Curing resin composition, dry film, cured product, and printed circuit board

Abstract

The present application provides a curable resin composition, and a dry film, a cured product and a printed circuit board using the same, the curable resin composition can form a resin layer with good resolution, can form a cured product with sufficient rigidity and good adhesion to the substrate. The curable resin composition is a curable resin composition containing a carboxyl-containing resin with unsaturated bonds, inorganic fillers, thermosetting resin and photopolymerization initiator, wherein the specific gravity of the inorganic fillers is 3.5 or more, and the Young's modulus of the inorganic fillers is 50 GPa or more, the content of the inorganic fillers is 50 mass% to 80 mass% in terms of solid content with respect to the whole curable resin composition, and the concentration of the unsaturated bonds with respect to the total mass of the curable resin composition is 0.0002 eq. / g to 0.0007 eq. / g.

Description

Technical Field

[0001] This invention relates to curable resin compositions, dry films, cured products, and printed circuit boards. Background Technology

[0002] Printed circuit boards (PCBs) used in electronic devices have copper-based circuit patterns printed on a substrate, allowing various components to be mounted. When components are mounted on PCBs with exposed copper wires, short circuits can occur due to external forces causing copper wire breakage, solder adhesion outside the circuit pattern, or other reasons. Therefore, a protective layer called a solder mask is formed to protect the circuit pattern and prevent short circuits.

[0003] The solder resist layer can be formed, for example, using a curable resin composition and an alkaline developing method (see, for example, Patent Document 1). The alkaline developing method involves coating the entire surface of a substrate with a curable resin composition and drying it to form a resin layer, exposing the resin layer to partial curing, and developing the uncured curable resin composition using an alkaline aqueous solution to form a circuit pattern. The alkaline developing method can also handle the formation of fine circuit patterns and is therefore suitable for manufacturing printed circuit boards.

[0004] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2007-49064 Summary of the Invention

[0005] (a) Technical problems to be solved In recent years, mobile devices and other devices have been rapidly becoming smaller and thinner. Correspondingly, the various components used in mobile devices are also required to be smaller and thinner, including printed circuit boards (PCBs). However, if PCBs are made thinner, problems such as deformation of the PCB itself can occur when external forces are applied to them.

[0006] To address this issue, it is necessary to increase the rigidity of the solder resist layer.

[0007] To improve the rigidity of the solder resist layer, it was considered to add filler of more than 50% by mass of the curing resin composition to the curing resin composition, that is, to use a curing resin composition that is highly filled with filler.

[0008] However, if a highly filler-filled curable resin composition is used to form circuit patterns, the filler may remain as residue on the circuit pattern when the uncured resin composition is removed after formation, potentially degrading the reliability of electrical connections in the electronic circuitry. Furthermore, when forming a resin layer on a substrate using a highly filler-filled curable resin composition, the high concentration of filler at the substrate-resin layer interface may impair the adhesion between the substrate and the cured material. Additionally, with highly filler-filled curable resin compositions, increased light scattering within the resin layer during exposure for circuit pattern formation may result in decreased resolution.

[0009] Based on the above circumstances, the present invention aims to provide a curable resin composition, a dry film using the curable resin composition, a cured product, and a printed circuit board, wherein the curable resin composition can form a resin layer with good resolution and a cured product with sufficient rigidity and good adhesion to the substrate.

[0010] (II) Technical Solution That is, the curable resin composition of the present invention is a curable resin composition containing a carboxyl-containing resin having unsaturated bonds, an inorganic filler, a thermosetting resin, and a photopolymerization initiator, characterized in that, The inorganic filler has a specific gravity of 3.5 or higher, and its Young's modulus is 50 GPa or higher. The inorganic filler content, relative to the curable resin composition as a whole, is 50% to 80% by mass (converted to solids). The concentration of the unsaturated bonds relative to the total mass of the curable resin composition is 0.0002 eq. / g to 0.0007 eq. / g.

[0011] Furthermore, in the present invention, it is preferable that the inorganic filler is spherical in shape and the volume average particle size of the inorganic filler is less than 1.0 μm.

[0012] Furthermore, in the embodiments of the present invention, it is preferred that the ratio of vinyl equivalent (eq.) to (meth)acryloyl equivalent (eq.) in the curable resin composition (vinyl: (meth)acryloyl) is 1:1 to 1:20.

[0013] Furthermore, another aspect of the dry film of the present invention is characterized by having a resin layer formed from the above-described curable resin composition.

[0014] Furthermore, another aspect of the dry film of the present invention preferably includes: in the ATR-based FT-IR measurement of the resin layer of the dry film formed by stacking a first film, a resin layer, and a second film in that order, Let the peak ratio ((meth)acryloyl peak height / filler peak height) on the first membrane side be set as A. When the peak ratio ((meth)acryloyl peak height / filler peak height) on the second membrane side is set to B, B / A ≥ 3.0.

[0015] Furthermore, another aspect of the present invention is characterized by a cured product obtained from the aforementioned resin layer.

[0016] Furthermore, another aspect of the printed circuit board of the present invention is characterized by having the aforementioned cured material.

[0017] (III) Beneficial Effects According to the present invention, a curable resin composition, a dry film using the curable resin composition, a cured product, and a printed circuit board are provided, wherein the curable resin composition can form a resin layer with good resolution and a cured product with sufficient rigidity and good adhesion to the substrate. Detailed Implementation

[0018] The following describes the curable resin composition, dry film, cured product, and printed circuit board of this embodiment.

[0019] (Curing resin composition) The curable resin composition contains a carboxyl-containing resin with unsaturated bonds, an inorganic filler, a thermosetting resin, and a photopolymerization initiator, and may further contain other components as needed.

[0020] <Carboxyl-containing resins with unsaturated bonds> Carboxyl-containing resins with unsaturated bonds are resins that have linear, branched, or cyclic unsaturated bonds and carboxyl groups. By including a carboxyl-containing resin with unsaturated bonds in a curable resin composition, the curable resin composition can be imparted with developability (specifically, alkaline developability). There are no particular limitations on the carboxyl-containing resin with unsaturated bonds, and it can be appropriately selected according to the purpose.

