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

Abstract

The purpose of the present invention is to provide a photosensitive resin composition which, while maintaining good resolution, prevents variations in color tones due to the influence of the color of copper in the base even if the photosensitive resin composition is formed into a thin film, and which provides a cured product having concealability. The present invention provides a photosensitive resin composition which contains (A) a coloring agent, (B) an alkali-soluble resin, (C) a photopolymerization initiator and (D) a photopolymerizable monomer, wherein the colorant (A) contains an anthraquinone-based blue pigment and carbon black.

Description

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

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

[0002] Solder resist is used on the surface layer of printed wiring boards and substrates for semiconductor packages, and serves to protect the circuit patterns formed on the substrate from external shocks and stresses such as heat and humidity.

[0003] With the increasing integration density of semiconductors and miniaturization of wiring, solder resists are now required to have various properties as a constituent material of semiconductor packages, such as high resolution, adaptability to thinner films, hiding power, and designability, in addition to simply protecting the wiring (e.g., crack resistance, insulation resistance, heat resistance, etc.) As one example, in recent years, there has been an increasing demand for black solder resists from the viewpoint of ensuring the hiding power of wiring patterns on printed wiring boards and designability.

[0004] Patent Document 1 discloses a black photosensitive resin composition containing, as a black colorant, at least one colorant selected from the group consisting of carbon black, perylene black, aniline black, and titanium black.

[0005] However, if a large amount of a black colorant such as carbon black is contained as a colorant, a large amount of light is absorbed during exposure, and light tends to be difficult to reach deep within the resin layer of the photosensitive resin composition that forms the solder resist. As a result, photocuring deep within the cured product becomes insufficient, and problems arise in terms of resolution, etc.

[0006] On the other hand, it is known that when a copper substrate is subjected to a copper surface roughening treatment as a pretreatment, the copper substrate has a reddish or yellowish tinge. ＊ , a ＊ and b ＊ The numerical value is 58<L ＊ <75, 16<a ＊ <22, 22<b ＊Therefore, when the content of black colorant is small, particularly when the solder resist is made into a thin film, the color of the solder resist is affected by the color of the underlying copper substrate, resulting in variations in the color tone of the solder resist, which reduces the design quality and makes it difficult to meet customer needs in terms of concealment of the wiring pattern.

[0007] Japanese Patent Application Laid-Open No. 2022-154993

[0008] In view of the above circumstances, an object of the present invention is to provide a photosensitive resin composition that maintains good resolution, prevents color variations due to the influence of the color of the underlying copper even when the film is thinned, and gives a cured product with hiding properties.

[0009] As a result of intensive research into achieving the above-mentioned object, the present inventors have found that a photosensitive resin composition containing (A) a colorant, (B) an alkali-soluble resin, (C) a photopolymerization initiator, and (D) a photopolymerizable monomer, wherein the (A) colorant contains an anthraquinone blue pigment and carbon black, has good resolution, is less susceptible to the influence of the color of the underlying copper even when formed into a thin film, prevents color variation, and gives a cured product with hiding properties, thereby completing the present invention.

[0010] In the photosensitive resin composition according to this embodiment of the present invention, it is preferable that the colorant (A) further contains at least one of an anthraquinone-based yellow pigment and a perylene-based red pigment.

[0011] In the photosensitive resin composition according to this embodiment of the present invention, the anthraquinone blue pigment is preferably contained in an amount of 0.01 to 4 parts by mass per 100 parts by mass of the total solid content in the photosensitive resin composition.

[0012] A dry film according to another embodiment of the present invention is characterized by having a first film and a resin layer formed on the first film, the resin layer being a dried coating film of the above-described photosensitive resin composition.

[0013] A cured product according to another aspect of the present invention is characterized in that it is a cured product obtained by curing the above-mentioned photosensitive resin composition or the resin layer of the above-mentioned dry film.

[0014] A printed wiring board according to another aspect of the present invention is a printed wiring board comprising the above-mentioned cured product.

[0015] According to the present invention, it is possible to provide a photosensitive resin composition that maintains good resolution while preventing color variations due to the influence of the color of the underlying copper even when the film is thinned, and that gives a cured product with hiding properties. Because the photosensitive resin composition of the present invention contains an anthraquinone-based blue pigment, it is possible to give a cured product with high transmittance for light with a wavelength of 365 nm, maintaining good resolution, and also having good hiding properties. Therefore, the photosensitive resin composition of the present invention can be suitably used as a resin layer in a dry film, and the cured product obtained by curing the composition is also useful as a solder resist or coverlay for printed wiring boards.

[0016] Preferred embodiments of the present invention will be described in detail below, but the present invention is not limited to the following embodiments.

[0017] In this specification, "(meth)acrylate" is a term that collectively refers to "acrylate," "methacrylate," and mixtures thereof, and the same applies to other similar expressions.

[0018] [1. Photosensitive Resin Composition] The photosensitive resin composition according to this embodiment is a photosensitive resin composition containing (A) a colorant, (B) an alkali-soluble resin, (C) a photopolymerization initiator, and (D) a photopolymerizable monomer, wherein the colorant (A) contains an anthraquinone blue pigment and carbon black. Below, the components (A) to (D) are explained in order, and then optional components of the photosensitive resin composition are also explained.

[0019] [1-1. (A) Colorant] The photosensitive resin composition according to this embodiment contains an anthraquinone blue pigment and carbon black as the colorant (A). The colorant (A) preferably contains at least one of an anthraquinone yellow pigment and a perylene red pigment. Furthermore, the colorant (A) may contain other colorants.

