned conductor layers (circuits) is also included in the circuit board referred to here. Note that the surface of the conductor layer may be roughened in advance by blackening, copper etching, etc.

As a coating method, full-surface printing by screen printing is generally used, but any other coating method that can apply the coating evenly may be used. For example, spray coating, hot melt coating, bar coating, applicator, blade coating, knife coating, air knife coating, curtain flow coating, roll coating, gravure coating, offset printing, dip coating, brush coating, and other common coating methods can all be used. After coating, the coating is dried in a hot air oven or far-infrared oven as necessary. Drying conditions are preferably 80°C to 120°C for 3 to 13 minutes. In this way, a photosensitive film is formed on the circuit board.

<Lamination process>
When a photosensitive film with a support is used, the photosensitive resin composition layer side is laminated to one or both sides of a circuit board using a vacuum laminator. In the lamination step, if the photosensitive film with a support has a protective film, the protective film is removed, and then the photosensitive film with a support and the circuit board are preheated as necessary, and the photosensitive resin composition layer is pressure-bonded to the circuit board while being pressurized and heated. For a photosensitive film with a support, a method of laminating the film to the circuit board under reduced pressure by a vacuum lamination method is preferably used.

The conditions for the lamination step are not particularly limited, but for example, the lamination temperature is preferably 70°C to 140°C, the lamination pressure is preferably 1 kgf/ ^cm2 to 11 kgf/ ^cm2 (9.8 x ¹⁰⁴ N/ ^m2 to 107.9 x ¹⁰⁴ N/ ^m2 ), the lamination time is preferably 5 seconds to 300 seconds, and lamination is preferably performed under reduced pressure with an air pressure of 20 mmHg (26.7 hPa) or less. The lamination step may be a batch type or a continuous type using rolls. The vacuum lamination method can be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum applicator manufactured by Nikko Materials Co., Ltd., a vacuum pressure laminator manufactured by Meiki Seisakusho Co., Ltd., a roll type dry coater manufactured by Hitachi Industries Co., Ltd., and a vacuum laminator manufactured by Hitachi AIC Co., Ltd. In this manner, a photosensitive film is formed on the circuit board.

<Exposure process>
After the photosensitive film is provided on the circuit board by the coating and drying process or the lamination process, an exposure process is then performed in which a predetermined portion of the photosensitive resin composition layer is irradiated with active light through a mask pattern to photocure the photosensitive resin composition layer in the irradiated portion. Examples of active light include ultraviolet light, visible light, electron beams, and X-rays, and ultraviolet light is particularly preferred. The amount of ultraviolet light is approximately 10 mJ/cm ² to 1000 mJ/cm ^2. There are two types of exposure method: a contact exposure method in which a mask pattern is closely attached to a printed wiring board, and a non-contact exposure method in which exposure is performed using parallel light without close contact, but either method may be used. In addition, when a support is present on the photosensitive resin composition layer, exposure may be performed from above the support, or exposure may be performed after peeling off the support.

The solder resist has excellent resolution because it uses the photosensitive resin composition of the present invention. For this reason, the exposure pattern in the mask pattern can be, for example, a pattern in which the ratio (L/S) of the circuit width (line; L) to the width between circuits (space; S) is 100 μm/100 μm or less (i.e., wiring pitch 200 μm or less), L/S = 80 μm/80 μm or less (wiring pitch 160 μm or less), L/S = 70 μm/70 μm or less (wiring pitch 140 μm or less), or L/S = 60 μm/60 μm or less (wiring pitch 120 μm or less). Note that the pitch does not need to be the same across the entire circuit board.

<Developing process>
After the exposure step, if a support is present on the photosensitive resin composition layer, the support is removed, and then the non-photocured portion (unexposed portion) is removed and developed by wet development or dry development, whereby a pattern can be formed.