[0021] Specific examples of carboxyl-containing resins with unsaturated bonds include the following compounds (which can be either oligomers or polymers). These compounds can be used alone or in combination.

[0022] (1) A carboxyl-containing resin is obtained by reacting (meth)acrylic acid with a difunctional or more multifunctional (solid) epoxy resin to add a dicarboxylic acid anhydride to a hydroxyl group present in the side chain.

[0023] (2) A multifunctional epoxy resin is obtained by reacting (meth)acrylic acid with the hydroxyl groups of a bifunctional (solid) epoxy resin further epoxidized with epichlorohydrin, and a carboxyl-containing resin is obtained by adding a dicarboxylic acid anhydride to the generated hydroxyl groups.

[0024] (3) A dicarboxylic acid such as adipic acid, phthalic acid, and hexahydrophthalic acid is reacted with a difunctional oxobutane resin to add phthalic anhydride, tetrahydrophthalic anhydride, and hexahydrophthalic anhydride to the generated primary hydroxyl group to obtain a carboxyl-containing polyester resin.

[0025] (4) A carboxyl-containing resin is obtained by reacting compounds such as p-hydroxyphenylethanol, which have at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule, and monocarboxylic acids such as (meth)acrylic acid containing unsaturated groups with epoxy compounds having multiple epoxy groups in one molecule, and by reacting polyacid anhydrides such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and adipic anhydride with the alcoholic hydroxyl group of the obtained reaction product.

[0026] (5) A carboxyl-containing resin is obtained by reacting a monocarboxylic acid containing unsaturated groups with a reaction product obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with ethylene oxide, propylene oxide, or other epoxides, and by reacting a polyacid anhydride with the obtained reaction product.

[0027] (6) A carboxyl-containing resin is obtained by reacting a monocarboxylic acid containing unsaturated groups with a reaction product obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with cyclic carbonates such as ethylene carbonate and propylene carbonate, and by reacting a polyacid anhydride with the obtained reaction product.

[0028] (7) Further, a compound having one epoxy group and one or more (meth)acryloyl groups in one molecule is added to the resin of (1) to (6) to obtain a carboxyl-containing resin.

[0029] In addition, in this specification, (meth)acrylate is a term used collectively to refer to acrylates, methacrylates and mixtures thereof, and so on.

[0030] The content of carboxyl-containing resin with unsaturated bonds is not particularly limited and can be appropriately selected according to the purpose. It is preferably 5% to 30% by mass, more preferably 10% to 25% by mass, relative to the total solid content of the curable resin composition.

[0031] <Inorganic packing> Inorganic fillers are components used to improve the rigidity of cured products obtained from curable resin compositions.

[0032] Inorganic fillers are not particularly limited as long as they are substances exhibiting the physical properties described below, and can be appropriately selected according to the purpose. Examples include alumina, zirconium oxide, and titanium oxide. These inorganic fillers can be used alone or in combination. Among them, alumina is preferred from the perspective of high Young's modulus.

[0033] The Young's modulus of the inorganic filler is 50 GPa or higher, preferably 100 GPa or higher, and more preferably 300 GPa or higher. If the Young's modulus of the inorganic filler is less than 50 GPa, the rigidity of the cured material may be insufficient.

[0034] The specific gravity of the inorganic filler is 3.5 or more, preferably 4.0 or more, and more preferably 4.5 or more. If the specific gravity of the inorganic filler is less than 3.5, the adhesion to copper and the wettability of the underfill may deteriorate.

[0035] Inorganic fillers that have undergone surface treatment are preferred. There are no particular limitations on the surface treatment agent; it can be selected appropriately depending on the purpose. For example, coupling agents with curing reactive groups as organic groups are preferred.

[0036] Examples of coupling agents include silane-based, titanate-based, aluminate-based, and zirconate aluminate-based agents. These coupling agents can be used individually or in combination. Silane-based coupling agents are preferred.

[0037] Examples of silane-based coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, N-(2-aminomethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-ureapropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane. These silane-based coupling agents can be used alone or in combination with two or more.

[0038] There is no particular limitation on the amount of coupling agent relative to 100 parts by weight of inorganic filler, and it can be appropriately selected according to the purpose, for example, preferably 0.5 parts by weight to 10 parts by weight.

[0039] There are no particular restrictions on the shape of inorganic fillers, and they can be selected appropriately according to the purpose. From the perspective of high filling, spherical shape is preferred.

[0040] The spherical shape in inorganic fillers is not limited to perfect spheres. Suitable shapes include, for example, spheres with a sphericity of 0.8 or higher, as determined by the following method. Sphericity can be determined by taking photographs using a SEM (scanning electron microscope) and, based on the area and perimeter of the observed particles, by using the formula (sphericity) = {4π × (area) ÷ (perimeter)}. 2 The value was calculated in the form of the calculated value. Specifically, it was the average value measured using an image processing device on 100 particles.

[0041] The volume average particle size of the inorganic filler is preferably 0.01 μm to 5 μm, more preferably 0.01 μm to 1 μm.

[0042] For the volume average particle size, a commercially available laser diffraction scattering particle size distribution measuring device can be used to determine the particle size distribution based on the laser diffraction scattering method, in the form of the median particle size (d50, volume basis) based on the cumulative distribution.

[0043] The content of inorganic filler, relative to the overall curable resin composition, is 50% to 80% by mass (converted to solids), preferably 60% to 80% by mass, and more preferably 65% ​​to 78% by mass. If the content of inorganic filler is less than 50% by mass, the rigidity of the cured product may be insufficient. If the content of inorganic filler is greater than 80% by mass, the adhesion to copper, the wettability of the underfill material, and the resolution may sometimes deteriorate.

[0044] Provided that the effects of this disclosure are not impaired, the resin composition may contain other fillers commonly known for use in resin compositions, particularly inorganic fillers. Examples of such inorganic fillers include silica, barium sulfate, barium titanate, Neuburg silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum hydroxide, silicon nitride, and aluminum nitride, among which silica and barium sulfate are particularly suitable. Other fillers may be used alone or in combination of two or more. When other fillers are included, their content is preferably 20% by mass or less.

