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

Abstract

To provide a photosensitive resin composition that suppresses a reduction in coating properties such as the modulus of elasticity and also exhibits excellent storage stability.MEANS: A photosensitive resin composition at least comprises (A) an alkali-soluble resin, (B) a photopolymerization initiator, (C) silica, and (D) a photopolymerizable monomer. The (C) silica is surface-treated with two silane coupling agents: a silane coupling agent that lacks reactive functional groups; and a silane coupling agent that has at least one reactive functional group selected from the group consisting of vinyl groups, (meth)acryloyl groups, and styryl groups.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a photosensitive resin composition, and more particularly to a photosensitive resin composition that can be suitably used for forming an insulating layer such as a solder resist, a dry film using the photosensitive resin composition, a cured product of the photosensitive resin composition or the dry film, and a printed wiring board using such a cured product.

Background Art

[0002] Generally, in a printed wiring board used in electronic devices or the like, in order to prevent solder from adhering to unnecessary portions of the printed wiring board in processes such as solder reflow when mounting electronic components on the printed wiring board, a solder resist layer is formed in a region excluding connection holes on a substrate on which a circuit pattern is formed. The solder resist layer is mainly formed by a so-called photo solder resist in which a photosensitive resin composition is applied to a substrate, dried, exposed, developed to form a pattern, and then the patterned resin is fully cured by heating or light irradiation. In addition, it has also been proposed to form a solder resist layer using a photosensitive dry film without using the liquid photosensitive resin composition as described above.

[0003] These photosensitive resin compositions and photosensitive dry films contain an alkali-soluble photosensitive resin component so that they can be exposed and developed, and other photopolymerizable monomers and thermosetting components such as epoxy are contained as necessary in consideration of heat resistance and substrate adhesion. In addition, an inorganic filler may be blended in the photosensitive resin composition in order to reduce the linear expansion coefficient and suppress peeling of the solder resist layer and warping of the substrate (Patent Document 1, etc.).

[0004] Among inorganic fillers, spherical silica in particular is excellent in filling properties and has a low coefficient of thermal expansion, so it is widely used to improve the properties of solder resist. However, as the blending amount of the inorganic filler increases, the interface between the inorganic filler and the resin increases, so there is a tendency for a decrease in the physical properties of the coating film such as elastic modulus and tensile strength. Therefore, even for silica with high filling properties, surface treatment with a silane coupling agent having a reactive functional group such as an amino group or a (meth)acryloyl group is performed to suppress the decrease in the physical properties of the coating film (Patent Document 2, etc.).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The surface treatment of silica is carried out by adding a silane coupling agent to silica and reacting them, and it is blended into the photosensitive resin composition as a silica slurry containing the silane coupling agent. Therefore, free silane coupling agents contained in the silica slurry may undergo a condensation reaction with each other, and this may react with the resin component in the photosensitive resin composition, not only reducing the storage stability but also affecting the crosslinking density of the resin component and sometimes reducing the sensitivity of the photosensitive resin composition. In addition, when the photosensitive resin composition is stored for a long time, the components in the photosensitive resin composition may react with the free silane coupling agent, and the sensitivity of the photosensitive resin composition may increase abnormally.

[0007] Therefore, an object of the present invention is to provide a photosensitive resin composition that suppresses a decrease in the physical properties of a coating film such as elastic modulus and also has excellent storage stability.

Means for Solving the Problems

[0008] As a result of investigations by the present inventors on the above problems, it has been found that by using silica surface-treated with two types of silane coupling agents, namely a silane coupling agent having a reactive functional group and a silane coupling agent having no reactive functional group, it is possible to suppress a decrease in coating film physical properties and obtain a photosensitive resin composition excellent in storage stability. The present invention is based on such findings. That is, the gist of the present invention is as follows.

[0009] [1] A photosensitive resin composition comprising at least (A) an alkali-soluble resin, (B) a photopolymerization initiator, (C) silica, and (D) a photopolymerizable monomer, wherein the (C) silica is surface-treated with two types of silane coupling agents, namely a silane coupling agent having no reactive functional group and a silane coupling agent having at least one reactive functional group selected from the group consisting of a vinyl group, a (meth)acryloyl group, and a styryl group. [2] The photosensitive resin composition according to [1], wherein among the silane coupling agents coated on the surface of the (C) silica, the amount coated with the silane coupling agent having the reactive functional group is larger than the amount coated with the silane coupling agent having no reactive functional group. [3] The photosensitive resin composition according to [2], wherein in the (C) silica, the ratio of the amount coated with the silane coupling agent having the reactive functional group to the amount coated with the silane coupling agent having no reactive functional group is 2:1 to 10:1 on a mass basis. [4] The photosensitive resin composition according to [1], wherein the (C) silica is contained in a proportion of 50 to 90% by mass based on the total solid content in the photosensitive resin composition. [5] The photosensitive resin composition according to [1], further comprising (E) a thermosetting component. [6] A dry film comprising a first film and a resin layer formed by coating and drying the photosensitive resin composition according to [1] on one surface of the first film. [7] The cured product obtained by curing the photosensitive resin composition according to any one of [1] to [5] or the resin layer of the dry film according to [6]. [8] A printed wiring board provided with a film made of the cured product according to [7].

Advantages of the Invention

[0010] According to the present invention, by using silica surface-treated with specific two silane coupling agents, it is possible to suppress a decrease in coating film physical properties such as elastic modulus and to realize a photosensitive resin composition excellent in storage stability.

Embodiments for Carrying Out the Invention

[0011] [Photosensitive Resin Composition] The photosensitive resin composition according to the present invention contains at least (A) an alkali-soluble resin, (B) a photopolymerization initiator, (C) silica, and (D) a photopolymerizable monomer. Hereinafter, each component constituting the photosensitive resin composition will be described. In the present specification, (meth)acryl is used as a term collectively referring to both acrylic and methacrylic. Also, (meth)acryloyl is used as a term collectively referring to both acryloyl and methacryloyl. Further, (meth)acrylate is used as a term collectively referring to acrylate, methacrylate, and a mixture thereof.