In the case of the above-mentioned wet development, a developer that is safe, stable, and easy to operate, such as an alkaline aqueous solution, a water-based developer, or an organic solvent, is used as the developer, and among these, a development process using an alkaline aqueous solution is preferred. In addition, as the development method, a known method such as spraying, rocking immersion, brushing, or scraping is appropriately adopted.

Examples of alkaline aqueous solutions used as the developer include aqueous solutions of alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; 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; and aqueous solutions of organic bases that do not contain metal ions, such as tetraalkylammonium hydroxide. An aqueous solution of tetramethylammonium hydroxide (TMAH) is preferred because it does not contain metal ions and does not affect the semiconductor chip.

To improve the development effect, surfactants, defoamers, etc. can be added to these alkaline aqueous solutions. The pH of the alkaline aqueous solution is preferably in the range of 8 to 12, and more preferably in the range of 9 to 11. The base concentration of the alkaline aqueous solution is preferably 0.1% by mass to 10% by mass. The temperature of the alkaline aqueous solution can be appropriately selected according to the developability of the photosensitive resin composition layer, but is preferably 20°C to 50°C.

Organic solvents used as developers include, for example, 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.

The concentration of such an organic solvent is preferably 2% by mass to 90% by mass based on the total amount of the developer. The temperature of such an organic solvent can be adjusted according to the developability. Furthermore, such organic solvents can be used alone or in combination of two or more kinds. Examples of organic solvent-based developers used alone include 1,1,1-trichloroethane, N-methylpyrrolidone, N,N-dimethylformamide, cyclohexanone, methyl isobutyl ketone, and γ-butyrolactone.

When forming a pattern, two or more of the above-mentioned development methods may be used in combination, if necessary. Development methods include the dip method, the bath method, the spray method, the high-pressure spray method, brushing, and slapping, and the high-pressure spray method is suitable for improving resolution. When using the spray method, the spray pressure is preferably 0.05 MPa to 0.3 MPa.

<Thermal curing (post-bake) process>
After the development step, a thermal curing (post-baking) step is performed to form a solder resist. Examples of the post-baking step include an ultraviolet irradiation step using a high-pressure mercury lamp and a heating step using a clean oven. When irradiating with ultraviolet light, the amount of irradiation can be adjusted as necessary, and for example, irradiation can be performed at an amount of irradiation of about 0.05 J/cm ² to 10 J/cm ^2. The heating conditions may be appropriately selected depending on the type and content of the resin component in the photosensitive resin composition, and are preferably selected in the range of 150° C. to 220° C. for 20 minutes to 180 minutes, and more preferably in the range of 160° C. to 200° C. for 30 minutes to 120 minutes.

<Other processes>
After the solder resist is formed, the printed wiring board may further include a drilling step and a desmearing step, which may be carried out according to various methods used in the manufacture of printed wiring boards and known to those skilled in the art.

After the solder resist is formed, if desired, a drilling process is performed on the solder resist formed on the circuit board to form via holes and through holes. The drilling process can be performed by known methods such as drilling, laser, plasma, etc., or by combining these methods as necessary, but a drilling process using a laser such as a carbon dioxide laser or YAG laser is preferred.

The desmear process is a process of performing a desmear treatment. Generally, resin residue (smear) adheres to the inside of the opening formed in the drilling process. Since such smears can cause poor electrical connections, a process to remove the smear (desmear treatment) is performed in this process.

The desmearing process may be performed by a dry desmearing process, a wet desmearing process, or a combination of these.

An example of a dry desmear process is a desmear process using plasma. A desmear process using plasma can be performed using a commercially available plasma desmear process. Among commercially available plasma desmear process devices, examples suitable for use in the manufacture of printed wiring boards include a microwave plasma device manufactured by Nissin Co., Ltd. and an atmospheric pressure plasma etching device manufactured by Sekisui Chemical Co., Ltd.

