Curable resin composition, dry film, cured product, and electronic component

Abstract

Provided are: a curable resin composition comprising an alkali-soluble resin (A), a photopolymerization initiator (B), a heat-curable compound (C), a triazine compound (D), and silica (E), wherein the triazine compound (D) is a compound having a heteroatom-containing group (1) and a photoreactive group (2) on the triazine skeleton and the silica (E) is contained in an amount of 20-70 mass% in terms of solid amount based on the whole curable resin composition; a cured object obtained from the curable resin composition; and an electronic component including the cured object.

Description

Curable resin composition, dry film, cured product, and electronic component

[0001] The present invention relates to a curable resin composition, a dry film, a cured product, and an electronic component.

[0002] In recent years, rapid advances in semiconductor components have led to a trend toward lighter, thinner, smaller, higher performance, and more multi-functional electronic devices. Following this trend, semiconductor packages are becoming smaller and have more pins.

[0003] Specifically, IC packages called BGA (ball grid array), CSP (chip scale package), etc. are being used in place of IC packages called QFP (quad flat pack package), SOP (small outline package), etc. In addition, in recent years, FC-BGA (flip chip ball grid array) has also been put to practical use as an even higher density IC package.

[0004] In printed wiring boards used in these IC packages, the amount of heat generated by the chips tends to increase due to increased chip area, higher packaging density, etc. Therefore, a high level of heat resistance is required for the solder resist. In order to improve this heat resistance, it has been proposed to include a predetermined inorganic filler, an alkali-soluble resin, a thermosetting component (epoxy resin), etc. in the curable resin composition that forms the solder resist (Patent Document 1, etc.).

[0005] When manufacturing a printed wiring board, electroless gold plating is applied to the conductor pads formed in the solder resist openings. Printed wiring boards treated in this manner have a problem in that discoloration (haloing) occurs around the solder resist openings after the electroless gold plating process. To solve the problem of the haloing phenomenon, a method has been proposed in which melamine is added to a curable resin composition forming the solder resist (Patent Document 2).

[0006] JP 2022-009428 A JP 2012-17444 A

[0007] Solder resist, particularly solder resist for the FC-BGA, is required to have a high level of heat resistance. However, even if the above characteristics are satisfied, when the curable resin composition forming the solder resist is applied to a dry film, the melt viscosity of the resin composition increases, which can cause air to be trapped between the substrate and the resin composition during thermocompression bonding to the substrate, resulting in lamination defects such as the generation of air bubbles.

[0008] Furthermore, in printed wiring boards, the problem of haloing occurring around solder resist openings after electroless gold plating can be solved by adding melamine to the curable resin composition, but adding melamine increases the melt viscosity of the resin layer of the dry film. Thus, with conventional curable resin compositions, it has been difficult to achieve both excellent lamination properties when applied to a dry film and excellent thermal properties (low thermal expansion coefficient) and haloing resistance when made into a solder resist (cured product).

[0009] Therefore, an object of the present invention is to provide a curable resin composition that, when applied to a dry film, can maintain a low melt viscosity of the resin layer, does not cause lamination defects when forming the resin layer on a substrate, and produces a cured product having excellent thermal properties (low thermal expansion coefficient) and haloing resistance. Furthermore, an object of the present invention is to provide a dry film having a resin layer obtained from the curable resin composition, a cured product of the curable resin composition or the resin layer of the dry film, and an electronic component having the cured product.

[0010] The present inventors have conducted extensive research to achieve the above object. As a result, they have found that by including a triazine compound having a predetermined chemical structure as a curing catalyst in a curable resin composition, even when a predetermined amount of silica is contained to improve thermal properties, an increase in the melt viscosity of the resin layer of the dry film forming the solder resist can be suppressed, and the occurrence of lamination defects can be effectively suppressed. They have also found that the occurrence of haloing can be suppressed in a cured product of a curable resin composition containing a triazine compound. Based on this finding, the present invention has been completed through further research.

[0011] That is, the present invention relates to the following curable resin compositions, dry films, cured products, and electronic components. Item 1. A curable resin composition containing an alkali-soluble resin (A), a photopolymerization initiator (B), a thermosetting compound (C), a triazine compound (D), and silica (E), wherein the triazine compound (D) is a compound having a heteroatom-containing group (1) and a photoreactive group (2) on a triazine skeleton, and the content of the silica (E) is 20 to 70 mass% in terms of solid content, based on the total amount of the curable resin composition. Item 2. The curable resin composition according to Item 1, wherein the heteroatom in the heteroatom-containing group (1) contained in the triazine compound (D) is a nitrogen atom or a sulfur atom. Item 3. The curable resin composition according to Item 1 or 2, wherein the photoreactive group (2) contained in the triazine compound (D) is a group containing an ethylenically unsaturated bond. Item 4. Item 5. The curable resin composition according to any one of Items 1 to 3, wherein the content of the triazine compound (D) is 0.1 to 5.0 mass% in terms of solid content, relative to the total amount of the curable resin composition. Item 6. The curable resin composition according to any one of Items 1 to 4, wherein the average particle size of the silica (E) is 0.1 to 1.0 μm. Item 7. A dry film comprising a first film and a resin layer formed from the curable resin composition according to any one of Items 1 to 5. Item 8. A cured product of the curable resin composition according to any one of Items 1 to 5, or the resin layer of the dry film according to Item 6. Item 9. An electronic component comprising the cured product according to Item 7.

[0012] 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 (e.g., (meth)acrylic acid, (meth)acryloyl). Furthermore, when a numerical range is expressed using "to," such as "A to B," this means "A or more and B or less," unless otherwise specified.

[0013] The curable resin composition of the present invention maintains a low melt viscosity when applied to a dry film, preventing lamination defects when forming a resin layer on a substrate. Furthermore, the cured product exhibits excellent thermal properties (small thermal expansion coefficient) and does not suffer from discoloration (haloing) around solder resist openings after electroless gold plating. Therefore, the curable resin composition of the present invention is suitable as a high-quality solder resist material for use in printed wiring boards on which IC packages such as FC-BGA are mounted.

