Curable resin composition, dry film, cured product, and printed wiring board

Abstract

[Problem] To provide a curable resin composition that has improved developability and chemical resistance without causing a decrease in resolution. [Solution] A curable resin composition according to the present invention is characterized by comprising: an alkali-soluble resin that has an imide skeleton and has a weight average molecular weight of 20,000 or less; and an ethylene oxide-modified monomer that is at least pentafunctional.

Description

Curable resin composition, dry film, cured product, and printed wiring board

[0001] The present invention relates to a curable resin composition. The present invention also relates to a dry film, a cured product, and a printed wiring board using the curable resin composition.

[0002] Conventionally, curable resin compositions containing amide-imide resins have been used as interlayer insulating materials for printed wiring boards to improve various properties such as heat resistance of the cured product. In particular, when the amide-imide resin contains carboxyl groups, the resin layer of the curable resin composition can be subjected to alkaline development. For example, Patent Document 1 proposes an active energy ray-curable polyimide resin composition containing a polymerizable polyimide resin having carboxyl groups, which can be patterned using a dilute alkaline aqueous solution.

[0003] Patent Document 2 proposes a curable resin composition that uses an amide-imide resin that is a reaction product of an isocyanurate-type polyisocyanate synthesized from an isocyanate having an aliphatic structure and a tricarboxylic acid anhydride, and that has a number-average molecular weight of 500 to 1,000.

[0004] Furthermore, wafer-level packaging is known as one type of packaging for semiconductor components, and there is a growing demand for alkaline-developable photosensitive insulating materials to form fine insulating patterns all at once when manufacturing wafer-level packaging.

[0005] JP 2003-221429 A International Publication No. 2021 / 044984

[0006] In the electronic components described above, there is a demand for higher density wiring, and further improvement in the resolution of photosensitive insulating materials has become an issue.

[0007] In the curable resin composition described in Patent Document 1, it is conceivable to further include a large amount of a carboxyl group-containing resin relative to the amide-imide resin in order to improve resolution, but in this case, the Tg of the cured product may decrease, and the chemical resistance of the cured product may decrease. Also, the resin composition described in Patent Document 2 can form a cured product that has both resolution and developability without impairing chemical resistance, but it has been found that the developability is insufficient when small diameter vias are opened, resulting in residues at the bottom of the vias.

[0008] Furthermore, when a process change was made and treatment using acetone was carried out, the problem was found that with conventional amide-imide resins, the crosslink density in the cured product was low because the amide-imide resin did not undergo photoreaction, and acetone caused cracks to form on the cured product.

[0009] The present invention has been made in view of the above problems, and aims to provide a curable resin composition that has improved developability and chemical resistance without reducing resolution. Another aim of the present invention is to provide a dry film having a resin layer formed from a dried coating film of the resin composition, a cured product of the resin composition or the resin layer of the dry film, and a printed wiring board having the cured product.

[0010] Means for Solving the Problems The present inventors have conducted extensive research to achieve the above object and have found that the above problems can be solved by using an alkali-soluble resin having an imide skeleton and a weight-average molecular weight of 20,000 or less, and an ethylene oxide-modified monomer having five or more functionalities, to improve the hydrophilicity and polymerization reactivity of a resin composition.

[0011] That is, the present invention provides the following inventions. [1] A curable resin composition comprising an alkali-soluble resin having an imide skeleton and a weight-average molecular weight of 20,000 or less, and an ethylene oxide-modified monomer having five or more functionalities. [2] The curable resin composition according to [1], wherein the imide skeleton comprises a structure derived from succinimide. [3] The curable resin composition according to [1] or [2], wherein the alkali-soluble resin having an imide skeleton has a weight-average molecular weight of 3,000 or more and 15,000 or less. [4] The curable resin composition according to any one of [1] to [3], wherein the content of the alkali-soluble resin having an imide skeleton is 5% by mass or more and 50% by mass or less, calculated as a solid content, relative to the total amount of the curable resin composition. [5] The curable resin composition according to any one of [1] to [4], further comprising an alkali-soluble resin not having an imide skeleton. [6] The curable resin composition according to any one of [1] to [5], wherein the content of the ethylene oxide-modified monomer is 1.0% by mass or more and 20.0% by mass or less, in terms of solid content, relative to the total amount of the curable resin composition. [7] The curable resin composition according to any one of [1] to [6], further comprising an epoxy resin. [8] The curable resin composition according to [7], wherein the content of the epoxy resin is 10% by mass or more and 50% by mass or less, in terms of solid content, relative to the total amount of the curable resin composition. [9] The curable resin composition according to any one of [1] to [8], further comprising a cellulose resin.

[10] The curable resin composition according to [9], wherein the cellulose resin has a number-average molecular weight of 5,000 or more and 500,000 or less.

[11] The curable resin composition according to [9] or

[10] , wherein the content of the cellulose resin is 0.1% by mass or more and 5.0% by mass or less, in terms of solid content, relative to the total amount of the curable resin composition.

[12] The curable resin composition according to any one of [9] to

[11] , wherein the content of the cellulose resin is 1.0 part by mass or more and 100.0 parts by mass or less relative to 100 parts by mass of the ethylene oxide-modified monomer having five or more functionalities.

[13] A dry film comprising a first film and a resin layer formed on the first film, the resin layer comprising a dried coating film of the curable resin composition according to any one of [1] to

[12] .

[14] A cured product obtained by curing the curable resin composition according to any one of [1] to

[12] .

[15] A cured product obtained by curing the resin layer of the dry film according to

[13] .

[16] A printed wiring board comprising the cured product according to

[14] .

[17] A printed wiring board comprising the cured product according to

[15] .

[0012] According to the present invention, it is possible to provide a curable resin composition having improved developability and chemical resistance of the cured product without reducing resolution. Furthermore, according to the present invention, it is possible to provide a dry film having a resin layer formed from a dried coating film of the resin composition, a cured product of the resin composition or the resin layer of the dry film, and a printed wiring board having the cured product.

[0013] [Curable Resin Composition] The curable resin composition according to the present invention contains an alkali-soluble resin having an imide skeleton and a weight-average molecular weight of 20,000 or less, and an ethylene oxide-modified monomer having five or more functionalities. The curable resin composition according to the present invention may further contain a cellulose resin, an epoxy resin, an inorganic filler, a curing agent, a colorant, etc.

[0014] Hereinafter, each component constituting the curable resin composition of the present invention will be described. In this specification, (meth)acrylic acid is a general term referring to acrylic acid, the corresponding methacrylic acid, and a mixture thereof, and (meth)acrylate is a general term referring to acrylate, the corresponding methacrylate, and a mixture thereof. Similarly, (meth)acryloyl group is a general term referring to an acryloyl group and the corresponding methacryloyl group, and (meth)acryloxy group is a general term referring to an acryloxy group and the corresponding methacryloxy group.

[0015] (Alkali-Soluble Resin) <Alkali-Soluble Resin Having an Imide Skeleton with a Weight-Average Molecular Weight of 20,000 or Less> The resin composition of the present invention contains an alkali-soluble resin having an imide skeleton with a weight-average molecular weight of 20,000 or less. This can improve the developability of the curable resin composition of the present invention, as well as the chemical resistance and mechanical properties, such as acetone crack resistance, of the cured product of the present invention, without reducing resolution. The alkali-soluble resin having an imide skeleton may be used alone or in combination of two or more. In the present invention, the imide skeleton of the alkali-soluble resin having an imide skeleton preferably contains a structure derived from succinimide.

[0016] An alkali-soluble resin having an imide skeleton derived from succinimide can be synthesized, for example, by copolymerizing a maleimide monomer with an unsaturated carboxylic acid monomer. The constituent units of the copolymer may contain a monomer having a hydroxyl group, if necessary, or may contain a structure obtained by reacting an acid group, such as a carboxyl group, of the polymer with a monomer having a functional group reactive with the acid group.

[0017] Examples of maleimide monomers include N-phenylmaleimide, N-(2-methylphenyl)maleimide, N-(4-methylphenyl)maleimide, N-(2,6-diethylphenyl)maleimide, N-(2-chlorophenyl)maleimide, N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-cyclohexylmaleimide, N-benzylmaleimide, N-phenylmethylmaleimide, and N-(2,4,6-tribromophenyl)maleimide. Examples of N-substituted or unsubstituted maleimides include N-substituted maleimides such as N-(2-methylphenyl)maleimide, N-(2,6-diethylphenyl)maleimide, N-laurylmaleimide, N-cyclohexylmaleimide, and N-benzylmaleimide. These include N-substituted or unsubstituted maleimides such as N-(2-methylphenyl)maleimide, N-(2,6-diethylphenyl)maleimide, N-laurylmaleimide, N-cyclohexylmaleimide, and N-benzylmaleimide. The content of the structural units derived from maleimide monomers is preferably 10% by mass or more and 60% by mass or less of all the structural units constituting the resin.

