JP2010191348A - Photosetting thermosetting resin composition, dry film, and cured product of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photosetting thermosetting resin composition having little shrinkage upon curing and capable of giving a substrate which does not have warpages, without impairing the developability and photoreactivity necessary for a photolithographic process, and to provide a dry film and a cured product of the resin composition. <P>SOLUTION: The photosetting thermosetting resin composition which is alkali developable contains a photosensitive component and a thermosetting component but does not contain a monomer having an unsaturated double bond. The photosensitive component comprises a compound having both of a (meth)acryloyl group and a carboxyl group in one molecule and having a weight average molecular weight of 2,000 to 50,000; and a photopolymerization initiator. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a photocurable thermosetting resin composition, a dry film and a cured product thereof useful for the production of a printed wiring board and a package substrate. More specifically, a photocurable thermosetting resin composition, a dry film, which can produce a substrate with little curing shrinkage and no warpage, and has excellent photosensitivity, developability and solder heat resistance required as a resist for solder resist and package substrate. And a cured product thereof.

Compositions that combine photocuring and thermal curing, including solder resists that are currently used as permanent protective films for printed wiring boards, are widely used in the electronics field where high density, high resolution, and high reliability are required. It's being used.
These compositions mainly improve the properties of the cured film and the photosensitive component containing a photopolymerization initiator and a resin that has been introduced with carboxyl groups into epoxy acrylate to give photosensitivity and developability in an aqueous alkaline solution. It is comprised by thermosetting components, such as an epoxy resin.

  For example, Patent Document 1 discloses a solder resist composition comprising a photosensitive resin obtained by adding an acid anhydride to a reaction product of a novolak type epoxy compound and an unsaturated monobasic acid, a photopolymerization initiator, a diluent, and an epoxy compound. Is disclosed. According to this composition, a resin containing a (meth) acryloyl group is radical-polymerized through a photomask in the exposure step, and after patterning with a known and commonly used developer, the carboxyl groups and epoxy groups remaining in the coating film By forming a three-dimensional network structure by a thermosetting reaction, a cured coating film having excellent adhesion, hardness, heat resistance, electrical insulation and the like can be obtained.

  Such a composition that uses both photocuring and thermal curing can improve the sensitivity for shortening the exposure tact and increase the crosslink density, for example, coating properties such as heat resistance, water resistance, and electroless plating resistance. In order to improve this, it was indispensable to add a low molecular weight (meth) acrylate as a monomer component. However, the photoreaction of (meth) acrylate in the dry coating does not complete, and these unsaturated double bonds remain after curing, so that the coating warps during the subsequent heat treatment process. There was a drawback of doing. That is, the actual situation is that the problem of warping caused by curing shrinkage not only during photocuring but also during thermal curing has not been completely solved.

JP 61-243869 (Claims)

  The present invention has been made in order to eliminate the above-mentioned drawbacks, and its main purpose is to provide a substrate with little curing shrinkage and no warpage without impairing the developability and photoreactivity required for the photolithography process. It is in providing the photocurable thermosetting resin composition which can be provided, a dry film, and those hardened | cured materials.

  As a result of intensive studies to achieve the above object, the present inventors have eliminated any low-molecular (meth) acrylate compounded in the composition, and (meth) acryloyl group and carboxyl in one molecule. By adding a compound having a weight average molecular weight of 2,000 to 50,000 and a photopolymerization initiator as a photosensitive component, the photolithographic process is equivalent to a conventional low molecular (meth) acrylate compounding system. Necessary developability and photoreactivity were obtained, and it was found that curing shrinkage could be reduced, and the present invention was completed.

That is, the photocurable thermosetting resin composition of the present invention comprises a compound having a (meth) acryloyl group and a carboxyl group in one molecule and a weight average molecular weight of 2,000 to 50,000, and a photopolymerization initiator. A photosensitive component constituted by a combination of the above and a thermosetting component are essential components, and a monomer component having an unsaturated double bond is not contained. This makes it possible to achieve the same photosensitivity and developability as conventional low-molecular (meth) acrylate-added systems, and to reduce the shrinkage caused by low-molecular (meth) acrylate to suppress warpage. A thermosetting resin composition can be provided.
The photocurable thermosetting resin composition of the present invention includes a carboxyl group as a compound having a (meth) acryloyl group and one or more carboxyl groups in one molecule and a weight average molecular weight of 2,000 to 50,000. It is preferable to use a containing urethane (meth) acrylate compound. Thereby, not only suppression of photosensitivity, developability and warpage but also characteristics such as electroless plating resistance are excellent.