[0014] As used herein, the singular forms (a, an, the, etc.) include both the singular and the plural unless otherwise specified herein or clearly contradictory in context. As used herein, "comprise" is a concept that also encompasses "consist essentially of" and "consist of."

[0015] The curable resin composition of the present invention contains an alkali-soluble resin (A), a photopolymerization initiator (B), a thermosetting compound (C), a triazine compound (D), and silica (E), wherein the triazine compound (D) is a compound having a heteroatom-containing group (1) and a photoreactive group (2) on a triazine skeleton, and the content of the silica (E) is 20 to 70 mass% in terms of solid content with respect to the total amount of the curable resin composition.

[0016] Each component of the curable resin composition of the present invention will be described below.

[0017] [Alkali-Soluble Resin (A)] The alkali-soluble resin (A) is a resin containing an alkali-soluble group in the molecule, and examples thereof include resins containing one or more alkali-soluble groups selected from the group consisting of phenolic hydroxyl groups and carboxyl groups. Specific examples include phenolic hydroxyl group-containing resins (particularly resins containing two or more phenolic hydroxyl groups), carboxyl group-containing resins, and resins containing phenolic hydroxyl groups and carboxyl groups.

[0018] From the viewpoints of developability, photocurability, development resistance, etc., the alkali-soluble resin (A) is preferably a carboxyl group-containing resin, and more preferably a resin containing two or more carboxyl groups. It is more preferable that the alkali-soluble resin (A) is a resin that further contains an ethylenically unsaturated group in addition to the carboxyl group. The ethylenically unsaturated group is preferably derived from acrylic acid, methacrylic acid, or a derivative thereof. Hereinafter, the carboxyl group-containing resin having such an ethylenically unsaturated group may be referred to as a "carboxyl group-containing photosensitive resin." It is also possible to use only a carboxyl group-containing resin that does not have an ethylenically unsaturated group as the alkali-soluble resin (A). When the carboxyl group-containing resin does not have an ethylenically unsaturated group, it is desirable to use a compound having multiple ethylenically unsaturated groups in its molecule, i.e., a photopolymerizable monomer, in combination with the carboxyl group-containing resin, as described below, to render the composition photocurable.

[0019] Specific examples of the alkali-soluble resin (A) include the compounds listed below. These compounds may be either oligomers or polymers. Examples of carboxyl group-containing resins include the following compounds: (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, isobutylene, etc.

[0020] (2) Carboxyl group-containing urethane resins obtained by 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.

[0021] (3) Carboxylic acid-containing urethane resins obtained by polyaddition reaction of a partially acid anhydride-modified product of a reaction product of a diisocyanate with a bifunctional epoxy resin such as bisphenol A epoxy resin, hydrogenated bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, bixylenol epoxy resin, or biphenol epoxy resin, and a monocarboxylic acid compound having an ethylenically unsaturated double bond such as (meth)acrylic acid, a carboxyl-containing dialcohol compound, and a diol compound.

[0022] (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).

[0023] (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).

[0024] (6) A carboxyl group-containing photosensitive resin obtained by reacting a difunctional or more polyfunctional epoxy resin with (meth)acrylic acid and adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the hydroxyl groups present in the side chains. Here, the difunctional or more polyfunctional epoxy resin is preferably solid.

[0025] (7) A carboxyl group-containing photosensitive resin obtained by reacting a polyfunctional epoxy resin in which the hydroxyl groups of a difunctional epoxy resin have been further epoxidized with epichlorohydrin with (meth)acrylic acid, and then adding a dibasic acid anhydride to the resulting hydroxyl groups. Here, the difunctional epoxy resin is preferably solid.

[0026] (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.

[0027] (9) A carboxyl group-containing photosensitive resin obtained by reacting an epoxy compound having two or more epoxy groups per molecule with a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group per 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 anhydride.

[0028] (10) A carboxyl group-containing photosensitive resin obtained by reacting a compound having two or more phenolic hydroxyl groups per molecule, such as bisphenol A, bisphenol F, bisphenol S, a novolac-type phenolic resin, poly-p-hydroxystyrene, a condensation product of naphthol and an aldehyde, or a condensation product of dihydroxynaphthalene and an aldehyde, with an alkylene oxide, such as ethylene oxide or propylene oxide, and then reacting the resulting reaction product with an unsaturated group-containing monocarboxylic acid, such as (meth)acrylic acid, and then reacting the resulting reaction product with a polybasic acid anhydride.

[0029] (11) A carboxyl group-containing photosensitive resin obtained by reacting a compound having two or more phenolic hydroxyl groups per 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.

[0030] (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 one or more resins selected from the group consisting of (1) to (11).

[0031] When the alkali-soluble resin (A) is a carboxyl group-containing resin, its acid value is preferably 40 to 150 mgKOH / g. By adjusting the acid value of the carboxyl group-containing resin to 40 mgKOH / g or more, alkaline development becomes favorable. Furthermore, by adjusting the acid value to 150 mgKOH / g or less, it becomes easier to draw a normal cured product pattern. More preferably, it is 50 to 130 mgKOH / g.

[0032] 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, it is a resin containing two or more phenolic hydroxyl groups per molecule. Examples of resins containing two or more phenolic hydroxyl groups per 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.

[0033] The weight-average molecular weight of the alkali-soluble resin (A) varies depending on the resin skeleton, but is generally preferably 1,500 to 150,000, and more preferably 2,000 to 100,000. By adjusting the weight-average molecular weight to 2,000 or more, tack-free performance and / or resolution can be improved. Furthermore, by adjusting the weight-average molecular weight to 150,000 or less, developability and / or storage stability can be improved. The weight-average molecular weight (Mw) can be determined from a standard polystyrene equivalent value by gel permeation chromatography (GPC).

[0034] The content of the alkali-soluble resin (A), calculated as solid content based on the total amount of the curable resin composition, is usually 15 to 60 mass%, preferably 20 to 60 mass%, and more preferably 20 to 40 mass%. By making it 15 mass% or more, preferably 20 mass% or more, the coating strength can be improved. Furthermore, by making it 60 mass% or less, the viscosity becomes favorable and the processability is improved.