[0020] <Anthraquinone-based blue pigment> The anthraquinone-based blue pigment is not particularly limited, and any known or commonly used pigment can be used. The anthraquinone-based blue pigment also includes those having a skeleton in which two or more anthraquinone skeletons are condensed, such as an indanthrone skeleton.

[0021] Examples of anthraquinone blue pigments include Pigment Blue 22 and Pigment Blue 60. These anthraquinone blue pigments may be used alone or in combination of two or more.

[0022] The content of the anthraquinone blue pigment in the photosensitive resin composition is preferably 0.01 to 4 parts by mass, more preferably 0.05 to 3 parts by mass, and even more preferably 0.1 to 2 parts by mass, relative to 100 parts by mass of the total solid content in the photosensitive resin composition.

[0023] <Carbon Black> The carbon black is not particularly limited, and any known or commonly used carbon black can be used. Examples of carbon black include channel black, oil furnace black, gas furnace black, thermal black, acetylene black, and bone black.

[0024] Examples of carbon black include Pigment Black 6, Pigment Black 7, Pigment Black 8, Pigment Black 9, and Pigment Black 10. These carbon blacks may be used alone or in combination of two or more.

[0025] The content of carbon black in the photosensitive resin composition is preferably 0.01 to 1 part by mass, more preferably 0.01 to 0.7 parts by mass, and even more preferably 0.01 to 0.4 parts by mass, relative to 100 parts by mass of the total solid content in the photosensitive resin composition.

[0026] <Anthraquinone-based yellow pigment> The anthraquinone-based yellow pigment is not particularly limited, and any known or commonly used pigment can be used. The anthraquinone-based yellow pigment also includes those having an anthrapyrimidine derivative skeleton, which is an anthraquinone derivative.

[0027] Examples of anthraquinone yellow pigments include Pigment Yellow 24, Pigment Yellow 108, Pigment Yellow 112, Pigment Yellow 147, and Pigment Yellow 193. These anthraquinone yellow pigments may be used alone or in combination of two or more.

[0028] The content of the anthraquinone yellow pigment in the photosensitive resin composition is preferably 0.01 to 2.5 parts by mass, more preferably 0.05 to 2 parts by mass, and even more preferably 0.1 to 1.5 parts by mass, relative to 100 parts by mass of the total solid content in the photosensitive resin composition.

[0029] <Perylene-based red pigment> The perylene-based red pigment is not particularly limited, and known and commonly used pigments can be used. Examples of perylene-based red pigments include Pigment Red 123, Pigment Red 149, Pigment Red 178, Pigment Red 179, Pigment Red 190, and Pigment Red 224. These perylene-based red pigments may be used alone or in combination of two or more.

[0030] The content of the perylene red pigment in the photosensitive resin composition is preferably 0.01 to 4 parts by mass, more preferably 0.05 to 3 parts by mass, and even more preferably 0.1 to 2 parts by mass, relative to 100 parts by mass of the total solid content in the photosensitive resin composition.

[0031] <Other Colorants> The photosensitive resin composition according to this embodiment may contain other colorants. Known colorants such as red, blue, green, yellow, orange, and black can be used as the other colorants, and they may be any of pigments, dyes, and coloring matters. However, from the viewpoint of reducing environmental impact and effects on the human body, it is preferable that the other colorants do not contain halogens.

[0032] Examples of red colorants include monoazos, disazos, azo lakes, benzimidazolones, diketopyrrolopyrroles, condensed azos, anthraquinones, and quinacridones. Specific examples include those having the following Color Index (C.I., published by The Society of Dyers and Colorists) numbers:

[0033] 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 diketopyrrolopyrrole-based red colorants include Pigment Red 254, 255, 264, 270, and 272. Condensed azo red colorants include Pigment Red 220, 144, 166, 214, 220, 221, and 242. Anthraquinone red colorants include Pigment Red 168, 177, and 216, and Solvent Red 52, 149, 150, and 207. Quinacridone red colorants include Pigment Red 122, 202, 206, 207, and 209.

[0034] Examples of blue colorants include phthalocyanine-based compounds, and examples of pigment-based compounds include compounds classified as pigments, such as Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, and 16. Examples of dye-based compounds that can be used include Solvent Blue 35, 63, 67, 68, 70, 83, 87, 94, 97, 122, and 136. In addition to the above, metal-substituted or unsubstituted phthalocyanine compounds can also be used.

[0035] Examples of yellow colorants include monoazo, disazo, condensed azo, benzimidazolone, and isoindolinone pigments. 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.

[0036] In addition, colorants such as purple, orange, brown, black, and white may be added. Specific examples include C.I. Pigment Black 1, 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, perylene black, titanium black, zirconium nitride, lactone black, and titanium oxide.

[0037] [1-2. (B) Alkali-Soluble Resin] The photosensitive resin composition according to this embodiment contains (B) an alkali-soluble resin. The alkali-soluble resin (B) is not particularly limited, and any known or commonly used resin may be used as long as it is alkali-soluble. Examples of the alkali-soluble resin (B) 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 from the viewpoint of excellent developability, and carboxyl group-containing resins are more preferred. The carboxyl group-containing resin may be a carboxyl group-containing photosensitive resin having an ethylenically unsaturated group, or a carboxyl group-containing resin not having an ethylenically unsaturated group. The alkali-soluble resin (B) may be used alone or in combination of two or more. By including the alkali-soluble resin (B) in the photosensitive resin composition, it becomes easier to form a pattern by alkaline development of the resin layer formed from the photosensitive resin composition.

