Alkali-developed photosensitive resin composition, dry film, cured product, and printed circuit board

Abstract

An alkali-developing type photosensitive resin composition comprising a carboxyl group-containing resin, an epoxy-based thermosetting component, a (meth)acrylic monomer, and a photopolymerization initiator, wherein the equivalent ratio of carboxyl groups to epoxy groups (carboxyl group equivalent / epoxy equivalent) is 5.0 to 8.0, and the epoxy-based thermosetting component comprises a novolak-type epoxy resin and a difunctional crystalline epoxy resin having a softening point of 70°C to 120°C.

Description

Technology Field

[0001] The present invention relates to an alkali-developed photosensitive resin composition, a dry film, a cured product, and a printed wiring board. Background Technology

[0002] Printed circuit boards used in electronic devices are boards on which circuit patterns of electronic circuits are printed using copper wires, and various components are mounted on them. When components are mounted on a printed circuit board where copper wires are exposed, there is a possibility of short circuits occurring due to external forces causing the copper wires to break or solder adhering to areas outside the circuit pattern. Therefore, a solder resist layer is formed to protect the circuit pattern and prevent short circuits.

[0003] A solder resist layer is formed, for example, by an alkaline development method using a photosensitive resin composition. The alkaline development method is a method of forming a pattern by applying a photosensitive resin composition to the entire surface of a substrate, drying it to form a film, partially curing the dried film by exposing it to light, and developing the uncured photosensitive resin composition with an alkaline solution.

[0004] Recently, with the miniaturization and high density of electronic devices, it is required to form finer patterns in addition to conventional sizes. Accordingly, in addition to the above method, by performing laser irradiation on the solder resist layer, it is possible to form pores and to form patterns of various sizes (see, for example, Patent Document 1). Prior art literature

[0005] Pamphlet International Publication No. 2013 / 094606 The problem to be solved

[0006] On the other hand, the formation of holes by laser irradiation is performed by removing a portion of the solder resist film using laser light. During this removal, a component of the solder resist film called "smear" is generated. If mounting is performed while smear remains on the surface of the solder resist layer, it may cause connection failures. For this reason, after forming holes with laser light, a "desmear" process is required to remove the smear. Desmearing is generally performed by swelling with a concentrated alkaline solution and then decomposing and removing it with a permanganate solution. However, if the solder resist layer is desmeared, the solder resist layer may peel off.

[0007] Meanwhile, in order to ensure that the solder resist layer withstands desmear treatment, there is a method to increase the proportion of epoxy resin in the photosensitive resin composition. However, if the proportion of epoxy resin in the photosensitive resin composition is increased, thermal stability and the like may deteriorate. In addition, the resolution, which is an indicator of the ease of pattern formation required for the photosensitive resin composition forming the solder resist layer, may also deteriorate.

[0008] The present invention is based on these circumstances, and its purpose is to provide an alkali-developed photosensitive resin composition, a dry film, a cured product, and a printed circuit board capable of forming a cured product with good resolution, thermal stability, and desmear resistance. means of solving the problem

[0009] The inventors, after careful examination, discovered that two factors are required for an alkali-developable photosensitive resin composition capable of forming a cured product with good resolution, thermal stability, and desmear resistance. One is the equivalent ratio of carboxyl groups to epoxy groups (carboxyl group equivalent / epoxy equivalent), which is the ratio of carboxyl group-containing resin to epoxy-based thermosetting component. If this equivalent ratio is less than 5.0, the proportion of the epoxy-based thermosetting component is low, resulting in insufficient desmear resistance; if it exceeds 8.0, the proportion of the epoxy-based thermosetting component is high, which worsens thermal stability, and at the same time, the proportion of the carboxyl group-containing resin, which improves the resolution of the alkali-developable resin composition, is low, resulting in poor resolution. The other factor is that the epoxy-based thermosetting component is a combination of novolac epoxy resin and bifunctional crystalline epoxy resin. Novolak-type epoxy resins have excellent desmear resistance, and difunctional crystalline epoxy resins have excellent thermal stability, so by combining them, the resolution, thermal stability, and desmear resistance can be improved.

[0010] That is, the alkali-developing type photosensitive resin composition according to the present invention is,

[0011] It contains a carboxyl group-containing resin, an epoxy-based thermosetting component, a (meth)acryl monomer, and a photopolymerization initiator,

[0012] The equivalent ratio of the carboxyl group to the epoxy group (carboxyl group equivalent / epoxy equivalent) is 5.0 to 8.0, and

[0013] The epoxy-based thermosetting component is characterized by containing a novolak-type epoxy resin and a difunctional crystalline epoxy resin having a softening point of 70°C to 120°C.

[0014] In addition, in an embodiment of the present invention, it is preferable that the weight ratio of novolak-type epoxy resin to difunctional crystalline epoxy resin (novolak-type epoxy resin / difunctional crystalline epoxy resin) is 1.0 to 2.0.

[0015] In addition, a dry film according to another aspect of the present invention is characterized by having a resin layer obtained from the alkali-developing type photosensitive resin composition described above.

[0016] In addition, a cured product according to another aspect of the present invention is characterized by being obtained by curing the alkali-developing type photosensitive resin composition or the resin layer described above.

[0017] In addition, a printed circuit board according to another aspect of the present invention is characterized by having the above-described cured material. Effects of the invention

[0018] According to the present invention, an alkali-developed photosensitive resin composition, a dry film, a cured product, and a printed circuit board capable of forming a cured product with good resolution, thermal stability, and desmear resistance can be provided. Specific details for implementing the invention

[0019] Hereinafter, an alkali-developed photosensitive resin composition, a dry film, a cured product, and a printed circuit board according to the present embodiment will be described.

[0020] Additionally, in this specification, when a numerical range is indicated by "~", it is understood to mean a range including those values ​​(i.e., ... or greater than or equal to ... or less than or equal to).