  The photocurable thermosetting dry film of the present invention is obtained by applying and drying the photocurable thermosetting resin composition of the present invention on a film.

The cured product of the present invention is obtained by curing the photocurable thermosetting resin composition of the present invention or the dry film of the present invention by irradiation with active energy rays and heating. The printed wiring board of the present invention is one in which a solder resist is formed on a substrate having a conductor layer of a circuit pattern, and the solder resist uses the photocurable thermosetting resin composition or dry film of the present invention. Formed.
Here, in the present invention, the “(meth) acryloyl group” means an acryloyl group and / or a methacryloyl group. In the present invention, “(meth) acrylate” means acrylate and / or methacrylate.

  The photocurable thermosetting resin composition or dry film of the present invention can significantly reduce the (meth) acryloyl group concentration in the coating film by eliminating low-molecular (meth) acrylate from the composition. Therefore, it is possible to reduce the occurrence of warpage due to curing shrinkage due to double bonds and to obtain a coating film excellent in flexibility. Therefore, a thin plate substrate, TAB, T-BGA, T-CSP, UT-CSP Can also be supported.

Hereinafter, the structural component of the photocurable thermosetting resin composition of this invention is demonstrated in detail.
In the photocurable thermosetting resin composition of the present invention, a compound having a (meth) acryloyl group and a carboxyl group in one molecule and a weight average molecular weight of 2,000 to 50,000 (hereinafter simply referred to as “carboxyl group”). Examples of the "containing photosensitive resin") include the following resins.
(1) A carboxyl group-containing photosensitive resin obtained by adding an ethylenically unsaturated group as a pendant to a copolymer of an unsaturated carboxylic acid and a compound having an unsaturated double bond,
(2) An unsaturated carboxylic acid is reacted with a copolymer of a compound having an epoxy group and an unsaturated double bond and a compound having an unsaturated double bond, and the resulting secondary hydroxyl group is saturated or unsaturated. A carboxyl group-containing photosensitive resin obtained by reacting a saturated polybasic acid anhydride,
(3) Carboxyl group-containing photosensitivity obtained by reacting a copolymer of an acid anhydride having an unsaturated double bond and a compound having an unsaturated double bond with a compound having a hydroxyl group and an unsaturated double bond. Resin,
(4) a carboxyl group-containing photosensitive resin obtained by reacting a polyfunctional epoxy compound with an unsaturated monocarboxylic acid and reacting the generated hydroxyl group with a saturated or polybasic acid anhydride,
(5) A hydroxyl group and a carboxyl group obtained by reacting a hydroxyl group-containing polymer with a saturated or polybasic acid anhydride and then reacting the resulting carboxylic acid with a compound having an epoxy group and an unsaturated double bond. Containing photosensitive resin,
(6) A polyfunctional epoxy compound, an unsaturated monocarboxylic acid with at least one alcoholic hydroxyl group in one molecule, and a compound having one reaction century other than an alcoholic hydroxyl group that reacts with an epoxy group A carboxyl group-containing photosensitive resin obtained by reacting the reaction product with a saturated or unsaturated polybasic acid anhydride,
(7) A polyfunctional oxetane compound having at least two oxetane rings in one molecule is reacted with an unsaturated monocarboxylic acid, and the primary hydroxyl group in the resulting modified oxetane resin is saturated or unsaturated. A carboxyl group-containing photosensitive resin obtained by reacting a saturated polybasic acid anhydride, and (8) a hydroxyl group-containing (meth) acrylate is reacted with a terminal isocyanate group of a polyurethane resin comprising a carboxyl group-containing polyol and a diisocyanate compound. Obtained carboxyl group-containing photosensitive resin.

Among these, the resin described in (8) is preferable, and a carboxyl group-containing urethane (meth) acrylate compound is particularly preferable.
This carboxyl group-containing urethane (meth) acrylate compound is a compound obtained by reacting a hydroxyl group-containing (meth) acrylate compound, dimethylolalkanoic acid and a diisocyanate compound, and / or a hydroxyl group-containing (meth) acrylate compound, It refers to a compound obtained by reacting a methylol alkanoic acid, a diisocyanate compound, and a polymer polyol, and its solid content acid value is preferably 30 to 200 mgKOH / g. A solid content acid value of less than 30 mg KOH / g is not preferable because developability with an aqueous alkaline solution cannot be obtained. On the other hand, when the solid content acid value exceeds 200 mgKOH / g, development resistance cannot be obtained, and electroless plating resistance and the like are not preferable.