[0038] Specific examples of the carboxyl group-containing resin include the compounds (which may be either oligomers or polymers) listed below.

[0039] (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.

[0040] (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 phenolic hydroxyl groups and alcoholic hydroxyl groups.

[0041] (3) Carboxylic acid group-containing photosensitive 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, carboxyl group-containing dialcohol compounds, and diol compounds.

[0042] (4) A carboxyl group-containing photosensitive urethane resin having a terminal (meth)acrylate formed 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).

[0043] (5) A carboxyl group-containing photosensitive 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).

[0044] (6) A carboxyl group-containing photosensitive 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 group present in the side chain.

[0045] (7) A carboxyl group-containing photosensitive 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.

[0046] (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.

[0047] (9) A carboxyl group-containing photosensitive 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.

[0048] (10) A carboxyl group-containing photosensitive 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.

[0049] (11) A carboxyl group-containing photosensitive 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.

[0050] (12) A carboxyl group-containing photosensitive 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).

[0051] 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 resins containing two or more phenolic hydroxyl groups per molecule include phenolic resins synthesized using catechol, resorcinol, hydroquinone, dihydroxytoluene, naphthalenediol, t-butylcatechol, t-butylhydroquinone, pyrogallol, phloroglucinol, bisphenol A, bisphenol F, bisphenol S, biphenol, bixylenol, or the like; novolac-type phenolic resins; novolac-type alkylphenolic resins; novolac resins of bisphenol A; dicyclopentadiene-type phenolic resins; Xylok-type phenolic resins; terpene-modified phenolic resins; polyvinylphenols; condensates of phenols and aromatic aldehydes having a phenolic hydroxyl group; and condensates of 1-naphthol or 2-naphthol and aromatic aldehydes, but are not limited to these.

[0052] From the viewpoint of improving the alkali developability of the photosensitive resin composition, the acid value of the alkali-soluble resin is preferably 20 to 180 mgKOH / g, more preferably 30 to 150 mgKOH / g, and even more preferably 40 to 120 mgKOH / g.

[0053] From the viewpoint of film-forming ability, the weight-average molecular weight of the alkali-soluble resin is preferably 3,000 to 30,000, more preferably 5,000 to 20,000, and even more preferably 7,000 to 15,000. The weight-average molecular weight can be determined from a standard polystyrene-equivalent value by gel permeation chromatography (GPC).

[0054] The content of the alkali-soluble resin in the photosensitive resin composition is preferably 10 to 80 parts by mass, more preferably 15 to 70 parts by mass, and even more preferably 20 to 60 parts by mass, relative to 100 parts by mass of the total solid content in the photosensitive resin composition.

[0055] [1-3. (C) Photopolymerization initiator] The photosensitive resin composition according to this embodiment contains (C) a photopolymerization initiator. The (C) photopolymerization initiator is not particularly limited, and any known or commonly used photopolymerization initiator can be used. One type of photopolymerization initiator may be used alone, or two or more types may be used in combination.

[0056] Examples of the photopolymerization initiator include α-aminoacetophenone-based photopolymerization initiators such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone, and N,N-dimethylaminoacetophenone; 1-hydroxy-cyclohexyl phenyl ketone, 1-[4-( hydroxyacetophenone-based photopolymerization initiators such as 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 2-hydroxy-2-methyl-1-phenylpropan-1-one; bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, and the like; Sphingoxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,4,6-trimethyl acylphosphine oxide photopolymerization initiators such as 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphine acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, pivaloylphenylphosphinic acid isopropyl ester, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide;Benzoin-based photopolymerization initiators such as benzoin, benzil, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, and benzoin n-butyl ether; benzoin alkyl ether-based photopolymerization initiators; benzophenone-based photopolymerization initiators such as benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, and 4,4'-bisdiethylaminobenzophenone; acetophenone-based photopolymerization initiators such as acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, and 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone; thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, and 2,4- Thioxanthone-based photopolymerization initiators such as diethylthioxanthone, 2-chlorothioxanthone, and 2,4-diisopropylthioxanthone; anthraquinone-based photopolymerization initiators such as anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, and 2-aminoanthraquinone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzoic acid ester-based photopolymerization initiators such as ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate, and p-dimethylbenzoic acid ethyl ester; 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); bis(η; ５and titanocene photopolymerization initiators such as bis(2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium and bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyr-1-yl)ethyl)phenyl]titanium. The photopolymerization initiators may be used alone or in combination of two or more. When two or more of the photopolymerization initiators are used in combination, the method of combining the photopolymerization initiators is not particularly limited. For example, it is preferable to use two or more photopolymerization initiators selected from the group consisting of α-aminoacetophenone-based polymerization initiators, acylphosphine oxide-based photopolymerization initiators, and titanocene-based photopolymerization initiators in combination, it is more preferable to use two or more photopolymerization initiators selected from the group consisting of α-aminoacetophenone-based polymerization initiators and titanocene-based photopolymerization initiators in combination, and it is even more preferable to select and use one or more α-aminoacetophenone-based polymerization initiators and one or more titanocene-based photopolymerization initiators in combination.

[0057] Commercially available α-aminoacetophenone-based photopolymerization initiators include, for example, Omnirad 907, 369, 369E, and 379 manufactured by IGM Resins. Commercially available acylphosphine oxide-based photopolymerization initiators include, for example, Omnirad 819 manufactured by IGM Resins. Commercially available titanocene-based photopolymerization initiators include, for example, JMT-784 manufactured by Yueyang Kimoutain Sci-tech Co., Ltd.