[0045] <Thermosetting Resins> Thermosetting resins are not particularly limited as long as they are resins that are cured (polymerized) by heating, and can be appropriately selected according to the purpose. Examples of commonly used thermosetting resins include isocyanate compounds, terminal isocyanate compounds, amino resins, maleimide compounds, benzoxazine resins, carbodiimide resins, cyclic carbonate compounds, epoxy resins, oxetane compounds, and cyclic sulfide resins. These thermosetting resins can be used alone or in combination. Epoxy resins are preferred.

[0046] Examples of epoxy resins 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, phenolic varnish type epoxy resin, cresol phenolic varnish type epoxy resin, bisphenol A phenolic varnish type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, and triphenylmethane type epoxy resin. These epoxy resins can be used alone or in combination.

[0047] There is no particular limitation on the content of thermosetting resin, which can be appropriately selected according to the purpose. It is preferably 1% to 30% by mass, more preferably 1.5% to 15% by mass, in terms of solid content relative to the whole curing resin composition.

[0048] <Photopolymerization Initiator> There are no particular restrictions on the photopolymerization initiator, as long as it is a commonly used photopolymerization initiator for curable resin compositions. It can be appropriately selected according to the purpose, and known photopolymerization initiators can be used.

[0049] Photopolymerization initiators include, for example, 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, and bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, as well as bisacylphosphine oxides; 2,6-dimethoxybenzoyl diphenylphosphine oxide. Monoacylphosphine oxides, including 2,6-dichlorobenzoyl diphenylphosphine oxide, 2,4,6-trimethylbenzoyl phenyl phosphate methyl ester, 2-methylbenzoyl diphenylphosphine oxide, isopropyl 2,4,6-trimethylbenzoyl diphenylphosphine oxide, etc.; hydroxyacetophenones, including phenyl(2,4,6-trimethylbenzoyl)phosphonate ethyl, 1-hydroxy-cyclohexylphenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propanoyl)-benzyl]phenyl}-2-methyl-propane-1-one, 2-hydroxy-2-methyl-1-phenylpropane-1-one, etc. Benzoin derivatives include: benzoin, bibenzoyl, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, benzoin n-butyl ether, etc.; benzoin alkyl ethers; benzophenone derivatives include: p-methylbenzophenone, mifepristone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bis(diethylamino)benzophenone, etc.; acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone, 1,2-(dimethylamino)-butanone, etc. -2-[(4-methylphenyl)methyl)-1-[4-(4-morpholinyl)phenyl]-1-butanone, N,N-dimethylaminoacetophenone and other acetophenone derivatives; thioxanone, 2-ethylthioxanone, 2-isopropylthioxanone, 2,4-dimethylthioxanone, 2,4-diethylthioxanone, 2-chlorothioxanone, 2,4-diisopropylthioxanone and other thioxanone derivatives; anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-pentylanthraquinone, 2-aminoanthraquinone and other anthraquinone derivatives; acetophenone dimethyl ketal, benzoyl dimethyl ketal and other ketals; 4-dimethylaminobenzoate ethyl ester, 2-(dimethylamino)ethyl benzoate, p-dimethylbenzoate ethyl ester and other benzoate derivatives;Oxime esters such as 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyl oxime), 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl] acetone 1-(O-acetyl oxime); titanium oxides such as bis(n5-2,4-cyclopentadien-1-yl)-bis[2,6-difluoro-3-(1H-pyrrolo-1-yl)phenyl]titanium), bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyrrolo-1-yl)ethyl)phenyl]titanium; diphenyl disulfide, 2-nitrofluorene, butylin, anisolein ethyl ether, azobisisobutyronitrile, tetramethylthiuram disulfide, etc. These photopolymerization initiators can be used alone or in combination with two or more.

[0050] Relative to 100 parts by weight of a carboxyl-containing resin with unsaturated bonds, the content of photopolymerization initiator, excluding oxime ester-based photopolymerization initiators, is preferably 0.01 to 30 parts by weight, more preferably 0.1 to 20 parts by weight, on a solids basis. When the content of photopolymerization initiator, excluding oxime ester-based photopolymerization initiators, is 0.01 parts by weight or more, the photocurability of the curable resin composition becomes good, the cured product is not easily peeled off, and properties such as chemical resistance also become good. On the other hand, when the content of photopolymerization initiator, excluding oxime ester-based photopolymerization initiators, is 30 parts by weight or less, the light absorption on the surface of the resin layer becomes good, and the deep curing properties are less likely to decrease.

[0051] The content of the oxime ester-based photopolymerization initiator, relative to 100 parts by weight of a carboxyl-containing resin with unsaturated bonds, is preferably 0.01 to 5 parts by weight, more preferably 0.1 to 3.9 parts by weight, on a solids basis. When the content of the oxime ester-based photopolymerization initiator is 0.01 parts by weight or more, the photocurability of the curable resin composition becomes good, and properties such as heat resistance and chemical resistance also become good. On the other hand, when the content of the oxime ester-based photopolymerization initiator is 5 parts by weight or less, the light absorption on the surface of the resin layer becomes good, and the deep curing properties are less likely to decrease.

[0052] <Other Ingredients> Other components are not particularly restricted as long as they are commonly used in curable resin compositions, and can be appropriately selected according to the purpose. Examples include colorants, thermosetting catalysts, and photosensitive monomers.

[0053] <<Coloring Agent>> There are no particular restrictions on the colorant, as long as it is a common colorant used in curable resin compositions. It can be selected appropriately according to the purpose. Commonly known colorants such as black, red, blue, green, yellow, and white can be used, and it can be any of the pigments, dyes, and colorants.

[0054] Examples of black colorants include carbon black, zirconium nitride, and Pigment Black (1, 6, 7, 8, 9, 10, 11, 12, 13, 18, 20, 25, 26, 28, 29, 30, 31, 32, etc.

[0055] As red coloring agents, there are monoazo, diazo, azo lake, benzimidazolone, perylene, pyrrolopyrroledione, condensed azo, anthraquinone, and quinacridone series, etc.

[0056] As blue colorants, there are phthalocyanine-based and anthraquinone-based compounds, while pigment-based compounds can use compounds classified as pigments. In addition, metal-substituted or unsubstituted phthalocyanine compounds can also be used.

