TW202415724A - Curable resin composition, dry film, cured product and printed wiring board capable of forming a cured product that achieves both good resolution and good crack resistance under harsher conditions than conventional TCT - Google Patents

Abstract

This invention aims to provide a curable resin composition capable of forming a cured product that achieves both good resolution and good crack resistance under harsher conditions than conventional TCT. The curable resin composition of this invention contains a curable resin, a surface-treated barium compound, a surface-treated silica, and rubber particles. The sum of the contents of the surface-treated barium compound and the surface-treated silica is, with respect to total mass of the solid content of the curable resin composition, adjusted to 20 to 80% by mass based on solid content, and the mass ratio of the surface-treated barium compound and the surface-treated silica based on solid content is adjusted to 1:1 to 1:4.

Description

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

The present invention relates to a curable resin composition, and in particular to a curable resin composition suitable for forming a solder resist layer. The present invention also relates to a dry film having a resin layer composed of the curable resin composition, a cured product of the curable resin composition or the resin layer of the dry film, and a printed wiring board having the cured product.

In recent years, with the miniaturization and high performance of electronic devices, the need for miniaturization of printed wiring board patterns, reduction of mounting area, and high density of component mounting has continued to increase. Therefore, the curing resin composition used to form the solder mask in the printed wiring board is required to have high resolution. On the other hand, high heat is applied at various stages during the manufacture and use of the printed wiring board, so the solder mask on the printed wiring board is also required to have resistance to thermal stress.

In the past, in order to improve the resistance to thermal stress, attempts have been made to add a highly heat-resistant resin or inorganic material to the curable resin composition to control the coefficient of thermal expansion (CTE) of the curable resin composition. In particular, silica is generally added to the curable resin composition not only for the purpose of lowering the CTE of the curable resin composition, but also for the sake of physical properties such as crack resistance, cost, and ease of handling.

However, if silica is added to the curable resin composition, especially spherical silica, an inorganic filler with low light transmittance, when the coating of the curable resin composition is cured by light irradiation to form an opening pattern, the silica will block the transmission of light, thereby reducing the curability of the curable resin composition in the deep part of the coating. As a result, the bottom of the opening pattern of the solder mask will be excessively melted during development (so-called undercut), which will cause problems such as poor formation of fine line patterns and reduced resolution.

In order to improve the resolution when silica is added to a curable resin composition, a method of adding barium sulfate in addition to silica is known. For example, Patent Document 1 discloses that a solder resist film formed by a curable resin composition containing spherical silica and barium sulfate in a volume ratio of 1: (0.5 to 5) exhibits excellent resistance to a temperature cycling test (TCT).

However, in recent years, the use of FC-BGA (Flip Chip-Ball Grid Array) substrates has continued to increase in semiconductor packages from the perspective of high speed and multifunctionality. Also, from the perspective of high speed and multifunctionality, semiconductor packages require miniaturization of patterns and larger chips. On the other hand, as the chip area increases, the amount of heat generated during driving increases, so semiconductor packages are required to have reliability that exceeds today's severe temperature changes. Therefore, the solder mask used to manufacture FC-BGA substrates is also required to have higher reliability. In the past, TCT has been used to evaluate the reliability of solder masks, but in recent years, solder masks have become highly reliable, and it has become difficult to fully confirm the difference through TCT, making it difficult to evaluate the reliability of solder masks. Therefore, in the reliability evaluation of the solder mask used for FC-BGA substrates, a more stringent thermal shock test (TST) is generally used to replace the previous TCT. TCT is a hot and cold cycle test conducted in a gas phase tank, while TST is a hot and cold cycle test conducted in a liquid phase tank. The thermal conductivity of liquid is higher than that of gas, so in TST, the substrate is exposed to more rapid temperature changes than in TCT. As a result, it is easier to generate cracks in the solder mask formed on the substrate in TST than in TCT.

Prior art documents Patent documents Patent document 1: Japanese Patent Publication No. 2019-178305

Problem to be solved by the invention Under such circumstances, the existing technical problem is to provide a curable resin composition that can form a cured product that has both good resolvability and good crack resistance under conditions more severe than conventional TCT.

Therefore, an object of the present invention is to provide a curable resin composition, a dry film having a resin layer composed of the curable resin composition, a cured product of the curable resin composition or the resin layer of the dry film, and a printed wiring board having the cured product, wherein the curable resin composition can form a cured product having both good resolving power and good crack resistance under conditions more severe than conventional TCT.

Means for Solving the Problem As a result of the inventors' research, they have obtained the following knowledge that can solve the above-mentioned problem: a hardening resin composition comprising (A) a hardening resin, (B) a surface-treated barium compound and (C) a surface-treated silica, and further blending (D) rubber particles into the hardening resin composition; and the total content of (B) the surface-treated barium compound and (C) the surface-treated silica is adjusted to 20-80% by mass on a solid basis relative to the total mass of the solid components of the hardening resin composition; and the mass ratio of (B) the surface-treated barium compound to (C) the surface-treated silica on a solid basis is adjusted to 1:1-1:4. This invention is made based on the above-mentioned knowledge and understanding. That is, the gist of this invention is as follows.

[1] A curable resin composition comprising: (A) a curable resin, (B) a surface-treated barium compound, (C) a surface-treated silica, and (D) rubber particles; and relative to the total mass of the solid components of the curable resin composition, the total content of the surface-treated barium compound (B) and the surface-treated silica (C) is 20 to 80% by mass on a solid basis; and the mass ratio of the surface-treated barium compound (B) to the surface-treated silica (C) is 1:1 to 1:4 on a solid basis. [2] The curable resin composition of [1], wherein the curable resin (A) comprises (A-1) a photocurable resin. [3] The hardening resin composition of [1] or [2], wherein the hardening resin (A) comprises (A-2) a thermosetting resin. [4] The hardening resin composition of any one of [1] to [3], wherein the rubber particles (D) comprise core-shell rubber particles. [5] The hardening resin composition of any one of [1] to [4], further comprising (E) a photopolymerization initiator. [6] A dry film comprising a first film and a resin layer, wherein the resin layer is formed on at least one side of the first film and is composed of the hardening resin composition of any one of [1] to [5]. [7] A cured product obtained by curing a curable resin composition as described in any one of [1] to [5] or a resin layer of a dry film as described in [6]. [8] A printed wiring board having the cured product as described in [7].

Effect of the invention According to the present invention, a curable resin composition, a dry film having a resin layer composed of the curable resin composition, a cured product of the curable resin composition or the resin layer of the dry film, and a printed wiring board having the cured product can be provided, wherein the curable resin composition can form a cured product that takes into account both good resolvability and good crack resistance under conditions more severe than conventional TCT. According to the present invention, in particular, in the cured product of the curable resin composition, good resolvability and good crack resistance under TST more severe than TCT can be taken into account.