[0012] <(A) Alkali-Soluble Resin> (A) The alkali-soluble resin contained in the photosensitive resin composition according to the present invention may be any resin that can be dissolved in alkali, and known and commonly used ones are used. The alkali-soluble resin can be used alone or in combination of two or more. Examples include water-soluble resins such as carboxyl group-containing resins and phenolic hydroxyl group-containing resins. Among them, carboxyl group-containing resins and phenolic hydroxyl group-containing resins are preferred because of their excellent developability, and carboxyl group-containing resins are more preferred. When the alkali-soluble resin contains a carboxyl group, it can be made alkali-developable. Also, from the viewpoint of photosensitivity, in addition to the carboxyl group, it is preferably having an ethylenically unsaturated double bond in the molecule, but only a carboxyl group-containing resin having no ethylenically unsaturated double bond may be used. When the carboxyl group-containing resin has no ethylenically unsaturated double bond, it is necessary to use a photopolymerizable monomer in combination to make the composition photocurable. As the ethylenically unsaturated double bond, those derived from acrylic acid or methacrylic acid or their derivatives are preferred.

[0013] Specific examples of the carboxyl group-containing resin can include the following compounds (either oligomers or polymers). In this specification, (meth)acrylate is a general term for acrylate, methacrylate, and their mixtures, and the same applies to other similar expressions.

[0014] (1) A carboxyl group-containing resin obtained by copolymerization of an unsaturated carboxylic acid such as (meth)acrylic acid and an unsaturated group-containing compound such as styrene, α-methylstyrene, lower alkyl (meth)acrylate, isobutylene.

[0015] (2) A carboxyl group-containing urethane resin obtained by polyaddition reaction of diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates, 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-based alkylene oxide adduct diols, and compounds having phenolic hydroxyl groups and alcoholic hydroxyl groups.

[0016] (3) A carboxyl group-containing photosensitive urethane resin obtained by partial acid anhydride modification of a reaction product of a diisocyanate with a bifunctional epoxy resin such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol type epoxy resin, and biphenol type epoxy resin and a monocarboxylic acid compound having an ethylenically unsaturated double bond such as (meth)acrylic acid, and polyaddition reaction of a carboxyl group-containing dialcohol compound and a diol compound.

[0017] (4) A carboxyl group-containing photosensitive urethane resin having terminal (meth)acrylation by adding a compound having one hydroxyl group and one or more (meth)acryloyl groups in the molecule such as hydroxyalkyl (meth)acrylate during the synthesis of the resin of (2) or (3) above.

[0018] (5) A carboxyl group-containing photosensitive urethane resin having terminal (meth)acrylation 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 of (2) or (3) above.

[0019] (6) A carboxyl group-containing photosensitive resin obtained by reacting a bifunctional or higher polyfunctional (solid) epoxy resin with (meth)acrylic acid and adding a dibasic acid anhydride to the hydroxyl groups present in the side chain.

[0020] (7) A carboxyl group-containing photosensitive resin obtained by reacting (meth)acrylic acid with a polyfunctional epoxy resin obtained by further epoxidizing the hydroxyl groups of a difunctional (solid) epoxy resin with epichlorohydrin and adding a dibasic acid anhydride to the resulting hydroxyl groups.

[0021] (8) A carboxyl group-containing polyester resin obtained by reacting a difunctional oxetane resin with a dicarboxylic acid such as adipic acid, phthalic acid, or hexahydrophthalic acid and adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the resulting primary hydroxyl groups.

[0022] (9) A carboxyl group-containing photosensitive resin obtained by reacting an epoxy compound having a plurality of 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 reacting a polybasic acid anhydride such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, or adipic acid with the alcoholic hydroxyl groups of the resulting reaction product.

[0023] (10) A carboxyl group-containing photosensitive resin obtained by reacting a compound having a plurality of 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 reacting the resulting reaction product with a polybasic acid anhydride.

[0024] (11) A carboxyl group-containing photosensitive resin obtained by reacting a compound having a plurality of 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 reacting the resulting reaction product with a polybasic acid anhydride.

[0025] (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 the resins of (1) to (11) above.

[0026] These carboxyl group-containing resins can be used not limited to those listed above, and may be used alone or in combination of multiple types. Among those described above, carboxyl group-containing resins synthesized using compounds having phenolic hydroxyl groups such as carboxyl group-containing resins (10) and (11) can be preferably used because of their excellent HAST resistance and PCT resistance.

[0027] The acid value of the carboxyl group-containing resin is preferably 40 to 150 mgKOH / g. By setting the acid value of the carboxyl group-containing resin to 4 mgKOH / g or more, alkali development becomes good. Also, by setting the acid value to 150 mgKOH / g or less, it becomes easier to draw a good resist pattern. More preferably, it is 50 to 130 mgKOH / g.

[0028] The weight average molecular weight of the carboxyl group-containing resin varies depending on the resin skeleton, but is generally preferably 2,000 to 150,000. By setting the weight average molecular weight to 2,000 or more, the tack-free performance and resolution can be improved. Also, by setting the weight average molecular weight to 150,000 or less, the developability and storage stability can be improved. More preferably, it is 5,000 to 15,000. The weight average molecular weight can be measured by gel permeation chromatography (GPC).

[0029] The blending amount of the above-mentioned (A) alkali-soluble resin is preferably 10 to 50% by mass in terms of solid content in the photosensitive resin composition. By setting it to 10% by mass or more, the coating film strength can be improved. Also, by setting it to 50% by mass or less, the viscosity becomes appropriate and the printability is improved. More preferably, it is 10 to 30% by mass.

[0030] <(B) Photoinitiator>The photosensitive resin composition according to the present invention contains (B) a photopolymerization initiator for photopolymerizing the above-mentioned (A) alkali-soluble resin and the (D) photopolymerizable monomer described later. As the photopolymerization initiator, known ones can be used. For example, 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, N,N-dimethylaminoacetophenone; hydroxyacetophenone-based photopolymerization initiators such as 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-propane-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one; acylphosphine oxide-based photopolymerization initiators such as 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, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphine acid methyl ester, 2-methylbenzoyldiphenylphosphine oxide, pivaloylphenylphosphine acid isopropyl ester, 2,4,6-trimethylbenzoyldiphenylphosphine oxide;Benzoin-based photoinitiators such as benzoin, benzyl, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, benzoin n-butyl ether, etc.; benzoin alkyl ether-based photoinitiators; benzophenone-based photoinitiators such as benzophenone, p-methylbenzophenone, Michler's ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone, etc.; acetophenone-based photoinitiators such as 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-pmorpholino; thioxanthone-based photoinitiators such as thioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diisopropylthioxanthone, etc.; anthraquinone-based photoinitiators such as anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, 2-aminoanthraquinone, etc.; ketal-based photoinitiators such as acetophenone dimethyl ketal, benzyl dimethyl ketal, etc.; benzoic acid ester-based photoinitiators such as ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate, ethyl p-dimethylbenzoate, etc.; oxime ester-based photoinitiators such as 1,2-octanedione, 1-[4-(phenylthio)phenyl]-, 2-(O-benzoyloxime)], ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acet yloxime), etc.; titanocene-based photoinitiators such as bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)phenyl)titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyr-1-yl)ethyl)phenyl]titanium, etc.;Examples thereof include the following. These photoinitiators may be used alone or in combination of two or more kinds.;