[0035] [Photopolymerization initiator (B)] As the photopolymerization initiator (B), any known photopolymerization initiator that is widely used as a photopolymerization initiator, a photoradical generator, or the like can be used.

[0036] Examples of the photopolymerization initiator (B) 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-trimethylphenylphosphine oxide. bisacylphosphine oxides such as 2,6-dimethoxybenzoyldiphenylphosphine 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, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; monoacylphosphine oxides such as valoylphenylphosphinic acid isopropyl ester and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; 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-hydroxy-2-methyl- Hydroxyacetophenones such as 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; thioxanthones such as anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone anthraquinones such as acetophenone dimethyl ketal and 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)-, 2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime) 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, etc. The photopolymerization initiator (B) may be used alone or in combination of two or more.

[0037] The content of the photopolymerization initiator (B) is preferably 0.1 to 5.0 mass% in terms of solid content, more preferably 1.0 to 5.0 mass%, and even more preferably 1.0 to 3.5 mass%, relative to the total amount of the curable resin composition. Furthermore, the content of the photopolymerization initiator (B) is preferably 0.5 to 20 mass parts, more preferably 3 to 15 mass parts, relative to 100 mass parts of the alkali-soluble resin (A), in terms of solid content. When the content is 0.5 mass parts or more, good surface curability is achieved, and when the content is 20 mass parts or less, halation is less likely to occur and good resolution can be achieved.

[0038] [Thermosetting Compound (C)] The curable resin composition of the present invention contains a thermosetting compound (C). The thermosetting compound (C) improves the heat resistance of the cured product and also improves adhesion to the substrate. As the thermosetting compound (C), known and commonly used thermosetting compounds such as isocyanate compounds, blocked isocyanate compounds, amino resins, benzoxazine resins, carbodiimide resins, cyclocarbonate compounds, epoxy compounds, polyfunctional oxetane compounds, and episulfide resins can be used. Among these, epoxy compounds, polyfunctional oxetane compounds, and episulfide resins are preferred, and epoxy compounds are more preferred. The thermosetting compound (C) can be used alone or in combination of two or more.

[0039] The epoxy compound is a compound having an epoxy group, and any conventionally known compound can be used. Examples include polyfunctional epoxy resins having multiple epoxy groups in the molecule. Hydrogenated epoxy resins may also be used.

[0040] Examples of polyfunctional epoxy resins include epoxidized vegetable oils, bisphenol A type epoxy resins, hydroquinone type epoxy resins, bisphenol type epoxy resins, thioether type epoxy resins, brominated epoxy resins, novolac type epoxy resins, biphenol novolac type epoxy resins, bisphenol F type epoxy resins, hydrogenated bisphenol A type epoxy resins, glycidylamine type epoxy resins, hydantoin type epoxy resins, alicyclic epoxy resins, trihydroxyphenylmethane type epoxy resins, bixylenol type or biphenol type epoxy resins, and mixtures thereof. Examples of epoxy resins include, but are not limited to, bisphenol S epoxy resins, bisphenol A novolac epoxy resins, tetraphenylolethane epoxy resins, heterocyclic epoxy resins, diglycidyl phthalate resins, tetraglycidylxylenoylethane resins, naphthalene group-containing epoxy resins, epoxy resins having a dicyclopentadiene skeleton, glycidyl methacrylate copolymer epoxy resins, cyclohexylmaleimide and glycidyl methacrylate copolymer epoxy resins, epoxy-modified polybutadiene rubber derivatives, and CTBN-modified epoxy resins. These epoxy resins can be used alone or in combination of two or more. Among these, novolac epoxy resins, bisphenol epoxy resins, bixylenol epoxy resins, biphenol epoxy resins, biphenol novolac epoxy resins, naphthalene epoxy resins, and mixtures thereof are particularly preferred.

[0041] Examples of polyfunctional oxetane compounds include bis[(3-methyl-3-oxetanylmethoxy)methyl]ether, bis[(3-ethyl-3-oxetanylmethoxy)methyl]ether, 1,4-bis[(3-methyl-3-oxetanylmethoxy)methyl]benzene, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, (3-methyl-3-oxetanyl)methyl acrylate, and (3-ethyl-3-oxetanyl)methyl acrylate. Examples of suitable oxetane compounds include polyfunctional oxetanes such as acrylate, (3-methyl-3-oxetanyl)methyl methacrylate, (3-ethyl-3-oxetanyl)methyl methacrylate, and oligomers or copolymers thereof, as well as ethers of oxetane alcohols with novolak resins, poly(p-hydroxystyrene), cardo-type bisphenols, calixarenes, calixresorcinarenes, or hydroxyl group-containing resins such as silsesquioxane. Other examples include copolymers of unsaturated monomers having an oxetane ring with alkyl (meth)acrylates.

[0042] Examples of episulfide resins include bisphenol A episulfide resins, etc. Also, episulfide resins in which the oxygen atoms of the epoxy groups of novolac epoxy resins are replaced with sulfur atoms using a similar synthesis method can be used.

[0043] The content of the thermosetting compound (C) is preferably 3.0 to 20 mass%, more preferably 4.0 to 15 mass%, and even more preferably 5.0 to 14.5 mass%, in terms of solid content, relative to the total amount of the curable resin composition. The content of the thermosetting compound (C) is preferably 15 to 60 mass parts, more preferably 25 to 50 mass parts, relative to 100 mass parts of the alkali-soluble resin (A), in terms of solid content.

[0044] [Triazine Compound (D)] The curable resin composition of the present invention contains a triazine compound (D). The triazine compound (D) has a heteroatom-containing group (1) and a photoreactive group (2) on the triazine skeleton. The triazine compound (D) may be used alone or in combination of two or more.

[0045] Examples of the triazine compound (D) include compounds having a heteroatom-containing group (1) and a photoreactive group (2) on three carbon atoms of a 1,3,5-triazine skeleton. Specific examples include compounds having the same or different heteroatom-containing groups (1) on two carbon atoms of a 1,3,5-triazine skeleton, and a photoreactive group (2) on the remaining carbon atom, and compounds having the same or different photoreactive groups (2) on two carbon atoms of a 1,3,5-triazine skeleton, and a heteroatom group (1) on the remaining carbon atom.