Form for implementing the invention [Hardening resin composition] The hardening resin composition of the present invention is characterized in that it contains the following as essential components: (A) hardening resin, (B) surface-treated barium compound, (C) surface-treated silicon dioxide and (D) rubber particles; and the total content of (B) surface-treated barium compound and (C) surface-treated silicon dioxide is adjusted to 20-80% by mass on a solid basis relative to the total mass of the solid components of the hardening resin composition; and the mass ratio of (B) surface-treated barium compound to (C) surface-treated silicon dioxide on a solid basis (mass of surface-treated barium compound: mass of surface-treated silicon dioxide) is adjusted to 1:1-1:4. The curable resin composition of the present invention contains (D) rubber particles, and the total content of (B) the surface-treated barium compound and (C) the surface-treated silicon dioxide is adjusted to 20-80% by mass based on the total mass of the solid components of the curable resin composition, and the mass ratio of (B) the surface-treated barium compound to (C) the surface-treated silicon dioxide based on the solid components is adjusted to 1:1-1:4. Therefore, a cured product having good resolvability and good crack resistance under TST which is more stringent than TCT can be formed. In the above-mentioned manner, rubber particles are mixed in the curable resin composition, and the total content of the surface-treated barium compound and the surface-treated silica is adjusted to 20-80 mass % on a solid basis with respect to the total mass of the solid components of the curable resin composition, and the mass ratio of the surface-treated barium compound to the surface-treated silica on a solid basis is adjusted to 1:1-1:4. In this case, it is possible to achieve both good resolvability and good crack resistance under conditions more severe than conventional TCT. Although the reason is not clear, it can be inferred as follows. It is believed that the coefficient of thermal expansion (CTE) of fillers such as silica or barium is low, so by mixing surface-treated silica or barium into the hardening resin composition, the dimensional change of the hardening resin composition during the hot and cold cycle will be reduced, and the stress generation can be suppressed, resulting in the improvement of the crack resistance of the hardening resin composition. The CTE of silica is particularly low, so the effect of improving the crack resistance brought about by mixing it into the hardening resin composition is very large. On the other hand, by increasing the mixing amount of surface-treated silica, the crack resistance of the hardening resin composition can be improved, but if the mixing amount is too large, the problem of reduced resolution may occur. In contrast, if a portion of the surface-treated silica is replaced with a surface-treated barium compound for mixing, the resolution when forming a small-diameter pattern can be improved. This is believed to be because the difference in refractive index between barium sulfate and the resin component is small, so in the exposure step, light can easily move straight through the curable resin composition, resulting in improved resolution. However, the CTE of silica is lower than that of barium sulfate, so it is believed that in order to improve crack resistance, it is appropriate to mix a large amount of silica. On the other hand, it is believed that if rubber particles are mixed into the curable resin composition, the stress generated during hot and cold cycles will be alleviated, and good crack resistance can be maintained while reducing the amount of surface-treated silica mixed, thereby achieving high resolution. In other words, it can be considered that the stress generated during the hot and cold cycle is alleviated by mixing rubber particles, thereby reducing the amount of surface-treated silica required to improve crack resistance, and making the total content of the surface-treated barium compound and the surface-treated silica, as well as the mass ratio of the solid component standard within the above-mentioned specific range, so that the effect of improving crack resistance brought by the surface-treated silica and the effect of improving resolvability brought by the surface-treated barium can be obtained at the same time. The following is a detailed description of each component of the curable resin composition of the present invention. In addition, each component can use commercially available products or those obtained by appropriate synthesis.

(Hardening resin) The curing resin composition of the present invention includes (A) a curing resin. As the curing resin, any resin that can be cured by heat or light, etc., is not particularly limited and can be used. Specifically, as the curing resin, a photocuring resin, a thermosetting resin, etc. can be used. The curing resin can be used alone or in combination of two or more. For example, a thermosetting resin or a photocuring resin can be used alone or in combination. The curing resin composition preferably includes a photocuring resin and a thermosetting resin.

In the curable resin composition, a photocurable resin (A-1) may be mixed as a curable resin. As the photocurable resin, a known and commonly used photocurable resin may be used. Among them, from the perspective of photocurability or development resistance, it is preferable to use a photocurable resin that can be cured by a free radical addition polymerization reaction by active energy rays, and it is preferable to use a photocurable resin having an ethylenic unsaturated group in the molecule. In addition, the ethylenic unsaturated group is preferably derived from acrylic acid, methacrylic acid or a derivative thereof. The photocurable resin may be used alone or in combination of two or more. As the photocurable resin, it is preferable to use a carboxyl group-containing photosensitive resin described later.

As the photocurable resin having an ethylenic unsaturated group in the molecule, known and commonly used photopolymerizable oligomers and photopolymerizable monomers can be used. Among them, the photopolymerizable oligomers include unsaturated polyester oligomers and (meth)acrylate oligomers. The (meth)acrylate oligomers include the following: epoxy (meth)acrylates such as phenol novolac epoxy (meth)acrylate, cresol novolac epoxy (meth)acrylate, and bisphenol type epoxy (meth)acrylate, urethane (meth)acrylate, epoxy urethane (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, and polybutadiene modified (meth)acrylate.

On the other hand, as the photopolymerizable monomer, a monomer having an ethylenically unsaturated group is preferably used. Examples of such photopolymerizable monomers include conventionally known polyester (meth)acrylates, polyether (meth)acrylates, urethane (meth)acrylates, carbonate (meth)acrylates, epoxy (meth)acrylates, and the like. Specifically, alkyl acrylates such as 2-ethylhexyl acrylate and cyclohexyl acrylate; hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; monoacrylates or diacrylates of alkylene oxide derivatives such as ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol; acrylamides such as N,N-dimethylacrylamide, N-hydroxymethylacrylamide, and N,N-dimethylaminopropylacrylamide; aminoalkyl acrylates such as N,N-dimethylaminoethyl acrylate and N,N-dimethylaminopropyl acrylate; polyols such as hexanediol, trihydroxymethylpropane, pentaerythritol, ditrihydroxymethylpropane, dipentaerythritol, trihydroxyethyl isocyanate, or epoxy derivatives thereof. Polyacrylates such as alkyl adducts or ε-caprolactone adducts; polyacrylates such as phenols such as phenoxy acrylate and bisphenol A diacrylate or alkylene oxide adducts thereof; acrylates of epoxypropyl ethers such as glycerol diglycidyl ether, trihydroxymethyl propane triglycidyl ether, and triglycidyl triisocyanate; and not limited to the above, at least one of the following can be appropriately selected for use: acrylates and melamine acrylates obtained by directly acrylated polyols such as polyether polyols, polycarbonate diols, hydroxyl-terminated polybutadiene, and polyester polyols or urethane acrylated through diisocyanates, and methacrylates corresponding to the above acrylates. The photopolymerizable monomer can be used alone or in combination of two or more. In addition, the photopolymerizable monomer can also be used as a reactive diluent. In addition, the so-called "photopolymerizable monomer" refers to a compound that is a monomer in a photocurable resin. As the photopolymerizable monomer, a difunctional to hexafunctional photopolymerizable monomer is preferably used. Examples of difunctional to hexafunctional photopolymerizable monomers include dipentatriol hexaacrylate (DPHA), pentatriol pentaacrylate, tricyclodecane dimethanol diacrylate, tricyclodecane dimethanol dimethacrylate, ethoxylated bisphenol A diacrylate, ethoxylated bisphenol A dimethacrylate, trihydroxymethyl tripropane triacrylate, and the like.

The content of the photocurable resin in the curable resin composition is not particularly limited as long as the effect of the present invention can be exerted. For example, it can be set to 10-50 mass % based on the total mass of the solid components of the curable resin composition.

In order to impart alkaline developing properties to the hardening resin composition, the hardening resin may be mixed with a carboxyl group-containing resin. As the carboxyl group-containing resin, various resins known to date having a carboxyl group in the molecule may be used. As specific examples of the carboxyl group-containing resin, the following compounds (which may be either oligomers or polymers) may be cited.

(1) A carboxyl group-containing resin obtained by copolymerizing an unsaturated carboxylic acid such as (meth) acrylic acid with an unsaturated group-containing compound such as styrene, α-methylstyrene, a lower alkyl (meth)acrylate, isobutylene, etc.

(2) A carboxyl group-containing urethane resin obtained by the polyaddition reaction of a diisocyanate such as an aliphatic diisocyanate, a branched aliphatic diisocyanate, an alicyclic diisocyanate, an aromatic diisocyanate, a diol compound containing a carboxyl group such as dihydroxymethylpropionic acid, dihydroxymethylbutyric acid, and a diol compound such as a polycarbonate polyol, a polyether polyol, a polyester polyol, a polyolefin polyol, an acrylic polyol, a bisphenol A-based epoxide adduct diol, and a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group.

(3) A carboxyl group-containing photosensitive urethane resin obtained by a polyaddition reaction of a diisocyanate with a partially anhydride-modified product of a reaction product of 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, biphenol type epoxy resin and a monocarboxylic acid compound having an ethylenically unsaturated group such as (meth) acrylic acid, a carboxyl group-containing diol compound and a diol compound.