[0031] Examples of commercially available α-aminoacetophenone-based photoinitiators include Omnirad 907, 369, 369E, 379, etc. manufactured by IGM Resins. Examples of commercially available acylphosphine oxide-based photoinitiators include Omnirad 819, etc. manufactured by IGM Resins. Examples of commercially available titanocene-based photoinitiators include JMT-784 manufactured by Yueyang Kimoutain Sci-tech Co., Ltd., GR-FMT manufactured by Hubei Gurun Sci-tech Co., Ltd., etc.

[0032] In addition, a photoinitiator having two oxime ester groups in the molecule can also be preferably used. Specifically, an oxime ester compound having a carbazole structure represented by the following general formula (I) can be mentioned.

Chemical formula

[0033] In the above formula, X represents a hydrogen atom, an alkyl group having 1 to 17 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, a phenyl group, a phenyl group (substituted by an alkyl group having 1 to 17 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an amino group, an alkylamino group or a dialkylamino group having an alkyl group having 1 to 8 carbon atoms), a naphthyl group (substituted by an alkyl group having 1 to 17 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an amino group, an alkylamino group or a dialkylamino group having an alkyl group having 1 to 8 carbon atoms), Y and Z each represent a hydrogen atom, an alkyl group having 1 to 17 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, a halogen group, a phenyl group, a phenyl group (substituted by an alkyl group having 1 to 17 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an amino group, an alkylamino group or a dialkylamino group having an alkyl group having 1 to 8 carbon atoms), a naphthyl group (substituted by an alkyl group having 1 to 17 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an amino group, an alkylamino group or a dialkylamino group having an alkyl group having 1 to 8 carbon atoms), an anthryl group, a pyridyl group, a benzofuryl group, a benzothienyl group, Ar represents an alkylene having 1 to 10 carbon atoms, vinylene, phenylene, biphenylene, pyridylene, naphthylene, thiophene, anthrylene, thienylene, furylene, 2,5-pyrrole-diyl, 4,4'-stilbene-diyl, 4,2'-styrene-diyl, and n is an integer of 0 or 1.

[0034] In particular, in the above formula, an oxime ester-based photoinitiator in which X1 and Y1 are each a methyl group or an ethyl group, Z is methyl or phenyl, n is 0, and Ar is phenylene, naphthylene, thiophene or thienylene is preferable.

[0035] In addition to the above-mentioned photoinitiators, benzoin compounds, acetophenone compounds, anthraquinone compounds, thioxanthone compounds, ketal compounds, benzophenone compounds, tertiary amine compounds, and xanthone compounds can be used as photoinitiators. However, it is preferable to use these compounds as a photopolymerization initiation aid or a sensitizer in combination with the above-mentioned photopolymerization initiators rather than using them alone as a photopolymerization initiator. Among the above, from the viewpoint of deep section curing, thioxanthone compounds and tertiary amine compounds are preferred, and thioxanthone compounds are more preferred. Two or more of the above compounds may also be used in combination.

[0036] The amount of the (B) photopolymerization initiator in the photosensitive resin composition is preferably 1 to 50 parts by mass, more preferably 1 to 20 parts by mass, based on 100 parts by mass of the (A) alkali-soluble resin, calculated as solid content, which can improve the curability in deep areas.

[0037] When the photosensitive resin composition contains the benzoin compound or the like as a photopolymerization initiation aid, the amount of the benzoin compound or the like is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the alkali-soluble resin (A) in terms of solid content, which can improve the curability in deep portions.

[0038] <(C) Silica> The photosensitive resin composition according to the present invention contains (C) silica. The (C) silica used in the present invention is surface-treated with two silane coupling agents: one silane coupling agent without a reactive functional group, and the other silane coupling agent with at least one reactive functional group selected from the group consisting of a vinyl group, a (meth)acryloyl group, and a styryl group. By using silica surface-treated with two silane coupling agents, one without a reactive functional group and the other with a specific reactive functional group, it is possible to suppress the deterioration of coating film properties such as elastic modulus and to obtain a photosensitive resin composition with excellent storage stability. The reason for this is unclear, but the following can be speculated. That is, from the viewpoint of improving the physical properties of the coating film such as the elastic modulus, it is preferable that the surface of the silica to be blended has a predetermined reactive functional group. However, as described above, when a silane coupling agent having a reactive functional group is present in the photosensitive resin composition as a free silane coupling agent, the silane coupling agents may react with each other, or the silane coupling agent may react with other components in the photosensitive resin composition, resulting in deterioration of the storage stability. Therefore, although reducing the amount of the silane coupling agent having a reactive functional group used for surface-treating the silica improves the storage stability, it is considered that the hydrophilicity of the surface-treated silica increases and problems such as aggregation occur. In the present invention, among the silane coupling agents coating the silica, by using a silane coupling agent having a reactive functional group to improve the physical properties of the coating film and also using a silane coupling agent having no reactive functional group in combination, it can be presumed that a photosensitive resin composition having hydrophobicity imparted to the silica, suppressing aggregation, etc., and excellent in storage stability can be obtained.

[0039] Examples of silane coupling agents without reactive functional groups include compounds containing Si elements having an alkoxysilyl group or a silanol group. For example, methyltrimethoxysilane, ethyltrimethoxysilane, n-propyltrimethoxysilane, isopropyltrimethoxysilane, n-butyltrimethoxysilane, isobutyltrimethoxysilane, n-pentyltrimethoxysilane, cyclopentyltrimethoxysilane, n-hexyltrimethoxysilane, cyclohexyltrimethoxysilane, n-octyltrimethoxysilane, isooctyltrimethoxysilane, n-decyltrimethoxysilane, n-dodecyltrimethoxysilane, n-tetradecyltrimethoxysilane, n-hexadecyltrimethoxysilane, n-octadecyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, 7-octenyltrimethoxysilane, phenyltrimethoxysilane, benzyltrimethoxysilane, 1-naphthyltrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, n-propyltriethoxysilane, isopropyltriethoxysilane, n-butyltriethoxysilane, isobutyltriethoxysilane, n-pentyltriethoxysilane, cyclopentyltriethoxysilane, n-hexyltriethoxysilane, cyclohexyltriethoxysilane, n-octyltriethoxysilane, isooctyltriethoxysilane, n-decyltriethoxysilane, n-dodecyltriethoxysilane, n-tetradecyltriethoxysilane, n-hexadecyltriethoxysilane, n-octadecyltriethoxysilane, etc. These silane coupling agents without reactive functional groups may be used alone or in combination of two or more. Among these, methyltrimethoxysilane and ethyltrimethoxysilane can be preferably used.