[0018] Examples of unsaturated carboxylic acids (monomers) include (meth)acrylic acid, crotonic acid, cinnamic acid, sorbic acid, fumaric acid, and maleic acid. Among these, (meth)acrylic acid is preferred due to its excellent properties in cured products. In another embodiment, other acid groups may be introduced together with or in place of the carboxyl group. Examples of other acid groups include functional groups that undergo a neutralization reaction with alkaline water, such as phenolic hydroxyl groups, carboxylic anhydride groups, phosphate groups, and sulfonic acid groups. Only one of these groups may be present, or two or more may be present. In the following description, descriptions of carboxyl groups also apply to the above-mentioned other acid groups.

[0019] Examples of the hydroxyl group-containing monomer include (di)hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 2,3-dihydroxypropyl (meth)acrylate, and hydroxyalkyl (meth)acrylamides such as 2-hydroxymethyl (meth)acrylamide, 2-hydroxyethyl (meth)acrylamide, 2-hydroxypropyl (meth)acrylamide, 3-hydroxypropyl (meth)acrylamide, 4-hydroxybutyl (meth)acrylamide, hydroxypivalyl (meth)acrylamide, 5-hydroxypentyl (meth)acrylamide, and 6-hydroxyhexyl (meth)acrylamide, and one or more of these can be used. Among these, from the viewpoint of copolymerizability, hydroxyalkyl (meth)acrylates are preferred, and 2-hydroxyethyl (meth)acrylate is particularly preferred.

[0020] The monomer having a functional group capable of reacting with an acid group such as a carboxyl group preferably has a radically polymerizable carbon-carbon double bond (hereinafter, may be simply referred to as a radically polymerizable double bond). The functional group capable of reacting with an acid group such as a carboxyl group is preferably selected from the group consisting of a glycidyl group, an oxazolinyl group, an isocyanate group, and an oxetanyl group. The radically polymerizable carbon-carbon double bond is preferably a (meth)acryloyl group. Specific examples of the monomer include glycidyl (meth)acrylate and 3,4-epoxycyclohexylmethyl (meth)acrylate.

[0021] Furthermore, other copolymerizable monomers may be contained as long as they do not adversely affect the properties. Examples of other copolymerizable monomers include aromatic monomers not having an ester bond, such as styrene, α-methylstyrene, α-chlorostyrene, and vinyltoluene; vinyl ester monomers, such as vinyl acetate and vinyl adipate; (meth)acrylic monomers, such as methyl (meth)acrylate, ethyl (meth)acrylate, and butyl (meth)acrylate; alkyl vinyl ethers and corresponding alkyl vinyl (thio)ethers, such as n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, n-hexyl vinyl ether, cyclohexyl vinyl ether, and 2-ethylhexyl vinyl ether; acid anhydride group-containing monomers, such as maleic anhydride, or monomers obtained by ring-opening the acid anhydride group with alcohols or the like, and unsaturated basic acids other than those mentioned above; N-vinyl monomers, such as N-vinylpyrrolidone and N-vinyloxazolidone; and cyano group-containing monomers, such as acrylonitrile and methacrylonitrile.

[0022] [Weight-average molecular weight of alkali-soluble resin having an imide skeleton with a weight-average molecular weight of 20,000 or less] The weight-average molecular weight of the alkali-soluble resin having an imide skeleton is 20,000 or less, preferably 3,000 or more and 15,000 or less, and more preferably 4,000 or more and 10,000 or less. When the weight-average molecular weight of the alkali-soluble resin having an imide skeleton is 20,000 or less, the resin has excellent developability and is particularly effective in reducing residues during development. The weight-average molecular weight can be determined from a standard polystyrene equivalent value by gel permeation chromatography (GPC). The GPC measurement was performed using tetrahydrofuran as an eluent and an RI detector.

[0023] [Content of alkali-soluble resin having an imide skeleton with a weight-average molecular weight of 20,000 or less] The content of the alkali-soluble resin having an imide skeleton with a weight-average molecular weight of 20,000 or less is, in terms of solid content, preferably 5% by mass or more and 50% by mass or less, more preferably 7% by mass or more and 45% by mass or less, and even more preferably 10% by mass or more and 40% by mass or less, relative to the total amount of the curable resin composition. By making it 5% by mass or more, the strength of the cured product can be improved. Furthermore, by making it 50% by mass or less, the viscosity of the composition can be appropriate, and the coatability, etc. can be improved.

[0024] <Alkali-Soluble Resin Without an Imide Skeleton> In the present invention, in addition to the alkali-soluble resin having an imide skeleton and having a weight-average molecular weight of 20,000 or less, another alkali-soluble resin having no imide skeleton may be contained. That is, the alkali-soluble resin having an imide skeleton and having a weight-average molecular weight of 20,000 or less may be used alone or in combination with an alkali-soluble resin having no imide skeleton. In a preferred embodiment of the present invention, by using an alkali-soluble resin having an imide skeleton and having a weight-average molecular weight of 20,000 or less in combination with an alkali-soluble resin having no imide skeleton, it is possible to further improve developability in particular without reducing resolution.

[0025] The alkali-soluble resin without an imide skeleton is not particularly limited, and known resins may be used. Examples of the alkali-soluble resin include water-soluble resins such as carboxyl group-containing resins and phenolic hydroxyl group-containing resins. Among these, carboxyl group-containing resins and phenolic hydroxyl group-containing resins are preferred due to their excellent developability. The alkali-soluble resins may be used alone or in combination of two or more. Furthermore, the alkali-soluble resin can be made photosensitive by having an ethylenically unsaturated double bond in the molecule in addition to the carboxyl group. The ethylenically unsaturated double bond is preferably derived from acrylic acid, methacrylic acid, or a derivative thereof. In the present invention, the alkali-soluble resin is preferably photosensitive.

[0026] Specific examples of the carboxyl group-containing resin include the following compounds (which may be either oligomers or polymers):

[0027] (1) Carboxyl group-containing resins obtained by copolymerizing an unsaturated carboxylic acid such as (meth)acrylic acid with an unsaturated group-containing compound such as styrene, α-methylstyrene, lower alkyl (meth)acrylate, or isobutylene.

[0028] (2) Carboxyl group-containing urethane resins obtained by the polyaddition reaction of diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates with carboxyl group-containing dialcohol compounds such as dimethylolpropionic acid and dimethylolbutanoic acid, and diol compounds such as polycarbonate polyols, polyether polyols, polyester polyols, polyolefin polyols, acrylic polyols, bisphenol A alkylene oxide adduct diols, and compounds having a phenolic hydroxyl group and an alcoholic hydroxyl group.

[0029] (3) Carboxylic acid group-containing urethane resins obtained by polyaddition reaction of diisocyanates with partially acid anhydride-modified products of reaction products of bifunctional epoxy resins such as bisphenol A epoxy resins, hydrogenated bisphenol A epoxy resins, bisphenol F epoxy resins, bisphenol S epoxy resins, bixylenol epoxy resins, and biphenol epoxy resins with monocarboxylic acid compounds having ethylenically unsaturated double bonds such as (meth)acrylic acid, carboxylic acid-containing dialcohol compounds, and diol compounds.

[0030] (4) A curable urethane resin containing a carboxyl group, which is (meth)acrylated at the terminal by adding a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule, such as a hydroxyalkyl (meth)acrylate, during the synthesis of the resin (2) or (3).

[0031] (5) A carboxyl group-containing curable urethane resin that has been (meth)acrylated at its terminal by adding a compound having one isocyanate group and one or more (meth)acryloyl groups in the molecule, such as an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate, during the synthesis of the resin (2) or (3).

[0032] (6) A carboxyl group-containing resin obtained by reacting a difunctional or more polyfunctional (solid) epoxy resin with (meth)acrylic acid and adding a dibasic acid anhydride to the hydroxyl groups present in the side chains.

[0033] (7) A carboxyl group-containing resin obtained by reacting a polyfunctional epoxy resin in which the hydroxyl groups of a bifunctional (solid) epoxy resin are further epoxidized with epichlorohydrin with (meth)acrylic acid, and then adding a dibasic acid anhydride to the resulting hydroxyl groups.

[0034] (8) Carboxyl group-containing polyester resins obtained by reacting a dicarboxylic acid such as adipic acid, phthalic acid, or hexahydrophthalic acid with a bifunctional oxetane resin, and then adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the resulting primary hydroxyl groups.

[0035] (9) A carboxyl group-containing resin obtained by reacting an epoxy compound having multiple epoxy groups in one molecule with a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule, such as p-hydroxyphenethyl alcohol, and an unsaturated group-containing monocarboxylic acid, such as (meth)acrylic acid, and then reacting the alcoholic hydroxyl groups of the resulting reaction product with a polybasic acid anhydride, such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, or adipic acid.

[0036] (10) A carboxyl group-containing resin obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide, reacting the resulting reaction product with an unsaturated group-containing monocarboxylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride.

[0037] (11) A carboxyl group-containing resin obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate, reacting the resulting reaction product with an unsaturated group-containing monocarboxylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride.

[0038] (12) A carboxyl group-containing resin obtained by adding a compound having one epoxy group and one or more (meth)acryloyl groups in one molecule to any of the resins (1) to (11).