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

(5) A carboxyl group-containing photosensitive urethane resin obtained by adding an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate to the synthesis of the resin of (2) or (3) above, and subjecting the resulting resin to terminal (meth)acrylization.

(6) A carboxyl-containing photosensitive resin obtained by reacting (meth) acrylic acid with a difunctional or more multifunctional (solid) epoxy resin and adding a dibasic acid anhydride to a hydroxyl group existing in a side chain.

(7) A carboxyl-containing photosensitive resin obtained by reacting (meth)acrylic acid with a polyfunctional epoxy resin obtained by epoxidizing the hydroxyl group of a bifunctional (solid) epoxy resin with epichlorohydrin, and adding a dibasic acid anhydride to the generated hydroxyl group.

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

(9) A carboxyl group-containing photosensitive resin obtained by reacting a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule such as p-hydroxyphenylethanol with an unsaturated group-containing monocarboxylic acid such as (meth)acrylic acid with an epoxy compound having a plurality of epoxy groups in one molecule, and reacting the alcoholic hydroxyl group of the reaction product with a polyacid anhydride such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyrophyllitic anhydride, adipic acid, etc.

(10) A carboxyl group-containing photosensitive resin obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with a monocarboxylic acid containing an unsaturated group and an alkylene oxide such as ethylene oxide or propylene oxide, and reacting the obtained reaction product with a polyacid anhydride.

(11) A carboxyl group-containing photosensitive resin obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with a monocarboxylic acid containing an unsaturated group and a cyclic carbonate compound such as ethyl carbonate or propylene carbonate with a reaction product, and reacting the reaction product with a polyacid anhydride.

(12) A carboxyl group-containing photosensitive resin, which is obtained by further adding a compound having one epoxy group and one or more (meth)acrylic groups in one molecule to the resins of (1) to (11). In addition, in this specification, the so-called (meth)acrylate is a general term for acrylate, methacrylate and mixtures thereof, and other similar expressions are the same.

The acid value of the carboxyl resin is preferably in the range of 30~150mgKOH/g, preferably in the range of 50~120mgKOH/g. If the acid value of the carboxyl resin is above 30mgKOH/g, alkaline development can be properly performed. On the other hand, if the acid value of the carboxyl resin is below 150mgKOH/g, the exposed part will not be dissolved by the developer, so the developer can distinguish and dissolve the exposed part and the unexposed part and peel them off, so that it is easy to draw a normal anti-etching pattern, which is better.

The weight average molecular weight of the carboxyl-containing resin varies depending on the resin skeleton, and is generally preferably in the range of 2,000 to 150,000, and more preferably in the range of 5,000 to 100,000. If the weight average molecular weight is above 2,000, the moisture resistance of the coating after exposure is good, the film will not be reduced during development, and excellent resolution can be easily obtained. On the other hand, if the weight average molecular weight is below 150,000, good development properties and good storage stability can be easily obtained. The weight average molecular weight can be measured by gel permeation chromatography (GPC).

The carboxyl-containing resins can be used without limitation to those listed above, and can be used alone or in combination of two or more. Among them, the carboxyl-containing resins (10) and (11) synthesized using a compound having a phenolic hydroxyl group as a starting material are suitable for use because of their excellent HAST resistance and PCT resistance.

The (A-2) thermosetting resin may be blended into the curable resin composition as the curable resin. By blending the thermosetting resin into the curable resin composition, it is expected that the heat resistance, chemical resistance and adhesion of the curable resin composition will be improved. The thermosetting resin may be used alone or in combination of two or more. Any known thermosetting resin may be used. For example, known thermosetting resins such as melamine resin, benzoguanamine resin, melamine derivatives, benzoguanamine derivatives, amino resins, isocyanate compounds, blocked isocyanate compounds, cyclocarbonate compounds, epoxy compounds, oxycyclobutane compounds, oxazoline compounds, cyclosulfide resins, dimaleimide, and carbodiimide resins can be used. Each of these thermosetting resins may be monofunctional or polyfunctional.

Examples of epoxy compounds include: epoxidized vegetable oils; bisphenol A epoxy resins; hydroquinone epoxy resins; bisphenol epoxy resins; thioether epoxy resins; brominated epoxy resins; novolac epoxy resins; phenol novolac epoxy resins; biphenol novolac epoxy resins; Lacquer type epoxy resin; bisphenol F type epoxy resin; hydrogenated bisphenol A type epoxy resin; glycidylamine type epoxy resin; hydantoin type epoxy resin; alicyclic epoxy resin; trihydroxyphenylmethane type epoxy resin; dixylenol type or diphenol type epoxy resin or the like mixture; bisphenol S type epoxy resin; bisphenol A novolac type epoxy resin; tetrahydroxyphenylethane type epoxy resin; hybrid epoxy resin; diglycidyl phthalate resin; tetraglycidyl xylenol ethane resin; naphthyl-containing epoxy resin; epoxy resin having a dicyclopentadiene skeleton; epoxy resin copolymerized with epoxy propyl methacrylate; epoxy resin copolymerized with cyclohexylmaleimide and epoxy propyl methacrylate; epoxy-modified polybutadiene rubber derivative; CTBN-modified epoxy resin, but not limited to the above. These epoxy resins may be used alone or in combination of two or more.

As the cyclohexane compound, a polyfunctional cyclohexane compound having two or more cyclohexane groups in one molecule is preferably used. Examples of the polyfunctional cyclohexane compound include bis[(3-methyl-3-cyclohexanebutanylmethoxy)methyl]ether, bis[(3-ethyl-3-cyclohexanebutanylmethoxy)methyl]ether, 1,4-bis[(3-methyl-3-cyclohexanebutanylmethoxy)methyl]benzene, 1,4-bis[(3-ethyl-3-cyclohexanebutanylmethoxy)methyl]benzene, (3-methyl-3-cyclohexanebutanyl)methacrylate, (3-ethyl-3-cyclohexanebutanyl)methyl Examples of the present invention include polyfunctional cyclobutanes such as acrylate, (3-methyl-3-cyclooxobutane) methyl methacrylate, (3-ethyl-3-cyclooxobutane) methyl methacrylate, oligomers or copolymers thereof, and ethers of cyclooxobutane alcohol and resins having a hydroxyl group such as novolac resin, poly(p-hydroxystyrene), cardo-type bisphenols, calixarene, calixresorcinarene or silsesquioxane. In addition, copolymers of unsaturated monomers having cyclooxobutane rings and alkyl (meth)acrylates can also be mentioned.

Examples of the oxazoline compound include compounds having two or more oxazoline groups in one molecule. Examples of such oxazoline compounds include polymers containing oxazoline group monomers, copolymers of oxazoline group-containing monomers and other monomers, and other oxazoline group-containing polymers. Examples of the oxazoline group-containing monomers include 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, 2-isopropenyl-2-oxazoline, and 2-isopropenyl-4,4-dimethyl-2-oxazoline.

Examples of the epoxide sulfide resin include compounds obtained by replacing the oxygen atom constituting the epoxy group in any epoxy compound with a sulfur atom. Examples of the epoxy compound include the same as those mentioned above. As a method for replacing the oxygen atom constituting the epoxy group in the epoxy compound with a sulfur atom, a conventionally known method can be used.

Amino resins such as melamine derivatives and benzoguanamine derivatives can be used to produce hydroxymethylmelamine compounds, hydroxymethylbenzoguanamine compounds, hydroxymethylacetylene urea compounds, and hydroxymethylurea compounds.

A polyisocyanate compound may be mixed as the isocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as 4,4'-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,5-naphthalene diisocyanate, o-isocyanate, m-isocyanate, and 2,4-toluene dimer; tetramethylene diisocyanate, hexaisocyanate, and the like. Aliphatic polyisocyanates such as methylene diisocyanate, methylene diisocyanate, trimethylhexamethylene diisocyanate, 4,4-methylenebis(cyclohexyl isocyanate) and isophorone diisocyanate; alicyclic polyisocyanates such as dicycloheptane triisocyanate; and adducts, biuret forms and isocyanurate forms of the isocyanate compounds listed above.