[0058] The amount of photopolymerization initiators, excluding oxime ester photopolymerization initiators, blended is preferably 0.5 to 10 parts by mass per 100 parts by mass of the total solid content in the photosensitive resin composition. When the amount is 0.5 parts by mass or more, the photocurability of the photosensitive resin composition is improved, the cured product is less likely to peel, and coating properties such as chemical resistance are also improved. On the other hand, when the amount is 10 parts by mass or less, the effect of reducing outgassing is achieved, and further, light absorption at the surface of the resin layer is improved, and deep curing properties are less likely to decrease. More preferably, it is 0.8 to 8 parts by mass. Furthermore, the amount of oxime ester photopolymerization initiator blended is preferably 0.1 to 5 parts by mass per 100 parts by mass of the total solid content in the photosensitive resin composition. When the amount is 0.1 part by mass or more, the photocurability of the photosensitive resin composition is improved, and coating properties such as heat resistance and chemical resistance are also improved. On the other hand, when the amount is 5 parts by mass or less, light absorption at the surface of the resin layer is improved, and deep curing properties are less likely to decrease. More preferably, it is 0.5 to 3 parts by mass.

[0059] [1-4. (D) Photopolymerizable Monomer] The photosensitive resin composition according to this embodiment contains (D) a photopolymerizable monomer. The (D) photopolymerizable monomer may be any monomer having an ethylenically unsaturated double bond in the molecule, and any known or commonly used monomer may be used.

[0060] Examples of photopolymerizable monomers include polyester (meth)acrylate, polyether (meth)acrylate, urethane (meth)acrylate, carbonate (meth)acrylate, and epoxy (meth)acrylate. Specific examples include alkyl acrylates such as 2-ethylhexyl acrylate and cyclohexyl acrylate; hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; mono- or diacrylates of alkylene oxide derivatives such as ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol; acrylamides such as N,N-dimethylacrylamide, N-methylolacrylamide, and N,N-dimethylaminopropylacrylamide; aminoalkyl acrylates such as N,N-dimethylaminoethyl acrylate and N,N-dimethylaminopropyl acrylate; and polyols such as hexanediol, trimethylolpropane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, and trishydroxyethyl isocyanurate. Examples of suitable photopolymerizable monomers include polyhydric acrylates derived from hydroxyl alcohols or their alkylene oxide adducts or ε-caprolactone adducts; polyhydric acrylates such as phenols such as phenoxy acrylate and bisphenol A diacrylate or their alkylene oxide adducts; acrylates derived from glycidyl ethers such as glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, and triglycidyl isocyanurate; and, without limitation, acrylates and melamine acrylates obtained by directly acridating polyols such as polyether polyols, polycarbonate diols, hydroxyl-terminated polybutadienes, and polyester polyols or by urethane acrylate via diisocyanates, as well as methacrylates corresponding to the above acrylates. Such photopolymerizable monomers can also be used as photopolymerizable monomers.

[0061] The photopolymerizable monomer may be used alone or in combination of two or more. The amount of the photopolymerizable monomer is preferably 10 to 60 parts by mass relative to 100 parts by mass of the total solid content in the photosensitive resin composition. When the amount is 10 parts by mass or more, the photocurability is good and pattern formation is easy in alkaline development after irradiation with active energy rays. On the other hand, when the amount is 60 parts by mass or less, halation is less likely to occur and good resolution can be obtained.

[0062] [1-5. Optional Components] The photosensitive resin composition according to this embodiment may contain a thermosetting component, an inorganic filler, an antifoaming agent, other additive components, and the like.

[0063] [1-5-1. Thermosetting Component] The thermosetting component used in the photosensitive resin composition according to this embodiment is not particularly limited, and any known or commonly used component may be used, such as an epoxy resin, a triazine resin, a phenolic resin, or a polyester resin. An epoxy resin is preferably used. One type of thermosetting component may be used alone, or two or more types may be used in combination.

[0064] As the epoxy resin, an epoxy resin having two or more epoxy groups in the molecule can be used, and examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenol type epoxy resin, hydroquinone type epoxy resin, bisphenol fluorene type epoxy resin, naphthalene diol type epoxy resin, bisphenol S type epoxy resin, bisthioether type epoxy resin, resorcinol type epoxy resin, hydrogenated bisphenol A type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, and alkyl novolac type epoxy resin.