[0046] More specifically, the triazine compound (D) includes a compound represented by formula (I). (In the formula, R １ and R ２ are the same or different groups (1) containing a heteroatom, and R ３ is a photoreactive group (2), or R １ and R ２ are the same or different and are photoreactive groups (2), and R ３ is a group (1) containing a heteroatom.

[0047] Examples of the heteroatom in the heteroatom-containing group (1) include a nitrogen atom and a sulfur atom. Examples of the heteroatom-containing group (1) include groups represented by the formula: -NR Ａ ２ (wherein R Ａ are the same or different and represent a hydrogen atom, an alkyl group, or an aryl group; Ｂ (wherein R Ｂ represents a hydrogen atom, an alkyl group, or an aryl group. ２ and more preferably —NH ２ is.

[0048] R Ａ and R Ｂ Examples of the alkyl group represented by R include C1 to C6 alkyl groups such as methyl and ethyl groups, and the alkyl group may be either linear or branched. Ａ and RＢ The aryl group shown includes, for example, a phenyl group, a toluyl group, and the like.

[0049] Examples of the photoreactive group (2) include groups containing an ethylenically unsaturated bond, such as an alkenyl group, a (mono- or di-)alkenylamino group, a (meth)acryloyloxy group, and a (meth)acryloyloxyalkyl group.

[0050] Examples of alkenyl groups include C2 to C6 alkenyl groups such as vinyl, allyl, and butenyl, with vinyl or allyl being preferred. Examples of (mono- or di-)alkenylamino groups include (mono- or di-)C2 to C6 alkenylamino groups, with di-C2 to C6 alkenylamino groups being preferred, and diallylamino groups being more preferred. Examples of (meth)acryloyloxyalkyl groups include (meth)acryloyloxy C1 to C6 alkyl groups, with (meth)acryloyloxy C1 to C3 alkyl groups being preferred, and (meth)acryloyloxyethyl groups being more preferred.

[0051] The triazine compound (D) is preferably a compound represented by formula (Ia). (In the formula, R ３０ is a group containing an ethylenically unsaturated bond. ３０ Examples of the group having an ethylenically unsaturated bond represented by the formula: include those mentioned above.

[0052] Particularly preferred examples of the triazine compound (D) include 2,4-diamino-6-vinyl-s-triazine (VT), 2,4-diamino-6-diallylamino-1,3,5-triazine, and 2,4-diamino-6-methacryloyloxyethyl-s-triazine (MAVT).

[0053] These triazine compounds (D) may be commercially available or may be synthesized by known methods, such as MAVT and VT heat curing catalysts manufactured by Shikoku Chemical Industry Co., Ltd. and N,N-diallylmelamine heat curing catalysts manufactured by Tokyo Chemical Industry Co., Ltd.

[0054] The content of the triazine compound (D), in terms of solid content relative to the total amount of the curable resin composition, is preferably 0.1 to 5.0 mass%, more preferably 0.2 to 5.0 mass%, even more preferably 0.4 to 4.5 mass%, and most preferably 0.5 to 3.0 mass%. Furthermore, the content of the triazine compound (D), in terms of solid content relative to 100 parts by mass of the alkali-soluble resin (A), is preferably 0.03 to 20.0 parts by mass, more preferably 0.1 to 10.0 parts by mass, even more preferably 0.1 to 8.0 parts by mass, and most preferably 2.0 to 8.0 parts by mass. By keeping the content within the above range, the melt viscosity of the resin layer of the dry film prepared from the curable resin composition can be maintained lower, and better haloing resistance is imparted to the cured product (solder resist) of the resin layer.

[0055] [Silica (E)] The curable resin composition of the present invention contains silica (E) as a filler. Examples of silica (E) include amorphous silica, crystalline silica, fused silica, and spherical silica, with spherical silica being preferred. The silica (E) may be used singly or in combination of two or more thereof. The content of silica (E) is 20 to 70 mass%, more preferably 25 to 70 mass%, and even more preferably 30 to 70 mass%, calculated as solid content, based on the total amount of the curable resin composition. Silica typically has a low thermal expansion coefficient (linear expansion coefficient) of 0.5 to 6. Therefore, by adjusting the content of silica (E) in the curable resin composition to this range, the cured product is endowed with toughness and excellent thermal properties (low thermal expansion coefficient).

[0056] Silica (E) may be surface-treated to enhance dispersibility in the curable resin composition, and preferably the surface of silica (E) is subjected to a surface treatment that can introduce curable reactive groups.Here, the curable reactive group is not particularly limited as long as it is a group that undergoes a curing reaction with a curable compound such as an alkali-soluble resin (A) or a thermosetting compound (C), and may be a photocurable reactive group or a thermosetting reactive group.Examples of the photocurable reactive group include a methacrylic group, an acrylic group, a vinyl group, a styryl group, etc., and examples of the thermosetting reactive group include an epoxy group, an amino group, a hydroxyl group, a carboxyl group, an isocyanate group, an imino group, an oxetanyl group, a mercapto group, a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, an ethoxyethyl group, an oxazoline group, etc. The method for introducing curable reactive groups onto the silica surface is not particularly limited, and may be carried out using a known, commonly used method. The silica surface may be treated with a surface treatment agent having a curable reactive group, such as a coupling agent having a curable reactive group as an organic group. Examples of coupling agents that can be used include silane coupling agents, titanium coupling agents, zirconium coupling agents, and aluminum coupling agents. Examples of surface-treated silica that does not have a curable reactive group include silica-alumina surface treatment, titanate-based coupling agent treatment, aluminate-based coupling agent treatment, fluorene-based coupling agent treatment, and organically treated silica. Alternatively, the silica may be coated with a hydrated oxide of silicon, a hydrated oxide of aluminum, a hydrated oxide of zirconium, a hydrated oxide of zinc, or a hydrated oxide of titanium, for example.