The blocked isocyanate compound may be an addition reaction product of an isocyanate compound and an isocyanate blocking agent. Examples of the isocyanate compound that can react with the isocyanate blocking agent include the above-mentioned polyisocyanate compound, etc. Examples of the isocyanate blocking agent include: phenol-based blocking agents; lactam-based blocking agents; active methylene-based blocking agents; alcohol-based blocking agents; oxime-based blocking agents; thiol-based blocking agents; amide-based blocking agents; imide-based blocking agents; amine-based blocking agents; imidazole-based blocking agents; imine-based blocking agents, etc.

The content of the thermosetting resin in the curable resin composition is not particularly limited as long as the effect of the present invention can be exerted. For example, it can be set to 3-50 mass % based on the solid content relative to the total mass of the solid components of the curable resin composition.

(Filler) The curable resin composition of the present invention contains (B) a surface-treated barium compound and (C) a surface-treated silicon dioxide as fillers. The total content of the surface-treated barium compound and the surface-treated silicon dioxide in the curable resin composition is 20-80% by mass, preferably 20-50% by mass, and more preferably 30-40% by mass, based on the total mass of the solid components of the curable resin composition. In addition, the mass ratio of the surface-treated barium compound to the surface-treated silicon dioxide in the curable resin composition based on the solid components is 1:1-1:4, preferably 1:1-1:3, and more preferably 1:1.5-1:2. By making the total content of the surface-treated barium compound and the surface-treated silicon dioxide, and their solid component-based mass ratio within the above range, both good resolvability and crack resistance can be achieved.

Regarding the surface-treated barium compound, the concept of the so-called barium compound includes barium monomers and various compounds containing barium. That is, the surface-treated barium compound includes a compound obtained by surface-treating a barium monomer and a compound obtained by surface-treating a compound containing barium. The surface-treated barium compound may be used alone or in combination of two or more.

The compound containing barium is not particularly limited as long as it is a compound that can be used as a filler, and examples thereof include barium sulfate, barium titanate, barium oxide, and barium hydroxide. Barium sulfate is preferably used as the compound containing barium. Commercial products of barium sulfate include B-30 and B-33 manufactured by Sakai Chemical Industry Co., Ltd.

The surface treatment of the barium compound is not particularly limited as long as it is a treatment that can impart reactive functional groups to the surface of the barium compound, and the surface treatment of fillers known to date can be performed. Examples of the reactive functional groups imparted to the surface of the barium compound include methacryloyl groups, carboxyl groups, hydroxyl groups, sulfonic acid groups, amino groups, epoxy groups, vinyl groups, butyl groups, acid anhydrides, and the like. The surface-treated barium compound may have one reactive functional group, or may have two or more reactive functional groups. Furthermore, when two or more surface-treated barium compounds are used, they may have the same reactive functional groups, or may have different reactive functional groups. The surface-treated barium compound is preferably a barium compound having a methacryloyl group on its surface.

As a method for obtaining a surface-treated barium compound, that is, a method for imparting a reactive functional group to the surface of a barium compound, a method known to date can be used. For example, the following methods can be cited: a method of bonding various coupling agents having reactive functional groups (such as silane compounds (so-called silane-based coupling agents)) to a barium compound (bonding the barium compound to the reactive functional group via the coupling agent). In addition, in this specification, the concept of "bonding" between a coupling agent and a barium compound includes not only bonding accompanied by a chemical reaction between the coupling agent and the barium compound (chemical adsorption), but also bonding not accompanied by the chemical reaction (physical adsorption).

Examples of coupling agents include silane-based, aluminate-based, titanium ester-based, zirconium-aluminate-based, etc. Among these, silane-based coupling agents are preferably used. Examples of the silane coupling agent include vinyl trimethoxysilane, vinyl triethoxysilane, N-(2-aminomethyl)-3-aminopropyl methyl dimethoxysilane, N-(2-aminoethyl)-3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, 3-anilinopropyl trimethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl methyl dimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, 3-methacryloyloxypropyl trimethoxysilane, and 3-butyl trimethoxysilane. The coupling agent may be used alone or in combination of two or more.

When the surface-treated barium compound is obtained by bonding a coupling agent having a reactive functional group to a barium compound, the method can use a method known to date. Specifically, the following methods can be cited: a method in which a powdered barium compound is dispersed in a solution obtained by dissolving a coupling agent having a reactive functional group in a solvent (the solvent is removed as required) and the two are brought into contact; a method in which a powdered barium compound is directly added to a coupling agent having a reactive functional group and mixed to bring the two into contact. In addition, a step of heating may be included after bringing the coupling agent having a reactive functional group into contact with the powdered barium compound as required. The amount of the coupling agent having a reactive functional group to be brought into contact with the barium compound in the powder (the amount of the coupling agent to be treated) can be appropriately set according to the method of bonding the coupling agent having a reactive functional group to the barium compound, the type of the reactive functional group, the type of the coupling agent, etc.

The particle size of the surface-treated barium compound is not particularly limited and can be appropriately set, but the average particle size is preferably 0.1~1µm, and more preferably 0.1~0.5µm. By setting the average particle size of the surface-treated barium compound to be within the above range, good resolvability can be obtained. In addition, in this specification, the average particle size of the filler is the average particle size before being mixed into the curable resin composition, and is the D50 value measured by the laser diffraction method. The average particle size (D50) measuring device of the laser diffraction method can use Microtrac MT3300EXII manufactured by MicrotracBEL Co., Ltd.

The content of the surface-treated barium compound in the curable resin composition is not particularly limited as long as it satisfies the range of the total content of the surface-treated barium compound and the surface-treated silica on a solid component basis, and the mass ratio of the solid component basis thereof. However, for example, the content of the surface-treated barium compound is 7 to 28% by mass on a solid component basis relative to the total mass of the solid component of the curable resin composition. In addition, when two or more surface-treated barium compounds are used in combination, the content of the surface-treated barium compound refers to the total content of all surface-treated barium compounds.

As the silicon dioxide constituting the surface-treated silicon dioxide, any one of amorphous silicon dioxide, non-crystalline silicon dioxide, crystalline silicon dioxide, fused silicon dioxide, spherical silicon dioxide, etc. can be used. Silicon dioxide can be used alone or in combination of two or more. As silicon dioxide, spherical silicon dioxide is preferably used. Commercially available products of spherical silicon dioxide include SO-C2 and SO-E2 manufactured by Admatechs Co., Ltd. and SFP-20M manufactured by Denka Co., Ltd.

The type and method of surface treatment of silicon dioxide are not particularly limited, and can be, for example, the same as the surface treatment of the barium compound described above.

The particle size of the surface-treated silicon dioxide is not particularly limited and can be appropriately set, but the average particle size can be set to, for example, 0.01 to 1 µm. By setting the average particle size of the surface-treated silicon dioxide to be within the above range, good resolvability can be obtained.

The content of the surface-treated silica in the curable resin composition is not particularly limited as long as it satisfies the range of the total content of the surface-treated barium compound and the surface-treated silica based on the solid component, and the mass ratio of the solid component based on the solid component. For example, the content of the surface-treated silica is 13 to 52% by mass based on the solid component relative to the total mass of the solid component of the curable resin composition. In addition, when two or more surface-treated silicas are used in combination, the content of the surface-treated silica refers to the total content of all surface-treated silicas.

In addition to the surface-treated barium compound and the surface-treated silica, the curable resin composition may further contain other fillers. Other fillers may include known inorganic or organic fillers, such as hydrotalcite, talc, and metal oxides such as titanium oxide for obtaining a white appearance or flame retardancy, and metal hydroxides such as aluminum hydroxide.