[0057] As green colorants, there are also phthalocyanine, anthraquinone, and perylene-based compounds. In addition, metal-substituted or unsubstituted phthalocyanine compounds can also be used.

[0058] As yellow coloring agents, there are monoazo, diazo, condensed azo, benzimidazolone, isoindolinone, and anthraquinone series, etc.

[0059] Examples of white colorants include rutile or anatase titanium dioxide. In addition, colorants such as purple, orange, and brown can be added to adjust the hue.

[0060] <<Thermosetting Catalyst>> Examples of thermosetting catalysts include imidazole derivatives such as imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, and 1-(2-cyanoethyl)-2-ethyl-4-methylimidazole; amine compounds such as dicyandiamide, benzyldimethylamine, 4-(dimethylamino)-N,N-dimethylbenzylamine, 4-methoxy-N,N-dimethylbenzylamine, and 4-methyl-N,N-dimethylbenzylamine; acylhydrazides such as adipate dihydrazides and sebacate dihydrazides; and phosphorus compounds such as triphenylphosphine. In addition, S-triazine derivatives such as guanidine, acetylguanidine, benzoguanidine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, 2-vinyl-4,6-diamino-S-triazine isocyanuric acid adduct, and 2,4-diamino-6-methacryloyloxyethyl-S-triazine isocyanuric acid adduct can also be used. It is preferable to use these compounds, which can also function as adhesion promoters, in conjunction with the thermosetting catalyst. These thermosetting catalysts can be used alone or in combination with two or more.

[0061] <<Photosensitive Monomer>> The photosensitive monomer is a monomer containing an olefinically unsaturated double bond. Examples of such photosensitive monomers include conventionally known polyester (meth)acrylates, polyether (meth)acrylates, urethane (meth)acrylates, carbonate (meth)acrylates, and epoxy (meth)acrylates. Specifically, examples include 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 epoxide alkane 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; and derivatives such as trimethylolpropane, pentaerythritol, bis(trimethylolpropane), dipentaerythritol, and trihydroxyethylisocyanurate. Polyacrylates such as esters and polyols or their epoxy alkane adducts or ε-caprolactone adducts; polyacrylates such as phenoxy acrylates, bisphenol A diacrylates and phenols or their epoxy alkane adducts; acrylates derived from glycidyl ethers such as glyceryl diglycidyl ether, trimethylolpropane triglycidyl ether, and isocyanurate triglycidyl ester; and acrylates not limited to those obtained by directly acrylate-esterifying polyether polyols, polycarbonate diols, hydroxyl-terminated polybutadiene, polyester polyols, etc., or by acrylate-esterifying polyols via diisocyanate, as well as melamine acrylates and various methacrylates corresponding to the aforementioned acrylates. These photosensitive monomers may be used individually or in combination with two or more.

[0062] The concentration of unsaturated bonds in the curable resin composition is 0.0002 eq. / g to 0.0007 eq. / g, preferably 0.00025 eq. / g to 0.0006 eq. / g.

[0063] If the concentration of unsaturated bonds is less than 0.0002 eq. / g, the curable resin composition may sometimes fail to cure. If the concentration of unsaturated bonds is greater than 0.0007 eq. / g, the resolution of the resin layer obtained from the curable resin composition may sometimes deteriorate.

[0064] The concentration of unsaturated bonds can be calculated from the concentration of unsaturated bonds in each of the components containing unsaturated bonds in the curable resin composition. Specifically, the concentration of unsaturated bonds in each component is calculated from the ratio of the amount of unsaturated bonds to the equivalent amount of unsaturated bonds (content (parts by mass) / equivalent amount of unsaturated bonds). By summing the concentrations of the individual unsaturated bonds obtained, and dividing this sum by the content (parts by mass) of the raw materials contained in the total curable resin composition, the concentration of unsaturated bonds in the curable resin composition can be calculated.

[0065] The ratio of vinyl equivalent (eq.) to (meth)acryloyl equivalent (eq.) in the curable resin composition (vinyl:(meth)acryloyl) is preferably 1:1 to 1:20, more preferably 1:1 to 1:17.

[0066] <Preparation Method of Curable Resin Composition> The method for preparing the curable resin composition is not particularly limited. For example, it can be prepared by mixing the above-mentioned components in a specified ratio and then mixing or blending them at room temperature using a mixing means such as a three-roll mill, ball mill, bead mill, or sand mixer, or using a stirring means such as a super mixer or planetary mixer. In addition, pre-mixing or blending can be performed as needed before mixing or blending.

[0067] (dry film) The dry film of this embodiment has a first film and a resin layer, and may further have other components as needed.

[0068] <Resin Layer> The resin layer is formed on the first film and is formed from the aforementioned curable resin composition. Here, the resin layer refers to a layer formed by coating and drying the curable resin composition, and is a layer without any other layers such as the first film or other components.

[0069] There are no particular restrictions on the thickness of the resin layer; it can be selected appropriately according to the purpose.

[0070] <First Membrane> The first film (hereinafter also referred to as the "support film") serves as a resin layer that supports the dry film and is coated with the curable resin composition during the formation of the resin layer formed by the curable resin composition.

[0071] In this invention, the first film refers to a film that is at least bonded to the resin layer during integral molding by laminating it onto a substrate or other material through heating or other means to bring it into contact with the resin layer side of the dry film. In subsequent lamination processes, the first film can be peeled off from the resin layer.

[0072] As the first membrane, any known membrane can be used without particular restrictions. For example, films formed from thermoplastic resins such as polyethylene terephthalate or polyethylene naphthalate, polyimide films, polyamide-imide films, polypropylene films, and polystyrene films can be appropriately used. Among these, polyester films are preferred from the perspectives of heat resistance, mechanical strength, and operability. Furthermore, laminates of these films can also be used as the first membrane.

[0073] Furthermore, from the perspective of improving mechanical strength, the film formed from thermoplastic resin is preferably a film that has been stretched in a uniaxial or biaxial direction.

[0074] When a thermoplastic resin film is used as the first film, a film with a specific surface morphology can be used by adding filler to the resin during film formation (kneading treatment); or by applying a matte coating (coating treatment); or by performing a blasting treatment such as sandblasting on the film surface; or by performing hairline processing or chemical etching, etc.