[0057] The average particle size of silica (E) is usually 0.1 to 3.0 μm, preferably 0.1 to 1.0 μm. In this specification, the average particle size of silica refers to the average particle size (D50) including not only the particle size of primary particles but also the particle size of secondary particles (aggregates), and is the D50 value measured by laser diffraction. An example of a measuring device using the laser diffraction method is Microtrac MT3300EXII manufactured by Microtrac Bell Corporation.

[0058] The average particle size of the silica (E) can be adjusted, and is preferably adjusted by pre-dispersing it using, for example, a bead mill or a jet mill. The silica is preferably blended in the form of a slurry, which facilitates high dispersion, prevents aggregation, and makes handling easier.

[0059] As the silica (E), commercially available products can be used, and examples thereof include silica manufactured by Admatechs Co., Ltd. (SO-C2, SO-C1, SO-C4, etc.) and silica manufactured by Denka Co., Ltd. (SFP-30M, SFP-20M, SFP-130MC).

[0060] The curable resin composition of the present invention does not exclude the inclusion of a filler other than silica (E), but the content thereof can be adjusted within a range in which the effects of the curable resin composition of the present invention are exhibited.

[0061] [Photopolymerizable Monomer (F)] The curable resin composition of the present invention may further contain a photopolymerizable monomer (F). Examples of the photopolymerizable monomer (F) include compounds having one or more ethylenically unsaturated bonds in the molecule. The photopolymerizable monomer (F) assists in photocuring of the alkali-soluble resin (A) (particularly, a carboxyl group-containing resin) by irradiation with active energy rays.

[0062] Examples of compounds used as the photopolymerizable monomer (F) include commonly known polyester (meth)acrylates, polyether (meth)acrylates, urethane (meth)acrylates, carbonate (meth)acrylates, epoxy (meth)acrylates, etc. Specific examples include hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; glycol diacrylates such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene 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; polyhydric alcohols such as hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, and tris-hydroxyethyl isocyanurate, or ethylene oxide adducts, propylene oxide adducts, or ε-caprolactone adducts thereof. and the like; polyhydric acrylates such as phenoxy acrylate, bisphenol A diacrylate, and ethylene oxide adducts or propylene oxide adducts of these phenols; polyhydric acrylates derived from glycidyl ethers such as glycerin diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, and triglycidyl isocyanurate; and, without being limited to the above, acrylates and melamine acrylates obtained by directly acridating polyols such as polyether polyols, polycarbonate diols, hydroxyl group-terminated polybutadienes, and polyester polyols or by urethane acrylates via diisocyanates, and methacrylates corresponding to the above acrylates can be suitably selected and used.

[0063] The content of the photopolymerizable monomer (F), in terms of solid content, relative to the total amount of the curable resin composition, is usually 15% by mass or less, preferably 1 to 15% by mass, more preferably 1 to 10% by mass, and even more preferably 3 to 9% by mass. The content of the photopolymerizable monomer (F), in terms of solid content, relative to 100 parts by mass of the alkali-soluble resin (A) (particularly, the carboxyl group-containing resin), is usually 100 parts by mass or less, more preferably 5 to 100 parts by mass, and even more preferably 5 to 70 parts by mass.

[0064] (Thermosetting Catalyst) The curable resin composition of the present invention may contain, in addition to the triazine compound (D), other thermosetting catalysts, within the range that does not impair the properties of the present invention. Examples of such thermosetting catalysts 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. Guanamine, acetoguanamine, and benzoguanamine can also be used, and it is preferable to use these compounds that also function as adhesion promoters in combination with the heat curing catalyst.

[0065] The content of the thermosetting catalyst is usually 20 parts by mass or less, preferably 0.05 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, based on 100 parts by mass of the thermosetting compound (C), calculated as solid content.

[0066] (Curing Agent) The curable resin composition of the present invention may contain a curing agent. Examples of the curing agent include phenolic resins, polycarboxylic acids and their acid anhydrides, cyanate ester resins, active ester resins, maleimide compounds, and alicyclic olefin polymers. The curing agents may be used alone or in combination of two or more.

[0067] (Colorant) The curable resin composition of the present invention may contain a colorant. As the colorant, known colorants such as red, blue, green, yellow, black, and white can be used, and any of pigments, dyes, and coloring matters can be used. However, from the viewpoint of reducing environmental load and effects on the human body, it is preferable that the colorant does not contain halogen.

[0068] The content of the colorant is not particularly limited, and is preferably 10 parts by mass or less, more preferably 0.1 to 7 parts by mass, based on 100 parts by mass of the alkali-soluble resin (A) in terms of solid content.

[0069] (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 applying it to a substrate or a carrier film (hereinafter referred to as the "first 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, carbitol 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.

[0070] (Other Optional Components) Furthermore, the curable resin composition of the present invention may contain other additives known and commonly used in the field of electronic materials. Examples of other additives include thermal polymerization inhibitors, ultraviolet absorbers, silane coupling agents, plasticizers, flame retardants, antistatic agents, antioxidants, antibacterial and antifungal agents, antifoaming agents, leveling agents, thickeners, adhesion-imparting agents, thixotropy-imparting agents, photoinitiator assistants, sensitizers, thermoplastic resins, organic fillers, release agents, surface treatment agents, dispersants, dispersion assistants, surface modifiers, stabilizers, phosphors, and AB or ABA block copolymers.

[0071] [Dry Film] The curable resin composition of the present invention can be formed into a dry film. The dry film of the present invention comprises a resin layer containing the curable resin composition of the present invention and a first film. The first film in the present invention is adhered to the resin layer and is at least adhered to the resin layer when the dry film is laminated onto a substrate or other base material so that the resin layer side of the dry film is in contact with the substrate to form an integral structure. 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 first diluted with the organic solvent described above 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 coated composition is then dried, typically at a temperature of 40 to 130°C for 1 to 30 minutes, to form a resin layer. There is no particular restriction on the thickness of the coating film, but it is generally selected appropriately within the range of 3 to 150 μm, preferably 5 to 60 μm, in terms of the thickness after drying.

[0072] The first film may be a plastic film, such as a polyester film such as polyethylene terephthalate (PET), a polyimide film, a polyamideimide film, a polypropylene film, or a polystyrene film. A laminate of these films may also be used as the first film. There are no particular restrictions on the thickness of the first film, but it is generally selected appropriately in the range of 10 to 150 μm. It is more preferably in the range of 15 to 130 μm.