(Rubber particles) The curable resin composition of the present invention includes (D) rubber particles. The material constituting the rubber particles is not particularly limited as long as it is a material with excellent flexibility, and various elastomers such as butadiene elastomers, silicone elastomers, styrene elastomers, acrylic elastomers, polyolefin elastomers, silicone/acrylic composite elastomers, etc. can be cited. As the material constituting the rubber particles, butadiene elastomers are preferably used. The rubber particles may be used alone or in combination of two or more.

The rubber particles preferably have a core-shell structure, and preferably have the following core-shell structure: A core-shell structure (core-shell rubber particles) having an inner core layer made of a material having excellent softness and an outer shell layer made of a material having excellent affinity for other components. The rubber particles have a core-shell structure, whereby the inner core layer is beneficial to impact resistance and the outer shell layer is beneficial to dispersibility in the curable resin composition, resulting in a high stress relief effect of the curable resin composition.

The material constituting the inner core layer is not particularly limited as long as it is a material with excellent flexibility, and examples thereof include the various elastic bodies mentioned above.

The material constituting the outer shell layer can be a material having excellent affinity with other components, and can be appropriately set according to the relationship with the components other than the rubber particles mixed in the curable resin composition. For example, if the curable resin composition includes epoxy resin, the outer shell layer can be composed of a material having excellent affinity with epoxy resin, such as acrylic resin or epoxy resin.

The rubber particles may also have a curable reactive group on the surface thereof that can undergo a curing reaction with the curable resin. The curable reactive group may be a photocurable reactive group or a thermocurable reactive group. The rubber particles may have one type of curable reactive group alone or may have two or more types of curable reactive groups in combination.

The photocurable reactive group may include a vinyl group, a styryl group, a methacryl group, an acryl group, and the like.

Examples of the thermosetting reactive group include a hydroxyl group, a carboxyl group, an isocyanate group, an imino group, an epoxy group, an oxacyclobutane group, an oxadiazole group, a methoxymethyl group, a methoxyethyl group, an ethoxymethyl group, an ethoxyethyl group, and an oxazoline group.

The method of introducing the curing reactive group into the surface of the rubber particles is not particularly limited, and a known and conventional method can be adopted. For example, when forming an outer shell layer around the inner core layer, a material having a curing reactive group as a material constituting the outer shell layer can be polymerized into the inner core layer to introduce the curing reactive group; the curing reactive group is different from the functional group used for polymerization reaction with the inner core layer.

The particle size of the rubber particles is not particularly limited and can be appropriately set, but the average particle size can be set to, for example, 0.001 to 0.5 µm. By setting the average particle size of the rubber particles within the above range, good resolvability can be obtained. In addition, in this specification, the average particle size of the rubber particles is the average particle size before being mixed with the curable resin composition, and is the D50 value measured by the laser diffraction method. The average particle size (D50) measuring device of the laser diffraction method can use the laser diffraction scattering particle size distribution measuring device Microtrac MT3300 manufactured by MicrotracBEL Co., Ltd.

The content of the rubber particles in the curable resin composition is not particularly limited and can be appropriately set, but for example, the rubber particle content is 0.3 to 5% by mass based on the solid content relative to the total mass of the solid components of the curable resin composition. By setting the rubber particle content within the above range, good crack resistance can be obtained.

(Photopolymerization initiator) If the curable resin composition of the present invention contains a photocurable resin, the curable resin composition preferably further contains (E) a photopolymerization initiator. Any known photopolymerization initiator can be used. Furthermore, the photopolymerization initiator can be used alone or in combination of two or more.

Specific examples of the photopolymerization initiator include bis-(2,6-dichlorobenzyl)phenylphosphine oxide, bis-(2,6-dichlorobenzyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzyl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzyl)phenylphosphine oxide, bis-(2,6-dimethoxybenzyl)-2,4,4-trimethylpentylphosphine oxide, bis-(2,6-dimethoxybenzyl)-2,5-dimethylphenylphosphine oxide, Bis-(2,4,6-trimethylbenzyl)-phenylphosphine oxide and other bisacylphosphine oxides; 2,6-dimethoxybenzyldiphenylphosphine oxide, 2,6-dichlorobenzyldiphenylphosphine oxide, 2,4,6-trimethylbenzylphenylphosphinate methyl ester, 2-methylbenzyldiphenylphosphine oxide, trimethylacetylphenylisophosphinate isopropyl ester, 2,4,6-trimethylbenzyldiphenylphosphine oxide and other monoacylphosphine oxides; ethyl phenyl (2,4,6-trimethylbenzyl)phosphinate, 1-hydroxy-cyclohexylphenyl ketone, 1-[4-(2-hydroxyethyl)phenyl]phosphine oxide; [4-(2-hydroxy-2-methyl-propionyl)-benzyl]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-1-phenylpropan-1-one and other hydroxyacetophenones; benzoin, benzyl, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, benzoin n-butyl ether and other benzoin alkyl ethers; diphenyl ketone, p-methyl diphenyl ketone, michler's ketone, methyl diphenyl ketone, 4,4'-dichlorodiphenyl ketone, 4,4'-bis(diethylamino)phenyl ketone Diphenyl ketone and other diphenyl ketones; acetophenones 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-oxoformyl-1-propanone, 2-benzyl-2-dimethylamino-1-(4-oxoformylphenyl)-butan-1-one, 2-(dimethylamino)-2-[(4-methylphenyl)methyl)-1-[4-(4-oxoformyl)phenyl]-1-butanone, N,N-dimethylaminoacetophenone, etc.; 9-oxosulfuron , 2-ethyl 9-oxosulfuron , 2-isopropyl 9-oxysulfide , 2,4-dimethyl 9-oxosulfuron , 2,4-diethyl 9-oxysulfide , 2-chloro-9-oxysulfuron 、2,4-Diisopropyl 9-oxysulfide 9-Oxysulfuron anthraquinones such as anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-pentylanthraquinone, and 2-aminoanthraquinone; acetophenone dimethyl ketal, benzyl dimethyl ketal, and other ketones; ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethylbenzoate, ethyl p-dimethylbenzoate, and other benzoate esters; 1,2-octanedione, 1-[4-(phenylthio)phenyl]-, 2-(O-benzoyl oxime), ethanol, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-, 1- Oxime esters such as (O-acetyl oxime); 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-pyrrol-1-yl)ethyl)phenyl]titanium and other diocenes; alkyl phenones such as 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-oxofolinylphenyl)-butane-1-one; 2-nitrofluorene disulfide phenyl 2-nitrofluorene, butyroin, anisolein ethyl ether, azobisisobutyronitrile, tetramethylthiuram disulfide, etc. Commercially available photopolymerization initiators include, for example, Omnirad TPO H (2,4,6-trimethylbenzyldiphenylphosphine oxide), IRGACURE OXE02 (ethanol, 1-[9-ethyl-6-(2-methylbenzyl)-9H-carbazol-3-yl]-, 1-(o-acetyl oxime)), Omnirad 369E (2-benzyl-2-(dimethylamino)-4'-morphofolinylbutyrophenone), Omnirad 907 (2-methyl-1-[4-(methylthio)phenyl]-2-morphofolinylpropan-1-one), and Omnirad 819 (bis(2,4,6-trimethylbenzyl)-phenylphosphine oxide) manufactured by IGM Resins BV.

A photopolymerization aid or sensitizer may also be used together with the above-mentioned photopolymerization initiator. Examples of the photopolymerization aid or sensitizer include benzoin compounds, anthraquinone compounds, 9-oxysulfuronium, Compounds, acetal compounds, diphenyl ketone compounds, tertiary amine compounds and thiophene compounds. In particular, 2,4-dimethyl 9-oxysulfide is preferably used. , 2,4-diethyl 9-oxysulfide , 2-chloro-9-oxysulfuron , 2-isopropyl 9-oxysulfide , 4-isopropyl 9-oxysulfide 9-Oxysulfuron Compound. By containing 9-oxosulfuron Compounds can improve deep curability. These compounds can sometimes be used as photopolymerization initiators, but it is best to use them together with photopolymerization initiators. In addition, photoinitiator aids or sensitizers can be used alone or in combination of two or more.