As the wet desmear treatment, for example, a desmear treatment using an oxidizing agent solution can be mentioned. When performing the desmear treatment using an oxidizing agent solution, it is preferable to perform the swelling treatment using a swelling liquid, the oxidation treatment using an oxidizing agent solution, and the neutralization treatment using a neutralizing liquid in this order. As the swelling liquid, for example, "Swelling Dip Securigans P" and "Swelling Dip Securigans SBU" manufactured by Atotech Japan can be mentioned. The swelling treatment is preferably performed by immersing the substrate on which the via holes and the like are formed in the swelling liquid heated to 60°C to 80°C for 5 to 10 minutes. As the oxidizing agent solution, an alkaline permanganate solution is preferable, and for example, a solution in which potassium permanganate or sodium permanganate is dissolved in an aqueous solution of sodium hydroxide can be mentioned. The oxidation treatment using the oxidizing agent solution is preferably performed by immersing the substrate after the swelling treatment in the oxidizing agent solution heated to 60°C to 80°C for 10 to 30 minutes. Commercially available alkaline permanganate aqueous solutions include, for example, "Concentrate Compact CP" and "Dosing Solution Securiganth P" manufactured by Atotech Japan. The neutralization treatment using a neutralizing solution is preferably carried out by immersing the substrate after the oxidation treatment in the neutralizing solution at 30°C to 50°C for 3 to 10 minutes. The neutralizing solution is preferably an acidic aqueous solution, and a commercially available product is, for example, "Reduction Solution Securiganth P" manufactured by Atotech Japan.

When dry desmear treatment and wet desmear treatment are performed in combination, the dry desmear treatment may be performed first, or the wet desmear treatment may be performed first.

When the insulating layer is used as an interlayer insulating layer, it can be carried out in the same manner as the solder resist, and after the thermal curing process, a drilling process, a desmear process, and a plating process may be carried out.

The plating process is a process for forming a conductor layer on an insulating layer. The conductor layer may be formed by combining electroless plating and electrolytic plating, or a plating resist having a reverse pattern to the conductor layer may be formed and the conductor layer may be formed only by electroless plating. Subsequent pattern formation methods may include, for example, subtractive methods and semi-additive methods known to those skilled in the art.

[Semiconductor device]
The semiconductor device of the present invention includes a printed wiring board. The semiconductor device of the present invention can be manufactured using the printed wiring board of the present invention.

Semiconductor devices include various semiconductor devices used in electrical appliances (e.g., computers, mobile phones, digital cameras, and televisions) and vehicles (e.g., motorcycles, automobiles, trains, ships, and aircraft).

The semiconductor device of the present invention can be manufactured by mounting a component (semiconductor chip) on a conductive portion of a printed wiring board. A "conductive portion" is a portion of a printed wiring board that transmits an electrical signal, and the portion may be either on the surface or embedded. There are no particular limitations on the semiconductor chip, so long as it is an electrical circuit element made of semiconductor material.

The method of mounting the semiconductor chip when manufacturing the semiconductor device of the present invention is not particularly limited as long as the semiconductor chip functions effectively, but specific examples include a wire bonding mounting method, a flip chip mounting method, a bumpless buildup layer (BBUL) mounting method, an anisotropic conductive film (ACF) mounting method, a non-conductive film (NCF) mounting method, etc. Here, a "bumpless buildup layer (BBUL) mounting method" refers to a "mounting method in which a semiconductor chip is directly embedded in a recess in a printed wiring board and the semiconductor chip is connected to the wiring on the printed wiring board."

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the following description, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified.