[0073] After forming a resin layer made of the curable resin composition of the present invention on the first film, it is preferable to further laminate a peelable cover film (hereinafter referred to as a "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 contacts a base material such as a substrate to form an integral mold. Examples of peelable second films that can be used include polyethylene film, polytetrafluoroethylene film, polypropylene film, and surface-treated paper. The second film may be any film whose adhesive strength is smaller than that between the resin layer and the first film when peeled off.

[0074] In the present invention, the curable resin composition of the present invention 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 the present invention, either the first film or the second film may be used as the film to which the curable resin composition of the present invention is applied when producing a dry film.

[0075] The dry film of the present invention has a resin layer made of the above-mentioned curable resin composition, and the resin layer maintains a low melt viscosity. This effect is believed to be achieved by the inclusion of the above-mentioned specific triazine compound (D) in the curable resin composition of the present invention. This allows the resin layer to flexibly conform to the substrate surface when bonded to the substrate, preventing the entrapment of air bubbles. In other words, the lamination properties between the resin layer (and its cured product) and the substrate are dramatically improved, resulting in high adhesion. The melt viscosity of the resin layer can be set to a lowest melt viscosity of less than 1000 dPa·s in the range from 70°C to 120°C, and can even be set to 600 dPa·s or less, and even less than 500 dPa·s. In the present invention, the melt viscosity is a value measured by the method described in the Examples section of this specification.

[0076] [Method for producing cured product] The electronic component of the present invention has a cured product obtained from the resin layer of the dry film. In the present invention, the electronic component means a component used in an electronic circuit, and includes active components such as printed wiring boards, transistors, light-emitting diodes, and laser diodes, as well as passive components such as resistors, capacitors, inductors, and connectors. The cured product obtained from the curable resin composition of the present invention serves as an insulating cured film for these components, thereby achieving the effects of the present invention.

[0077] The cured product of the present invention can be produced, for example, as follows: A resin layer is formed on a substrate by laminating the dry film onto the substrate using a laminator or the like so that the resin layer of the dry film comes into contact with the substrate.

[0078] 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, 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.

[0079] 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, even if a circuit-formed substrate is used, the dry film adheres to the circuit substrate, even if the circuit substrate surface is uneven, preventing the inclusion of air bubbles and improving the ability to fill 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. This allows the resin layer of the dry film to adhere to the substrate.

[0080] The first film side of the dry film attached to the substrate is selectively exposed to active energy rays through a photomask with a predetermined pattern formed thereon. The first film is then peeled off from the dry film, and the unexposed areas are developed with a dilute alkaline aqueous solution (e.g., a 0.3 to 3 mass % sodium carbonate aqueous solution) to form a cured product pattern. Note that, as long as the properties are not impaired, the first film may be peeled off from the dry film before exposure, and the exposed resin layer may be exposed and developed.

[0081] Furthermore, the cured product is irradiated with active energy rays and then heat-cured (for example, at 100 to 220°C), or is heat-cured and then irradiated with active energy rays, or is heat-cured alone to form a final finish curing (main curing) to form a cured product with excellent properties such as adhesion and hardness.

[0082] 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:

[0083] 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.

[0084] When the cured product of the present invention obtained as described above is used as a solder resist for printed wiring boards, etc., it does not cause discoloration (haloing) around the solder resist openings after electroless gold plating. The reason for this effect is not entirely clear, but it is presumed that this is because the heteroatom-containing group (1) and the photoreactive group (2) present in the triazine compound (D) react with the metal and resin on the substrate, respectively, to firmly bond or adhere them together.

[0085] Furthermore, the cured product of the present invention has excellent thermal properties, such as a low coefficient of thermal expansion (linear expansion coefficient). The coefficient of thermal expansion (CTE(α1)) of the cured product is usually less than 45 ppm / K, preferably 40 ppm / K or less, and more preferably less than 35 ppm / K. The coefficient of thermal expansion (CTE(α1)) can be measured by the method described in the Examples of this specification.

[0086] As described above, the dry film obtained from the curable resin composition of the present invention is suitably used for forming a cured product on a printed wiring board used for semiconductor packaging, etc., more suitably used for forming a permanent film, and even more suitably used for forming a solder resist, an interlayer insulating layer, a coverlay, etc. Furthermore, the dry film obtained from the curable resin composition of the present invention has a low melt viscosity and is therefore excellent in lamination to a substrate, and the cured product thereof has excellent thermal properties (low thermal expansion coefficient) and haloing resistance, and therefore can be suitably used for forming a permanent film such as a solder resist used in a high-density IC package substrate, for example.

[0087] 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 unless otherwise specified.

[0088] (Synthesis of Alkali-Soluble Resin A-1) 119.4 parts by mass of a novolac cresol resin (trade name "Shounol CRG951", manufactured by Aica Kogyo Co., Ltd., OH equivalent: 119.4), 1.19 parts by mass of potassium hydroxide, and 119.4 parts by mass of toluene were introduced into an autoclave equipped with a thermometer, a nitrogen introducing device / alkylene oxide introducing device, and a stirrer. The system was purged with nitrogen while stirring, and the temperature was raised by heating. Next, 63.8 parts by mass of propylene oxide was gradually added dropwise, and the temperature was raised to 125 to 132°C and 0 to 4.8 kg / cm. ２ The mixture was reacted at 400°C for 16 hours. The mixture was then cooled to room temperature, and 1.56 parts by mass of 89% phosphoric acid was added to the reaction solution to neutralize the potassium hydroxide, yielding a propylene oxide reaction solution of a novolac cresol resin with a solids content of 62.1% and a hydroxyl value of 182.2 mgKOH / g (307.9 g / eq.). An average of 1.08 moles of propylene oxide was added per equivalent of phenolic hydroxyl groups.