In addition, these photopolymerization initiators, photoinitiator aids and sensitizers absorb specific wavelengths, so in some cases, they can reduce sensitivity and function as ultraviolet absorbers. However, they are not only used to increase the sensitivity of curable resin compositions. They can absorb light of specific wavelengths as needed to increase the light reactivity of the surface, change the line shape and opening of the anti-corrosion layer into vertical, conical, or inverted conical shapes, and improve the accuracy of line width and opening diameter.

(Thermosetting catalyst) If the curable resin composition of the present invention contains a thermosetting resin, the curable resin composition preferably further contains a thermosetting catalyst. The thermosetting catalyst may include, for example, 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, 2-phenyl-4,5-dihydroxymethylimidazole; 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 dihydrazide adipic acid and dihydrazide sebacic acid; phosphorus compounds such as triphenylphosphine, etc. In addition, commercially available ones include, for example, 2MZ-A, 2MZ-OK, 2PHZ, 2PHZ-PW, 2P4BHZ, 2P4MHZ (all trade names of imidazole compounds) manufactured by Shikoku Chemical Industries, Ltd., U-CAT 3513N (trade name of dimethylamine compounds), DBU, DBN, U-CAT SA 102 (all bicyclic amidine compounds and their salts) manufactured by San-Apro Ltd. However, the present invention is not particularly limited to these, and any heat-curing catalyst for epoxy resin or cyclohexane compound, or any catalyst that can promote the reaction between at least one of epoxy group and cyclohexane group and carboxyl group can be used, and it can be used alone or in combination of two or more. In addition, guanamine, methylguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triacontium, 2-vinyl-2,4-diamino-S-triacontium, 2-vinyl-4,6-diamino-S-triacontium・isocyanuric acid adduct, 2,4-diamino-6-methacryloyloxyethyl-S-triacontium・isocyanuric acid adduct and other S-triacontium derivatives can also be used. It is preferable to use these compounds that can also function as adhesion imparting agents together with the thermosetting catalyst. The thermosetting catalyst can be used alone or in combination of two or more. Melamine and dicyandiamide (DICY) are preferably used as the thermosetting catalyst, and melamine and dicyandiamide are preferably used in combination.

(Organic solvent) An organic solvent may be mixed into the curable resin composition of the present invention for the purpose of preparing the resin composition or adjusting the viscosity when the resin composition is applied to a substrate or a film. As the organic solvent, a well-known and commonly used organic solvent can be used, for example, ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers such as cellulose, methyl cellulose, butyl cellulose, 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, cellulose acetate, butyl cellulose 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; petroleum-based solvents such as petroleum ether, petroleum naphtha, and solvent naphtha, etc. Organic solvents may be used alone or in combination of two or more.

The amount of the organic solvent blended in the curable resin composition is not particularly limited and can be appropriately changed according to the components and amounts constituting the curable resin composition.

In the present invention, the volatile drying of the organic solvent can be performed using a hot air circulation drying furnace, an IR furnace, a heating plate, a convection oven, etc. (using a heat source having an air heating method using steam and making the hot air in the dryer contact by convection, and a method of blowing to the support through a nozzle).

(Other additives) The following ingredients may be further blended into the curable resin composition of the present invention as required: coloring agent, photoinitiator, cyanate compound, elastomer, sulfonyl compound, urethane catalyst, catalytic agent, adhesion promoter, block copolymer, chain transfer agent, polymerization inhibitor, copper corrosion inhibitor, antioxidant, rust inhibitor, thickener such as organic bentonite and montmorillonite, at least one of polysilicone, fluorine, polymer defoamer and leveling agent, imidazole, thiazole, triazole and other silane coupling agents, phosphonate, phosphate derivatives, phosphorus compounds such as phosphazene compounds and flame retardants. These may use what is known in the field of electronic materials.

The curable resin composition of the present invention can be used in a liquid form or after being dried as described below. When used in a liquid form, it can be a single liquid or a two-liquid or more liquid form.

[Dry film] The curable resin composition of the present invention can also be made into a dry film form, and the dry film has a first film and a resin layer, and the resin layer is formed on the first film and is composed of the curable resin composition. The first film in the present invention refers to at least the film that is in contact with the resin layer when the substrate such as a substrate and the layer (resin layer) composed of the curable resin composition formed on the dry film are laminated and formed as a whole by heating or the like. The first film can also be peeled off from the resin layer in the step after lamination. In particular, in the present invention, it is preferable to peel it off from the resin layer in the step after exposure. During the drying process, the curable resin composition of the present invention can be diluted with the above-mentioned organic solvent to adjust to an appropriate viscosity, and then coated on the first film to a uniform thickness by a notch wheel coater, a scraper coater, a lip coater, a rod coater, an extrusion coater, a reverse coater, a transfer roll coater, a gravure coater, a spray coater, etc., and usually dried at a temperature of 50-130°C for 1-30 minutes to obtain a film. There is no particular restriction on the coating film thickness. It can generally be appropriately selected within the range of 1-150µm, and preferably within the range of 5-60µm, based on the film thickness after drying.

As the first film, any known material can be used without particular limitation. For example, films made of thermoplastic resins such as polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyimide films, polyamide imide films, polypropylene films, and polystyrene films can be suitably used. Among these, polyester films are preferred from the viewpoints of heat resistance, mechanical strength, and handling properties. In addition, a laminate of these films can also be used as the first film.

In addition, from the viewpoint of improving mechanical strength, the above-mentioned thermoplastic resin film is preferably a film stretched along a uniaxial direction or a biaxial direction.

The thickness of the first film is not particularly limited, but can be set to, for example, 5µm to 150µm.

After forming a resin layer of the curable resin composition of the present invention on the first film, a peelable second film is preferably further deposited on the surface of the resin layer in order to prevent dust from adhering to the surface of the resin layer. The second film refers to a film that is peeled off from the resin layer before lamination when a substrate such as a substrate is laminated and formed integrally with a layer (resin layer) composed of a curable resin composition formed on a dry film. As the peelable second film, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, a surface-treated paper, etc. can be used. The second film can be used as long as the adhesion between the resin layer and the second film is smaller than the adhesion between the resin layer and the first film when the second film is peeled off.

The thickness of the second film is not particularly limited, but can be set to, for example, 5 μm to 150 μm.

In addition, the dry film may be formed by coating the curable resin composition of the present invention on the second film and drying it to form a resin layer, and then laminating the first film on the surface of the resin layer. That is, in the present invention, when manufacturing the dry film, either the first film or the second film may be used as the film on which the curable resin composition of the present invention is coated.

(Hardened product) The cured product of the present invention is obtained by curing the above-mentioned curable resin composition of the present invention or the resin layer of the dry film. The cured product particularly has high dielectric properties and good resolution required for the solder resist layer.

(Printed wiring board) The printed wiring board of the present invention has a cured product obtained from the curable resin composition of the present invention or a resin layer of a dry film. As a manufacturing method of the printed wiring board of the present invention, for example, the curable resin composition of the present invention is adjusted to a viscosity suitable for the coating method using the above-mentioned organic solvent, and then coated on the substrate by a dip coating method, a flow coating method, a roller coating method, a rod coating method, a screen printing method, a curtain coating method, etc., and then the organic solvent contained in the composition is volatilized and dried (temporarily dried) at a temperature of 60~100℃, thereby forming a non-sticky resin layer. In addition, when it is a dry film, the resin layer is attached to the substrate by lamination or the like in such a way that the resin layer contacts the substrate, and then the first film is peeled off to form a resin layer on the substrate.

The substrate of the printed wiring board can be a printed wiring board or a flexible printed wiring board with a circuit formed in advance by copper or the like, and can also be a copper-clad laminate of all grades (FR-4, etc.) using materials such as phenolic paper, epoxy paper, epoxy glass cloth, polyimide glass, epoxy glass cloth/non-woven fabric, epoxy glass cloth/paper, epoxy synthetic fiber, fluorine resin, polyethylene, polyphenylene ether, polyoxyphenylene, cyanate, etc., and copper-clad laminates for high-frequency circuits, etc., and other materials include metal substrates, polyimide films, polyethylene terephthalate films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafer boards, etc.