[0021] (Alkaline developing type photosensitive resin composition)

[0022] The alkali-developing type photosensitive resin composition according to the present embodiment (hereinafter also referred to as the "photosensitive resin composition") contains a carboxyl group-containing resin, an epoxy-based thermosetting component, a (meth)acrylic monomer, and a photopolymerization initiator, and also contains other components as needed.

[0023] <Carboxyl group-containing resin>

[0024] A carboxyl group-containing resin is a resin having carboxyl groups in its molecule, and various conventionally known resins may be used. By including a carboxyl group-containing resin in a photosensitive resin composition, resolution can be imparted to the photosensitive resin composition. In particular, a carboxyl group-containing photosensitive resin having ethylenically unsaturated double bonds in its molecule is preferred in terms of photocurability and resolution. The ethylenically unsaturated double bonds are preferably derived from acrylic acid, methacrylic acid, or derivatives thereof.

[0025] Specific examples of carboxyl group-containing resins include the following compounds (which may be either oligomers or polymers). These may be used as a single type or in combination of two or more types.

[0026] (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, lower alkyl (meth)acrylate, isobutylene.

[0027] (2) A carboxyl group-containing urethane resin produced by the heavy addition reaction of a diisocyanate such as an aliphatic diisocyanate, a branched aliphatic diisocyanate, alicyclic diisocyanate, aromatic diisocyanate, a carboxyl group-containing dialcohol compound such as dimethylolpropionic acid, dimethylolbutanoic acid, and a diol compound such as a polycarbonate-based polyol, a polyether-based polyol, a polyester-based polyol, a polyolefin-based polyol, an acrylic-based polyol, a bisphenol A-based alkylene oxide adduct diol, and a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group.

[0028] (3) A partially acid anhydride modified product of a reaction product between a difunctional epoxy resin such as a diisocyanate, a bisphenol A type epoxy resin, a hydrogenated bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol S type epoxy resin, a bixyl ethyleneol type epoxy resin, a biphenol type epoxy resin, and a monocarboxylic acid compound having an ethylenically unsaturated double bond such as (meth)acrylic acid, a carboxyl group-containing dialcohol compound, and a diol compound, a photosensitive urethane resin containing a carboxyl group, produced by a reaction of a diisocyanate and a difunctional epoxy resin such as a bisphenol A type epoxy resin, a hydrogenated bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol S type epoxy resin, a bixyl ethyleneol type epoxy resin, a biphenol type epoxy resin, a monocarboxylic acid compound having an ethylenically unsaturated double bond, and a diol compound.

[0029] (4) A carboxyl group-containing photosensitive urethane resin in which one hydroxyl group and one or more (meth)acryloyl groups are added during the synthesis of the resin of (2) or (3) above to (meth)acrylate, thereby (meth)acrylating the terminals.

[0030] (5) A carboxyl group-containing photosensitive urethane resin in which the ends are (meth)acrylated by adding a compound having one isocyanate group and one or more (meth)acryloyl groups in the molecule, such as an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate, during the synthesis of the resin of (2) or (3) above.

[0031] (6) A carboxyl group-containing photosensitive resin formed by reacting (meth)acrylic acid with a difunctional or multifunctional (solid) epoxy resin and adding a dibasic acid anhydride to a hydroxyl group present in a side chain.

[0032] (7) A photosensitive resin containing carboxyl groups, formed by reacting (meth)acrylic acid with a polyfunctional epoxy resin in which the hydroxyl groups of a difunctional (solid) epoxy resin are further epoxidized with epichlorohydrin, and adding a dibasic acid anhydride to the resulting hydroxyl groups.

[0033] (8) A carboxyl group-containing polyester resin produced by reacting a dicarboxylic acid such as adipic acid, phthalic acid, or hexahydrophthalic acid with a dicarboxylic acid, and adding a dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, or hexahydrophthalic anhydride to the primary hydroxyl group produced.

[0034] (9) A carboxylic acid-containing photosensitive resin obtained by reacting an epoxy compound having multiple epoxy groups in one molecule with a compound having at least one alcoholic hydroxyl group and one phenolic hydroxyl group in one molecule, such as p-hydroxyphenylalcohol, and a monocarboxylic acid containing an unsaturated group, such as (meth)acrylic acid, and reacting the alcoholic hydroxyl group of the reaction product with a polybasic acid anhydride, such as maleic anhydride, tetrahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and adipic acid.

[0035] (10) A carboxyl group-containing photosensitive resin obtained by reacting a reaction product obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide with a monocarboxylic acid containing an unsaturated group, and then reacting the reaction product obtained with a polybasic acid anhydride.

[0036] (11) A carboxyl group-containing photosensitive resin obtained by reacting a reaction product obtained by reacting a compound having multiple phenolic hydroxyl groups in one molecule with a cyclic carbonate compound such as ethylene carbonate or propylene carbonate with a monocarboxylic acid containing an unsaturated group, and then reacting the reaction product obtained with a polybasic acid anhydride.

[0037] (12) A carboxyl group-containing photosensitive resin formed by adding a compound having one epoxy group and one or more (meth)acryloyl groups in one molecule to the resins of (1) to (11) above.

[0038] Additionally, in this specification, the term (meth)acrylate is a collective term for acrylates, methacrylates, and mixtures thereof, and the same applies to other similar expressions.

[0039] The acid value of the carboxyl group-containing photosensitive resin is preferably 40 mgKOH / g to 150 mgKOH / g, and more preferably 50 mgKOH / g to 130 mgKOH / g. By setting the acid value of the carboxyl group-containing photosensitive resin to 40 mgKOH / g to 150 mgKOH / g, the resolution becomes good.

[0040] The weight-average molecular weight of the carboxyl group-containing photosensitive resin varies depending on the resin backbone, but is generally preferably 2,000 to 150,000, and more preferably 2,000 to 100,000. By making the weight-average molecular weight 2,000 or more, tack-free performance or resolution can be improved. In addition, by making the weight-average molecular weight 150,000 or less, resolution or storage stability can be improved.