[0065] Commercially available epoxy resins include, for example, "jER828", "jER834", "jER1001", and "jER1004" manufactured by Mitsubishi Chemical Corporation; "Epicron 840", "Epicron 850", "Epicron 1050", and "Epicron 2055" manufactured by DIC Corporation; Epotohto "YD-011", "YD-013", "YD-127", and "YD-128" manufactured by Nippon Steel Chemical & Material Co., Ltd.; "D.E.R.317", "D.E.R.331", "D.E.R.661", and "D.E.R.664" manufactured by Dow Chemical Company; Sumi-Epoxy "ESA-011", "ESA-014", "ELA-115", and "ELA-128" manufactured by Sumitomo Chemical Co., Ltd.; and "A.E.R.330" and "A.E.R.33" manufactured by Asahi Chemical Industry Co., Ltd. 1", "A.E.R.661", "A.E.R.664", and other bisphenol A type epoxy resins; "JER152" and "jER154" manufactured by Mitsubishi Chemical Corporation, "D.E.N.431" and "D.E.N.438" manufactured by Dow Chemical Company, "Epicron N-730", "Epicron N-770", and "Epicron N-865" manufactured by DIC Corporation, Epotohto "YDCN-701" and "YDCN-704" manufactured by Nippon Steel Chemical & Material Co., Ltd., "EPPN-201", "EOCN-1025", "EOCN-1020", "EOCN-104S", "RE-306", and "NC-3000H" manufactured by Nippon Kayaku Co., Ltd., Sumi-Epoxy "ESCN-195X" and "ESCN-220" manufactured by Sumitomo Chemical Co., Ltd., and A. Novolac type epoxy resins such as "ECN-235" and "ECN-299" manufactured by E.R.; bisphenol F type epoxy resins such as "Epicron 830" manufactured by DIC Corporation, "jER807" manufactured by Mitsubishi Chemical Corporation, and Epotohto "YDF-170", "YDF-175", and "YDF-2004" manufactured by Nippon Steel Chemical & Material Co., Ltd.; trisphenol type epoxy resins such as "TECHMORE VG3101L" manufactured by Printec Co., Ltd.; hydrogenated bisphenol A type epoxy resins such as Epotohto "ST-2004", "ST-2007", "ST-3000", "ST-4000D", and "ST-6100" manufactured by Nippon Steel Chemical & Material Co., Ltd.;Glycidylamine type epoxy resins such as "jER604" manufactured by Mitsubishi Chemical Corporation, Epotohto "YH-434" manufactured by Nippon Steel Chemical & Material Co., Ltd., and Sumi-Epoxy "ELM-120" manufactured by Sumitomo Chemical Co., Ltd.; hindatoin type epoxy resins; alicyclic epoxy resins such as "Celloxide 2021P" manufactured by Daicel Corporation and "CY179" manufactured by Huntsman Advanced Materials; trichloroethylene resins such as "YL-933" manufactured by Mitsubishi Chemical Corporation, and "T.E.N.", "EPPN-501", and "EPPN-502" manufactured by The Dow Chemical Company; Hydroxyphenylmethane type epoxy resins; bixylenol type or biphenol type epoxy resins or mixtures thereof, such as "YL-6056," "YX-4000," and "YL-6121" manufactured by Mitsubishi Chemical Corporation; bisphenol S type epoxy resins, such as "EBPS-200" manufactured by Nippon Kayaku Co., Ltd., "EPX-30" manufactured by ADEKA Corporation, and "EXA-1514" manufactured by DIC Corporation; bisphenol A novolac type epoxy resins, such as "jER157S" manufactured by Mitsubishi Chemical Corporation; and "jERYL-931" manufactured by Mitsubishi Chemical Corporation. tetraphenylolethane type epoxy resins such as "TEPIC" manufactured by Nissan Chemical Industries, Ltd.; heterocyclic epoxy resins such as "TEPIC" manufactured by Nissan Chemical Industries, Ltd.; diglycidyl phthalate resins such as "BLEMMER DGT" manufactured by NOF Corporation; tetraglycidylxylenoylethane resins such as "ZX-1063" manufactured by Nippon Steel Chemical & Material Co., Ltd.; naphthalene group-containing epoxy resins such as "ESN-190" and "ESN-360" manufactured by Nippon Steel Chemical & Material Co., Ltd., and "HP-4032", "EXA-4750", and "HP-4700" manufactured by DIC Corporation; and "HP-7" manufactured by DIC Corporation. Epoxy resins having a dicyclopentadiene skeleton, such as "200" and "HP-7200H"; special-function epoxy resins, such as "890", "YL6810", "1750", "YX7700", "YX8000", "YX8034", "YX8800", "YL980", "YL983U", "YX7400N", "YX7105", "YX7110B80", and "YX7760", manufactured by Mitsubishi Chemical Corporation; flexible and tough epoxy resins, such as "EXA-4816", "EXA-4822", and "EXA-4850" series manufactured by DIC Corporation;Examples include glycidyl methacrylate copolymer epoxy resins such as "CP-50S" and "CP-50M" manufactured by NOF Corporation; and further examples include copolymer epoxy resins of cyclohexylmaleimide and glycidyl methacrylate.

[0066] The amount of the thermosetting component to be blended is preferably 5 to 50 parts by mass, and more preferably 10 to 40 parts by mass, per 100 parts by mass of the total solid content in the photosensitive resin composition.

[0067] [1-5-2. Inorganic filler] The inorganic filler used in the photosensitive resin composition according to this embodiment is not particularly limited, and known and commonly used inorganic fillers can be used. These inorganic fillers may be used alone or in combination of two or more.

[0068] Examples of inorganic fillers include talc, silica, kaolin, montmorillonite, synthetic mica, hydrotalcite, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, gold, aluminum, copper, and nickel.

[0069] The shape of the inorganic filler is not particularly limited, and examples thereof include spherical, fibrous, plate-like, amorphous, and balloon-like shapes. The average particle size of the inorganic filler is also not particularly limited, and examples thereof include those having a particle size of 0.01 to 3.0 μm. Furthermore, the inorganic filler may be subjected to various surface treatments, such as an insulating treatment or a high-dispersibility treatment, as needed.

[0070] The inorganic filler used in this embodiment is preferably one selected from the group consisting of barium sulfate, hydrotalcite, talc, and silica, from the viewpoint of improving the adhesion of the cured product obtained by curing the photosensitive resin composition after leveling treatment or gold plating treatment.

[0071] The amount of the inorganic filler to be blended is preferably 15 to 70 parts by mass, more preferably 20 to 60 parts by mass, even more preferably 25 to 55 parts by mass, and particularly preferably 30 to 50 parts by mass, relative to 100 parts by mass of the total solid content in the photosensitive resin composition.