It is preferable to use a vacuum laminator or the like to laminate the dry film onto the substrate under pressure and heating. When using a substrate after forming a circuit using the vacuum laminator, even if the circuit substrate surface has bumps and depressions, the dry film will still adhere to the circuit substrate, so that no air bubbles will be mixed in, and the filling property of the concave part of the substrate surface will also be improved. The pressure condition is preferably about 0.1~2.0MPa, and the heating condition is preferably 40~120℃.

The volatile drying after coating the curable resin composition of the present invention can be performed using a hot air circulation drying furnace, an IR furnace, a heating plate, a convection oven, etc. (a method of using a heat source having an air heating method using steam and making the hot air in the dryer contact by convection, and a method of blowing the support through a nozzle).

After forming a resin layer on a substrate, it is selectively exposed by active energy rays through a photomask formed with a predetermined pattern, and then the unexposed portion is developed with a dilute alkaline aqueous solution (e.g., 0.3~3 mass% sodium carbonate aqueous solution) to form a pattern of the cured product. In the case of a dry film, the first film is peeled off from the dry film after exposure and developed, thereby forming a patterned cured product on the substrate. In addition, if it is within the range that does not damage the properties, the first film can also be peeled off from the dry film before exposure, and then the exposed resin layer can be exposed and developed. Further, after irradiating the cured product with active energy rays, it is heat-cured (e.g., 100~220°C), or after heat-curing, it is irradiated with active energy rays, or only heat-cured for final fine curing (formal curing), thereby forming a cured film with excellent properties such as adhesion and hardness. In one embodiment, the above exposure and development can be used to form an exposed portion (circular opening) of the conductor on the substrate. The diameter of the opening is not particularly limited, but can be set to, for example, 30 to 120 μm.

The exposure machine used for active energy ray irradiation can be a device that irradiates ultraviolet rays in the range of 350~450nm, equipped with high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halogen lamps, mercury short arc lamps, etc., and can also use direct drawing devices (such as laser direct imaging devices that directly draw images with lasers based on CAD data from computers). The lamp light source or laser light source of the direct drawing machine can be one with a maximum wavelength in the range of 350~450nm. The exposure amount used to form an image will vary depending on the film thickness, etc., and can generally be set in the range of 10~1000mJ/ ^cm2 , preferably in the range of 20~800mJ/ ^cm2 .

The developing method can utilize immersion method, spray method, spray coating method, brush coating method, etc., and the developer can adopt alkaline aqueous solution such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amine, etc.

When curing the curable resin composition of the present invention, after the exposure and development by the active energy ray irradiation, ultraviolet rays can be irradiated to promote further curing (post-UV), or heating can be performed to promote thermal curing (post-curing). By performing post-UV and post-curing, the heat resistance, chemical resistance, moisture absorption resistance, adhesion, electrical properties and other properties of the cured product of the curable resin composition can be further improved. Post-UV can be performed by irradiating UV at a cumulative exposure of 1000mJ/ ^cm2 using a UV conveyor belt, etc. In addition, post-curing can be performed by heating at 150°C for 60 minutes using the above-mentioned various dryers, for example.

The curable resin composition or dry film of the present invention is suitable for use in manufacturing electronic components such as printed wiring boards. Specifically, it can be used to form a curing film (permanent film) in electronic components, and is suitable for forming permanent insulating films such as solder resist films, interlayer insulating layers, and cover layers. More specifically, the curable resin composition or dry film of the present invention is suitable for use in printed wiring boards that require high reliability, such as semiconductor packaging substrates, and is particularly suitable for use in FC-BGA substrates.

Examples The following examples are given to further illustrate the present invention, but the present invention is not limited to the examples. In addition, in the examples, the "parts" and "%" are all based on quality unless otherwise specified.

[Preparation of curable resin composition] (Synthesis example of photocurable resin) Before preparing the curable resin composition, the photocurable resin used in this embodiment is prepared according to the procedure shown below. First, 456 parts of bisphenol A, 228 parts of water and 649 parts of 37% formalin are added to a flask equipped with a cooling tube and a stirrer, and the temperature is maintained below 40°C, and 228 parts of a 25% sodium hydroxide aqueous solution are added. After the addition is completed, the mixture is reacted at 50°C for 10 hours. After the reaction is completed, the mixture is cooled to 40°C, and a 37.5% phosphoric acid aqueous solution is added while the temperature is maintained below 40°C to neutralize to pH 4, and then the mixture is left to stand to separate the water layer. After separating the aqueous layer, 300 parts of methyl isobutyl ketone were added and uniformly dissolved, and then washed with 500 parts of distilled water three times, and the pressure was reduced at a temperature below 50°C to remove water, solvents, etc. to obtain a polyhydroxymethyl compound. The obtained polyhydroxymethyl compound was dissolved in 550 parts of methanol to obtain 1230 parts of a methanol solution of a polyhydroxymethyl compound. A portion of the obtained methanol solution of a polyhydroxymethyl compound was dried in a vacuum dryer at room temperature, and the solid content was 55.2%. Then, 500 parts of the obtained methanol solution of a polyhydroxymethyl compound and 440 parts of 2,6-xylenol were added and uniformly dissolved at 50°C. After uniform dissolution, methanol was removed under reduced pressure at a temperature below 50°C. Then, 8 parts of oxalic acid were added and the reaction was carried out at 100°C for 10 hours. After the reaction was completed, the distilled part was removed at 180°C and under a reduced pressure of 50 mmHg to obtain 550 parts of phenolic varnish resin A.

Next, 130 parts of the phenolic varnish resin A obtained in the above procedure, 2.6 parts of a 50% sodium hydroxide aqueous solution, and 100 parts of toluene/methyl isobutyl ketone (mass ratio = 2/1) were fed into an autoclave equipped with a thermometer, a nitrogen introduction device and an oxirane introduction device, and a stirring device. The system was replaced with nitrogen while stirring, and then the temperature was raised, and 45 parts of ethylene oxide was slowly introduced at 150°C at 8kg/ ^cm2 to react. The reaction lasted for about 4 hours until the gauge pressure reached 0.0kg/ ^cm2 , and then cooled to room temperature. 3.3 parts of a 36% hydrochloric acid aqueous solution were added to the obtained reaction solution and mixed to neutralize the sodium hydroxide. The neutralization reaction product was diluted with toluene and washed with water three times, and then the solvent was removed using a distiller to obtain an ethylene oxide adduct of novolac resin A having a hydroxyl value of 175 g/eq. The ethylene oxide adduct of novolac resin A has an average of 1 mol of ethylene oxide added per 1 equivalent of phenolic hydroxyl group.

Next, 175 parts of the obtained ethylene oxide adduct of the novolac resin A, 50 parts of acrylic acid, 3.0 parts of p-toluenesulfonic acid, 0.1 parts of hydroquinone monomethyl ether and 130 parts of toluene were fed into a reactor equipped with a stirrer, a thermometer and an air blowing tube, and stirred while blowing air, and the temperature was raised to 115°C to react, and then the water generated by the reaction was distilled off as an azeotropic mixture with toluene, and the reaction was further carried out for 4 hours, and then cooled to room temperature. The obtained reaction solution was washed with a 5% NaCl aqueous solution, and after toluene was removed by distillation under reduced pressure, diethylene glycol monoethyl ether acetate was added to obtain an acrylic resin solution with a solid content of 68%.

Next, 312 parts of the obtained acrylic resin solution, 0.1 parts of hydroquinone monomethyl ether and 0.3 parts of triphenylphosphine were added to a four-necked flask equipped with a stirrer and a reflux cooler, and the mixture was heated to 110°C, and then 45 parts of tetrahydrophthalic anhydride were added and reacted for 4 hours. After cooling, a solution of a photocurable resin (containing a carboxyl resin) having a solid content of 70% and a solid acid value of 65 mgKOH/g was obtained.