[0041] The carboxyl group equivalent of the carboxyl group-containing photosensitive resin is preferably 100 g / eq. to 1,000 g / eq., and more preferably 400 g / eq. to 800 g / eq. Here, "eq." is an abbreviation for "equivalent."

[0042] By making the carboxyl group equivalent weight 100 g / eq. or more, the number of carboxyl groups becomes appropriate, so the developability is improved. In addition, by making the carboxyl group equivalent weight 1,000 g / eq. or less, the crosslinking density can be increased, so the strength of the cured product can be improved.

[0043] The content of the carboxyl group-containing photosensitive resin in the photosensitive resin composition is preferably 20 mass% to 60 mass% in terms of solid content, and more preferably 20 mass% to 50 mass%. By making the content of the carboxyl group-containing photosensitive resin 20 mass% or more, the strength of the cured product can be improved. In addition, by making the content of the carboxyl group-containing photosensitive resin 60 mass% or less, the viscosity of the photosensitive resin composition becomes suitable, and printability is improved.

[0044] Epoxy-based thermosetting components

[0045] An epoxy-based thermosetting component is a compound having an epoxy group in its molecule. By including an epoxy-based thermosetting component in a photosensitive resin composition, desmear resistance can be imparted to the cured product of the photosensitive resin composition.

[0046] The epoxy-based thermosetting component contains a novolak-type epoxy resin and a difunctional crystalline epoxy resin.

[0047] Novolak-type epoxy resins include, for example, those obtained by reacting a novolak obtained by reacting a phenol such as phenol, cresol, halogenated phenol, alkylphenol, or bisphenol A with formaldehyde under an acidic catalyst, with an epihalohydrin such as epichlorohydrin or methyl epichlorohydrin. These may be used individually or in combination of two or more types.

[0048] Novolak-type epoxy resin can be used in liquid, semi-solid, or solid forms, but among these, the solid form is preferably used.

[0049] When the novolak-type epoxy resin has a softening point, it is 60 to 140°C, and 60 to 130°C is preferred.

[0050] A difunctional crystalline epoxy resin is a crystalline epoxy resin having two epoxy groups. The crystalline epoxy resin is, for example, an epoxy resin having a biphenyl structure, a sulfide structure, a phenylene structure, a naphthalene structure, a bisphenol structure, etc.

[0051] The softening point of the difunctional crystalline epoxy resin is 70°C to 120°C, and preferably 70°C to 110°C.

[0052] The weight ratio of novolak-type epoxy resin to bifunctional crystalline epoxy resin (novolak-type epoxy resin / bifunctional crystalline epoxy resin) is preferably 1.0 to 2.0, and more preferably 1.4 to 1.8. If the weight ratio (novolak-type epoxy resin / bifunctional crystalline epoxy resin) is 1.0 or higher, the desmear resistance of the cured product of the photosensitive resin composition can be improved, and if the weight ratio is 2.0 or lower, the thermal stability of the photosensitive resin composition can be improved.

[0053] The epoxy equivalent of the epoxy-based heat-curing component is preferably 100 g / eq. to 1,000 g / eq., and more preferably 150 g / eq. to 200 g / eq.

[0054] Here, epoxy equivalent is the mass of a resin containing 1 equivalent of an epoxy group, as defined in JIS K 7236:2001. Also, "eq." is an abbreviation for "equivalent."

[0055] The equivalent ratio of carboxyl groups to epoxy groups (carboxyl group equivalent (g / eq.) / epoxy equivalent (g / eq.)) is 5.0 to 8.0, and preferably 6.0 to 7.0. If this equivalent ratio is less than 5.0, the desmear resistance of the cured product of the photosensitive resin composition may deteriorate, and if it exceeds 8.0, the resolution may deteriorate. The epoxy equivalent and carboxyl group equivalent here refer to the epoxy groups and carboxyl groups of all compounds included in the alkali-developed photosensitive resin composition.

[0056] <(Matte)Acrylic Monomer>

[0057] (Met)acrylic monomer is a compound having a (meth)acryloyl group in its molecule, which is included to promote the photocuring of carboxyl group-containing resins.

[0058] As the (meth)acrylic monomer, known and commonly used (meth)acrylic monomers may be used. For example, polyfunctional allyl compounds such as trialyl isocyanurate, diallyl phthalate, and diallyl isophthalate; alkylene polyol poly(meth)acrylate compounds such as ethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate; Polyoxyalkylene glycol poly(meth)acrylates such as diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, ethoxylated trimethylolpropane triacrylate, propoxylated trimethylolpropane tri(meth)acrylate; poly(meth)acrylates such as hydroxypivalsan neopentyl glycol ester di(meth)acrylate; isocyanurate-type poly(meth)acrylates such as tris[(meth)acryloxyethyl]isocyanurate; acrylamides such as N,N-dimethylacrylamide, N-methylolacrylamide, N,N-dimethylaminopropylacrylamide; Examples include aminoalkyl acrylates such as N,N-dimethylaminoethyl acrylate and N,N-dimethylaminopropyl acrylate, polyvalent acrylates of glycidyl ethers such as glycerin diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, and triglycidyl isocyanurate. These may be used individually or in combination of two or more.

[0059] The content of the (meth)acrylic monomer, in terms of solid content, is preferably 5 to 100 parts by mass with respect to 100 parts by mass of the aforementioned carboxyl group-containing resin, and more preferably 5 to 70 parts by mass. By setting the content of the (meth)acrylic monomer to 5 to 100 parts by mass with respect to 100 parts by mass of the carboxyl group-containing resin, photocurability is improved and resolution is improved.

[0060] Photopolymerization Initiator

[0061] A photopolymerization initiator is included to cure the photosensitive resin composition. As long as the photopolymerization initiator is used in a conventional photosensitive resin composition, there are no particular restrictions, and it can be appropriately selected according to the purpose, and any known type may be used. The photopolymerization initiator may be used as a single type or in combination of two or more types.