[0039] The phenolic hydroxyl group-containing resin is not particularly limited as long as it has a phenolic hydroxyl group in the main chain or side chain, i.e., a hydroxyl group bonded to a benzene ring. Preferably, the resin has two or more phenolic hydroxyl groups in one molecule. Examples of the resin containing two or more phenolic hydroxyl groups in one molecule include, but are not limited to, catechol, resorcinol, hydroquinone, dihydroxytoluene, naphthalenediol, t-butylcatechol, t-butylhydroquinone, pyrogallol, phloroglucinol, bisphenol A, bisphenol F, bisphenol S, biphenol, bixylenol, novolac-type phenolic resins, novolac-type alkylphenolic resins, bisphenol A novolac resins, dicyclopentadiene-type phenolic resins, Xylok-type phenolic resins, terpene-modified phenolic resins, polyvinylphenols, condensates of phenols with aromatic aldehydes having a phenolic hydroxyl group, and condensates of 1-naphthol or 2-naphthol with aromatic aldehydes.

[0040] [Weight-average molecular weight of alkali-soluble resin having no imide skeleton] The weight-average molecular weight of the alkali-soluble resin having no imide skeleton is preferably 1,000 or more and 10,000 or less, more preferably 2,000 or more and 5,000 or less. When the weight-average molecular weight of the alkali-soluble resin having no imide skeleton is within the above range, the resin has excellent developability, and is particularly effective in reducing residues during development. The weight-average molecular weight can be determined from a standard polystyrene-equivalent value by gel permeation chromatography (GPC). The GPC measurement was performed using tetrahydrofuran as an eluent and an RI detector.

[0041] [Content of Alkali-Soluble Resin Without Imide Skeleton] The total content of the alkali-soluble resin with an imide skeleton and an alkali-soluble resin without an imide skeleton, each having a weight-average molecular weight of 20,000 or less, is preferably 5% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 45% by mass or less, and even more preferably 20% by mass or more and 40% by mass or less, calculated as solid content, relative to the total amount of the curable resin composition. By making it 5% by mass or more, the strength of the cured product can be improved. Furthermore, by making it 50% by mass or less, the viscosity of the composition can be appropriate, and the coatability, etc. can be improved.

[0042] The content of the alkali-soluble resin having an imide skeleton and a weight-average molecular weight of 20,000 or less is preferably 10% by mass or more and 100% by mass or less, more preferably 20% by mass or more and 100% by mass or less, and even more preferably 40% by mass or more and 100% by mass or less, based on the total content of the alkali-soluble resin having an imide skeleton and a weight-average molecular weight of 20,000 or less and the alkali-soluble resin not having an imide skeleton. When the content of the alkali-soluble resin having an imide skeleton and a weight-average molecular weight of 20,000 or less is within the above numerical range, the strength of the cured product can be improved, and the viscosity of the composition can be appropriate, thereby improving the coatability, etc.

[0043] (Pentafunctional or higher ethylene oxide modified monomer) In the present invention, the pentafunctional or higher ethylene oxide modified monomer is a photopolymerizable monomer having five or more ethylenically unsaturated double bonds in one molecule, and has an ethylene oxide unit (—CH ２ CH ２ O-). By including a photopolymerizable monomer, the crosslink density of the curable resin composition during photopolymerization increases, and the heat resistance of the curable resin composition and the chemical resistance, such as acetone crack resistance, of the cured product can be improved. Furthermore, by including an ethylene oxide unit, hydrophilicity is improved and development residues are reduced. Examples of such monomers include A-DPH-6E and A-DPH-12E (ethoxylated dipentaerythritol polyacrylate, both trade names, manufactured by Shin-Nakamura Chemical Co., Ltd.). The above monomers may be used alone or in combination of two or more. Hereinafter, "ethylene oxide" will also be referred to as "EO."

[0044] [Content of Pentafunctional or Higher Ethylene Oxide-Modified Monomer] The content of the pentafunctional or higher ethylene oxide-modified monomer is, in terms of solid content, preferably 1.0% by mass or more and 20.0% by mass or less, more preferably 1.5% by mass or more and 15.0% by mass or less, and even more preferably 2.0% by mass or more and 9.0% by mass or less, relative to the total amount of the curable resin composition. When the content of the photopolymerizable monomer is 1.0% by mass or more, the hydrophilicity of the resin composition is improved and development residues are suppressed. Furthermore, when the content is 20.0% by mass or less, water absorption due to hydrophilicity is suppressed.

[0045] The content of the pentafunctional or higher ethylene oxide-modified monomer is preferably 1 part by mass or more and 50 parts by mass or less, more preferably 3 parts by mass or more and 45 parts by mass or less, even more preferably 5 parts by mass or more and 40 parts by mass or less, and even more preferably 7 parts by mass or more and 25 parts by mass or less, relative to 100 parts by mass of the total content of the alkali-soluble resin having an imide skeleton and having a weight-average molecular weight of 20,000 or less and the alkali-soluble resin not having an imide skeleton. When the content of the photopolymerizable monomer is 1 part by mass or more, photocurability is good and pattern formation is easy in alkaline development after irradiation with active energy rays. Furthermore, when the content is 50 parts by mass or less, halation is less likely to occur and good resolution is easily obtained.

[0046] (Other Photopolymerizable Monomers) In the present invention, in addition to the pentafunctional or higher ethylene oxide-modified monomer, other photopolymerizable monomers may be contained. The other photopolymerizable monomers may not be pentafunctional or higher, may not be ethylene oxide-modified, or may be both. The number of functions of the other photopolymerizable monomers is not particularly limited. For example, trifunctional or higher photopolymerizable monomers include trimethylolpropane tri(meth)acrylate, glycerin tri(meth)acrylate, bis-(2-acryloxyethyl)isocyanurate, tris-(2-acryloxyethyl)isocyanurate, pentaerythritol tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, polyepoxy tetra(meth)acrylate, polyester tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, acrylate, penta(meth)acrylates such as tripentaerythritol penta(meth)acrylate, hexa(meth)acrylates such as dipentaerythritol hexa(meth)acrylate and tripentaerythritol hexa(meth)acrylate, hepta(meth)acrylates such as tripentaerythritol hepta(meth)acrylate, octa(meth)acrylates such as tripentaerythritol octa(meth)acrylate, penta- or higher functional polyurethane poly(meth)acrylates, penta- or higher functional polyepoxy poly(meth)acrylates, penta- or higher functional polyester poly(meth)acrylates, etc. Further examples include modified products such as polycaprolactone-modified adducts and polycarbonate-modified adducts of these penta- or higher functional (meth)acrylate monomers, tetra- or higher functional polyurethane poly(meth)acrylates, penta- or higher functional polyepoxy poly(meth)acrylates, and penta- or higher functional polyester poly(meth)acrylates, etc. These pentafunctional or higher photopolymerizable monomers may be used alone or in combination of two or more. Such photopolymerizable monomers may also be used as reactive diluents.

[0047] Preferred examples of commercially available polyfunctional modifying monomers include dipentaerythritol triacrylate (a commercially available product is KAYARAD D-330; manufactured by Nippon Kayaku Co., Ltd.), dipentaerythritol tetraacrylate (a commercially available product is KAYARAD D-320; manufactured by Nippon Kayaku Co., Ltd.), dipentaerythritol penta(meth)acrylate (a commercially available product is KAYARAD D-310; manufactured by Nippon Kayaku Co., Ltd.), and dipentaerythritol hexa(meth)acrylate (a commercially available product is KAYARAD DPHA; manufactured by Nippon Kayaku Co., Ltd.). Furthermore, examples of the polymerizable compound that can be used include pentaerythritol tetraacrylate (NK Ester A-TMMT, manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,6-hexanediol diacrylate (KAYARAD HDDA, manufactured by Nippon Kayaku Co., Ltd.), RP-1040 (manufactured by Nippon Kayaku Co., Ltd.), Aronix TO-2349 (manufactured by Toagosei Co., Ltd.), NK Oligo UA-7200 (manufactured by Shin-Nakamura Chemical Co., Ltd.), 8UH-1006, 8UH-1012 (manufactured by Taisei Fine Chemical Co., Ltd.), and Light Acrylate POB-A0 (manufactured by Kyoeisha Chemical Co., Ltd.).

[0048] (Thermoplastic Resin) The curable resin composition may further contain a thermoplastic resin, from the viewpoint of improving the film-forming properties of the dry film.

[0049] Examples of thermoplastic resins include styrene-based resins, (meth)acrylic polymers, organic acid vinyl ester-based polymers, vinyl ether-based polymers, halogen-containing resins, polyolefins (including alicyclic polyolefins), polycarbonates, polyesters, polyamides, thermoplastic polyurethanes, polysulfone-based resins (polyethersulfone, polysulfone, etc.), polyphenylene ether-based resins (2,6-xylenol polymers, etc.), cellulose derivatives (cellulose esters, cellulose carbamates, cellulose ethers, etc.), silicone resins (polydimethylsiloxane, polymethylphenylsiloxane, etc.), rubber or elastomers (diene rubbers such as polybutadiene and polyisoprene, styrene-butadiene copolymers, acrylonitrile-butadiene copolymers, acrylic rubbers, urethane rubbers, silicone rubbers, etc.), etc. These thermoplastic resins can be used alone or in combination of two or more.