(Synthesis example of surface-treated barium compound) Before preparing the curable resin composition, the surface-treated barium compound used in this example was prepared according to the procedure shown below. First, 700 g of barium sulfate B-30 (average particle size 0.3 µm) manufactured by Sakai Chemical Industry Co., Ltd., 295 g of diethylene glycol monoethyl ether acetate (carbitol acetate) as a solvent, and 5 g of a wetting dispersant were mixed and stirred, and a bead mill was used to perform a dispersion treatment until the average particle size became 0.3 µm. After the dispersion treatment, the obtained dispersion was filtered with a 3 µm filter to remove foreign matter or coarse particles, and a barium sulfate slurry with an average particle size of 0.3 µm was obtained. The solid content of the obtained barium sulfate slurry was 70% by mass.

(Synthesis example of surface-treated silica) Before preparing the curable resin composition, the surface-treated silica used in this example was prepared according to the procedure shown below. 700 g of spherical silica SO-C2 manufactured by Admatechs Co., Ltd. and 300 g of propylene glycol monomethyl ether acetate (PMA) as a solvent were mixed and stirred, and dispersed using a bead mill until the average particle size became 0.7 µm. After the dispersion treatment, the obtained dispersion was filtered with a 3 µm filter to remove foreign matter or coarse particles, and a silica slurry with an average particle size of 0.7 µm was obtained. The solid content of the obtained silica slurry was 70% by mass. Then, methacrylic silane coupling agent KBM-503 manufactured by Shin-Etsu Chemical Co., Ltd. was added to the obtained silica slurry in an amount of 4% by mass, and the mixture was dispersed in a bead mill for 10 minutes to obtain spherical silica slurry surface-treated with methacrylic silane. The solid content of the obtained spherical silica slurry was 70% by mass.

The components shown in Table 1 below were mixed in the amounts (solid content) shown in the same table, pre-mixed with a stirrer, and then kneaded with a three-roll mill to prepare the curable resin compositions of Examples 1 to 7 and Comparative Examples 1 to 5. In addition, the details of the components in Table 1 are as follows. (A-1) Photocurable resin: carboxyl resin obtained in the above-mentioned synthesis example of photocurable resin (A-2) Thermocurable resin: jER (registered trademark) 834 manufactured by Mitsubishi Chemical Co. (B) Surface-treated barium compound: Surface-treated barium sulfate slurry obtained in the above-mentioned synthesis example of surface-treated barium compound (C) Surface-treated silica: Surface-treated spherical silica slurry obtained in the above-mentioned synthesis example of surface-treated silica (D) Rubber particles: Butadiene rubber Metablen (registered trademark) C-223A manufactured by Mitsubishi Chemical Co. (E) Photopolymerization initiator: 2,4,6-trimethylbenzyldiphenylphosphine oxide Photopolymerizable monomer: Acrylate monomer (DPHA: dipentatriol hexaacrylate) Thermosetting catalyst 1: Melamine Thermosetting catalyst 2: Dicyandiamide [Table 1]

[Preparation of laminated structures] Using each hardening resin composition obtained by the above procedure, a laminated structure (dry film) corresponding to each hardening resin composition was prepared by the procedure shown below. First, each hardening resin composition was appropriately diluted with methyl ethyl ketone using a bar coater, and then applied to PET film FB-50 (thickness 16µm) manufactured by TORAY Co., Ltd. using a sprinkler so that the film thickness after drying became 18µm, and dried at 80°C for 10 minutes to obtain a dry film corresponding to each hardening resin composition.

[Analytical evaluation] Using a vacuum laminator CVP-300 manufactured by Nikko-Materials Co., Ltd., the dry films prepared according to the above procedure were heat-laminated on a substrate having a copper circuit formed thereon by chemical polishing using MECetchBOND CZ-8101 manufactured by MEC Co., Ltd. at a temperature of 80°C and a vacuum pressure of 3 hPa at a pressure of 0.4 MPa for 1 minute. Then, flat-plate pressing was performed at a temperature of 70°C at a pressure of 0.5 MPa to obtain a substrate having a layer (dry film) of each unexposed curable resin composition. Using a φ50µm mask and an exposure device equipped with a high-pressure mercury lamp (short arc lamp), the obtained substrates were exposed at a standard exposure amount, and then the PET film was peeled off from the dry film. Then, at 30°C and a spray pressure of 2kg/ ^cm2 , a 1 mass% _{Na2CO3 aqueous} solution was used for development for 60 seconds to obtain each sample substrate, and each sample substrate had a cured product with a microporous pattern formed. Using a UV conveyor furnace, each obtained sample substrate was irradiated with ultraviolet light with a cumulative exposure of 1000mJ/ ^cm2 , and then heated at 150°C for 60 minutes to formally cure the cured product on each sample substrate.

After the Pt sputtering treatment was performed on each sample substrate produced according to the above procedure, the diameter of the bottom of the micropores on each sample substrate was measured using a scanning electron microscope (SEM), and the analytical properties were evaluated according to the following evaluation criteria. The results are shown in Table 1. ◎: The bottom diameter is greater than 25µm and less than 50µm. ○: The bottom diameter is greater than 20µm and less than 25µm. △: The bottom diameter is greater than 15µm and less than 20µm. ×: The bottom diameter is less than 15µm.

[Evaluation of crack resistance] Except that the φ50µm micro-hole pattern was replaced with the Si chip mounting pattern, a substrate with a hardened product having a Si chip mounting pattern was obtained by the same manufacturing procedure as the evaluation substrate used for the above analytical evaluation. Then, Au plating treatment was performed to form solder bumps, and the Si chip was mounted to obtain each sample substrate required for the thermal shock test (TST). Each obtained sample substrate was placed in a hot and cold cycler that can cycle the temperature between -65℃ and 150℃ in the liquid layer, and TST was performed. During the TST period, the hardened surface on each sample substrate was observed at 600 cycles, 800 cycles, and 1000 cycles, and the crack resistance was evaluated according to the following evaluation criteria. The results are shown in Table 1. ◎: No abnormality even at 1000 cycles. ○: No abnormality at 750 cycles, but cracks were observed at 1000 cycles. △: No abnormality at 500 cycles, but cracks were observed at 750 cycles. ×: Cracks were observed at 500 cycles.

From the evaluation results shown in Table 1, it can be seen that the cured products formed by the curable resin compositions of Examples 1 to 7 have both good developing properties and good crack resistance under TST. On the other hand, it can be seen that the cured products formed by the curable resin compositions of Comparative Examples 1 to 5 do not have both good developing properties and good crack resistance under TST.

(without)

Claims (8)

A curable resin composition, characterized by comprising: (A) a curable resin, (B) a surface-treated barium compound, (C) a surface-treated silicon dioxide, and (D) rubber particles; and relative to the total mass of the solid components of the curable resin composition, the total content of the surface-treated barium compound (B) and the surface-treated silicon dioxide (C) is 20-80% by mass on a solid component basis; and the mass ratio of the surface-treated barium compound (B) to the surface-treated silicon dioxide (C) is 1:1-1:4 on a solid component basis. The curable resin composition of claim 1, wherein the (A) curable resin comprises (A-1) a photocurable resin. The curable resin composition of claim 1, wherein the (A) curable resin comprises (A-2) a thermosetting resin. The hardening resin composition of claim 1, wherein the aforementioned (D) rubber particles comprise inner core and outer shell rubber particles. The curable resin composition of claim 1 further comprises (E) a photopolymerization initiator. A dry film comprises a first film and a resin layer, wherein the resin layer is formed on at least one side of the first film and is composed of the hardening resin composition of claim 1. A hardened material is obtained by hardening the hardening resin composition as claimed in claim 1 or the resin layer of the dry film as claimed in claim 6. A printed wiring board comprises the hardened material as claimed in claim 7.