(Synthesis Example 1: Synthesis of Resin (A-1))
In a four-neck flask, 60.8 parts (0.26 mol) of bisphenol A, 43.4 parts (0.11 mol) of bisphenol A type epoxy compound (YD8125, manufactured by Nippon Steel Chemical Co., Ltd.), 145.8 parts (0.13 mol) of polyethylene glycol diglycidyl ether (EX861, manufactured by Nagase ChemteX Corporation), 1.25 parts of triphenylphosphine as a catalyst, 1.25 parts of N,N-dimethylbenzylamine, and 250 parts of toluene as a solvent were charged, and the mixture was heated to 110 ° C. with stirring under a nitrogen stream and reacted for 8 hours to obtain a hydroxyl group-containing resin. Next, 49.8 parts (0.48 mol) of succinic anhydride (RIKACID SA, manufactured by New Japan Chemical Co., Ltd.) was charged as an acid anhydride and reacted for 4 hours at 110 ° C. After confirming the absorption and disappearance of the acid anhydride group by FT-IR measurement, it was cooled to room temperature. Next, 41.1 parts (0.29 mol) of glycidyl methacrylate (GMA, manufactured by NOF Corp.) and 0.17 parts of hydroquinone as a polymerization inhibitor were added while stirring, and the mixture was reacted at 80 ° C. for 8 hours. After the reaction was completed, 26.0 parts (0.25 mol) of Rikacid SA (manufactured by New Japan Chemical Co., Ltd.: succinic anhydride) were added as an acid anhydride, and the mixture was reacted at 80 ° C. for 4 hours. After confirming that the absorption of the acid anhydride group had disappeared by FT-IR measurement, the mixture was cooled to room temperature. Methyl ethyl ketone was added to this solution to adjust the solid content to 50%. The weight average molecular weight of the obtained resin (A-1) was 20,000, and the acid value of the resin solid content was 70 mg KOH / g.

Resin (A-1) is a copolymer. Therefore, M _AO in formula (1) was calculated from formula (2). Specifically, it was calculated as follows.
The monomer having an alkylene oxide chain is polyethylene glycol diglycidyl ether (EX861). Since the molecular weight of EX861 is 1098, A in formula (2) is 1098. In addition, since the molecular weight of the alkylene oxide chain is 968, A _AO in formula (2) is 968.
Resin (A-1) is a copolymer of bisphenol A, bisphenol A type epoxy compound, polyethylene glycol diglycidyl ether, succinic anhydride, and glycidyl methacrylate. Since the monomer containing an alkylene oxide chain is polyethylene glycol diglycidyl ether, B _AO in formula (2) is 0.13. Also, B in formula (2) is 0.26 + 0.11 + 0.13 + 0.48 + 0.29 + 0.25 = 1.52.
Therefore, equation (2) becomes (968/1098)×(0.13/1.52)≈0.08.

(Synthesis Example 2: Synthesis of Polymer 1)
Into a four-neck flask were added 510 g of propylene glycol monomethyl ether acetate, 50 g of methyl methacrylate, 90 g of butyl methacrylate, 60 g of hydroxyethyl methacrylate, and 2 g of azobisisobutyronyl, and the mixture was heated at 80° C. for 6 hours while blowing in nitrogen gas. The weight average molecular weight of the obtained polymer 1 was 40,000.

(Preparation of resin varnish)
The resin materials were mixed as shown in the following recipe, and a resin varnish was obtained using a high-speed rotating mixer.

The abbreviations in the table are as follows:
(A-1): Resin (A-1) synthesized in Synthesis Example 1, methyl ethyl ketone solution with a solid content of 50%, M _AO × 100 = 8
ZFR-1491H: bis-F skeleton-containing acid-modified epoxy acrylate, manufactured by Nippon Kayaku Co., Ltd., EDGAc (ethyl diglycol acetate) cut, solid content 70%, M _AO × 100 = 0
ZAR-2000: bis-A skeleton-containing acid-modified epoxy acrylate, manufactured by Nippon Kayaku Co., Ltd., EDGAc cut, solid content 70%, M _AO × 100 = 0
EX-821: polyethylene glycol diglycidyl ether, n=4, epoxy equivalent 185, manufactured by Nagase ChemteX Corporation, M _AO ×100=58
EX-920: Polypropylene glycol diglycidyl ether, n=3, epoxy equivalent 176, manufactured by Nagase Chemtex Corporation) M _AO x 100 = 57
NC3000H: biphenyl type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: about 272), M _AO × 100 = 0
R-551: EO-modified bisphenol A-type acrylate, manufactured by Nippon Kayaku Co., Ltd., M _AO × 100 = 34
A-PTMG-65: Polytetramethylene glycol #650 diacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd., M _AO × 100 = 83
1.9ND-A: 1.9-nonanediol diacrylate, manufactured by Kyoeisha Chemical Co., Ltd., M _AO × 100 = 0
NCI-831: Oxime ester photopolymerization initiator, manufactured by ADEKA Corporation.
EP4-A: Aminosilane-treated magnesium hydroxide (manufactured by Konoshima Chemical Co., Ltd.)
MEK: methyl ethyl ketone, manufactured by Junsei Chemical Co., Ltd. Polymer 1: Polymer 1 synthesized in Synthesis Example 2, propylene glycol monomethyl ether acetate solution with a solid content of 25%, M _AO × 100 = 8