[0072] [1-5-3. Antifoaming Agent] The antifoaming agent used in this embodiment is not particularly limited, and any known or commonly used agent can be used. Among these, silicone-based or acrylic copolymer-based antifoaming agents can be preferably used.

[0073] Commercially available silicone-based defoaming agents include, for example, BYK-322 and BYK-333 manufactured by BYK Corporation, and KS-66 manufactured by Shin-Etsu Chemical Co., Ltd. Commercially available acrylic copolymer-based defoaming agents include, for example, BYK-361N, BYK-1794, BYK-350, and BYK-1791 manufactured by BYK Corporation.

[0074] The amount of the antifoaming agent to be added is not particularly limited, and can be set to 0.1 to 10 parts by mass per 100 parts by mass of the total solid content in the photosensitive resin composition.

[0075] [1-5-4. Other Additive Components] The photosensitive resin composition according to this embodiment may further contain, as necessary, components such as organic solvents, photopolymerization initiator aids, cyanate compounds, elastomers, mercapto compounds, curing catalysts, polymerization inhibitors, thixotropic agents, adhesion promoters, block copolymers, chain transfer agents, copper inhibitors, antioxidants, rust inhibitors, thickeners such as organic bentonite and montmorillonite, silane coupling agents such as imidazoles, thiazoles, and triazoles, and flame retardants such as phosphorus compounds such as phosphinates, phosphate ester derivatives, and phosphazene compounds. These may be compounds known in the field of electronic materials.

[0076] [2. Dry Film] The photosensitive resin composition according to this embodiment 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 photosensitive resin composition. In this embodiment, the first film 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 this embodiment, it is particularly preferable to peel from the resin layer in a post-exposure step. To form a dry film, the photosensitive resin composition according to this embodiment is diluted with the organic solvent to adjust the viscosity to an appropriate level, 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 10 to 60 μm, in terms of the thickness after drying.

[0077] 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.

[0078] From the viewpoint of improving mechanical strength, the thermoplastic resin film as described above is preferably a film stretched in a uniaxial or biaxial direction.

[0079] The thickness of the first film is not particularly limited, but can be, for example, 10 μm to 150 μm.

[0080] After forming a resin layer of the photosensitive resin composition according to this embodiment 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 this embodiment refers to a film that is peeled from the photosensitive resin layer before lamination when the resin layer side of the photosensitive film laminate is laminated onto a substrate or other base material by heating or the like to be in contact with the substrate and integrally molded. Examples of the peelable second film include polyethylene film, polytetrafluoroethylene film, polypropylene film, and surface-treated paper, and any film may 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.

[0081] The thickness of the second film is not particularly limited, but can be, for example, 10 μm to 150 μm.

[0082] In this embodiment, the photosensitive resin composition according to this embodiment may be applied to the second film and dried to form a resin layer, and the first film may be laminated on the surface of the resin layer. That is, in this embodiment, when producing a dry film, either the first film or the second film may be used as the film to which the photosensitive resin composition according to this embodiment is applied.

[0083] [3. Cured Product] When forming a cured product using the photosensitive resin composition according to this embodiment, the photosensitive resin composition is applied to a substrate, and the organic solvent is evaporated and dried to obtain a resin layer. The resulting resin layer is then exposed (irradiated with light), thereby curing the exposed portions (irradiated portions). Specifically, a resist pattern is formed by selectively exposing the resin to active energy rays through a photomask on which a pattern has been formed using a contact or non-contact method, or by directly exposing the pattern using a laser direct exposure machine, and developing the unexposed portions with an alkaline aqueous solution (e.g., a 0.3 to 3% by weight sodium carbonate aqueous solution). In the case of a dry film, after exposure, the first film is peeled from the dry film and developed to form a patterned cured product on the substrate. The first film may be peeled from the dry film before exposure, and the exposed resin layer may be exposed and developed, provided that this does not impair the properties of the resin layer. Furthermore, by subjecting the cured product to irradiation with active energy rays and then heat curing (for example, at 100 to 220°C), or by subjecting the cured product to heat curing and then irradiating it with active energy rays, or by subjecting the cured product to heat curing alone for final finish curing (main curing), it is possible to form a cured product that has excellent solder heat resistance, gold plating resistance, and insulation reliability.

[0084] The photosensitive resin composition according to this embodiment can be adjusted to a viscosity suitable for the coating method using an organic solvent, and applied to a substrate by a method such as an inkjet method, a dip coating method, a flow coating method, a roll coating method, a bar coater method, a screen printing method, or a curtain coating method, and then the organic solvent contained in the composition is evaporated and dried at a temperature of about 60 to 100°C, thereby forming a tack-free resin layer.

[0085] Examples of substrates 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 from materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / nonwoven cloth epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, fluororesin / polyethylene / polyphenylene ether, polyphenylene oxide / cyanate, and the like, including copper-clad laminates of all grades (FR-4, etc.), as well as metal substrates, polyimide films, PET films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafer plates, etc.

[0086] The volatilization drying or thermal curing can be carried out using a hot air circulation drying oven, an IR oven, a hot plate, a convection oven, or the like (a method in which hot air in a dryer equipped with a heat source of an air heating type 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).

[0087] When using a dry film according to another embodiment, a resin layer can be formed on a substrate by laminating the dry film to the substrate using a laminator or the like so that the resin layer comes into contact with the substrate. The lamination of the dry film to the substrate is preferably performed under pressure and heat using a vacuum laminator or the like. By using such a vacuum laminator, even if a circuit-formed substrate is used, the dry film adheres to the circuit board even if the circuit board surface is uneven, preventing the inclusion of air bubbles and improving the filling of recesses in the substrate surface. The pressure conditions are preferably about 0.1 to 2.0 MPa, and the heating conditions are preferably 40 to 120°C.