[0075] There is no particular limitation on the thickness of the first membrane; for example, it can be 10 μm to 150 μm.

[0076] <Other Components> Other components are not particularly restricted as long as they are commonly used for dry films, and can be appropriately selected according to the purpose; for example, a second film can be listed.

[0077] <<Second Membrane>> The second film (hereinafter also referred to as "protective film") is a film laminated for the purpose of preventing dust from adhering to the surface of the resin layer. Specifically, the second film refers to the film that is peeled off from the resin layer before lamination when it is integrally formed on a substrate such as a substrate by means of heating or the like to contact the resin layer side of the dry film.

[0078] The second film can be made of materials such as polyethylene film, polytetrafluoroethylene film, polypropylene film, or surface-treated paper. Furthermore, regarding the adhesion between the second film and the resin layer, it is sufficient that the adhesion between the resin layer and the second film is less than the adhesion between the resin layer and the first film. By making the adhesion of the second film less than that of the first film, the second film can be peeled off without causing the first film to move.

[0079] The thickness of the second membrane is not particularly limited; for example, it can be 10 μm to 150 μm.

[0080] To improve the adhesion between the cured material and the substrate, the preferred dry film of the embodiment is that, in the FT-IR measurement based on the ATR method of the resin layer when the first film, resin layer and second film are stacked in sequence, when the peak ratio on the first film side is set as A and the peak ratio on the second film side is set as B, the ratio of A to B (B / A) is 3.0 or more.

[0081] A higher (B / A) ratio indicates that there is more filler on the first film side and more resin on the second film side of the resin layer. This filler distribution deviation suggests increased adhesion between the resin layer and the substrate when the resin layer is placed on the substrate, i.e., increased adhesion between the cured material and the substrate.

[0082] For the peak ratio on the first film side, a curable resin composition was coated onto a polyethylene terephthalate (PET) film using a coater and allowed to dry. The resulting resin layer was then peeled off with tape, and the peeled portion, along with the tape, was pressed onto an FT-IR apparatus for measurement using the ATR method. The peak height ratio was calculated from the obtained spectrum.

[0083] For the peak ratio on the second film side, a curable resin composition was coated onto a PET film using a coater and allowed to dry. The resulting resin layer was directly pressed onto an FT-IR apparatus and measured. The peak ratio, as the ratio of peak heights, was calculated from the obtained spectrum.

[0084] For the peak ratio, the height of the apex (peak) of the (meth)acryloyl group and the filler peak from the baseline shown in Table 1 below is measured, and the ratio of the (meth)acryloyl group peak height to the filler peak height ((meth)acryloyl group peak height / filler peak height) is calculated.

[0085] Then, the peak ratio ((meth)acryloyl peak height / filler peak height) on the first membrane side is set as A, and the peak ratio ((meth)acryloyl peak height / filler peak height) on the second membrane side is set as B, and B / A is calculated.

[0086] [Table 1] <Method for manufacturing dry film> The above-mentioned curable resin composition is diluted with an organic solvent to adjust to a suitable viscosity, and then coated onto a first film with a uniform thickness using a corner roller coater, doctor blade coater, lip coater, rod coater, extrusion coater, reverse coater, transfer roller coater, gravure coater, sprayer, applicator, etc. The film is typically dried at a temperature of 50°C to 130°C for 1 to 30 minutes to obtain a dry film. There are no particular limitations on the coating thickness; it is generally selected appropriately within the range of 1 μm to 150 μm, preferably within the range of 5 μm to 60 μm, based on the dried film thickness.

[0087] (cured material) The cured product of the embodiment is obtained by curing the above-mentioned curable resin composition or the resin layer of the above-mentioned dry film.

[0088] There are no particular restrictions on the size and shape of the solidified material; it can be selected appropriately according to the purpose.

[0089] As a method for manufacturing the cured product, for example, the viscosity of the curable resin composition of the present invention is adjusted to a viscosity suitable for the coating method using an organic solvent, and then coated onto a substrate using methods such as dip coating, flow coating, roller coating, bar coating, screen printing, or curtain coating. The organic solvent contained in the composition is then evaporated and dried (pre-dried) at a temperature of 60-100°C for 15-90 minutes, thereby forming a non-sticky resin layer. Alternatively, in the case of a dry film, the resin layer is bonded to the substrate in contact with the substrate using a laminator or the like, forming a resin layer on the substrate.

[0090] As a substrate, in addition to printed circuit boards or flexible printed circuit boards in which circuits are pre-formed using copper, copper-clad laminates of all grades (FR-4, etc.) using materials such as phenolic bakelite paper, epoxy paper, epoxy glass cloth, glass polyimide, glass cloth / epoxy nonwoven fabric, glass cloth / epoxy paper, epoxy synthetic fiber, fluoropolymer, polyethylene, polyphenylene ether, polyphenylene ether cyanate, etc., as well as metal substrates, polyimide films, polyethylene terephthalate films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafer boards, etc.

[0091] After forming a resin layer on a substrate, selective exposure is performed using an active energy beam through a photomask with a predetermined circuit pattern. The unexposed areas are then developed using a dilute alkaline aqueous solution (e.g., 0.3-3% by mass sodium carbonate aqueous solution) to form the circuit pattern. In the case of a dry film, after exposure, the first film is peeled off from the dry film and developed, thereby forming a patterned cured product on the substrate. Alternatively, provided it does not impair the properties, the first film can be peeled off from the dry film before exposure, exposing and developing the exposed resin layer. Then, the cured product is irradiated with active energy beams and then heat-cured (e.g., 100-220°C), or heat-cured and then irradiated with active energy beams, or finally cured by heat alone, resulting in a cured product with excellent adhesion, hardness, and other properties.

[0092] As an exposure machine for irradiation with active energy rays, any device equipped with a high-pressure mercury lamp, ultra-high-pressure mercury lamp, metal halide lamp, or mercury short-arc lamp, and irradiating with ultraviolet light at a wavelength of 350 nm to 450 nm, is acceptable. Direct drawing devices (e.g., laser direct imaging devices that directly draw images using lasers based on CAD data from a computer) can also be used. The light source or laser source for the direct drawing machine can be a light source with a maximum wavelength falling within the 350 nm to 450 nm range. The exposure dose used for image formation varies depending on the thickness or size of the cured material, but is preferably 10 mJ / cm². 2 ~1000mJ / cm 2 More preferably 20 mJ / cm2 ~800 mJ / cm 2 .