[0050] Among these thermoplastic resins, in the form used for photosensitive materials, optical applications, and the like, styrene-based resins, (meth)acrylic polymers, vinyl acetate-based polymers, vinyl ether-based polymers, halogen-containing resins, alicyclic polyolefins, polycarbonates, polyesters, polyamides, cellulose derivatives, silicone-based resins, rubbers, elastomers, and the like are commonly used because of their excellent transparency, and cellulose esters are preferred.

[0051] Examples of cellulose esters include aliphatic organic acid esters (cellulose acetates such as cellulose diacetate and cellulose triacetate; C esters such as cellulose propionate, cellulose butyrate, cellulose acetate propionate, and cellulose acetate butyrate); １－６ aliphatic carboxylic acid esters, aromatic organic acid esters (cellulose phthalate, cellulose benzoate, etc.) ７－１２Examples of the cellulose ester include aromatic carboxylic acid esters, inorganic acid esters (e.g., cellulose phosphate, cellulose sulfate, etc.), and mixed acid esters such as cellulose acetate-nitrate esters. These cellulose esters can be used alone or in combination of two or more. Among these, cellulose C such as cellulose diacetate, cellulose triacetate, cellulose acetate propionate, and cellulose acetate butyrate are particularly preferred. ２―４ Acylate is preferred, and cellulose acetate C such as cellulose acetate propionate is preferred. ３－４ Acylates are particularly preferred.

[0052] More preferred cellulose esters are those in which the hydroxyl groups of cellulose are esterified with an organic acid, and specifically, those represented by the following general formula (1): (In formula (1), R １ , R ２ and R ３ are each independently hydrogen, an acyl group, or a group represented by the following general formula (2): (In formula (2), R ４ is hydrogen or a methyl group, and R ５ is hydrogen, a methyl group, an ethyl group, or a glycidyl group; １ , R ２ and R ３ At least one of the groups is hydrogen, and n is an integer of 1 or more, the upper limit of which is limited by the molecular weight described below.

[0053] In the cellulose ester represented by the formula (1), the content of acyl groups relative to the cellulose resin is preferably more than 0% by mass and not more than 60% by mass, more preferably from 5% by mass to 55% by mass.

[0054] In the cellulose ester represented by the formula (1), the hydroxyl group content relative to the cellulose resin is preferably 0% by mass or more and 8% by mass or less, more preferably 1% by mass or more and 7% by mass or less, and even more preferably 3% by mass or more and 6% by mass or less.As the organic acid ester, the acetyl group content is preferably 0% by mass or more and 40% by mass or less, more preferably 0.2% by mass or more and 20% by mass or less, and even more preferably 0.4% by mass or more and 2.0% by mass or less.The propionyl group and / or butyryl group content is preferably 0% by mass or more and 55% by mass or less, more preferably 40% by mass or more and 50% by mass or less, and even more preferably 41% by mass or more and 44% by mass or less.When the amount of the functional group is within the above numerical range, the viscosity of the composition in which the cellulose ester is dissolved is good, and the handling is good.It should be noted that "mass%" here refers to the mass% of hydrogen or organic acid ester relative to the mass of cellulose.

[0055] Commercially available products of such cellulose esters include cellulose acetates such as CA-398-3, CA-398-6, CA-398-10, CA-398-30, and CA-394-60S; cellulose acetate butyrates such as CAB-551-0.01, CAB-551-0.2, CAB-553-0.4, CAB-531-1, CAB-500-5, and CAB-381-0.1; Examples of cellulose esters include CAB-381-0.5, CAB-381-2, CAB-381-20, CAB-381-20BP, CAB-321-0.1, and CAB-171-15, and examples of cellulose acetate propionate include CAP-504-0.2, CAP-482-0.5, and CAP-482-20 (all of the above cellulose esters are trade names manufactured by Eastman Chemical Japan Co., Ltd.). Among these, cellulose acetate butyrate and cellulose acetate propionate are preferred from the viewpoint of solubility in solvents, and cellulose acetate propionate is more preferred from the viewpoint of odor reduction. The cellulose derivatives can be used alone or in combination of two or more.

[0056] The number average molecular weight of the cellulose resin is not particularly limited, but is preferably 5,000 to 500,000, more preferably 7,000 to 100,000, and even more preferably 10,000 to 50,000. If the molecular weight is within the above numerical range, the balance between film-forming property and developability is good. The number average molecular weight can be determined from the standard polystyrene equivalent value by gel permeation chromatography (GPC). For GPC measurement, tetrahydrofuran was used as the eluent and an RI detector was used.

[0057] [Cellulose Resin Content] The cellulose resin content, in terms of solid content, relative to the total amount of the curable resin composition, is preferably 0.1% by mass or more and 5.0% by mass or less, more preferably 0.3% by mass or more and 4.0% by mass or less, and even more preferably 0.5% by mass or more and 3.0% by mass or less. When the cellulose resin content is 0.1% by mass or more, film-forming properties are improved. On the other hand, when it is 5.0% by mass or less, a good balance between film-forming properties and developability can be achieved.

[0058] The content of the cellulose resin is preferably 1.0 part by mass or more and 100.0 parts by mass or less, more preferably 3.0 parts by mass or more and 75.0 parts by mass or less, and even more preferably 5.0 parts by mass or more and 50.0 parts by mass or less, relative to 100 parts by mass of the pentafunctional or higher ethylene oxide-modified monomer. When the content of the cellulose resin is 1.0 part by mass or more and 100.0 parts by mass or less, a good balance between film-forming properties and developability can be achieved.

[0059] The glass transition temperature Tg of the cellulose resin is preferably 70°C or higher and lower than 200°C, and more preferably 100°C or higher and lower than 180°C. If the glass transition temperature is lower than 70°C, it is difficult to obtain sufficient tack-free properties, while if it is higher than 200°C, the folding resistance of the cured product may be impaired. Note that the glass transition temperature Tg referred to in this specification refers to the glass transition temperature measured by differential scanning calorimetry (DSC) in accordance with the method described in "5.17.5 DSC method" of JIS C 6481:1996.

[0060] The cellulose resin used in the present invention is preferably derived from a natural product from the viewpoint of preventing fossil fuel depletion. Furthermore, the starting material used for the cellulose resin of the present invention can be produced from recycled materials such as recycled pulp, which can provide a composition that is environmentally preferable from the viewpoint of reducing CO2 emissions.

[0061] (Other Thermoplastic Resins) The curable resin composition of the present invention may further contain other thermoplastic resins in order to improve the film-forming properties of the dry film.

[0062] Examples of the other thermoplastic resin include the thermoplastic resins other than the cellulose resins listed above. These thermoplastic resins can be used alone or in combination. The content of the other thermoplastic resin is not particularly limited and can be appropriately set depending on the effect of improving film-forming properties and the mechanical properties of the film and cured product of the present invention.

[0063] (Epoxy Resin) As the epoxy resin, a known compound having one or more epoxy groups can be used. Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, and triphenylmethane type epoxy resin.

[0064] Examples of commercially available epoxy resins include jER 828, 806, 807, YX8000, YX8034, and 834 manufactured by Mitsubishi Chemical Corporation; YD-128, YDF-170, ZX-1059, and ST-3000 manufactured by Nippon Steel Chemical & Material Co., Ltd.; EPICLON 830, 835, 840, 850, N-730A, N-695, and HP-7200L manufactured by DIC Corporation; and RE-306 manufactured by Nippon Kayaku Co., Ltd.

[0065] The content of the epoxy resin is, in terms of solid content, preferably 10% by mass or more and 50% by mass or less, more preferably 15% by mass or more and 45% by mass or less, and even more preferably 20% by mass or more and 40% by mass or less, relative to the total amount of the curable resin composition. By setting the content of the epoxy resin within the above numerical range, a cured product having excellent developability and excellent flexibility, adhesion, and heat resistance can be obtained.

[0066] (Inorganic Filler) As the inorganic filler, conventionally known inorganic fillers can be used, including silica, talc, mica, aluminum oxide, calcium oxide, magnesium oxide, zinc oxide, calcium carbonate, magnesium carbonate, fly ash, dewatered sludge, kaolin, clay, calcium hydroxide, aluminum hydroxide, magnesium hydroxide, hydrotalcite, aluminum silicate, magnesium silicate, calcium silicate, wollastonite, potassium titanate, magnesium sulfate, calcium sulfate, magnesium phosphate, sepiolite, zonolite, boron nitride, aluminum borate, silica balloons, glass flakes, glass balloons, steelmaking slag, copper, iron, iron oxide, sendust, alnico magnets, magnetic powders such as various ferrites, cement, glass powder, Neuburg silica, diatomaceous earth, antimony trioxide, magnesium oxysulfate, aluminum hydrate, hydrated gypsum, alum, and barium sulfate. Among these, silica is preferred. These inorganic fillers may be used alone or in combination of two or more.