[0062] The photopolymerization initiator is, for example, a bis-acylphosphine oxide class such as bis-(2,6-dichlorobenzoyl)phenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis-(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis-(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis-(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; Monoacylphosphine oxides such as 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphine methyl ester, 2-methylbenzoyldiphenylphosphine oxide, pivaloylphenylphosphine isopropyl ester, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; Hydroxyacetophenones such as phenyl(2,4,6-trimethylbenzoyl)phosphinate ethyl, 1-hydroxy-cyclohexylphenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzoins such as benzoin, benzyl, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isopropyl ether, benzoin n-butyl ether, etc.; benzoin alkyl ethers; Benzophenones such as benzophenone, p-methylbenzophenone, mihiller ketone, methylbenzophenone, 4,4'-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone;Acetophenones such as 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)-2-[(4-methylphenyl)methyl)-1-[4-(4-morpholinyl)phenyl]-1-butanone, N,N-dimethylaminoacetophenone; Thioxantones such as thioxantone, 2-ethylthioxantone, 2-isopropylthioxantone, 2,4-dimethylthioxantone, 2,4-diethylthioxantone, 2-chlorothioxantone, 2,4-diisopropylthioxantone; anthraquinones such as anthraquinone, chloroanthraquinone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone, 2-aminoanthraquinone; ketal compounds such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzoic acid esters such as ethyl-4-dimethylaminobenzoate, 2-(dimethylamino)ethyl benzoate, and p-dimethyl benzoic acid ethyl ester; Oxime esters such as 1,2-octanedione, 1-[4-(phenylthio)phenyl]-, 2-(O-benzoyloxime), ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-, 1-(O-acetyloxime); titanocenes such as bis(η5-2,4-cyclopentadiene-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole-1-yl)phenyl)titanium, bis(cyclopentadienyl)-bis[2,6-difluoro-3-(2-(1-pyrrole-1-yl)ethyl)phenyl]titanium; Examples include phenyl disulfide, 2-nitrofluorene, butyroine, anisophosphorus ethyl ether, azobisisobutyronitrile, tetramethylthiuram disulfide, etc.

[0063] The content of the photopolymerization initiator, excluding the oxime ester-based photopolymerization initiator, is preferably 0.01 to 30 parts by mass and more preferably 0.1 to 20 parts by mass, based on solid content, per 100 parts by mass of the carboxyl group-containing resin. By setting the content of the photopolymerization initiator, excluding the oxime ester-based photopolymerization initiator, to 0.01 parts by mass or more, the photocurability of the photosensitive resin composition is improved, the film is less likely to peel off, and film properties such as chemical resistance are also improved. Furthermore, by setting the content of the photopolymerization initiator, excluding the oxime ester-based photopolymerization initiator, to 30 parts by mass or less, light absorption on the surface of the solder resist film is improved, and it is less likely for the deep curability to decrease.

[0064] The content of the oxime ester-based photopolymerization initiator is preferably 0.01 to 5 parts by mass and more preferably 0.1 to 3.9 parts by mass, based on solid content, per 100 parts by mass of the carboxyl group-containing resin. By setting the content of the oxime ester-based photopolymerization initiator to 0.01 parts by mass or more, the photocurability of the photosensitive resin composition is improved, and film properties such as heat resistance and chemical resistance are also improved. Furthermore, by setting the content of the oxime ester-based photopolymerization initiator to 5 parts by mass or less, light absorption on the surface of the solder resist film is improved, and it is difficult for the deep curability to decrease.

[0065] Other ingredients

[0066] Other components are not particularly limited as long as they are used in conventional photosensitive resin compositions and can be appropriately selected according to the purpose, such as curing catalysts, colorants, fillers, etc. These may be used individually or in combination of two or more types.

[0067] <<Curing Catalyst>>

[0068] A curing catalyst is a compound that has the property of curing by heat. Curing catalysts 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; 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, dihydrazide sebacic acid; and phosphorus compounds such as triphenylphosphine. Examples include S-triazine derivatives such as guanamine, acetoguanamin, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-S-triazine, 2-vinyl-2,4-diamino-S-triazine, 2-vinyl-4,6-diamino-S-triazine·isocyanuric acid adduct, and 2,4-diamino-6-methacryloyloxyethyl-S-triazine·isocyanuric acid adduct.

[0069] Coloring Agent

[0070] As long as the coloring agent is used in a conventional photosensitive resin composition, there are no particular restrictions, and it can be appropriately selected according to the purpose. Commonly known coloring agents such as black, red, blue, green, yellow, and white may be used, and it may be any of pigments, dyes, or colorants.

[0071] Black coloring agents include, for example, carbon black, zirconium nitride, Pigment Black 1, 6, 7, 8, 9, 10, 11, 12, 13, 18, 20, 25, 26, 28, 29, 30, 31, 32, etc.

[0072] Red coloring agents include monoazo, disazo, azolake, benzimidazolone, perylene, diketopyrrolopyrrole, condensed azo, anthraquinone, and quinacridone.

[0073] Blue coloring agents include phthalocyanine and anthraquinone types, and pigment-based compounds classified as pigments can be used. In addition to these, metal-substituted or non-substituted phthalocyanine compounds can also be used.

[0074] Green coloring agents include phthalocyanine, anthraquinone, and perylene compounds. In addition to these, metal-substituted or unsubstituted phthalocyanine compounds can also be used.

[0075] Yellow coloring agents include monoazo, disazo, condensed azo, benzimidazolone, isoindolinone, and anthraquinone types.

[0076] Examples of white coloring agents include rutile-type or anatase-type titanium oxide. Additionally, coloring agents such as purple, orange, or brown may be added to adjust the color tone.

[0077] <<Filler>>

[0078] As fillers, known inorganic or organic fillers may be used, but barium sulfate, spherical silica, and talc are particularly preferably used.