[0093] As a developing method, methods such as immersion, rinsing, spraying, and brushing can be used. As a developing solution, alkaline aqueous solutions such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, and amines can be used.

[0094] (Printed Circuit Board) One embodiment of the present invention provides a printed circuit board having a cured product of the above-described curable resin composition.

[0095] There are no particular restrictions on the size or type of printed circuit boards; they can be selected appropriately according to the purpose.

[0096] Example The following describes the experiments conducted by the inventors of this application, but the present invention is not limited thereto.

[0097] (Examples 1-10, Comparative Examples 1-5) The materials were blended in the proportions shown in Tables 2-4, premixed using a mixer, and then kneaded using a three-roll mill to prepare a curable resin composition. Note that the values ​​in the tables are converted from solid content values. Furthermore, the units in the tables are parts by mass.

[0098] [Table 2] [Table 3] [Table 4] Details of each component in Tables 2-4 are as follows.

[0099] Synthesis of Carboxyl-Containing Resins with Unsaturated Bonds 119.4 g of phenolic varnish-type cresol resin (Shonol CRG951, manufactured by Aica Kogyo Co..Ltd., OH equivalent: 119.4), 1.19 g of potassium hydroxide, and 119.4 g of toluene were added to a high-pressure reactor equipped with a thermometer, a nitrogen introduction device that also serves as an epoxy alkane introduction device, and a stirring device. Nitrogen replacement was carried out in the system while stirring, and the system was heated to increase the temperature.

[0100] Next, 63.8 g of propylene oxide was slowly added dropwise at a temperature of 125°C to 132°C and 0 kg / cm³. 2 ~4.8kg / cm 2The reaction was allowed to proceed for 16 hours. Then, it was cooled to room temperature, and 1.56 g of 89% phosphoric acid was added to the reaction solution to neutralize the potassium hydroxide, yielding a propylene oxide reaction solution of phenolic varnish-type cresol resin with a non-volatile content of 62.1% and a hydroxyl value of 182.2 g / eq. This solution contained an average of 1.08 moles of alkyl epoxides added per 1 equivalent of phenolic hydroxyl group.

[0101] Next, 293.0 g of the obtained phenolic varnish-type cresol resin propylene oxide reaction solution, 43.2 g of acrylic acid, 11.53 g of methanesulfonic acid, 0.18 g of methylhydroquinone, and 252.9 g of toluene were loaded into a reactor equipped with a stirrer, thermometer, and air blow-in pipe. Air was blown in at a rate of 10 mL / min, and the reaction was carried out at 110 °C for 12 hours with stirring. The water produced in the reaction was prepared into an azeotropic mixture with toluene, and 12.6 g of water was distilled off. Then, the mixture was cooled to room temperature, neutralized with 35.35 g of 15% sodium hydroxide aqueous solution, and then washed with water. Then, using an evaporator, toluene was removed by distillation while replacing it with 118.1 g of diethylene glycol monoethyl ether acetate, to obtain a phenolic varnish-type acrylate resin solution.

[0102] Next, 332.5 g of the obtained phenolic varnish-type acrylate resin solution and 1.22 g of triphenylphosphine were loaded into a reactor equipped with a stirrer, thermometer, and air blow-in pipe. Air was blown in at a rate of 10 mL / min, and 60.8 g of tetrahydrophthalic anhydride was slowly added while stirring. The reaction was carried out at 95℃~101℃ for 6 hours. In this manner, a resin solution of carboxyl-containing photosensitive resin with a solid content of 88 mg KOH / g, a solid content of 71%, a weight-average molecular weight of 2,000, and an unsaturated bond equivalent of 800 eq. / g was obtained (hereinafter referred to as carboxyl-containing resin with unsaturated bonds).

[0103] Details of the components with unsaturated bonds, excluding carboxyl-containing resins, in Tables 2-4 are as follows.

[0104] <Inorganic packing> • Alumina 1 (Specific gravity: 4.0, Young's modulus: 350 GPa) This substance is prepared by surface treatment of alumina (ASFP-40, manufactured by Denka Company Limited) with a silane coupling agent (vinylsilane, KBM-1003, manufactured by Shin-Etsu Chemical Co., Ltd., with an unsaturated bond equivalent of 248 eq. / g). The silane coupling agent is added in such a manner that the mass percentage of the silane coupling agent relative to the alumina is 1.0 wt%, and then the surface treatment is performed.

[0105] • Alumina 2 (Specific gravity: 4.0, Young's modulus: 350 GPa) A substance obtained by surface treatment of alumina (ASFP-40, manufactured by Denka Company Limited) with a silane coupling agent (vinylsilane, KBM-1003, manufactured by Shin-Etsu Chemical Co., Ltd.). The silane coupling agent is added in such a manner that the mass percentage of the silane coupling agent relative to the alumina is 2.0% by mass, and then the surface treatment is performed.

[0106] • Alumina 3 (Specific gravity: 4.0, Young's modulus: 350 GPa) A substance obtained by surface treatment of alumina (ASFP-40, manufactured by Denka Company Limited) with a silane coupling agent (vinylsilane, KBM-1003, manufactured by Shin-Etsu Chemical Co., Ltd.). The surface treatment is performed by adding the silane coupling agent in a manner that makes the silane coupling agent 4.0% by mass relative to the alumina.

[0107] • Alumina 4 (Specific gravity: 4.0, Young's modulus: 350 GPa) A substance obtained by surface treatment of alumina (ASFP-40, manufactured by Denka Company Limited) with a silane coupling agent (silane methacrylate, KBM-503, manufactured by Shin-Etsu Chemical Co., Ltd.). The silane coupling agent is added in such a manner that the mass percentage of the silane coupling agent relative to the alumina is 2.0% by mass, and then the surface treatment is performed.