[0067] The inorganic filler may be surface-treated to enhance dispersibility in the curable resin composition. Use of a surface-treated inorganic filler can suppress aggregation. The surface treatment method is not particularly limited, and any known or commonly used method may be used. However, it is preferable to treat the surface of the inorganic filler with a surface treatment agent having a curable reactive group, such as a coupling agent having a curable reactive group as an organic group.

[0068] Examples of coupling agents that can be used include silane-based, titanate-based, aluminate-based, and zircoaluminate-based coupling agents. Among these, silane-based coupling agents are preferred. Examples of such silane-based coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, N-(2-aminomethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-anilinopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane. These can be used alone or in combination. It is preferred that these silane-based coupling agents are immobilized in advance on the surface of the inorganic filler by adsorption or reaction. Here, the amount of the coupling agent to be treated with respect to 100 parts by mass of the inorganic filler is preferably 0.5 to 10 parts by mass.

[0069] From the viewpoint of dispersibility, the inorganic filler preferably has an average particle size (D50) of 5 nm or more and 500 nm or less, more preferably 7 nm or more and 180 nm or less, and even more preferably 10 nm or more and 100 nm or less. The average particle size refers to the particle size at 50% cumulative volume obtained using a laser diffraction / scattering particle size distribution measurement method. The average particle size of silica refers to the value measured as described above for the inorganic filler before preparing (stirring, kneading) the curable resin composition.

[0070] The content of the inorganic filler is preferably 3% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 40% by mass or less, in terms of solid content, relative to the total amount of the curable resin composition. When the content of the inorganic filler is within the above range, the resolution, thermal expansion coefficient, and dielectric properties of the cured product are more likely to be improved.

[0071] (Curing Agent) Examples of the curing agent include imidazole derivatives such as imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole; amine compounds such as dicyandiamide, benzyldimethylamine, 4-(dimethylamino)-N,N-dimethylbenzylamine, 4-methoxy-N,N-dimethylbenzylamine, and 4-methyl-N,N-dimethylbenzylamine; hydrazine compounds such as adipic acid dihydrazide and sebacic acid dihydrazide; and phosphorus compounds such as triphenylphosphine. Commercially available examples include Curesol 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, and 2P4MHZ (all trade names of imidazole-based compounds) manufactured by Shikoku Chemicals Corporation, and U-CAT 3513N (trade name of dimethylamine-based compound), DBU, DBN, and U-CAT SA 102 (all bicyclic amidine compounds and salts thereof) manufactured by San-Apro Co., Ltd. However, the curing agent is not limited to these, and any curing agent that promotes the reaction of at least one of an epoxy group and an oxetanyl group with a carboxyl group may be used, and they may be used alone or in combination of two or more.

[0072] Furthermore, S-triazine derivatives such as guanamine, acetoguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, 2-vinyl-4,6-diamino-S-triazine·isocyanuric acid adduct, and 2,4-diamino-6-methacryloyloxyethyl-S-triazine·isocyanuric acid adduct can also be used, and these compounds that also function as adhesion-imparting agents are preferably used in combination with a curing agent. One type of curing agent may be used alone, or two or more types may be used in combination.

[0073] The content of the curing agent is preferably 0.1 to 8 mass %, more preferably 0.3 to 5 mass %, calculated as solid content, based on the total amount of the curable resin composition.

[0074] (Photopolymerization initiator) The photopolymerization initiator is used to react a photosensitive alkali-soluble resin or a photopolymerizable monomer by exposure to light. Any known photopolymerization initiator can be used. One photopolymerization initiator may be used alone, or two or more photopolymerization initiators may be used in combination.

[0075] Specific examples of the photopolymerization initiator include bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, and bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentyl bisacylphosphine oxides such as phosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, and bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphinic acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, pivaloylphenylphosphine monoacylphosphine oxides such as isopropyl sphinic acid ester and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate, 1-hydroxy-cyclohexyl phenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, 2 hydroxyacetophenones such as 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzoins such as benzoin, benzil, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, and benzoin n-butyl ether; benzoin alkyl ethers; benzophenones such as benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, and 4,4'-bisdiethylaminobenzophenone;Acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 2-(dimethylamino)-2-[(4-methylphenyl)methyl)-1-[4-(4-morpholinyl)phenyl]-1-butanone acetophenones such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone; anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, Anthraquinones such as 2-aminoanthraquinone; ketals such as acetophenone dimethyl ketal and benzil dimethyl ketal; benzoic acid esters such as ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate and p-dimethylbenzoic acid ethyl ester; 1,2-octanedione, 1-[4-(phenylthio)phenyl]-, 2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyl oxime esters such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium and titanocenes such as bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyr-1-yl)ethyl)phenyl]titanium; phenyl disulfide 2-nitrofluorene, butyroin, anisoin ethyl ether, azobisisobutyronitrile, tetramethylthiuram disulfide, and the like.

[0076] Commercially available α-aminoacetophenone photopolymerization initiators include Omnirad 907, 369, 369E, and 379 manufactured by IGM Resins. Commercially available acylphosphine oxide photopolymerization initiators include Omnirad 819 manufactured by IGM Resins. Commercially available oxime ester photopolymerization initiators include Irgacure OXE01 and OXE02 manufactured by BASF Japan Ltd., N-1919 manufactured by ADEKA Corporation, ADEKA Arcles NCI-831 and NCI-831E, and TR-PBG-304 manufactured by Changzhou New Advanced Electronic Materials Co., Ltd.

[0077] Other examples include carbazole oxime ester compounds described in JP-A-2004-359639, JP-A-2005-097141, JP-A-2005-220097, JP-A-2006-160634, JP-A-2008-094770, JP-T-2008-509967, JP-T-2009-040762, and JP-A-2011-80036.

[0078] The content of the photopolymerization initiator is preferably 0.1 to 10 mass %, more preferably 1 to 7 mass %, calculated as solid content, relative to the total amount of the curable resin composition. When the content of the photopolymerization initiator is 0.1 mass % or more, the photocurability of the curable resin composition is good, and the properties of the cured product, such as chemical resistance, are also good. On the other hand, when the content is 10 mass % or less, light absorption at the surface of the resist film (cured product) is good, and deep curing is less likely to decrease.

[0079] A photoinitiator aid, sensitizer, or catalyst may be used in combination with the above-described photopolymerization initiator. Examples of the photoinitiator aid, sensitizer, or catalyst include benzoin compounds, anthraquinone compounds, thioxanthone compounds, ketal compounds, benzophenone compounds, tertiary amine compounds, and xanthone compounds. In particular, it is preferable to use thioxanthone compounds such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, and 4-isopropylthioxanthone. The inclusion of a thioxanthone compound can improve deep curing properties. While these compounds may be used as photopolymerization initiators, it is preferable to use them in combination with a photopolymerization initiator. Furthermore, one type of photoinitiator aid, sensitizer, or catalyst may be used alone, or two or more types may be used in combination.

[0080] These photopolymerization initiators, photoinitiator assistants, sensitizers, and catalysts absorb light of specific wavelengths, which can reduce sensitivity in some cases and function as ultraviolet absorbers. However, they are not used solely for the purpose of improving the sensitivity of the resin composition. By absorbing light of specific wavelengths as needed, they can increase the photoreactivity of the surface, change the line shape and openings of the resist pattern to vertical, tapered, or reverse tapered, and improve the accuracy of the line width and opening diameter.

[0081] (Colorant) The curable resin composition of the present invention can be blended with a colorant. The colorant is not particularly limited, and known colorants such as red, blue, green, and yellow can be used. Any of pigments, dyes, and coloring matters can be used, but from the viewpoint of reducing the environmental load and having little effect on the human body, a colorant that does not contain halogen is preferred.

[0082] Red colorants include monoazos, disazos, azo lakes, benzimidazolone, perylene, diketopyrrolopyrrole, condensed azos, anthraquinones, and quinacridones, and specific examples thereof include those having the following Color Index (C.I., published by The Society of Dyers and Colorists) numbers:

[0083] Examples of monoazo red colorants include Pigment Red 1, 2, 3, 4, 5, 6, 8, 9, 12, 14, 15, 16, 17, 21, 22, 23, 31, 32, 112, 114, 146, 147, 151, 170, 184, 187, 188, 193, 210, 245, 253, 258, 266, 267, 268, and 269. Examples of disazo red colorants include Pigment Red 37, 38, and 41. Examples of monoazo lake-based red colorants include Pigment Red 48:1, 48:2, 48:3, 48:4, 49:1, 49:2, 50:1, 52:1, 52:2, 53:1, 53:2, 57:1, 58:4, 63:1, 63:2, 64:1, and 68. Examples of benzimidazolone-based red colorants include Pigment Red 171, 175, 176, 185, and 208. Examples of perylene-based red colorants include Solvent Red 135, 179, Pigment Red 123, 149, 166, 178, 179, 190, 194, and 224. Examples of diketopyrrolopyrrole red colorants include Pigment Red 254, 255, 264, 270, and 272. Examples of condensed azo red colorants include Pigment Red 220, 144, 166, 214, 220, 221, and 242. Examples of anthraquinone red colorants include Pigment Red 168, 177, and 216, and Solvent Red 149, 150, 52, and 207. Examples of quinacridone red colorants include Pigment Red 122, 202, 206, 207, and 209.