[0040] Examples of silane coupling agents with reactive functional groups include vinyl group-containing silane coupling agents, (meth)acryloyl group-containing silane coupling agents, and styryl group-containing silane coupling agents. These may be used alone or in combination of two or more.

[0041] Examples of the vinyl group-containing silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltris(2-methoxyethoxy)silane, vinylmethyldimethoxysilane, octenyltrimethoxysilane, allyltrimethoxysilane, and the like.

[0042] Examples of the (meth)acryloyl group-containing silane coupling agent include 1,3-bis(acryloyloxymethyl)-1,1,3,3-tetramethyldisilazane, 1,3-bis(methacryloyloxymethyl)-1,1,3,3-tetramethyldisilazane, 1,3-bis(γ-acryloyloxypropyl)-1,1,3,3-tetramethyldisilazane, 1,3-bis(γ-methacryloyloxypropyl)-1,1,3,3-tetramethyldisilazane, acryloyloxymethylmethyltrisilazane, methacryloyloxymethylmethyltrisilazane, acryloyloxymethylmethyltetrasilazane, methacryloyloxymethylmethyltetrasilazane, acryloyloxymethylmethylpolysilazane, methacryloyloxymethylmethylpolysilazane, 3-acryloyloxypropylmethyltrisilazane, 3-methacryloyloxypropylmethyltrisilazane, 3-acryloyloxypropylmethyltetrasilazane, 3-methacryloyloxypropylmethyltetrasilazane, 3-acryloyloxypropylmethylpolysilazane, 3-methacryloyloxypropylmethylpolysilazane, acryloyloxymethylpolysilazane, methacryloyloxymethylpolysilazane, 3-acryloyloxypropylpolysilazane, 3-methacryloyloxypropylpolysilazane, and the like.

[0043] Examples of the styryl group-containing silane coupling agent include p-styryltrimethoxysilane and the like.

[0044] Among the silane coupling agents having the above-described reactive functional groups, a (meth)acryloyl group-containing silane coupling agent can be used, and for example, methacryloyloxypropyltrimethoxysilane can be preferably used.

[0045] (C) The surface treatment of silica is preferably carried out by adding a silane coupling agent in a proportion of 0.5 to 10 parts by mass, more preferably 0.5 to 2.0 parts by mass, based on 100 parts by mass of silica. The surface treatment of silica can be carried out by preparing a dispersion in which silica is dispersed in an appropriate solvent, adding a predetermined amount of the silane coupling agent to the silica dispersion, and stirring. In order to promote the reaction of the surface treatment, stirring may be carried out in a heating environment at a temperature of 50 to 100 °C.

[0046] (C) For silica, among the silane coupling agents coated on the silica surface, the amount coated with the silane coupling agent having the reactive functional group is preferably larger than the amount coated with the silane coupling agent not having the reactive functional group. A silane having the above coating ratio can be obtained, for example, by adjusting the blending amounts of both when adding the silane coupling agent to the silica dispersion so that the amount of the silane coupling agent having the reactive functional group is larger than that of the silane coupling agent not having the reactive functional group when performing the surface treatment of silica. In particular, it is preferable that the ratio of the amount coated with the silane coupling agent having the reactive functional group to the amount coated with the silane coupling agent not having the reactive functional group is 2:1 to 10:1 on a mass basis. Silica having such a coating ratio can be obtained, for example, by surface-treating silica using a silane coupling agent containing a silane coupling agent having a reactive functional group and a silane coupling agent not having a reactive functional group in a mass ratio of 2:1 to 10:1. The presence or absence of the surface treatment can be confirmed by quantifying the free unreacted coupling agent in the silica slurry by LC-MS. Note that approximately 60 - 90% of the added silane coupling agent is coated. Also, a higher effect can be obtained by using the surface-treated silica as compared with the case where silica and the silane coupling agent are put in separately at the same time.

[0047] As the silica to be surface-treated, conventionally known ones can be used without limitation, and it may be either amorphous or crystalline, or a mixture thereof. Particularly, amorphous (fused) silica is preferred.

[0048] From the viewpoint of dispersibility and the like, the silica preferably has an average particle size (D50) of 0.1 to 1.0 μm, more preferably 0.4 to 0.8 μm. The average particle size means the particle size at 50% volume cumulative obtained by using the laser diffraction scattering type particle size distribution measurement method. Also, the average particle size of the silica refers to the value measured as described above for the silica before preparing (preliminary stirring, kneading) the photosensitive resin composition.

[0049] From the viewpoint of coating film physical properties and the like, the blending amount of the silica in the photosensitive resin composition is preferably 50 to 90% by mass, more preferably 60 to 90% by mass, based on the total solid content in the photosensitive resin composition.

[0050] <Inorganic filler> In addition to the above-mentioned (C) silica, the photosensitive resin composition according to the present invention may contain other inorganic fillers. As the inorganic filler, known ones can be used, such as talc, mica, aluminum oxide, calcium oxide, magnesium oxide, zinc oxide, calcium carbonate, magnesium carbonate, fly ash, dehydrated sludge, kaolin, clay, calcium hydroxide, aluminum hydroxide, magnesium hydroxide, hydrotalcite, aluminum silicate, magnesium silicate, calcium silicate, wollastonite, potassium titanate, magnesium sulfate, calcium sulfate, magnesium phosphate, sepiolite, zonolite, boron nitride, aluminum borate, silica balloon, glass flake, glass balloon, ironmaking slag, copper, iron, iron oxide, sendust, alnico magnet, magnetic powder such as various ferrites, cement, glass powder, nobelgu silica, diatomaceous earth, antimony trioxide, magnesium oxysulfate, hydrated aluminum, hydrated gypsum, alum and barium sulfate. These inorganic fillers may be used alone or in combination of two or more. In addition, the inorganic filler other than (C) silica may be surface-treated in the same manner as silica.