[0108] Zirconia (specific gravity: 5.7, Young's modulus: 200 GPa, UEP-100, manufactured by DAIICHI KIGENSO KAGAKUKOGYO CO., LTD.) Titanium oxide (specific gravity 4.26, Young's modulus 150 GPa, JR-301, manufactured by TAYCA Co., Ltd.) • Barium sulfate (specific gravity 4.5, Young's modulus 15 GPa, B-30, manufactured by SAKAI CHEMICAL INDUSTRY CO., LTD.) • Aluminum hydroxide (specific gravity 2.4, Young's modulus 150 GPa, Higilite H-42M, manufactured by Resonac Holdings Corporation) • Silica (specific gravity 2.2, Young's modulus 72 GPa, SFP-30M, manufactured by Denka Company Limited) <Thermosetting Resins> Epoxy Resin 1 (N-730-A, manufactured by DIC Corporation) Epoxy Resin 2 (YX-4000, manufactured by Mitsubishi Chemical Corporation) <Photopolymerization Initiator> • Photopolymerization initiator 1 (Omnirad 907, manufactured by IGM Resin BV) Photopolymerization initiator 2 (diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide) • Photopolymerization initiator 3 (SpeedCure 2-ITX, manufactured by Sartomer) <Other Ingredients> • Blue pigment (CIPigment Blue 15:3) • Yellow pigment (CIPigment Yellow 147) ·Melamine ·DICY (Dicyandiamide) •DPHA (photosensitive monomer, dipentaerythritol hexaacrylate, manufactured by Nippon Kayaku Co., Ltd., with an unsaturated bond equivalent of 96 eq. / g) <Calculations of vinyl equivalent, (meth)acryloyl equivalent, and unsaturated bond concentration> The vinyl equivalent, (meth)acryloyl equivalent, and unsaturated bond concentration were calculated from the contents of the compounds containing vinyl groups and (meth)acryloyl groups in each component in Tables 2-4, as well as the unsaturated bond equivalent (double bond equivalent) of each compound.

[0109] For example, the vinyl equivalent in Example 1 is the value obtained by dividing the content (g) of vinylsilane as a surface treatment agent for alumina containing vinyl compounds by the unsaturated bond equivalent of 247.4 (g / eq.). Specifically, it is 400 × 0.01 / 247.4.

[0110] The (meth)acryloyl equivalent in Example 1 is the value obtained by dividing the content (g) of the carboxyl-containing resin with unsaturated bonds (which is a compound containing (meth)acryloyl groups) by the unsaturated bond equivalent of 816 (g / eq.), and adding the value obtained by dividing the content (g) of DPHA by the unsaturated bond equivalent of 96 (g / eq.). Specifically, it is 100 / 816 + 15 / 96.

[0111] The unsaturated bond concentration in Example 1 was obtained by adding the total vinyl equivalents (eq.) and (meth)acryloyl equivalents (eq.) in the cured resin composition and dividing by the total amount (g) of the cured resin composition. Specifically, it was (400 × 0.01 / 247.4 + 100 / 816 + 15 / 96) / 589.5.

[0112] <Dry Film Preparation> Using the obtained curable resin compositions, dry films are prepared according to the steps shown below.

[0113] The obtained curable resin composition was coated onto the entire surface of a polyethylene terephthalate film (T-60, manufactured by Toray Industries, Inc., 38 μm thick) as the first film, with a dried film thickness of 15 μm, and dried at 80°C for 20 minutes to form a resin layer. A polypropylene film (OPP-FOA, manufactured by FUTAMURA CHEMICAL CO., LTD., 18 μm thick) as the second film was then laminated onto the formed resin layer to produce a dry film.

[0114] The resin layer obtained from the obtained curable resin composition was subjected to FT-IR determination based on the ATR method in the following manner.

[0115] <<Measurement of the first membrane side>> Peel the second membrane off from the dry membrane prepared by the above steps to expose the resin layer. Attach transparent tape to the exposed resin layer side of the second membrane and peel it off to expose the resin layer side of the first membrane. Press the resin layer side of the first membrane onto the FT-IR apparatus and perform measurements using the ATR method.

[0116] <<Measurement of the second membrane side>> The second membrane is peeled off from the dry membrane prepared by the above steps, exposing the resin layer. The exposed resin layer on the second membrane side is pressed into an FT-IR device, and the ATR method is used for measurement.

[0117] Based on the measurement results from the first and second membrane sides, the ratio of the (meth)acryloyl peak height derived from the (meth)acryloyl group to the filler peak height derived from the filler ((meth)acryloyl peak height / filler peak height), i.e., the ratio of peak heights, is calculated.

[0118] Specifically, in the obtained measurement spectrum, the height of the (meth)acryloyl group or the peak (apex of the peak) of the filler is calculated from the baseline shown in Table 5 below.

[0119] Then, the B / A ratio was calculated when the peak ratio ((meth)acryloyl peak height / filler peak height) on the first membrane side was set as A, and the peak ratio ((meth)acryloyl peak height / filler peak height) on the second membrane side was set as B. The calculation results are recorded in Tables 2-4.

[0120] [Table 5] The rigidity of the cured resin composition, its adhesion to the copper substrate, the wettability of the underfill, and the resolution were evaluated as follows. The evaluation results are recorded in Table 6.

[0121] <Rigidity of cured materials> In the above-mentioned "Preparation of Dry Film", each dry film was prepared in the same way except that the entire surface was coated so that the film thickness after drying was 40 μm.

[0122] The resin layer of the dry film is exposed by peeling off the second film from each dry film. The exposed resin layer on the second film side is then bonded to the glossy side (copper foil) of GTS-MP foil (Furukawa Circuit Foil Co., Ltd.) and laminated using a vacuum laminator (CVP-600, manufactured by Nikko-Materials Co., Ltd.) at a temperature of 80°C to 110°C and a pressure of 0.5 MPa. The entire surface is then exposed using an exposure apparatus equipped with a high-pressure mercury short-arc lamp to remove the first film. Furthermore, the exposure amount is set based on the first film in contact with the resin layer, and a 7-step exposure meter (Stouffer 41-step exposure meter) is used for exposure.

[0123] Next, a UV conveyor belt furnace was used to achieve a cumulative exposure of 1000 mJ / cm. 2 The sample was subjected to ultraviolet irradiation under specific conditions, followed by curing at 160°C for 60 minutes. The cured material was then peeled off from the copper foil, and the sample was cut to the measurement size (5mm × 50mm). The storage modulus at 25°C was measured using a DMS6100 (manufactured by Hitachi High-Tech Science Corporation) at a frequency of 1Hz.