Ａ－ＰＴＭＧ－６５の分子量は７７４である。また、アルキレンオキシド鎖の分子量は６４８（７２×９＝６４８）である。よって、Ｍ_ＡＯは、６４８／７７４≒０．８３である。 "A-PTMG-65" manufactured by Shin-Nakamura Chemical Co., Ltd. has the following structural formula: Since A-PTMG-65 is not a copolymer, _MAO was calculated from formula (1).

The molecular weight of A-PTMG-65 is 774. In addition, the molecular weight of the alkylene oxide chain is 648 (72×9=648). Therefore, _MAO is 648/774≈0.83.

X in the formula (1) of Example 1 was determined as follows.
X={(2.5÷55)×58}+{(7÷55)×34}+{(3÷55)×83}≒11.5

(Preparation of a photosensitive film with a support)
A PET film (Toray Industries, Inc., "Lumirror T6AM", thickness 38 μm, softening point 130° C., "release PET") that had been release-treated with an alkyd resin-based release agent (Lintec Corporation, "AL-5") was prepared as a support. The prepared resin varnish was uniformly applied to the release PET with a die coater so that the thickness of the photosensitive resin composition layer after drying would be 25 μm, and the film was dried at 80° C. to 120° C. to obtain a photosensitive film with a support.

(Formation of Laminate for Evaluation)
The copper layer of a glass epoxy substrate (copper-clad laminate) on which a circuit patterned with a copper layer having a thickness of 18 μm was formed was roughened by treatment with a surface treatment agent containing an organic acid (CZ8100, manufactured by MEC Co., Ltd.). Next, the photosensitive resin composition layer of the photosensitive film with a support obtained in the examples and comparative examples was arranged so as to be in contact with the surface of the copper layer, and laminated using a vacuum laminator (manufactured by Nikko Materials Co., Ltd., VP160) to form a laminate in which the copper-clad laminate, the photosensitive resin composition layer, and the support were laminated in this order. The pressure bonding conditions were a vacuum drawing time of 30 seconds, a pressure bonding temperature of 80° C., a pressure bonding pressure of 0.7 MPa, and a pressure application time of 30 seconds. The laminate was left at room temperature for 30 minutes or more, and exposed to ultraviolet light from above the support of the laminate using a pattern forming device using a round hole pattern. The exposure pattern was a quartz glass mask that draws an opening: 50 μm/60 μm/70 μm/80 μm/90 μm/100 μm round hole (via), L/S (line/space): 50 μm/50 μm, 60 μm/60 μm, 70 μm/70 μm, 80 μm/80 μm, 90 μm/90 μm, 100 μm/100 μm line and space, and a 1 cm x 2 cm square. After leaving it at room temperature for 30 minutes, the support was peeled off from the laminate. The entire surface of the insulating layer on the laminate was spray-developed with a 1% by mass aqueous sodium carbonate solution at 30 ° C. as a developer at a spray pressure of 0.2 MPa for 2 minutes. After spray development, the laminate was irradiated with ultraviolet light at 1 J/cm ² and further heated at 180 ° C. for 30 minutes to form an insulating layer having an opening on the laminate. This was used as an evaluation laminate.