[0089] 293.0 parts by mass of the resulting propylene oxide reaction solution of novolac cresol resin, 43.2 parts by mass of acrylic acid, 11.53 parts by mass of methanesulfonic acid, 0.18 parts by mass of methylhydroquinone, and 252.9 parts by mass of toluene were introduced into a reactor equipped with a stirrer, thermometer, and air inlet tube. Air was blown in at a rate of 10 ml / min, and the mixture was stirred while reacting at 110°C for 12 hours. The water produced by the reaction was distilled as an azeotrope with toluene, and 12.6 parts by mass of water was distilled off. The mixture was then cooled to room temperature, and the resulting reaction solution was neutralized with 35.35 parts by mass of 15% aqueous sodium hydroxide solution and then washed with water. The toluene was then distilled off while being replaced with 118.1 parts by mass of diethylene glycol monoethyl ether acetate using an evaporator, yielding a novolac acrylate resin solution.

[0090] Next, 332.5 parts by mass of the obtained novolac acrylate resin solution and 1.22 parts by mass of triphenylphosphine were introduced into a reactor equipped with a stirrer, a thermometer, and an air inlet tube, and while blowing air in at a rate of 10 ml / min and stirring, 60.8 parts by mass of tetrahydrophthalic anhydride was gradually added, and the mixture was reacted at 95 to 101°C for 6 hours, cooled, and then removed. In this way, a solution of alkali-soluble resin A-1 (photosensitive carboxyl group-containing resin) having a solids content of 70.6% and an acid value of the solids content of 87.7 mgKOH / g was obtained.

[0091] (Preparation of Curable Resin Compositions) Using the obtained alkali-soluble resin A-1, various components shown in Table 1 were blended in the ratios (parts by mass) shown, premixed in a mixer, and then kneaded in a planetary mixer to prepare the curable resin compositions of Examples 1 to 6 and Comparative Examples 1 to 5. The values ​​in Table 1 are values ​​converted into solid contents. (*1) Alkali-soluble resin A-1 synthesized above (*2) Photopolymerization initiator Omnirad 819 manufactured by IGM Resins (*3) Dicyclopentadiene-type epoxy resin HP-7200L manufactured by DIC Corporation (*4) Heat curing catalyst MAVT manufactured by Shikoku Chemicals Corporation, having a structure represented by the following formula: (*5) N,N-diallylmelamine manufactured by Tokyo Chemical Industry Co., Ltd., having a structure represented by the following formula. (*6) Thermosetting catalyst VT manufactured by Shikoku Chemicals Corporation, having a structure represented by the following formula: (*7) Melamine, which has the structure represented by the following formula: (*8) Benzoguanamine manufactured by Nippon Shokubai Co., Ltd., having the structure represented by the following formula. (*9) Thermosetting catalyst 2E4MZ-A manufactured by Shikoku Chemicals Corporation, having a structure represented by the following formula: (*10) Silica SO-C2 (average particle size 0.4-0.6 μm) manufactured by Admatechs Co., Ltd. (*11) Photopolymerizable monomer dipentaerythritol hexaacrylate DPHA manufactured by Nippon Kayaku Co., Ltd.

[0092] (Preparation of Dry Film) Each of the curable resin compositions of Examples 1 to 6 and Comparative Examples 1 to 5 obtained as described above was diluted with 300 g of propylene glycol monomethyl ether acetate (PMA) and stirred for 15 minutes with a stirrer to obtain a coating solution. The coating solution was applied to a 38 μm thick polyethylene terephthalate film (Emblet PTH-25: manufactured by Unitika Ltd.) as a first film and dried at 80°C for 20 minutes to form a 20 μm thick resin layer. Next, a 18 μm thick polypropylene film (OPP-FOA: manufactured by Futamura Chemical Co., Ltd.) as a second film was laminated onto the resin layer to prepare a dry film.

[0093] (Evaluation of Melt Viscosity) Two dry films prepared as described above (Preparation of Dry Film) were prepared, the second film was peeled off from each, and the resin layers were laminated at a lamination temperature of 40 ° C. using a vacuum laminator (CVP-300: manufactured by Nikko Materials Co., Ltd.), and one of the first films was peeled off to produce a resin layer having a thickness of about 40 μm and a first film on one side. Furthermore, one dry film prepared as described above (Preparation of Dry Film) was prepared, and after peeling off the second film, the resin layers were laminated together with the resin layer having a thickness of about 40 μm prepared above to produce a resin layer having a thickness of about 60 μm. This operation was repeated two more times to produce a resin layer having a thickness of about 100 μm. A resin layer having a thickness of approximately 100 μm was divided into four, and the resin layers were repeatedly laminated together to produce a resin layer having a thickness of approximately 400 μm and a size of 25 mm x 25 mm (resin layer laminate). The produced resin layer laminate was heated from 30 ° C. to 150 ° C. at a heating rate of 5 ° C. / min using a HAAKE MARS 40 manufactured by Thermo Fisher Scientific Co., Ltd., and the melt viscosity was measured under the measurement conditions of a measurement frequency of 1 Hz and a measurement pressure of 3 Pa. The evaluation criteria for melt viscosity were as follows: A: The melt viscosity at the lowest point in the range from 70 ° C. to 120 ° C. was less than 500 dPa s. B: The melt viscosity at the lowest point in the range from 70 ° C. to 120 ° C. was 500 dPa s or more and less than 1000 dPa s. C: The melt viscosity at the lowest point in the temperature range from 70°C to 120°C was 1000 dPa·s or more.

[0094] (Evaluation of Haloing) A substrate with 17 μm of electrolytic copper plating on an FR-4.0 glass cloth-based epoxy resin multilayer substrate material (a copper-clad laminate with a thickness of 1.6 mm and a thickness of 18 μm of copper foil) was treated using CZ-8101B manufactured by MEC Co., Ltd., and subjected to an etching treatment equivalent to 1.0 μm. Next, the second film was peeled from the resin layer of the dry film prepared in the above (Preparation of Dry Film), and the resin layer was attached to the substrate. Using a vacuum laminator (CVP-300: manufactured by Nikko Materials Co., Ltd.), the laminate was laminated in a first chamber at 90° C. under conditions of a vacuum pressure of 3 hPa and a vacuum time of 30 seconds, and then pressed under conditions of a press pressure of 0.5 MPa and a press time of 30 seconds.