[0051] From the viewpoint of dispersibility and the like, the inorganic filler other than the above-mentioned (C) silica preferably has an average particle size (D50) of 0.1 to 100 μm, more preferably 0.1 to 50 μm. The average particle size has the same meaning as the above-mentioned definition.

[0052] The blending amount of the inorganic filler other than (C) silica in the photosensitive resin composition can be appropriately adjusted in relation to the blending amount of (C) silica, but is usually adjusted in the range of 0 to 20% by mass.

[0053] <Photopolymerizable monomer> The photosensitive resin composition of the present invention contains (D) a photopolymerizable monomer. The photopolymerizable monomer is a monomer having an ethylenically unsaturated double bond. Examples of such photopolymerizable monomers include commonly known polyester (meth)acrylates, polyether (meth)acrylates, urethane (meth)acrylates, carbonate (meth)acrylates, epoxy (meth)acrylates, etc. Specifically, alkyl acrylates such as 2-ethylhexyl acrylate and cyclohexyl acrylate; hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; mono- or di-acrylates 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; polyacrylates of polyhydric alcohols such as hexanediol, trimethylolpropane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, and tris-hydroxyethyl isocyanurate, or their alkylene oxide adducts or ε-caprolactone adducts; polyacrylates of phenols such as phenoxy acrylate and bisphenol A diacrylate, or their alkylene oxide adducts; acrylates of glycidyl ethers such as glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, and triglycidyl isocyanurate; not limited to the above, acrylates obtained by directly acrylate-modifying polyols such as polyether polyol, polycarbonate diol, hydroxyl-terminated polybutadiene, and polyester polyol, or urethane acrylate-modifying via diisocyanate, and melamine acrylate, and at least one of the corresponding methacrylates of the above acrylates can be appropriately selected and used. Such a photopolymerizable monomer can also be used as a reactive diluent.

[0054] (D) The photopolymerizable monomer can be used alone or in combination of two or more. The compounding amount of the photopolymerizable monomer is preferably 0.5 to 30 parts by mass in terms of solid content with respect to 100 parts by mass of the (A) alkali-soluble resin. When the compounding amount is 0.5 part by mass or more, the photocurability is good, and pattern formation is easy in alkali development after irradiation with active energy rays. Further, when the compounding amount is 30 parts by mass or less, halation hardly occurs and good resolution can be obtained.

[0055] <(E) Thermosetting component> In addition to the above-described components, the photosensitive resin composition of the present invention may contain an (E) thermosetting component. Examples of the thermosetting component include known and commonly used ones such as isocyanate compounds, blocked isocyanate compounds, amino resins, maleimide compounds, benzoxazine resins, carbodiimide resins, cyclocarbonate compounds, epoxy compounds, oxetane compounds, and episulfide resins. Among these, a preferable thermosetting component is an epoxy resin.

[0056] Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, novolak type epoxy resin of bisphenol A, biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, triphenylmethane type epoxy resin, etc. These may be used alone or in combination of two or more.

[0057] Examples of commercially available epoxy resins include jER 828, 806, 807, YX8000, YX8034, 834 manufactured by Mitsubishi Chemical Corporation, YD-128, YDF-170, ZX-1059, ST-3000 manufactured by Nippon Steel Chemical & Material Co., Ltd., EPICLON 830, 835, 840, 850, N-730A, N-695 manufactured by DIC Corporation, RE-306 manufactured by Nippon Kayaku Co., Ltd., and the like.

[0058] In the photosensitive resin composition, the equivalent weight of the epoxy group of the epoxy resin is preferably 0.5 to 2.5 in terms of solid content with respect to 1 of the equivalent weight of the carboxyl group of the carboxyl group-containing resin. By setting it to 0.5 equivalent or more, the residual carboxyl group in the cured product can be prevented, and good heat resistance, alkali resistance, electrical insulation, etc. can be obtained. Further, by setting the above blending amount to 2.5 equivalents or less, the residual low molecular weight cyclic (thio) ether group in the dry coating film can be prevented, and the strength of the cured product can be ensured well.

[0059] When the photosensitive resin composition of the present invention contains a thermosetting component, it may contain a thermosetting catalyst for promoting the curing of the thermosetting component. Examples of the thermosetting catalyst include imidazole derivatives such as imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole; amine compounds such as dicyandiamide, benzyldimethylamine, 4-(dimethylamino)-N,N-dimethylbenzylamine, 4-methoxy-N,N-dimethylbenzylamine, 4-methyl-N,N-dimethylbenzylamine; hydrazine compounds such as adipic acid dihydrazide, sebacic acid dihydrazide; phosphorus compounds such as triphenylphosphine and the like. Further, as commercially available ones, for example, 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, 2P4MHZ (all are trade names of imidazole-based compounds) manufactured by Shikoku Kasei Kogyo Co., Ltd., U-CAT 3513N (trade name of dimethylamine-based compound) manufactured by San-Apro Ltd., DBU, DBN, U-CAT SA 102 (all are bicyclic amidine compounds and their salts) and the like can be mentioned.

[0060] It is not limited to the above-mentioned compounds, and any thermosetting catalyst for epoxy resins or oxetane compounds, or any one that promotes the reaction between at least one of epoxy groups and oxetanyl groups and carboxyl groups may be used, and they may be used alone or in combination of two or more. In addition, S-triazine derivatives such as guanamine, acetoguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, 2-vinyl-4,6-diamino-S-triazine·isocyanuric acid adduct, 2,4-diamino-6-methacryloyloxyethyl-S-triazine·isocyanuric acid adduct can also be used, and preferably, a compound that also functions as an adhesion promoter among these is used in combination with the thermosetting catalyst.

[0061] The thermosetting catalyst can be used alone or in combination of two or more. From the viewpoints of the storage stability of the resin composition and the heat resistance of the cured film, the compounding amount of the thermosetting catalyst is preferably 0.01 to 30 parts by mass in terms of solid content based on 100 parts by mass of the alkali-soluble resin, and more preferably 0.1 to 20 parts by mass.