<Evaluation of via bottom residue>
The evaluation was performed according to the following criteria for a 100 μm round hole formed in the evaluation laminate.
A: No residue.
×: Residue is observed, or the film is peeled off or the resin is partially dissolved.

<Evaluation of Flexibility>
The photosensitive resin composition layer of the photosensitive film with the support obtained in the examples and comparative examples was exposed to light, developed, and heated. The conditions of exposure, development, and heat treatment were the same as those for forming the laminate for evaluation. The support was peeled off to obtain a cured film. This cured film was cut to 15 mm x 110 mm, and its bending property was evaluated using an MIT folding fatigue tester (manufactured by Toyo Seiki Co., Ltd.). The test was performed in accordance with JIS P8115, with tension: 500 g, test speed: 175 times/min, folding angle: 135°, and bending clamp R: 0.38 mm. The number of foldings until breakage was counted, and the average of the three folding times was evaluated according to the following criteria.
◎: 300 times or more ○: 100 times or more but less than 300 times ×: Less than 100 times

<Evaluation of copper adhesion>
A rolled copper foil (JX Nippon Mining & Metals Corporation, BHY-22B-T, thickness 18 μm) was prepared by washing with 10% sulfuric acid and drying. A photosensitive film with a support was attached to the shiny surface of the rolled copper foil, and the entire surface was exposed to light, developed, and heated to obtain a substrate. The exposure, development, and heat treatment conditions were the same as those for the evaluation of flexibility. The insulating layer side of the obtained substrate was joined to a glass epoxy substrate, and the peel strength of the copper foil was measured using a tensile tester (TSE Corporation, "AC-50C-SL") in accordance with the Japanese Industrial Standards (JIS C6481), and evaluated according to the following criteria.
○: Adhesion strength is 0.5 kgf or more ×: Adhesion strength is less than 0.5 kgf

<Evaluation of insulation (HHBT)>
A comb-shaped wiring pattern with L (wiring width)/S (spacing) = 20 μm/20 μm was used on the support of the photosensitive film with a support, and the entire surface was exposed to ultraviolet light, developed, and heated. The conditions of the entire surface exposure, development, and heat treatment were the same as those for forming the evaluation laminate. Copper wires were soldered as electrodes on both sides of the comb-shaped wiring pattern, and a voltage of 50 V was applied at 85° C. and 85% RH. After 500 hours, the resistance value (Ω) was measured, and the average value was calculated from the resistance values at seven points and evaluated according to the following criteria.
○: The average resistance value is 10 ⁸ Ω or more. ×: The average resistance value is less than 10 ⁸ Ω.

The results in the above table show that the use of the photosensitive resin composition of the present invention results in good developability, flexibility, adhesion, and insulation. In Comparative Example 3, an acrylic polymer having an alkylene oxide chain (Polymer 1) is used, but since Polymer 1 is a thermoplastic resin, it is not incorporated into the curing system, and therefore it is believed that the desired results were not obtained.

In each example, it has been confirmed that even when components (E) and (F) are not included, the results are similar to those of the above examples, although to a lesser extent.

Claims (15)

(A) a resin containing an ethylenically unsaturated group and a carboxyl group,
(B) an epoxy resin,
A photosensitive resin composition comprising: (C) a photopolymerizable monomer; and (D) a photopolymerization initiator,
The weight average molecular weight of the component (A) is 2,000 or more and 50,000 or less,
The component (A) contains an acid-modified unsaturated epoxy ester resin,
Any one of the components (A), (B), and (C) contains an alkylene oxide chain represented by the following formula (a), and a parameter X represented by the following formula (1) is 4 or more and 25 or less.

In formula (a), each R independently represents an alkylene group having 1 to 6 carbon atoms, and q represents an integer of 2 to 100.