[0079] The photosensitive resin composition of the present invention may additionally contain, if necessary, components such as a photoinitiator, a cyanate compound, an elastomer, a mercapto compound, a urethane catalyst, a thixotropic agent, an adhesion promoter, a block copolymer, a chain transfer agent, a polymerization inhibitor, a copper damage inhibitor, an antioxidant, a rust inhibitor, a thickener such as organic bentonite or montmorillonite, at least one of a defoaming agent such as a silicone-based, fluorine-based, or polymer-based agent and a leveling agent, a silane coupling agent such as an imidazole-based, thiazole-based, or triazole-based agent, and a flame retardant such as a phosphorus compound such as a phosphinate, a phosphate ester derivative, or a phosphazene compound.

[0080] The content of other components is not particularly limited as long as it does not impede the effects of the present invention, and can be appropriately selected according to the purpose.

[0081] Method for manufacturing a photosensitive resin composition

[0082] The method for manufacturing a photosensitive resin composition is not particularly limited, and, for example, after mixing each of the above components in a predetermined ratio, it can be manufactured by mixing or blending at room temperature using a mixing means such as a 3-roll mill, ball mill, bead mill, or sand mill, or a stirring means such as a super mixer or planetary mixer. In addition, prior to the mixing or blending, pre-mixing or pre-blending may be performed if necessary.

[0083] (Dry film)

[0084] The dry film according to the present embodiment has a resin layer and, if necessary, has other members.

[0085] Resin layer

[0086] A resin layer is formed on a first film described below and is obtained from the photosensitive resin composition described above. Here, the resin layer refers to a material that has been coated and dried with a photosensitive resin composition, and does not have any other layer laminated thereon, such as the first film described below or other materials.

[0087] There are no specific restrictions on the thickness of the resin layer, and it can be appropriately selected according to the purpose.

[0088] Other materials

[0089] Other components are not particularly limited and can be appropriately selected according to the purpose, such as a first film, a second film, etc.

[0090] Film 1

[0091] The first film serves to support the resin layer of the dry film, and when forming the resin layer composed of a photosensitive resin composition, the photosensitive resin composition is applied.

[0092] In the present invention, when integrally molding by laminating by heating or the like so that the resin layer side of a dry film contacts a substrate or the like, it refers to a film that is at least adhered to the resin layer. The first film may be peeled off from the resin layer in a process after lamination. In particular, in this embodiment, it is preferable to peel off from the resin layer in a process after exposure.

[0093] As for the first film, any known film may be used without special limitations. For example, films made of thermoplastic resins such as polyester films (e.g., polyethylene terephthalate or polyethylene naphthalate), polyimide films, polyamideimide films, polypropylene films, or polystyrene films may be suitably used. Among these, polyester films are preferred from the perspective of heat resistance, mechanical strength, and handling properties. Additionally, a laminate of these films may be used as the first film.

[0094] In addition, for the sake of improving mechanical strength, it is preferable that the film made of a thermoplastic resin be a film stretched in a uniaxial or biaxial direction.

[0095] When using a thermoplastic resin film as the first film, a film having a specific surface shape may be used by adding a filler to the resin when forming the film (kneading treatment), applying a matte coating (coating treatment), applying a blast treatment such as sandblasting to the film surface, or by hairline processing or chemical etching.

[0096] The thickness of the first film is not particularly limited, but can be, for example, 10 μm to 150 μm.

[0097] <<Film 2>>

[0098] The second film is a film laminated for purposes such as preventing dust from adhering to the surface of the resin layer. Specifically, it is a film that is peeled off from the resin layer before lamination when the resin layer side of the dry film is laminated by heating or the like so that it comes into contact with a substrate or other material to form a single integral mold.

[0099] The second film may be, for example, a polyethylene film, a polytetrafluoroethylene film, a polypropylene film, surface-treated paper, etc. Additionally, the adhesion of the second film to the resin layer may be smaller than the adhesion between the resin layer and the first film. Since the adhesion of the second film is smaller than that of the first film, the second film can be peeled off without moving the first film.

[0100] The thickness of the second film is not particularly limited, but, for example, can be 10 μm to 150 μm.

[0101] Method for manufacturing dry film

[0102] A dry film can be obtained by diluting the above-described photosensitive resin composition with the above-described organic solvent to adjust the viscosity to an appropriate level, applying it to a first film with a uniform thickness using a comma coater, blade coater, lip coater, rod coater, squeeze coater, reverse coater, transfer roll coater, gravure coater, spray coater, applicator, etc., and drying it at a temperature of typically 50°C to 130°C for 1 minute to 30 minutes. Although there are no particular limitations on the thickness of the applied film, generally, the film thickness after drying is appropriately selected in the range of 1 μm to 150 μm, preferably 5 μm to 60 μm.

[0103] (hardened material)

[0104] The cured product according to the embodiment is obtained by curing the photosensitive resin composition described above or the resin layer of the dry film described above.

[0105] There are no specific restrictions on the size and shape of the cured material, and it can be appropriately selected according to the purpose.

[0106] As a method for manufacturing a cured product, for example, the photosensitive resin composition of the present invention is adjusted to a viscosity suitable for a coating method using an organic solvent, and then applied to a substrate by a method such as a dip coat method, flow coat method, roll coat method, bar coater method, screen printing method, or curtain coat method to a thickness of, for example, 10 μm to 100 μm after drying, and then the organic solvent contained in the composition is evaporatively dried (temporarily dried) at a temperature of 60 to 100°C for 15 to 90 minutes to form a tack-free resin layer. In addition, in the case of a dry film, the resin layer is bonded to the substrate so that it comes into contact with the substrate using a laminator or the like, and then the first film is peeled off to form a resin layer on the substrate.