[0084] Blue colorants include phthalocyanine-based and anthraquinone-based ones, and examples of pigment-based agents include compounds classified as pigments, such as Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, and 60, and examples of dye-based agents include Solvent Blue 35, 63, 68, 70, 83, 87, 94, 97, 122, 136, 67, and 70. In addition to the above, metal-substituted or unsubstituted phthalocyanine compounds can also be used.

[0085] Examples of yellow colorants include monoazo, disazo, condensed azo, benzimidazolone, isoindolinone, and anthraquinone. Examples of anthraquinone yellow colorants include Solvent Yellow 163, Pigment Yellow 24, 108, 193, 147, 199, and 202. Examples of isoindolinone yellow colorants include Pigment Yellow 110, 109, 139, 179, and 185. Examples of condensed azo yellow colorants include Pigment Yellow 93, 94, 95, 128, 155, 166, and 180. Examples of benzimidazolone yellow colorants include Pigment Yellow 120, 151, 154, 156, 175, and 181. Examples of monoazo yellow colorants include Pigment Yellow 1, 2, 3, 4, 5, 6, 9, 10, 12, 61, 62, 62:1, 65, 73, 74, 75, 97, 100, 104, 105, 111, 116, 167, 168, 169, 182, and 183. Examples of disazo yellow colorants include Pigment Yellow 12, 13, 14, 16, 17, 55, 63, 81, 83, 87, 126, 127, 152, 170, 172, 174, 176, 188, and 198.

[0086] In addition, colorants such as purple, orange, brown, and black may be added. Specific examples include C.I. Pigment Black 1, 6, 7, 8, 9, 10, 11, 12, 13, 18, 20, 25, 26, 28, 29, 30, 31, and 32, C.I. Pigment Violet 19, 23, 29, 32, 36, 38, and 42, Solvent Violet 13 and 36, C.I. Pigment Orange 1, 5, 13, 14, 16, 17, 24, 34, 36, 38, 40, 43, 46, 49, 51, 61, 63, 64, 71, and 73, C.I. Pigment Brown 23 and 25, and carbon black.

[0087] (Organic Solvent) The curable resin composition of the present invention may contain an organic solvent for the purpose of adjusting the viscosity when preparing the composition or when applying it to a substrate or film. Examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, diethylene glycol monomethyl ether acetate, and tripropylene glycol monomethyl ether; esters such as ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, diethylene glycol monoethyl ether acetate, butyl carbitol acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, and propylene carbonate; aliphatic hydrocarbons such as octane and decane; and petroleum-based solvents such as petroleum ether, petroleum naphtha, and solvent naphtha. These organic solvents may be used alone or in combination of two or more.

[0088] The content of the organic solvent is not particularly limited, and can be appropriately set depending on the target viscosity so as to facilitate preparation of the curable resin composition.

[0089] (Other Additive Components) The curable resin composition of the present invention may further contain, as necessary, components such as cyanate compounds, elastomers, mercapto compounds, urethanization catalysts, thixotropic agents, adhesion promoters, block copolymers, chain transfer agents, polymerization inhibitors, copper inhibitors, antioxidants, rust inhibitors, thickeners, at least one of silicone-based, fluorine-based, and polymer-based antifoaming agents and leveling agents, imidazole-based, thiazole-based, and triazole-based silane coupling agents, and flame retardants such as phosphinates, phosphate ester derivatives, and phosphorus compounds such as phosphazene compounds. These may be known in the field of electronic materials.

[0090] [Preparation Method] The curable resin composition of the present invention can be prepared by weighing and blending the components, pre-mixing them with a mixer, and then dispersing and kneading the components in a kneader.

[0091] Examples of the kneading machine include a bead mill, a ball mill, a sand mill, a three-roll mill, and a two-roll mill. Among these, a bead mill is preferably used to improve dispersibility. Dispersion conditions such as the type and particle size of the beads of the bead mill can be appropriately set depending on the target viscosity.

[0092] [Uses] The curable resin composition of the present invention is useful for forming a pattern layer as a permanent coating on a printed wiring board, and is also useful for forming a solder resist, a coverlay, an interlayer insulating layer, a rewiring layer, etc. Furthermore, since the curable resin composition of the present invention can form a cured product that has excellent film strength even when it is a thin film, it can also be suitably used for forming a pattern layer on a printed wiring board that requires a thin film, such as a package substrate (a printed wiring board used for a semiconductor package).

[0093] Furthermore, the curable resin composition of the present invention can be used not only for forming a pattern layer but also for applications in which a pattern layer is not formed, such as molding applications (sealing applications).

[0094] [Dry Film] The curable resin composition of the present invention can also be in the form of a dry film comprising a first film and a resin layer formed on the first film, the resin layer being a dried coating of the curable resin composition. The term "first film" as used herein refers to a film that is at least adhered to the resin layer when the dry film is laminated onto a substrate or other base material by heating or other means so that the resin layer side of the dry film is in contact with the resin layer formed on the dry film and integrally formed. The first film may be peeled from the resin layer in a post-lamination step. In particular, in the present invention, peeling from the resin layer in a post-exposure step is preferred. To form a dry film, the curable resin composition of the present invention is diluted with the organic solvent to an appropriate viscosity, and then coated to a uniform thickness on the first film using a comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater, gravure coater, spray coater, or the like. The film is then typically dried at a temperature of 50 to 130°C for 1 to 30 minutes to obtain a film. There is no particular restriction on the thickness of the coating film, but it is generally selected appropriately within the range of 1 to 150 μm, preferably 5 to 60 μm, in terms of the thickness after drying.

[0095] The first film can be any known film without particular limitation, and examples of suitable films include polyester films such as polyethylene terephthalate and polyethylene naphthalate, and films made of thermoplastic resins such as polyimide films, polyamideimide films, polypropylene films, and polystyrene films. Among these, polyester films are preferred from the viewpoints of heat resistance, mechanical strength, ease of handling, etc. A laminate of these films can also be used as the first film.

[0096] From the viewpoint of improving mechanical strength, the above-mentioned thermoplastic resin film is preferably a film stretched in a uniaxial or biaxial direction.

[0097] The thickness of the first film is not particularly limited, but can be, for example, 10 μm to 150 μm.

[0098] After forming a resin layer consisting of a dried coating film of the curable resin composition of the present invention on the first film, it is preferable to further laminate a peelable second film on the surface of the resin layer for the purpose of preventing dust from adhering to the surface of the resin layer. The second film in the present invention refers to a film that is peeled from the resin layer before lamination when the dry film is laminated by heating or the like so that the resin layer side of the dry film is in contact with a base material such as a substrate to form an integral mold. Examples of the peelable second film that can be used include polyethylene film, polytetrafluoroethylene film, polypropylene film, surface-treated paper, etc., and any film can be used as long as the adhesive strength between the resin layer and the second film is smaller than the adhesive strength between the resin layer and the first film when the second film is peeled off.

[0099] The thickness of the second film is not particularly limited, but can be, for example, 10 μm to 150 μm.

[0100] [Cured Product] The cured product of the present invention is obtained by curing the curable resin composition of the present invention or the resin layer of the dry film of the present invention. The manufacturing conditions such as curing conditions will be described later in [Method for manufacturing printed wiring board]. The cured product of the present invention can be suitably used for printed wiring boards, electronic components, etc.

[0101] [Printed Wiring Board] The printed wiring board of the present invention comprises a circuit board and a cured product obtained from the resin layer of the curable resin composition or dry film of the present invention.

[0102] Examples of the substrate include printed wiring boards and flexible printed wiring boards on which circuits have been formed in advance using copper or the like, as well as copper-clad laminates for high-frequency circuits made of materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven cloth epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, fluororesin / polyethylene / polyphenylene ether, polyphenylene oxide / cyanate, and the like, and include copper-clad laminates of all grades (FR-4, etc.), as well as metal substrates, polyimide films, polyethylene terephthalate films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafer plates, etc.

[0103] [Method for manufacturing printed wiring board] In a method for manufacturing a printed wiring board of the present invention, for example, the curable resin composition of the present invention is adjusted to a viscosity suitable for the coating method using the organic solvent, and applied to a substrate by a method such as dip coating, flow coating, roll coating, bar coating, screen printing, or curtain coating, and then the organic solvent contained in the composition is evaporated and dried (pre-dried) for 15 to 90 minutes at a temperature of 60 to 100° C. to form a tack-free resin layer. In addition, in the case of a dry film, the resin layer is attached to the substrate using a laminator or the like so that the resin layer is in contact with the substrate, and a resin layer is formed on the substrate.