In formula (1), M _AO represents a value shown by the following formula (2) when the component containing an alkylene oxide chain is a copolymer, or represents (molecular weight of alkylene oxide chain of each compound contained in components (A) to (C))/(molecular weight of each compound contained in components (A) to (C)) when the component containing an alkylene oxide chain is not a copolymer, N represents the solid content (parts by mass) of all compounds contained in components (A) to (C), and n represents the solid content (parts by mass) of each compound contained in components (A) to (C).

In formula (2), A _AO represents the molecular weight of the alkylene oxide chain of each monomer containing an alkylene oxide chain, A represents the molecular weight of each monomer containing an alkylene oxide chain, B _AO represents the number of moles of each monomer containing an alkylene oxide chain, and B represents the total number of moles of all monomers contained in the copolymer. (A) a resin containing an ethylenically unsaturated group and a carboxyl group,
(B) an epoxy resin,
(C) a photopolymerizable monomer, and
(D) a photopolymerization initiator;
The weight average molecular weight of the component (A) is 2,000 or more and 50,000 or less,
The component (B) contains an epoxy resin having a biphenyl skeleton,
Any one of the components (A), (B), and (C) contains an alkylene oxide chain represented by the following formula (a), and a parameter X represented by the following formula (1) is 4 or more and 25 or less.

In formula (a), each R independently represents an alkylene group having 1 to 6 carbon atoms, and q represents an integer of 2 to 100.

In formula (1), M _A.O. represents the value shown by the following formula (2) when the component containing an alkylene oxide chain is a copolymer, or represents (the molecular weight of the alkylene oxide chain of each compound contained in components (A) to (C))/(the molecular weight of each compound contained in components (A) to (C)) when the component containing an alkylene oxide chain is not a copolymer. N represents the solid content (parts by mass) of all compounds contained in components (A) to (C), and n represents the solid content (parts by mass) of each compound contained in components (A) to (C).

In formula (2), A _A.O. represents the molecular weight of the alkylene oxide chain of each monomer containing an alkylene oxide chain, A represents the molecular weight of each monomer containing an alkylene oxide chain, B _A.O. represents the number of moles of each monomer containing an alkylene oxide chain, and B represents the total number of moles of all monomers contained in the copolymer. The photosensitive resin composition according to claim 2 , wherein the component (A) comprises an acid-modified unsaturated epoxy ester resin. The photosensitive resin composition according to any one of claims 1 to 3 , wherein the component (A) comprises an acid-modified epoxy (meth)acrylate. The photosensitive resin composition according to any one of claims 1 to 4 , wherein the component (A) comprises any one of an acid-modified naphthalene skeleton-containing epoxy(meth)acrylate and an acid-modified bisphenol skeleton-containing epoxy(meth)acrylate. The photosensitive resin composition according to claim 5 , wherein the acid-modified bisphenol skeleton-containing epoxy (meth)acrylate has either a bisphenol A skeleton or a bisphenol F skeleton. The photosensitive resin composition according to claim 1 , further comprising (E) an inorganic filler. The photosensitive resin composition according to any one of claims 1 to 7 , wherein the alkylene oxide chain is contained in either the component (B) or the component (C). The photosensitive resin composition according to any one of claims 1 to 8, wherein component (D) contains an oxime ester-based photopolymerization initiator. The photosensitive resin composition according to any one of claims 1 to 9, wherein the content of component (C) is 0.5% by mass or more and 10% by mass or less, when the total solid content of the photosensitive resin composition is taken as 100% by mass. A photosensitive film containing the photosensitive resin composition according to any one of claims 1 to 10. A photosensitive film with a support, comprising a support and a photosensitive resin composition layer containing the photosensitive resin composition according to any one of claims 1 to 10 provided on the support. A printed wiring board comprising an insulating layer formed from a cured product of the photosensitive resin composition according to any one of claims 1 to 10. The printed wiring board according to claim 13, wherein the insulating layer is a solder resist. A semiconductor device including the printed wiring board according to claim 13 or 14.