[0107] Examples of substrates include printed circuit boards or flexible printed circuit boards with circuits formed in advance using copper, etc., paper phenol, paper epoxy, glass epoxy, glass polyimide, glass / non-woven epoxy, glass / paper epoxy, synthetic fiber epoxy, copper-clad laminates using materials such as fluoropolymer, polyethylene, polyphenylene ether, polyphenylene oxide, cyanate, metal substrates, polyimide films, polyethylene terephthalate films, polyethylene naphthalate (PEN) films, glass substrates, ceramic substrates, wafer plates, etc.

[0108] Bonding of the dry film onto a substrate is preferably performed under pressure and heat using a vacuum laminator or the like. By using such a vacuum laminator, when a circuit-formed substrate is used, the dry film adheres to the circuit board even if there are irregularities on the surface of the circuit board, so there is no incorporation of air bubbles, and the filling of concave areas on the surface of the substrate is also improved. The pressure condition is preferably about 0.1 to 2.0 MPa, and the heating condition is preferably 40 to 120°C.

[0109] The volatile drying performed after applying the photosensitive resin composition of the present invention can be carried out using a hot air circulation type dryer, an IR oven, a hot plate, a convection oven, etc. (a method of contacting hot air in a dryer with a counter-flow using a heat source equipped with a steam-based air heating method and a method of spraying onto a support from a nozzle).

[0110] After forming a resin layer on a substrate, the material is selectively exposed to an active energy beam through a photomask that has formed a predetermined pattern, and the unexposed portion is developed with a dilute alkaline aqueous solution (e.g., a 0.3 to 3 mass% sodium carbonate aqueous solution) to form a pattern of the cured material. In the case of a dry film, after exposure, the first film is peeled off from the dry film and developed to form a patterned cured material on the substrate. Additionally, if the properties are not damaged, the first film may be peeled off from the dry film before exposure to expose and develop the exposed resin layer. Furthermore, after irradiating the cured material with an active energy beam, heat curing (e.g., at 100 to 220°C, or irradiating the active energy beam after heat curing, or performing final finishing curing (main curing) solely through heat curing) is performed to form a cured film with excellent general properties such as adhesion and hardness.

[0111] The exposure device used for the above active energy irradiation may be a device equipped with a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a mercury short arc lamp, etc., and irradiating ultraviolet rays in the range of 350 to 450 nm; additionally, a direct imaging device (e.g., a laser direct imaging device that directly draws an image with a laser using CAD data from a computer) may also be used. The lamp light source or laser light source of the direct imaging device may have a maximum wavelength in the range of 350 to 450 nm. The exposure amount for image formation varies depending on the film thickness, etc., but is generally 10 to 1000 mJ / cm² 2 , preferably 20 to 800 mJ / cm² 2 It can be done within the range of.

[0112] The above development method may be by dipping, showering, spraying, brushing, etc., and as the developer, an alkaline aqueous solution such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, or amines may be used.

[0113] (Printed wiring board)

[0114] A printed circuit board according to one embodiment of the present invention has the cured material described above.

[0115] There are no specific restrictions on the size or type of printed circuit board, and they can be selected appropriately according to the purpose.

[0116] [Example]

[0117] Next, the tests conducted by the inventors will be described, but the present invention is not limited to these.

[0118] <Synthetic Example 1: Preparation of Carboxyl Group-Containing Resin (A-1)>

[0119] 220 parts (1 equivalent) of cresol novolak-type epoxy resin (ECON-104S, manufactured by Nihon Kayaku Co., Ltd., epoxy equivalent: 220 g / eq.) were placed in a 4-neck flask equipped with a stirrer and a reflux condenser, and 218 parts of carbitol acetate were added and heated to melt. Next, 0.46 parts of methylhydroquinone were added as a polymerization inhibitor and 1.38 parts of triphenylphosphine were added as a reaction catalyst. This mixture was heated to 95°C to 105°C, and 50.4 parts (0.7 equivalents) of acrylic acid and 41.5 parts (0.3 equivalents) of p-hydroxyphenethyl alcohol were slowly added dropwise, and the mixture was reacted for 16 hours. This reaction product (hydroxyl group: 1.3 equivalents) was cooled to 80°C to 90°C, 91.2 parts (0.6 equivalents) of tetrahydrophthalic anhydride were added and reacted for 8 hours, and then removed after cooling.

[0120] The carboxyl group-containing resin obtained in this way had a non-volatile content of 65%, an acid value of 83 mgKOH / g of solids, a carboxyl group equivalent of 676 g / eq. of solids, and a weight average molecular weight of 12,000. Hereinafter, this resin solution is abbreviated as A-1.

[0121] <Synthetic Example 2: Preparation of Carboxyl Group-Containing Resin (A-2)>

[0122] 119.4 g of novolak-type cresol resin (Shonol CRG951, manufactured by Aika Kogyo Co., Ltd., OH equivalent: 119.4), 1.19 g of potassium hydroxide, and 119.4 g of toluene were added to an autoclave equipped with a thermometer, a nitrogen introduction device and an alkylene oxide introduction device, and a stirring device; the system was nitrogen-substituted while stirring, and the temperature was raised. Next, 63.8 g of propylene oxide was slowly added dropwise, and the mixture was heated to 125°C to 132°C at 0 kg / cm². 2 up to 4.8 kg / cm² 2The reaction was carried out for 16 hours. Afterward, it was cooled to room temperature, and 1.56 g of 89% phosphoric acid was added and mixed to the reaction solution to neutralize potassium hydroxide, thereby obtaining a propylene oxide reaction solution of a novolak-type cresol resin with a non-volatile content of 62.1% and a hydroxyl value of 182.2 g / eq. This had an average of 1.08 molar addition of propylene oxide per 1 equivalent of phenolic hydroxyl group.