[0062] <Other components> In addition to the above-described components, the photosensitive resin composition according to the present invention may contain, if necessary, a colorant, an elastomer, a mercapto compound, a urethanization catalyst, a thixotropic agent, an adhesion promoter, a block copolymer, a chain transfer agent, a polymerization inhibitor, a copper damage inhibitor, an antioxidant, a rust inhibitor, a thickener such as organobentonite and montmorillonite, at least one of an antifoaming agent and a leveling agent such as a silicone-based, fluorine-based, and polymer-based one, and a flame retardant such as a phosphorus compound such as a phosphinate, a phosphate ester derivative, and a phosphazene compound. These can be materials known in the field of electronic materials.

[0063] In the photosensitive resin composition of the present invention, an organic solvent may be blended from the viewpoints of ease of preparation and coatability. 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 solvents such as petroleum ether, petroleum naphtha, and solvent naphtha. These known and commonly used organic solvents can be used alone or in combination of two or more kinds.

[0064] The blending amount of the organic solvent in the photosensitive resin composition can be appropriately changed according to the materials constituting the photosensitive resin composition. For example, it can be 30 to 300 parts by mass in terms of solid content based on 100 parts by mass of the (A) alkali-soluble resin.

[0065] The photosensitive resin composition of the present invention may be used in the form of a dry film or in a liquid state. When used in a liquid state, it may be a one-component type or a two-component type or more.

[0066] <Dry film> The photosensitive resin composition of the present invention can also be in the form of a dry film comprising a first film and a resin layer made of the above photosensitive resin composition formed on the first film. The first film in the dry film according to the present invention refers to a film that is at least adhered to the resin layer when it is laminated and integrally formed by heating or the like so that the resin layer side formed on the dry film is in contact with a base material such as a substrate. The first film may be peeled off from the resin layer in a process after lamination. In particular, in the present invention, it is preferably peeled off from the resin layer in a process after exposure.

[0067] To produce a dry film, the photosensitive resin composition of the present invention is diluted with an organic solvent to adjust to an appropriate viscosity, and then coated on the first film to a uniform thickness with a comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater, gravure coater, spray coater, etc. Usually, it can be dried at a temperature of 50 to 130 °C for 1 to 30 minutes to obtain a film. There is no particular limitation on the coating film thickness, but generally, it is appropriately selected in the range of 1 to 150 μm, preferably 5 to 60 μm, in terms of the film thickness after drying.

[0068] As the first film, any known film can be used without particular limitation. For example, polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyimide films, polyamideimide films, polypropylene films, and polystyrene films made of thermoplastic resins can be preferably used. Among these, polyester films are preferred from the viewpoints of heat resistance, mechanical strength, handleability, etc. Also, a laminate of these films can be used as the first film.

[0069] Also, the thermoplastic resin film as described above is preferably a film stretched in a uniaxial direction or a biaxial direction from the viewpoint of improving mechanical strength.

[0070] The thickness of the first film is not particularly limited, and for example, it can be 10 μm to 150 μm.

[0071] After forming the resin layer of the photosensitive resin composition of the present invention on the first film, it is preferable to laminate a second film that can be peeled off on the surface of the resin layer for the purpose of preventing dust from adhering to the surface of the resin layer, etc. The second film in the dry film according to the present invention refers to a film that peels off from the resin layer before lamination when it is integrally formed by laminating by heating or the like so that the resin layer side of the dry film is in contact with a base material such as a substrate.

[0072] As the second film that can be peeled off from the resin layer, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, surface-treated paper, etc. can be used, as long as the adhesive force between the resin layer and the second film is smaller than the adhesive force between the resin layer and the first film when the second film is peeled off.

[0073] The thickness of the second film is not particularly limited, and for example, it can be 10 μm to 150 μm.

[0074] <Cured product> The cured product of the present invention is obtained by curing the above-described photosensitive resin composition or the resin layer of the above-described dry film.

[0075] <Printed wiring board> The printed wiring board of the present invention has a cured product obtained from the photosensitive resin composition or the resin layer of the dry film of the present invention. As a method for manufacturing the printed wiring board of the present invention, for example, the photosensitive resin composition of the present invention is adjusted to a viscosity suitable for the coating method using the above organic solvent, and then applied onto a substrate by methods such as dip coating method, flow coating method, roll coating method, bar coating method, screen printing method, curtain coating method, etc. After that, the organic solvent contained in the composition is volatilized and dried (pre-dried) at a temperature of 60 to 100°C to form a tack-free resin layer. In the case of a dry film, after laminating the resin layer on the substrate so that the resin layer contacts the substrate by a laminator or the like, the first film is peeled off to form a resin layer on the substrate.

[0076] Examples of the above-mentioned substrate include printed wiring boards previously formed with circuits using copper or the like, flexible printed wiring boards, and in addition, high-frequency circuit copper-clad laminates using materials such as paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven fabric epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, fluororesin / polyethylene / polyphenylene ether, polyphenylene oxide / cyanate, etc. All grades (such as FR-4) of copper-clad laminates, as well as metal substrates, polyimide films, polyethylene terephthalate films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafer plates, etc. can be mentioned.

[0077] When in the form of a dry film, the lamination on the substrate is preferably carried out under pressure and heating using a vacuum laminator or the like. By using such a vacuum laminator, when using a circuit-formed substrate, even if there are irregularities on the surface of the circuit board, the dry film adheres tightly to the circuit board, so there is no mixing of air bubbles, and the hole filling property of the concave portions on the substrate surface is also improved. The pressure condition is preferably about 0.1 to 2.0 MPa, and the heating condition is preferably 40 to 120°C.

[0078] When the photosensitive resin composition of the present invention contains an organic solvent, it is preferable to perform volatilization drying after applying the photosensitive resin composition on the substrate surface. The volatilization drying can be carried out using a hot air circulation drying furnace, an IR furnace, a hot plate, a convection oven, etc. (a method of making the hot air in the dryer in countercurrent contact using a heat source of an air heating method by steam and a method of spraying onto the substrate from a nozzle).

[0079] After forming a resin layer on the substrate, it is selectively exposed to active energy rays through a photomask having a predetermined pattern, and the unexposed portion is developed with a dilute aqueous alkali solution (for example, a 0.3 to 3 mass% aqueous sodium carbonate solution) to form a pattern of the cured product. In the case of a dry film, after exposure, the first film is peeled off from the dry film and developed to form a patterned cured product on the substrate. In the case of the dry film form, as long as the characteristics 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. Further, by irradiating the cured product with active energy rays and then performing heat curing (for example, 100 to 220 ° C), or irradiating with active energy rays after heat curing, or performing final finishing curing (main curing) only by heat curing, a cured film excellent in various properties such as adhesion and hardness can be formed.