[0095] Next, exposure was performed using an exposure device equipped with a high-pressure mercury lamp with opening patterns of 40, 50, and 60 μm in diameter. The exposure dose was adjusted using a step tablet (Photec 41 step) so that the gloss sensitivity was 10 steps. After exposure, the first film was peeled off from the resin layer (including the cured product) of the dry film to expose the resin layer.

[0096] Then, 1 mass % Na ２ CO ３ The aqueous solution was sprayed at a pressure of 2 kg / cm ２ This substrate was then exposed to UV light for 30 seconds under the conditions of: ２ After irradiating with ultraviolet light under the conditions of , the substrate was heated and cured at 150°C for 60 minutes. Electroless gold plating (Ni: 3.00 μm, Au: 0.03 μm) was performed on the test substrate prepared according to this manufacturing process, and discoloration of the appearance around the opening after electroless gold plating was observed using an optical microscope. The evaluation method is as follows: A: No discoloration was observed. B: Slight discoloration was observed. C: Discoloration was observed.

[0097] (Preparation of Cured Product) The second film was peeled off from the dry film prepared above (Preparation of Dry Film) on a low-profile copper foil, and the resin layer of the dry film was attached to the copper foil surface side. Subsequently, using a vacuum laminator (CVP-300: manufactured by Nikko Materials Co., Ltd.), lamination was performed in a first chamber at 90°C under conditions of a vacuum pressure of 3 hPa and a vacuum time of 30 seconds, followed by lamination under conditions of a press pressure of 0.5 MPa and a press time of 30 seconds, thereby adhering the substrate and the resin layer to each other. Next, using an exposure device equipped with a high-pressure mercury lamp (short arc lamp), exposure (exposure amount: 200 to 600 mJ / cm) was performed from above the dry film. ２ After the curing, the first film was peeled off from the dry film to expose the resin layer (cured product). ２ CO ３ Using an aqueous solution, 30°C, spray pressure 2 kg / cm ２ Subsequently, the resist was developed for 60 seconds under the conditions of 1000 mJ / cm in a UV conveyor furnace equipped with a high-pressure mercury lamp. ２ After irradiating the resin layer with an exposure amount of 1000 ppm, the resin layer was heated at 150° C. for 60 minutes to completely cure the resin layer, thereby producing a cured product.

[0098] (Evaluation of CTE (α1)) The cured product obtained as described above was peeled from the copper foil, and the sample was set in a TMA-Q400EM manufactured by T.A. Instruments Japan Co., Ltd. so as to obtain a measurement size (3 mm x 16 mm), and the CTE was measured. The measurement conditions were a test load of 5 g, and the sample was heated from room temperature at a heating rate of 10°C / min, which was repeated twice, and the linear expansion coefficient (CTE (α1)) at or below Tg was obtained after the second heating. The evaluation method for CTE (α1) is as follows: A CTE (α1) = less than 35 ppm / K B CTE (α1) = 35 ppm / K or more and less than 45 ppm / K C CTE (α1) = 45 ppm / K or more

[0099] The results in Table 1 show that the resin layers of the dry films obtained in Examples 1 to 6 had sufficiently low melt viscosities. In particular, a comparison of Example 1 with Comparative Examples 3 and 5 shows that the resin layer of Example 1, which contains the triazine compound (D) having an ethylenically unsaturated bond of the present invention, has a significantly lower melt viscosity than the resin layer of Comparative Example 3, which contains conventional melamine, and the resin layer of Comparative Example 5, which contains a triazine compound (D') not having an ethylenically unsaturated bond. Furthermore, a comparison of Example 1 with Comparative Example 1 shows that the resin layer of Comparative Example 1, which contains too much silica, has a high melt viscosity.

[0100] It was found that the cured products obtained in Examples 1 to 6 did not exhibit haloing and had excellent haloing resistance. In particular, a comparison between Example 1 and Comparative Example 4 confirmed that the cured product of Example 1, obtained by curing a curable resin composition containing the triazine compound (D) of the present invention, had superior haloing resistance compared to the cured product of Comparative Example 4, obtained by curing a curable resin composition containing benzoguanamine, which has only two reactive sites.

[0101] It was found that the thermal expansion coefficients of the cured products obtained in Examples 1 to 6 were sufficiently small. In particular, a comparison between Example 1 and Comparative Example 2 revealed that if the content of silica in the curable resin composition was too low, the thermal expansion coefficient would be large.

[0102] When the curable resin composition of the present invention is applied to a dry film, the melt viscosity of the resin layer can be maintained low, and lamination defects do not occur when forming the resin layer on a substrate. In addition, the cured product has excellent thermal properties (low thermal expansion coefficient) and haloing resistance. Therefore, the curable resin composition of the present invention can be suitably used for forming permanent films such as solder resists used in high-density IC package substrates.

Claims

1. A curable resin composition containing an alkali-soluble resin (A), a photopolymerization initiator (B), a thermosetting compound (C), a triazine compound (D), and silica (E), wherein the triazine compound (D) is a compound having a heteroatom-containing group (1) and a photoreactive group (2) on a triazine skeleton, and the content of the silica (E) is 20 to 70 mass% in terms of solid content based on the total amount of the curable resin composition.

2. The curable resin composition according to claim 1, wherein the heteroatom in the heteroatom-containing group (1) contained in the triazine compound (D) is a nitrogen atom or a sulfur atom.

3. The curable resin composition according to claim 1, wherein the photoreactive group (2) contained in the triazine compound (D) is a group containing an ethylenically unsaturated bond.

4. The curable resin composition according to claim 1, wherein the content of the triazine compound (D) is 0.1 to 5.0 mass % in terms of solid content based on the total amount of the curable resin composition.

5. The curable resin composition according to claim 1, wherein the silica (E) has an average particle size of 0.1 to 1.0 μm.

6. A dry film comprising a first film and a resin layer formed from the curable resin composition according to claim 1.

7. A curable resin composition according to claim 1 or a cured product of the resin layer of the dry film according to claim 6.

8. An electronic part comprising the cured product according to claim 7.

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