[0124] -Evaluation Criteria- 〇: Energy storage modulus above 10 GPa at 25℃ ×: Energy storage modulus at 25℃ is less than 10 GPa <Adhesion to copper substrate> The copper foil surface of the FR-4 copper-clad laminate (100mm×150mm×0.8mm, copper foil on both sides, copper foil thickness 18μm on both sides) was chemically polished using an abrasive compound (CZ-8101B, manufactured by MEC COMPANY LTD.) at an etching rate of 1μm.

[0125] Next, the second film is peeled off from each dry film to expose the resin layer of the dry film. The exposed resin layer on the second film side is then bonded to the surface of a chemically polished copper foil, and lamination is performed using a vacuum laminator (CVP-600, manufactured by Nikko-Materials Co., Ltd.) at a temperature of 80°C to 110°C and a pressure of 0.5 MPa. Using a parallel light exposure device equipped with a short-arc high-pressure mercury lamp, the entire surface is exposed from the first film side through an exposure mask to remove the first film. Furthermore, the exposure amount is set based on the first film in contact with the resin layer, and a 7-step exposure meter (Stouffer 41-step exposure table) is used for exposure.

[0126] Next, a 1% by weight Na2CO3 aqueous solution was used at 30°C and a spray pressure of 2 kg / cm². 2 The development was performed for 90 seconds under the specified conditions, using a UV conveyor belt oven equipped with a high-pressure mercury lamp at a speed of 1,000 mJ / cm². 2 The substrate is irradiated with a certain amount of light and then heated at 160°C for 60 minutes to produce an evaluation substrate with cured material.

[0127] Using a knife, score 1mm x 1mm squares on the surface of the cured material to form a checkerboard pattern of 100 squares in each of the 10x ...

[0128] -Evaluation Criteria- 〇: The number of remaining chessboard squares is 80 or more. ×: The number of remaining chessboard squares is less than 80 <Bottom filler wettability> The evaluation substrate, obtained using the same method as the evaluation substrate for adhesion to the copper substrate described above, was subjected to plasma treatment (gas: O2, power: 300W, vacuum: 200mTorr). Then, 0.2g of underfill material (U8410-302 (manufactured by NAMICS CORPORATION.)) was added, and the substrate was cured at 165°C for 2 hours. The area of ​​the underfill portion was measured using an optical microscope (Digitalmicroscope) (VHX-6000, manufactured by KEYENCE CORPORATION.), and the average value for n=6 was calculated. Evaluation was then performed based on the following evaluation criteria.

[0129] -Evaluation Criteria- 〇: The bottom filler section is 1,500mm. 2 above ×: Bottom filler section less than 1,500mm 2 <Resolution> In addition to exposing with a negative pattern having an opening diameter of 80 μm, evaluation substrates were fabricated using the same method as those used for evaluating the adhesion of the copper substrate described above. The openings of each evaluation substrate with an opening diameter of 80 μm were observed using SEM, and evaluations were performed based on the following evaluation criteria.

[0130] -Evaluation Criteria- ◎: The aperture is 80±5μm relative to the diameter of 80μm in the negative pattern.

[0131] 〇: The aperture is 80±10μm relative to the diameter of 80μm in the negative pattern.

[0132] ×: The aperture exceeds 80±10μm relative to the diameter of 80μm in the negative pattern.

[0133] [Table 6] For cured products obtained by coating the curable resin compositions of Examples 1-9 onto a substrate and allowing them to cure, the evaluation results for the rigidity of the cured product, its adhesion to copper, the wettability of the underfill material, and the resolution are all "0".

[0134] However, the inorganic filler content of the curable resin composition of Comparative Example 1 was higher than that of the curable resin compositions of Examples 1-9, therefore the evaluation results for adhesion to copper, wettability of the underfill material, and resolution were "×". Furthermore, since the Young's modulus of the inorganic filler contained in the curable resin composition of Comparative Example 2 was less than 50 GPa, the evaluation result for the rigidity of the cured product was "×". The resolution evaluation result for Comparative Example 3, which had a high concentration of unsaturated bonds, was "×". The evaluation results for adhesion to copper and wettability of the underfill material for Comparative Examples 4 and 5, which had a low specific gravity of inorganic filler, were "×".

[0135] In summary, curable resin compositions containing inorganic fillers that meet specified physical properties can provide curable resin compositions that can form resin layers with good resolution and can form cured products with sufficient rigidity and good adhesion to the substrate.

[0136] The above description is based on the scheme for implementing the present invention, but the present invention is not limited thereto and various modifications can be made without departing from its spirit.

Claims

1. A curable resin composition comprising a carboxyl-containing resin having unsaturated bonds, an inorganic filler, a thermosetting resin, and a photopolymerization initiator, characterized in that, The inorganic filler has a specific gravity of 3.5 or higher, and its Young's modulus is 50 GPa or higher. The inorganic filler content, relative to the curable resin composition as a whole, is 50% to 80% by mass (converted to solids). The concentration of the unsaturated bonds relative to the total mass of the curable resin composition is 0.0002 eq. / g to 0.0007 eq. / g.

2. The curable resin composition according to claim 1, wherein, The inorganic filler is spherical in shape, and the volume average particle size of the inorganic filler is less than 1.0 μm.

3. The curable resin composition according to claim 1 or 2, wherein, The ratio of vinyl equivalent (eq.) to (meth)acryloyl equivalent (eq.) in the curable resin composition (vinyl:(meth)acryloyl) is 1:1 to 1:

20.

4. A dry film having a resin layer formed from the curable resin composition of claim 1.

5. The dry film according to claim 4, wherein, In the ATR-based FT-IR determination of the resin layer of the dry film formed by stacking the first film, the resin layer, and the second film in that order, When the peak ratio ((meth)acryloyl peak height / filler peak height) on the first membrane side is set as A, and the peak ratio ((meth)acryloyl peak height / filler peak height) on the second membrane side is set as B, B / A≥3.

0.

6. A cured product obtained from the resin layer of claim 4.

7. A printed circuit board having the cured material as described in claim 6.

Images