[0080] As the exposure machine used for the above active energy ray irradiation, any device equipped with a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a mercury short arc lamp, etc. and irradiating ultraviolet rays in the range of 350 to 450 nm may be used. Further, a direct drawing device (for example, a laser direct imaging device that directly draws an image with a laser based on CAD data from a computer) can also be used. The lamp light source or laser light source of the direct drawing machine may have a maximum wavelength in the range of 350 to 450 nm. The exposure amount for image formation varies depending on the film thickness and the like, but generally it can be in the range of 10 to 1000 mJ / cm 2 Preferably 20 to 800 mJ / cm 2 within the range.

[0081] As the above-described development method, a dipping method, a shower method, a spray method, a brush method, etc. can be used, and as the developer, an alkaline aqueous solution such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines, etc. can be used.

[0082] After forming a cured film on the substrate as described above, components such as electronic elements are mounted on the substrate by solder reflow processing. The solder reflow processing can be performed by a conventionally known method. Also, solder reflow is generally performed under processing conditions of, for example, 245 to 260 °C for 5 to 10 seconds.

[0083] The photosensitive resin composition or dry film of the present invention is suitably used for manufacturing electronic components such as printed wiring boards, and more preferably, it is used to form a permanent film. At that time, a cured product is formed by the above-described method or the like using the photosensitive resin composition or dry film of the present invention. When the resin layer of the photosensitive resin composition or dry film of the present invention is insulating, it is preferably used to form a solder resist, a coverlay, or an interlayer insulating layer. In particular, it can be suitably used for the application of forming a permanent coating film such as a solder resist used for a package substrate. Also, the photosensitive resin composition according to the present invention may be used to form a solder dam.

Examples

[0084] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the following, "parts" and "%" are all based on mass unless otherwise specified.

[0085] <Synthesis Example 1 (Synthesis of Alkaline Soluble Resin A)> Into an autoclave equipped with a thermometer, a nitrogen introduction device, an alkylene oxide introduction device, and a stirring device, 119.4 parts by mass of a novolak-type cresol resin (trade name "Shonol 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, and while stirring, the inside of the system was purged with nitrogen and the temperature was raised. Next, 63.8 parts by mass of propylene oxide was gradually added dropwise, and the reaction was carried out at 125 to 132 °C and 0 to 4.8 kg / cm 2 for 16 hours. Then, it was cooled to room temperature, and while adding and mixing 1.56 parts by mass of 89% phosphoric acid to this reaction solution, potassium hydroxide was neutralized to obtain a propylene oxide reaction solution of novolak-type cresol resin [solid content: 62.1%; hydroxyl value: 182.2 mgKOH / g (307.9 g / eq.)]. In this propylene oxide reaction solution, an average of 1.08 moles of propylene oxide was added per equivalent of phenolic hydroxyl group. 293.0 parts by mass of the obtained propylene oxide reaction solution of novolak-type cresol resin, 43.2 parts by mass of acrylic acid, 11.53 parts by mass of methanesulfonic acid, 0.18 part by mass of methylhydroquinone, and 252.9 parts by mass of toluene were introduced into a reactor equipped with a stirrer, a thermometer, and an air blowing tube, air was blown in at a rate of 10 ml / min, and the reaction was carried out at 110 °C for 12 hours while stirring. 12.6 parts by mass of water generated by the reaction was distilled off as an azeotropic mixture with toluene. Then, it was cooled to room temperature, the obtained reaction solution was neutralized with 35.35 parts by mass of a 15% aqueous sodium hydroxide solution, and then washed with water. Then, while replacing toluene with 118.1 parts by mass of diethylene glycol monoethyl ether acetate using an evaporator, it was distilled off to obtain a novolak-type acrylate resin solution. Next, 332.5 parts by mass of the obtained novolak-type 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 blowing tube, air was blown in at a rate of 10 ml / min, and while stirring, 60.8 parts by mass of tetrahydrophthalic anhydride was gradually added, and the reaction was carried out at 95 to 101 °C for 6 hours. After cooling, it was taken out. In this way, a solution of the alkali-soluble resin A (solid content: 65% by mass, acid value of solid content: 87.7 mgKOH / g) was obtained.

[0086] <Preparation of silica>[Silica 1] To 30 g of propylene glycol monomethyl ether acetate (PMA) as a solvent, 70 g of spherical silica (SFP-30M, manufactured by Denka Co., Ltd., average particle size 0.6 μm) was added and stirred to prepare a preliminary dispersion. Next, 0.8 g of methacryloxypropyltrimethoxysilane (KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.1 g of methyltrimethoxysilane (KBM-13, manufactured by Shin-Etsu Chemical Co., Ltd.) were added to this preliminary dispersion, and the mixture was stirred at 50 °C to obtain a silica slurry (solid content of silica 70% by mass) surface-treated with two types of silane coupling agents.

[0087] [Silica 2] To 30 g of propylene glycol monomethyl ether acetate (PMA) as a solvent, 70 g of spherical silica (SFP-30M, manufactured by Denka Co., Ltd., average particle size 0.6 μm) was added and stirred to prepare a preliminary dispersion. Next, 0.1 g of methacryloxypropyltrimethoxysilane (KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.8 g of methyltrimethoxysilane (KBM-13, manufactured by Shin-Etsu Chemical Co., Ltd.) were added to this preliminary dispersion, and the mixture was stirred at 50 °C to obtain a silica slurry (solid content of silica 70% by mass) surface-treated with two types of silane coupling agents.

[0088] [Silica 3] To 30 g of propylene glycol monomethyl ether acetate (PMA) as a solvent, 70 g of spherical silica (SFP-30M, manufactured by Denka Co., Ltd., average particle size 0.6 μm) was added and stirred to prepare a preliminary dispersion. Next, 3.0 g of methacryloxypropyltrimethoxysilane (KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.) was added to this preliminary dispersion, and the mixture was stirred at 50 °C to obtain a silica slurry (solid content of silica 70% by mass) surface-treated with only one type of silane coupling agent.

[0089] [Silica 4] 70 g of spherical silica (SFP-30M, manufactured by Denka Co., Ltd., average particle size 0.6 μm) was added to 30 g of propylene glycol monomethyl ether acetate (PMA) as a solvent and stirred to obtain a silica slurry not surface-treated (solid content of silica 70% by mass).