[0104] The dry film is preferably bonded to the substrate under pressure and heat using a vacuum laminator or the like. By using such a vacuum laminator, when a circuit-formed substrate is used, the dry film adheres tightly to the circuit substrate even if the circuit substrate surface is uneven, preventing the inclusion of air bubbles and improving the filling of recesses in the substrate surface. The pressure condition is preferably about 0.1 to 2.0 MPa, and the heating condition is preferably 40 to 120°C.

[0105] The volatilization drying carried out after the curable resin composition of the present invention is applied to a substrate can be carried out using a hot air circulation drying oven, an IR oven, a hot plate, a convection oven, etc. (a method in which hot air in a dryer equipped with a heat source of an air heating method using steam is brought into countercurrent contact with the substrate, or a method in which hot air is blown onto the substrate from a nozzle.) Examples of the apparatus include a hot air circulation drying oven such as DF610 manufactured by Yamato Scientific Co., Ltd.

[0106] After forming a resin layer on a substrate, the resin layer is selectively exposed to active energy rays through a photomask having a predetermined pattern formed thereon, and the unexposed areas are developed with a dilute alkaline aqueous solution (e.g., a 0.3 to 3.0 mass % aqueous sodium carbonate solution) to form a patterned cured product. In the case of a dry film, after exposure, the first film is peeled from the dry film and development is carried out to form a patterned cured product on the substrate. Note that, as long as the properties are not impaired, the first film may be peeled from the dry film before exposure, and the exposed resin layer may be exposed and developed.

[0107] The exposure device used for the active energy ray irradiation may be any device equipped with a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a mercury short arc lamp, or the like, and capable of irradiating ultraviolet rays in the range of 350 to 450 nm. Furthermore, a direct imaging device (for example, a laser direct imaging device that draws an image directly with a laser based on CAD data from a computer) may also be used. The lamp or laser light source of the direct imaging device may have a maximum wavelength in the range of 350 to 450 nm. The exposure dose for image formation varies depending on factors such as the film thickness, but is generally 10 to 1,000 mJ / cm. ２ , preferably 20 to 800 mJ / cm ２ The range may be:

[0108] The developing method may be a dipping method, a shower method, a spray method, a brush method, or the like, and the developing solution may be an aqueous alkali solution such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, or an amine.

[0109] Furthermore, the cured product is irradiated with active energy rays and then heat-cured (for example, at a temperature of 100 to 220°C for 30 to 90 minutes), or is irradiated with active energy rays (for example, at a temperature of 1,000 to 2,000 mJ / cm ２By performing final curing (main curing) by heating alone, or by heat curing alone, a cured product with excellent properties such as adhesion and hardness can be formed. Examples of equipment include a UV conveyor using a high-pressure mercury lamp, such as the QRM-2082 manufactured by Oak Manufacturing Co., Ltd.

[0110] The present invention will be described in more detail below using examples, but the present invention is not limited to the following examples. In the following, "parts" and "%" are all based on mass in terms of solid content unless otherwise specified.

[0111] Synthesis Example 1 Synthesis of Alkali-Soluble Resin Having an Imide Skeleton A separable flask equipped with a condenser was charged as a reaction vessel with 82.4 parts of propylene glycol monomethyl ether acetate and 35.3 parts of isopropanol, and the atmosphere was replaced with nitrogen and then heated to 100°C. Meanwhile, a mixture of 40 parts of N-phenylmaleimide, 128 parts of propylene glycol monomethyl ether acetate, and 32 parts of isopropanol was charged into dropping vessel 1, a mixture of 13 parts of styrene, 20 parts of 2-hydroxyethyl methacrylate, 27 parts of methacrylic acid, and 22.2 parts of isopropanol was charged into dropping vessel 2, and 10 parts of Perbutyl O (t-butylperoxy-2-ethylhexanoate, product of NOF Corporation) was charged as a polymerization initiator into dropping vessel 3. While maintaining the reaction temperature at 100°C, dropwise addition was carried out from dropping vessels 1 to 3 over a period of 3 hours. After the dropwise addition was completed, the reaction was continued for another 30 minutes at 100 ° C. After that, the reaction temperature was raised to 115 ° C., and the reaction was continued for 1.5 hours to obtain a polymer solution before the radical polymerizable double bond introduction reaction. Next, to this polymer solution, 13.7 parts of Cyclomer M100 (trade name; manufactured by Daicel Corporation, 3,4-epoxycyclohexylmethyl methacrylate), 31.2 parts of propylene glycol monomethyl ether acetate, 0.7 parts of triphenylphosphine as a reaction catalyst, and 0.2 parts of Antage W-400 (trade name; manufactured by Kawaguchi Chemical Industry Co., Ltd., 2,2'-methylenebis(4-methyl-6-tert-butylphenol)) as a polymerization inhibitor were added, and the mixture was reacted at 115 ° C. while bubbling a mixed gas of nitrogen and oxygen (oxygen concentration 7%) to obtain a solution of an alkali-soluble resin having a succinimide-derived structure. The alkali-soluble resin thus obtained was measured for various physical properties, and found to have a weight-average molecular weight of 7,400, a solids concentration of 32.0% after heat drying at 160°C under vacuum, and an acid value per solid of 124 mgKOH / g. The weight-average molecular weight was measured by gel permeation chromatography (GPC).

[0112] Synthesis Example 2: Synthesis of an alkali-soluble resin having no imide skeleton First, 119.4 parts of a novolac cresol resin (Showol CRG951 manufactured by Showa Denko K.K., OH equivalent: 119.4), 1.19 parts of potassium hydroxide, and 119.4 parts of toluene were charged into an autoclave equipped with a thermometer, a nitrogen introducing device / alkylene oxide introducing device, and a stirrer, and the system was purged with nitrogen while stirring, and heated to a temperature of 125 to 132°C and a pressure of 0 to 4.8 kg / cm. Next, 63.8 parts of propylene oxide were gradually added dropwise, and the temperature was increased to 125 to 132°C and a pressure of 0 to 4.8 kg / cm. ２The reaction was carried out at 100°C for 16 hours. The system was then cooled to room temperature, and 1.56 parts of 89% by weight phosphoric acid was added to the resulting reaction solution and mixed to neutralize the potassium hydroxide, yielding a propylene oxide reaction solution of novolac cresol resin with a nonvolatile content of 62.1% and a hydroxyl value of 182.2 g / eq. The resulting novolac cresol resin had an average of 1.08 moles of alkylene oxide added per equivalent of phenolic hydroxyl group. 293.0 parts of the resulting alkylene oxide reaction solution of novolac cresol resin, 43.2 parts of acrylic acid, 11.53 parts of methanesulfonic acid, 0.18 parts of methylhydroquinone, and 252.9 parts of toluene were charged into a reactor equipped with a stirrer, thermometer, and air inlet tube, and the mixture was reacted at 110°C for 12 hours while stirring and blowing air at a rate of 10 ml / min. The water produced by the reaction was distilled as an azeotrope with toluene, and 12.6 parts of water were distilled off. The system was then cooled to room temperature, and the resulting reaction solution was neutralized with 35.35 parts of 15% aqueous sodium hydroxide and washed with water. The toluene was then distilled off using an evaporator while being replaced with 118.1 parts of diethylene glycol monoethyl ether acetate (carbitol acetate), yielding a novolac acrylate resin solution. Next, 332.5 parts of the resulting novolac acrylate resin solution and 1.22 parts of triphenylphosphine were charged into a reactor equipped with a stirrer, thermometer, and air inlet tube. Air was blown in at a rate of 10 ml / min, and while stirring, 60.8 parts of tetrahydrophthalic anhydride was gradually added. The mixture was reacted at a temperature of 95 to 101°C for 6 hours, and then cooled to yield an alkali-soluble resin solution having an acid value of 88 mgKOH / g, a weight-average molecular weight of 2550, and a solids content of 65.8%. In the examples, the weight average molecular weight values ​​are values ​​measured by gel permeation chromatography (GPC).

[0113] (Preparation of Curable Resin Composition) For each curable resin composition, the components were blended according to the formulation shown in Table 1 below and mixed in a stirrer.

[0114]

[0115] The blend amounts in Table 1 are in parts by mass (solid content equivalent). Details of each component in Table 1 are as follows. *1: Alkali-soluble resin of Synthesis Example 1 (weight average molecular weight 7400) *2: Alkali-soluble resin of Synthesis Example 2 (weight average molecular weight 2550) *3: CAP-504-0.2, cellulose acetate propionate, manufactured by Eastman Chemical Japan Co., Ltd. (number average molecular weight 15000) *4: CAP-482-0.5, cellulose acetate propionate, manufactured by Eastman Chemical Japan Co., Ltd. (number average molecular weight 25000) *5: CAP-482-20, cellulose acetate propionate, manufactured by Eastman Chemical Japan Co., Ltd. (number average molecular weight 75000) *6: A-DPH-12E, ethoxylated dipentaerythritol polyacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd. *7: A-DPH-6E, ethoxylated dipentaerythritol polyacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd. *8: DPHA, dipentaerythritol hexaacrylate *9: Aronix M-350, trimethylolpropane EO-modified triacrylate, manufactured by Toagosei Co., Ltd. *10: ATM-4E, ethoxylated pentaerythritol tetraacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd. *11: EPICLON HP-7200L, dicyclopentadiene-type epoxy resin, manufactured by DIC Corporation *12: Admanano YA050C-HHL, spherical silica particles, manufactured by Admatechs Co., Ltd. (average particle size 50 nm, vinylsilane treatment) *13: Curesol 1B2PZ, imidazole-based epoxy resin hardener, manufactured by Shikoku Chemicals Corporation *14: 2,4,6-trimethylbenzoyldiphenylphosphine oxide, acylphosphine oxide-based photopolymerization initiator *15: Quinopower QS-30, 4-methoxy-1-naphthol, manufactured by Air Water Performance Chemicals Inc.