[0123] Next, 293.0 g of the propylene oxide reaction solution of the obtained novolak-type cresol resin, 43.2 g of acrylic acid, 11.53 g of methanesulfonic acid, 0.18 g of methylhydroquinone, and 252.9 g of toluene were introduced into a reactor equipped with a stirrer, a thermometer, and an air blower. Air was blown in at a rate of 10 mL / min, and the reaction was carried out at 110°C for 12 hours while stirring. The water produced by the reaction was an azeotropic mixture with toluene, and 12.6 g of water was discharged. Afterward, the mixture was cooled to room temperature, and the obtained reaction solution was neutralized with 35.35 g of a 15% aqueous sodium hydroxide solution and then washed with water. Subsequently, the toluene was evaporated using an evaporator while being replaced with 118.1 g of diethylene glycol monoethyl ether acetate to obtain a novolak-type acrylate resin solution.

[0124] Next, 332.5 g of the obtained novolak-type acrylate resin solution and 1.22 g of triphenylphosphine were introduced into a reactor equipped with a stirrer, a thermometer, and an air blower, air was blown in at a rate of 10 mL / min, and while stirring, 60.8 g of tetrahydrophthalic anhydride was slowly added and reacted at 95°C to 101°C for 6 hours, and after cooling, removed.

[0125] The carboxyl group-containing resin obtained in this way had a non-volatile content of 71%, an acid value of 88 mgKOH / g of solids, a carboxyl group equivalent of 638 g / eq. of solids, and a weight average molecular weight of 2,000. Hereinafter, this resin solution is abbreviated as A-2.

[0126] (Examples 1 to 7, Comparative Examples 1 to 3)

[0127] Preparation of Photosensitive Resin Composition

[0128] Each material was mixed in the proportions shown in Table 1, pre-mixed with a stirrer, and then kneaded with a three-roll mill to prepare a photosensitive resin composition. In addition, the values ​​in the table are the content in a solution containing a solvent. In addition, the units in the table are parts by mass.

[0129]

[0130] The details of each component in Table 1 are as follows.

[0131] <Carboxyl group-containing resin>

[0132] · A-1 (Synthetic Example 1)

[0133] · A-2 (Synthetic Example 2)

[0134] In addition, the values ​​of the carboxyl group-containing resins in Table 1 are the values ​​of the resin solutions.

[0135] Epoxy-based heat-curing components

[0136] · N-770 (Phenol novolak type epoxy resin, epoxy equivalent: 190 g / eq., softening point: 70℃ DIC, manufactured by K.A.)

[0137] · YX4000H (Difunctional crystalline epoxy resin, epoxy equivalent: 192 g / eq., softening point: 105℃, manufactured by Mitsubishi Chemical Corporation)

[0138] · jER-828 (Difunctional liquid epoxy resin (Bisphenol A type epoxy resin), Epoxy equivalent: 189 g / eq., Manufactured by Mitsubishi Chemical Corporation)

[0139] <(Matte)Acrylic Monomer>

[0140] · Dipentaerythritol Hexacrylate

[0141] Photopolymerization Initiator

[0142] · Omnirad907 (2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-1-propanone, manufactured by IGM Resins BV)

[0143] · DETX-S (2,4-diethylthioxantone, manufactured by Nihon Kayaku Co., Ltd.)

[0144] Other ingredients

[0145] <<Curing Catalyst>>

[0146] · DICY (Dicyandiamide, manufactured by Mitsubishi Chemical Corporation)

[0147] · Melamine (manufactured by Nissan Chemical Co., Ltd.)

[0148] Pigments

[0149] · Phthalocyanine Blue (manufactured by Tokyo Kasei High School Co., Ltd.)

[0150] · Chromium Phthalate Yellow (Manufactured by Tokyo Kasei High School Co., Ltd.)

[0151] <<Filler>>

[0152] · Admapine SO-E2 (spherical silica, manufactured by Admatex, Inc.)

[0153] The carboxyl group equivalent, epoxy equivalent, and softening point of the epoxy resin in Table 1 were measured or calculated as follows.

[0154] Calculation Method for Carboxyl Equivalents

[0155] First, the oxidation in each photosensitive resin composition is measured. The oxidation was measured in accordance with "7. Potentiometric titration method (acid value)" of JIS K2501:2003.

[0156] The carboxyl group equivalent was calculated from the measured acid value (mgKOH / g) according to the following formula.

[0157] Carboxyl equivalent (g / eq.) = 56.11 / acid value (mgKOH / g) × 1000

[0158] Method for Measuring Epoxy Equivalents

[0159] The first equivalent of each photosensitive resin composition was measured using tetraethylammonium bromide in accordance with JIS K7236:2001. Meanwhile, the second equivalent was measured in the same manner as the first equivalent measurement method, except that tetraethylammonium bromide was not used.

[0160] According to the following formula, the epoxy equivalent was calculated by subtracting the second equivalent from the first equivalent.

[0161] Epoxy equivalent (g / eq.) = 1 / ((1 / 1st equivalent) - (1 / 2nd equivalent))

[0162] Method for Measuring the Softening Point of Epoxy Heat-Curing Components

[0163] The softening point of the epoxy-based heat-curing component was measured in accordance with "4.1 Rounding Method" of JIS K7234:1986.

[0164] Thermal stability

[0165] The obtained photosensitive resin composition was applied to the entire surface of a copper foil substrate by screen printing so that the film thickness after drying was 20 μm, and dried at 80°C for 50 minutes and 70 minutes, respectively. After cooling to room temperature, development was performed for 60 seconds using a 1 mass% aqueous solution of Na2CO3 at 30°C under conditions of a spray pressure of 0.2 MPa, and the presence or absence of development residue on the dried film was visually observed and evaluated based on the following evaluation criteria.

[0166] - Evaluation Criteria -

[0167] ◎: There is no developed residue of the composition in both 50-minute and 70-minute drying.

[0168] ○: There is no developed residue of the composition after 50 minutes of drying, but there is a slight residue after 70 minutes of drying.

[0169] △: At 50 minutes of drying, there is a slight residual development of the composition, and at 70 minutes of drying, a clear residual development is confirmed.

[0170] ×: Clear residual characteristics of the composition are confirmed in both 50-minute drying and 70-minute drying.