[0090] [Preparation of photosensitive resin composition] Each photosensitive resin composition shown in the following Table 1 was obtained by blending each component described in Table 1 below and mixing at room temperature using a three-roll mill. In addition, each numerical value in the table indicates parts by mass (mass including solvent).

[0091] In addition, each component *1 to *6 in Table 1 below is as follows. *1: Acylphosphine oxide-based photoinitiator (2,4,6-trimethylbenzoyldiphenylphosphine oxide) *2: Dipentaerythritol hexaacrylate *3: Dicyandiamide *4: Phenol novolac type epoxy resin (manufactured by DIC Corporation) *5: Phenol novolac type epoxy resin (manufactured by DIC Corporation, diluted solution of diethylene glycol monoethyl ether acetate, solid content 75% by mass) *6: Biphenyl / phenol novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd.)

[0092] [Evaluation of storage stability] Immediately after preparing each photosensitive resin composition as described above, it was applied to the surface of a polyethylene terephthalate film (T-60, manufactured by Toray Industries, Inc., thickness 38 μm) using an applicator and dried at 80°C for 10 minutes to produce a dry film. In addition, after leaving each prepared photosensitive resin composition standing at room temperature for one week, a dry film was produced in the same manner as above.

[0093] Subsequently, the dry film was laminated onto a printed wiring board pretreated using CZ-8100 manufactured by Meck Co., Ltd. with a vacuum laminator (CVP-600, manufactured by Nikkō Materials Co., Ltd.) to form a resin layer on the substrate. On the resin layer side of the substrate, pattern exposure was performed at the optimum exposure amount via a step tablet using an exposure apparatus equipped with a high-pressure mercury lamp (short arc lamp), and development was carried out for 60 seconds under the condition of a spray pressure of 0.2 MPa with a 1 mass% aqueous sodium carbonate solution at 30°C. The obtained substrate was irradiated with ultraviolet rays in a UV conveyor furnace under the condition of an integrated exposure amount of 1000 mJ / cm 2 and then heated at 170°C for 60 minutes to cure the resin layer to obtain an evaluation substrate.

[0094] The gloss of the pattern of the step tablet of the evaluation substrate obtained as described above was compared, and the storage stability was evaluated according to the following evaluation criteria. ○: The change in sensitivity was within +1 step. ×: The sensitivity increased by 2 steps or more. The evaluation results were as shown in Table 1 below.

[0095] <Evaluation of Coating Film Physical Properties (Elastic Modulus)> The copper foil was pasted onto a copper-clad substrate with the shiny side of the copper foil facing up, and each dry film prepared above was laminated using a vacuum laminator so that the resin layer was in contact with the substrate to form a resin layer on the copper foil.

[0096] The resin layer was exposed at the above optimum exposure amount using an exposure apparatus equipped with a silver short arc lamp, and after ultraviolet irradiation in a UV conveyor furnace under the condition of an integrated exposure amount of 1000 mJ / cm 2 it was heated at 170°C for 60 minutes to cure the resin layer to form a cured film. Subsequently, after peeling the cured film from the copper foil, a sample was cut out to the measurement size. The sample was subjected to an autograph (AG-X, manufactured by Shimadzu Corporation) to measure the elastic modulus. The evaluation criteria were as follows. ◎: The elastic modulus was 8 GPa or more at room temperature. 〇: The elastic modulus was 6 - 8 GPa at room temperature. ×: Elastic modulus is less than 6 GPa at room temperature The evaluation results were as shown in Table 1 below.

[0097]

Table 1

[0098] As is clear from Table 1, photosensitive resin compositions (Examples 1 to 3) containing silica surface-treated with two types of silane coupling agents, namely a silane coupling agent having no reactive functional group and a silane coupling agent having a specific reactive functional group, have good coating film physical properties such as elastic modulus and are also excellent in storage stability. Also, in the photosensitive resin compositions (Examples 1 to 3) containing silica surface-treated with two types of coupling agents, the photosensitive resin composition (Example 1) containing silica in which the amount coated with the silane coupling agent having a reactive functional group is larger than the amount coated with the silane coupling agent having no reactive functional group has an elastic modulus superior to that of the photosensitive resin composition (Example 2) containing silica in which the amount coated with the silane coupling agent having a reactive functional group is less than the amount coated with the silane coupling agent having no reactive functional group. Furthermore, it can be seen that the photosensitive resin composition (Example 1) containing silica surface-treated with two types of coupling agents at a ratio of 50% by mass or more has an elastic modulus superior to that of the photosensitive resin composition (Example 3) containing silica surface-treated with two types of coupling agents at a ratio of less than 50% by mass. On the other hand, it can be seen that photosensitive resin compositions (Comparative Example 1) containing silica surface-treated only with a silane coupling agent having a specific reactive functional group and photosensitive resin compositions (Comparative Example 2) using untreated silica cannot achieve both good coating film physical properties and storage stability.

Claims

Claim 1 A photosensitive resin composition comprising at least (A) an alkali-soluble resin, (B) a photopolymerization initiator, (C) silica, and (D) a photopolymerizable monomer, wherein the (C) silica is surface-treated with two silane coupling agents, namely, a silane coupling agent having no reactive functional group and a silane coupling agent having at least one reactive functional group selected from the group consisting of a vinyl group, a (meth)acryloyl group, and a styryl group. The photosensitive resin composition is characterized by this. Claim 2 In the (C) silica, among the silane coupling agents coated on its surface, the amount coated with the silane coupling agent having the reactive functional group is greater than the amount coated with the silane coupling agent having no reactive functional group. The photosensitive resin composition according to Claim 1. Claim 3 In the (C) silica, the ratio of the amount coated with the silane coupling agent having the reactive functional group to the amount coated with the silane coupling agent having no reactive functional group is 2:1 to 10:1 on a mass basis. The photosensitive resin composition according to Claim 2. Claim 4 The (C) silica is contained in a proportion of 50 to 90% by mass based on the total solid content in the photosensitive resin composition. The photosensitive resin composition according to Claim 1. Claim 5 The photosensitive resin composition according to Claim 1, further comprising (E) a thermosetting component. Claim 6 A dry film comprising a first film and a resin layer obtained by applying and drying the photosensitive resin composition according to Claim 1 on one surface of the first film. Claim 7 A cured product obtained by curing the photosensitive resin composition according to any one of Claims 1 to 5 or the resin layer of the dry film according to Claim 6. Claim 8 A printed wiring board provided with a film made of the cured product according to Claim 7.

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