[0116] (Evaluation of Developability) <Preparation of Evaluation Substrate> The curable resin compositions obtained in Examples 1 to 5 and Comparative Examples 1 to 3 shown in Table 1 above were applied to a first film (PET film) using an applicator so that the film thickness after drying was 10 μm, dried at 80°C for 20 minutes, and allowed to cool to room temperature. This was laminated onto a copper-clad laminate at 90°C and left for at least 1 hour, after which an opening pattern was exposed to light at an optimal exposure dose using an i-line single-beam projection exposure machine. After leaving for 60 minutes, the first film on the surface was peeled off, and development was carried out for 90 seconds using a 1% by mass aqueous solution of sodium carbonate at 30°C under a spray pressure of 0.2 MPa. This substrate was then exposed to an integrated exposure dose of 1000 mJ / cm in a UV conveyor furnace. ２ After exposure to light at 1000 K, the coating was cured by heating at 180°C for 60 minutes. The resulting evaluation substrates were examined for residues on the bottom of vias with an opening diameter of 10 µm using a scanning electron microscope. Developability was evaluated based on the following criteria, and the evaluation results are shown in Table 2. A rating of ○ or △ was considered to be acceptable. [Evaluation criteria] ○: No residue was found on the bottom of the via. △: More than 0% but less than 50% of the via bottom was covered with residue. ×: 50% or more of the via bottom was covered with residue.

[0117] (Evaluation of resolution) A substrate having a cured product was obtained in the same manner as in the test (Evaluation of developability) above. The opening diameter of the obtained cured product was observed with a scanning electron microscope, and the resolution was evaluated based on the following criteria for the occurrence of halation or undercut, and the evaluation results are shown in Table 2. [Evaluation criteria] ◯: A good opening diameter was obtained with an opening diameter of 10 μm. ×: A good opening diameter was not obtained with an opening diameter of 10 μm.

[0118] (Evaluation of Chemical Resistance (Acetone Cracking Resistance)) The curable resin compositions obtained in Examples 1 to 5 and Comparative Examples 1 to 3 shown in Table 1 above were applied to a first film (PET film) using an applicator so that the film thickness after drying would be 10 μm, dried at 80°C for 20 minutes, and allowed to cool to room temperature. The film was laminated onto a 6-inch wafer at 90°C, left to stand for 1 hour or more, and then subjected to full-surface exposure at an optimum exposure dose using an i-line single-beam projection exposure machine. After leaving for 60 minutes, the first film on the surface was peeled off, and development was carried out for 90 seconds using a 1% by mass aqueous solution of sodium carbonate at 30°C under conditions of a spray pressure of 0.2 MPa. The substrate was then exposed to an integrated exposure dose of 1000 mJ / cm in a UV conveyor furnace. ２ After exposure to light at 400 K, the coating was cured by heating at 180°C for 60 minutes. The obtained evaluation substrate was immersed in acetone for 10 minutes, and then the presence or absence of cracks on the surface was observed using an optical microscope. The acetone crack resistance was evaluated based on the following criteria, and the evaluation results are shown in Table 2. [Evaluation criteria] ○: No cracks occurred after immersion in acetone. ×: Cracks occurred after immersion in acetone.

[0119] (Evaluation of Water Absorption) The curable resin compositions obtained in Examples 1 to 5 and Comparative Examples 1 to 3 shown in Table 1 above were applied to the shiny side (copper foil) of GTS-MP foil (manufactured by Furukawa Circuit Foil Co., Ltd.) using an applicator and cured for 30 minutes at 150°C in a hot air circulation drying oven (DF610, manufactured by Yamato Scientific Co., Ltd.). The cured product was then peeled from the copper foil, and a sample was cut to a measurement size (25 mm x 25 mm). The sample was then dried at 100°C for 2 hours to completely remove moisture, and the mass (W1) was measured using a precision balance. The sample was then immersed in boiling water for one hour, and the mass (W2) of the sample was measured. The water absorption rate was calculated by (W2 - W1) / W1 x 100 (%), and the average value of five measurements was taken as the water absorption rate. The water absorption rate was evaluated based on the following criteria, and the evaluation results are shown in Table 2. A rating of ◎, ○, or △ was considered acceptable. [Evaluation criteria] ◎: Water absorption rate less than 1.5% ○: Water absorption rate 1.5% or more and less than 2.0% △: Water absorption rate 2.0% or more and less than 2.5% ×: Water absorption rate 2.5% or more

[0120]

[0121] From the evaluation results shown in Table 2, Example 3 was the most preferable, and the other Examples also exhibited superior developability, resolution, acetone crack resistance, and water absorbency compared to the respective Comparative Examples. From this, it is believed that the inclusion of an alkali-soluble resin having an imide skeleton with a weight-average molecular weight of 20,000 or less and a pentafunctional or higher ethylene oxide-modified monomer improved developability and chemical resistance without reducing resolution. Furthermore, Example 3 exhibited even superior developability and water absorbency compared to the other Examples. This is believed to be due to the combined use of a pentafunctional or higher ethylene oxide-modified monomer and a non-ethylene oxide-modified pentafunctional or higher monomer, which enabled suppression of hydrophilicity while maintaining developability. Comparing Examples 3 and 6 to 8, all exhibited good developability, resolution, acetone crack resistance, and water absorbency, with Example 3 in particular exhibiting even superior developability compared to Examples 6 to 8. From this, in the case where a cellulose resin is included in the resin composition of the present invention, the cellulose resin may have a molecular weight of 5,000 to 500,000, and the content of the cellulose resin may be any value between 0.1% and 5.0% by mass. However, it is believed that the solubility in the developer is enhanced when a cellulose resin with a lower molecular weight than the other examples is included, or when the content of the cellulose resin is lower. On the other hand, Comparative Example 1 exhibited reduced developability compared to the other examples. This is believed to be due to the reduced hydrophilicity caused by the absence of an ethylene oxide-modified monomer in Comparative Example 1. Furthermore, Comparative Examples 2 and 3 exhibited reduced resolution and acetone crack resistance compared to the other examples. This is believed to be due to the fact that the functionality of the ethylene oxide-modified monomer in Comparative Examples 2 and 3 was less than 5, resulting in low photosensitivity and insufficient reaction of the resin composition.

Claims

1. A curable resin composition comprising an alkali-soluble resin having an imide skeleton and a weight-average molecular weight of 20,000 or less, and an ethylene oxide-modified monomer having five or more functionalities.

2. The curable resin composition according to claim 1, wherein the imide skeleton contains a structure derived from succinimide.

3. The curable resin composition according to claim 1, wherein the weight average molecular weight of the alkali-soluble resin having an imide skeleton is 3,000 or more and 15,000 or less.

4. The curable resin composition according to claim 1, wherein the content of the alkali-soluble resin having an imide skeleton is 5% by mass or more and 50% by mass or less in terms of solid content relative to the total amount of the curable resin composition.

5. The curable resin composition according to claim 1, further comprising an alkali-soluble resin having no imide skeleton.

6. The curable resin composition according to claim 1, wherein the content of the ethylene oxide-modified monomer is 1.0 mass % or more and 20.0 mass % or less in terms of solid content, relative to the total amount of the curable resin composition.

7. The curable resin composition of claim 1, further comprising an epoxy resin.

8. The curable resin composition according to claim 7, wherein the content of the epoxy resin is 10% by mass or more and 50% by mass or less in terms of solid content, based on the total amount of the curable resin composition.

9. The curable resin composition of claim 1, further comprising a cellulose resin.

10. The curable resin composition according to claim 9, wherein the number average molecular weight of the cellulose resin is 5,000 or more and 500,000 or less.

11. The curable resin composition according to claim 9, wherein the content of the cellulose resin is 0.1 mass % or more and 5.0 mass % or less in terms of solid content relative to the total amount of the curable resin composition.

12. A curable resin composition according to claim 9, wherein the content of the cellulose resin is 1.0 part by mass or more and 100.0 parts by mass or less per 100 parts by mass of the ethylene oxide-modified monomer having five or more functionalities.

13. A dry film comprising a first film and a resin layer formed on the first film, the resin layer being a dry coating of the curable resin composition according to any one of claims 1 to 12.

14. A cured product obtained by curing the curable resin composition according to any one of claims 1 to 12.

15. A cured product obtained by curing the resin layer of the dry film according to claim 13.

16. A printed wiring board comprising the cured product according to claim 14.

17. A printed wiring board comprising the cured product according to claim 15.

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