[0088] 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 active energy rays in the range of 350 to 450 nm. 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 410 nm. The exposure dose for image formation varies depending on factors such as the film thickness, but is generally 20 to 1,000 mJ / cm. ２ is preferably 20 to 800 mJ / cm ２ The range may be:

[0089] 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.

[0090] [4. Printed Wiring Board] The photosensitive resin composition or dry film resin layer according to this embodiment can be suitably used to form a surface protection film such as a solder resist on a printed wiring board. The photosensitive resin composition according to this embodiment may also be used as an interlayer insulating layer in a multilayer printed wiring board.

[0091] By applying the photosensitive resin composition or the resin layer of the dry film according to this embodiment to a substrate of a printed wiring board or the like and curing it, a printed wiring board can be produced that has a cured product that is excellent in solder heat resistance, gold plating resistance, and insulation reliability.

[0092] EXAMPLES The present invention will be specifically explained below by showing examples, but the present invention is not limited to these examples.

[0093] [1. Synthesis of Alkali-Soluble Resin] 1070 g of orthocresol novolac epoxy resin (EPICLON N-695, manufactured by DIC Corporation, softening point 95°C, epoxy equivalent 214, average functionality 7.6) was added to 650 parts by mass of diethylene glycol monoethyl ether acetate, and the mixture was heated to 100°C with stirring to achieve a homogeneous solution. Next, 4.3 parts by mass of triphenylphosphine was added, heated to 110°C, and reacted for 2 hours. An additional 1.6 parts by mass of triphenylphosphine was then added, and the mixture was heated to 120°C and reacted for an additional 12 hours. 525 g of aromatic hydrocarbon (T-Sol 150, manufactured by Standard Oil Corporation, Osaka Sales Office) and 608 g (4.0 mol) of tetrahydrophthalic anhydride were added to the resulting reaction solution, and the mixture was reacted at 110°C for 4 hours. Furthermore, 142.0 g of glycidyl methacrylate was added to the obtained reaction solution, and the reaction was carried out for 4 hours at 115° C. In this way, a solution of an alkali-soluble resin having a solid content of 65% and an acid value of the solid content of 77 mgKOH / g was obtained.

[0094] [2. Preparation of Test Photosensitive Resin Compositions] A colorant, an alkali-soluble resin, a photopolymerization initiator, a photopolymerizable monomer, a thermosetting component, an inorganic filler, and an antifoaming agent were blended in the amounts (unit: parts by mass) shown in Table 1, premixed by stirring, and then kneaded in a three-roll mill to prepare test photosensitive resin compositions of Examples 1 to 5 and Comparative Examples 1 and 2.

[0095] The details of each component listed in Table 1 are as follows: The amount of each component is expressed as a solid content value. <(A) Colorant> Paliogen Blue L6480 (manufactured by BASF): an anthraquinone-based blue pigment FA5380 (manufactured by DIC Corporation): a phthalocyanine-based blue pigment Pigment Blue 80: a benzimidazolone-dioxazine-based blue pigment Chromophthal Yellow S1515 (manufactured by BASF): an anthraquinone-based yellow pigment Paliogen Red K3580 (manufactured by BASF, C.I. Pigment Red 149): a perylene-based red pigment MA-100 (manufactured by Mitsubishi Chemical Corporation): carbon black <(B) Alkali-soluble Resin> *1: The alkali-soluble resin synthesized above (carboxyl group-containing photosensitive resin) <(C) Photopolymerization Initiator> Omnirad 379 (manufactured by IGM Resins): 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one JMT-784 (manufactured by Yueyang Kimoutain Sci-tech Co., Ltd.): bis(η ５ -2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium <(D) Photopolymerizable Monomer> A-9550 (manufactured by Shin-Nakamura Chemical Co., Ltd.): dipentaerythritol polyacrylate <Thermosetting Component> N-870 (manufactured by DIC Corporation): bisphenol A novolac epoxy resin (epoxy equivalent 205) <Inorganic Filler> B-30 (manufactured by Sakai Chemical Industry Co., Ltd.): barium sulfate ACEMATT82 (manufactured by EVONIK DEGUSSA): silica LMP-100 (manufactured by Fuji Talc Co., Ltd.): talc <Antifoaming Agent> KS-66 (manufactured by Shin-Etsu Chemical Co., Ltd.): silicone-based antifoaming agent BYK-1791 (manufactured by BYK): acrylic copolymer-based antifoaming agent

[0096]

[0097] [3. Evaluation of solder dam shape] As a pretreatment, a circuit pattern substrate with a copper thickness of 33 μm was subjected to a copper surface roughening treatment (MEC Etch Bond™ CZ-8101B manufactured by MEC Co., Ltd.) to etch the substrate to a depth equivalent to 1.0 μm. Next, the test photosensitive resin compositions of Examples 1 and 2 and Comparative Examples 1 and 2 were applied to the entire surface of the substrate by screen printing so that the dry film thickness was 30 μm, and the coating was dried for 30 minutes in a hot air circulation drying oven at 80°C. After drying, the coating was exposed using a high-pressure mercury lamp exposure device. The exposure pattern used was a pattern that drew 100 μm lines in the space areas. In Examples 1 and 4, the exposure dose was 400 mJ / cm ２ In Examples 2, 3 and 5, the exposure dose was 200 mJ / cm ２ The resist was then exposed to light using an exposure device so that the resist pattern was formed, followed by development using an aqueous solution of sodium carbonate (30°C, 0.2 MPa, 1 wt% aqueous solution of sodium carbonate) to form a pattern. The resist was then thermally cured at 150°C for 60 minutes to obtain a cured product.