[0171] <Resolution>

[0172] The obtained photosensitive resin composition was applied over the entire surface of a copper foil substrate by screen printing to achieve a film thickness of 20 μm after drying, and dried at 80°C for 30 minutes. After cooling to room temperature, Kodak Step Tablet No. 2 was placed on the dried film, and direct imaging exposure was performed using a direct imaging exposure device with an exposure amount such that the number of stages after exposure was 7, and an aperture size of SRO (Solder Resist Opening) of 60 μm. Subsequently, the film on the pattern-exposed substrate was developed for 60 seconds using a 1 mass% aqueous solution of Na2CO3 at 30°C, and then rinsed with water. Finally, a test specimen for resolution evaluation was prepared by curing at 150°C for 60 minutes.

[0173] Afterwards, the top diameter and bottom diameter of the SRO of the evaluation specimen were observed using a scanning electron microscope (SEM) at 1,000x magnification and evaluated based on the following evaluation criteria.

[0174] - Evaluation Criteria -

[0175] ◎: The ratio of bottom diameter to top diameter is 1.00 or less, 0.85 or more

[0176] ○: Ratio of bottom diameter to top diameter is less than 0.85, 0.70 or greater

[0177] ×: The ratio of bottom diameter to top diameter is less than 0.70

[0178] Desmear resistance

[0179] The evaluation specimen prepared in the above resolving performance evaluation was immersed in a swelling solution (a mixture of Swelling Dip Securigant P (manufactured by Atotech Japan) and 48% sodium hydroxide) at 60°C for 5 minutes. Next, it was immersed in a mixing solution (a mixture of Concentrate Compact CP (manufactured by Atotech Japan) and 48% sodium hydroxide) at 80°C for 20 minutes, and finally, it was immersed in a neutralizing solution (Reduction Securigant P500 (manufactured by Atotech Japan) and 96% sulfuric acid) at 40°C for 5 minutes to perform desmear treatment. After desmear treatment, the SRO periphery on the surface of the cured film was observed using a scanning electron microscope (SEM) at 1,000x magnification and evaluated based on the following evaluation criteria.

[0180] - Evaluation Criteria -

[0181] ◎: No damage is visible around the SRO even after desmearing.

[0182] ○: After desmearing, slight damage was observed around the SRO, but no delamination was seen.

[0183] △: After desmearing, some delamination was observed around the SRO.

[0184] ×: After desmearing, delamination was observed across the entire periphery of the SRO.

[0185]

[0186] For Examples 1 to 7, in which the equivalent ratio (carboxyl group equivalent / epoxy equivalent) was 5.0 to 8.0, the evaluation results for thermal stability, resolution, and desmear resistance were "◎", "○", or "△". In contrast, for Comparative Example 1, in which the equivalent ratio (carboxyl group equivalent / epoxy equivalent) was 4.1, the evaluation result for desmear resistance was "×", and for Comparative Example 2, in which the equivalent ratio (carboxyl group equivalent / epoxy equivalent) was 8.9, the evaluation results for thermal stability and resolution were "×". Furthermore, for Comparative Example 3, which does not contain a difunctional crystalline epoxy resin as an epoxy-based thermosetting component, the evaluation result for thermal stability was "×". That is, for the compositions of Comparative Examples 1 to 3, any one of the evaluation results for thermal stability, resolution, and desmear resistance was "×". From the above, regarding the alkali of Examples 1 to 7 The developing type photosensitive resin composition can be described as an alkali developing type photosensitive resin composition capable of forming a cured product with good resolution, thermal stability, and desmear resistance.

[0187] Examples 1 to 4 and 7, in which the equivalent ratio (carboxyl group equivalent / epoxy equivalent) is 5.0 to 8.0 and the weight ratio of the epoxy-based heat-curing component (novolak-type epoxy resin / bifunctional crystalline epoxy resin) is 1.0 to 2.0, showed a desmear resistance evaluation result of "◎" or "○", whereas Example 6, in which the weight ratio of the epoxy-based heat-curing component (novolak-type epoxy resin / bifunctional crystalline epoxy resin) is 0.7, showed a desmear resistance evaluation result of "△", and Example 5, in which the weight ratio is 2.3, showed a thermal stability evaluation result of "△". Accordingly, an alkali-developing type photosensitive resin composition having an equivalent ratio (carboxyl group equivalent / epoxy equivalent) of 5.0 to 8.0 and a weight ratio of an epoxy-based heat-curing component (novolak-type epoxy resin / bifunctional crystalline epoxy resin) of 1.0 to 2.0 can be described as an alkali-developing type photosensitive resin composition capable of forming a cured product with better resolution, thermal stability, and desmear resistance.

[0188] Although the embodiments for carrying out the present invention have been described in detail above, the present invention is not limited thereto and can be modified in various ways without departing from the gist thereof.

Claims

Claim 1 An alkali-developing type photosensitive resin composition comprising a carboxyl group-containing resin, an epoxy-based thermosetting component, a (meth)acrylic monomer, and a photopolymerization initiator, wherein the equivalent ratio of carboxyl groups to epoxy groups (carboxyl group equivalent / epoxy equivalent) is 5.0 to 8.0, and the epoxy-based thermosetting component comprises a novolak-type epoxy resin and a difunctional crystalline epoxy resin having a softening point of 70°C to 120°C. Claim 2 An alkali-developing photosensitive resin composition according to claim 1, wherein the weight ratio of the novolak-type epoxy resin to the bifunctional crystalline epoxy resin (novolak-type epoxy resin / bifunctional crystalline epoxy resin) is 1.0 to 2.

0. Claim 3 A dry film characterized by having a resin layer obtained from an alkali-developing type photosensitive resin composition described in claim 1. Claim 4 A cured product characterized by being obtained by curing the resin layer of the alkali-developing type photosensitive resin composition described in claim 1, or the dry film described in claim 3. Claim 5 A printed circuit board characterized by having the cured material described in paragraph 4.

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