[0098] A cross section of the cured solder dam with a line width of 100 μm was observed using an optical microscope, and the line width below the solder dam was calculated by subtracting the line width above the solder dam from the line width below the solder dam, and the evaluation was based on the following criteria. The results are shown in Table 1. ○: When the absolute value of the value obtained by subtracting the line width below the solder dam from the line width above the solder dam is 20 μm or less ×: When the absolute value of the value obtained by subtracting the line width below the solder dam from the line width above the solder dam is more than 20 μm

[0099] The results in Table 1 show that when a photosensitive resin composition containing a phthalocyanine blue pigment as a colorant is cured, as in Comparative Example 1, the resolution is unfavorable. This is thought to be due to the fact that when a phthalocyanine blue pigment is used, the amount of light transmitted during photocuring is reduced. On the other hand, when a photosensitive resin composition containing an anthraquinone blue pigment or a benzimidazolone-dioxazine blue pigment as a colorant is cured, as in Examples 1 to 5 and Comparative Example 2, the resolution is good. This is thought to be due to the fact that the above blue pigments have particularly good light transmittance at a wavelength of 365 nm.

[0100] [4. Evaluation of Concealing Property] As a pretreatment, a copper solid substrate with a copper thickness of 18 μm was subjected to etching equivalent to 1.0 μm using a copper surface roughening treatment (MEC Etch Bond™ CZ-8101B manufactured by MEC Co., Ltd.) Next, the test photosensitive resin compositions of Examples 1 to 5 and Comparative Examples 1 and 2 were applied to the entire surface of the substrate by screen printing so as to give dry film thicknesses of 10 μm and 20 μm, and then dried for 30 minutes in a hot air circulation drying oven at 80° C.

[0101] The appearance color of the solder resist layer on the copper foil was measured using a spectrophotometer CM-2600d (manufactured by Konica Minolta Japan Inc.) and expressed as a ＊ was quantified. ＊ The value was measured under the condition of including total reflected light in accordance with JIS Z 8792. The surface of the copper surface-roughened solid copper substrate was measured using a spectrophotometric colorimeter CM-2600d (manufactured by Konica Minolta Japan, Inc.), and the L ＊ , a ＊ and b ＊ The values ​​were calculated. ＊ , a ＊ and b ＊ The value was measured in accordance with JIS Z 8792 under conditions including total reflection light, and ＊ = 60, a ＊ = 21, b ＊ Here, the a of the copper substrate ＊ The numerical value of is 21, which shows that the copper solid board has a reddish tint. When the solder resist layer is thinned, if the concealing ability of the solder resist layer is low, it will be affected by the reddish tint of the underlying copper solid board, and compared to the case where there is only a solder resist layer, the solder resist layer on the copper solid board will have a reddish tint. ＊ Therefore, the value of a of the solder resist layer on the copper solid board changes to the positive side before and after thinning the solder resist layer on the copper solid board. ＊By measuring the change in the value of a, it is possible to evaluate the degree to which the solder resist layer is affected by the redness of the underlying copper solid board, and the concealing ability of the solder resist layer. ＊ From the value, the a of the solder resist layer of 10 μm thickness on the copper foil ＊ The absolute value Δa of the value obtained by subtracting the value ＊ The values ​​were measured, and the degree of influence of the copper color of the base and the hiding power when the solder resist layer was thinned were evaluated according to the following criteria. The results are shown in Table 1. ＊ Value is 1.0 or less ×: Δa ＊ Value is greater than 1.0

[0102] From the results in Table 1, it can be seen that when a photosensitive resin composition containing a benzimidazolone-dioxazine blue pigment as a colorant is cured as in Comparative Example 2, when the film thickness of the solder resist is thinned, ＊ There is a tendency for the value of Δa to increase. ＊ was greater than 1.0. This is thought to be due to the fact that when the thickness of the solder resist is reduced, the hiding power of the solder resist layer is insufficient, and the color of the underlying copper has a strong influence. On the other hand, when a photosensitive resin composition containing an anthraquinone blue pigment or a phthalocyanine blue pigment as a colorant is cured as in Examples 1 to 5 and Comparative Example 1, Δa ＊ The value was 1.0 or less. This is thought to be because the use of the blue pigment can sufficiently conceal the color of the underlying copper foil, making it less susceptible to its influence, even when the solder resist film thickness is thin.

Claims

1. (A) a colorant; (B) an alkali-soluble resin; (C) a photopolymerization initiator; (D) a photopolymerizable monomer; A photosensitive resin composition comprising: The colorant (A) contains at least one of an anthraquinone blue pigment and carbon black, and an anthraquinone yellow pigment and a perylene red pigment. Photosensitive resin composition.

2. 2. The photosensitive resin composition according to claim 1, wherein the anthraquinone blue pigment is contained in an amount of 0.01 to 5 parts by mass per 100 parts by mass of solids in the photosensitive resin composition.

3. A dry film comprising a first film and a resin layer formed on the first film, the resin layer comprising a dried coating of the photosensitive resin composition according to claim 1 or 2.

4. A cured product obtained by curing the photosensitive resin composition according to claim 1 or 2.

5. A printed wiring board comprising the cured product according to claim 4.