  Since such a carboxyl group-containing urethane (meth) acrylate compound is a carboxyl group-containing photosensitive resin having a linear urethane bond, it has flexibility and the structure itself is warped due to curing shrinkage. There is an effect of reducing.

  The hydroxy group-containing (meth) acrylate compound used for the synthesis of this carboxyl group-containing urethane (meth) acrylate compound is preferably a (meth) acrylate compound having one hydroxyl group or two (meth) hydroxyl groups. Acrylate.

  Examples of the (meth) acrylate compound having one hydroxyl group include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, trimethylolpropane di (meth) ) Acrylate, pentaerythritol tri (meth) acrylate, and a reaction product of glycidyl (meth) acrylate and (meth) acrylic acid.

  Such a (meth) acrylate compound having one hydroxyl group is added to the terminal of the carboxyl group-containing urethane (meth) acrylate compound of the present invention and functions as a terminator for stopping molecular growth.

  As a (meth) acrylate having two hydroxyl groups, a bifunctional epoxy (meth) acrylate compound obtained by adding (meth) acrylic acid to a bifunctional epoxy compound or a (meth) acrylic acid added to a bifunctional oxetane compound And bifunctional oxetane (meth) acrylate compounds.

  Specifically, (meth) acrylates of bifunctional epoxy resins with aromatic rings such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, biphenyl type epoxy resin, and bixylenol type epoxy resin Is preferred. The molecular weight of these bifunctional epoxy (meth) acrylates is preferably in the range of 450 to 2,000 from the viewpoint of cured coating film characteristics.

The dimethylol alkanoic acid is a compound having two tertiary carboxyl groups and two primary hydroxyl groups, specifically, dimethylolpropionic acid, dimethylolbutanoic acid, dimethylolpentanoic acid, dimethylolhexanoic acid, etc. Is mentioned.
Among these, dimethylolpropionic acid and dimethylolbutanoic acid are preferable from the viewpoint of characteristics of the cured coating film.

Examples of the diisocyanate compound include phenylene diisocyanate, toluylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, cyclohexane diisocyanate, trimethylphenylene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, and tetramethylxylylene diisocyanate.
Among these, isophorone diisocyanate is particularly preferable because the reaction can be easily controlled.

  In the synthesis of the carboxyl group-containing urethane (meth) acrylate compound, a polymer polyol may be further used to reduce curing shrinkage. As the polymer polyol, a diol compound that is difficult to be three-dimensional is preferable, but a triol may be added to give a branched structure. Specific examples include polyether polyols, polyester polyols, polycarbonate polyols, and polybutadiene glycols. In particular, polycarbonate polyols derived from diols or bisphenols and carbonates such as dimethyl carbonate are preferred from the standpoint of chemical resistance.

  The synthesis | combination of the carboxyl group containing urethane (meth) acrylate compound using these hydroxyl-containing (meth) acrylate compounds, dimethylol alkanoic acid, a diisocyanate compound, and a polymer polyol is implemented by urethanation by a well-known and usual method.

  Specifically, it is charged so that the equivalent ratio of isocyanate group to hydroxyl group is 0.8 to 1.05, and the resulting carboxyl group-containing urethane (meth) acrylate compound has a solid content acid value of 30 to 200 mgKOH / g. , React. As a reaction condition, it can be synthesized by using a metal catalyst that is difficult to be three-dimensionalized and reacting at room temperature to 150 ° C., preferably 60 to 120 ° C. in a solvent-free or aprotic solvent.

  In the photocurable thermosetting resin composition of the present invention, examples of the photopolymerization initiator include acetophenone, 2,2-diethoxy-2-phenylacetophenone, p-dimethylaminopropiophenone, dichloroacetophenone, trichloroacetophenone, p-tert-butyltrichloroacetophenone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) ) -Butanone-1 and other acetophenones; benzophenone, 2-chlorobenzophenone, p, p-dichlorobenzophenone, p, p-bisdimethylaminobenzophenone, p, p-bisdiethylaminobenzophenone, 4-benzoyl-4'-methyldiphenyl Sulfide etc. Benzophenones; benzoin ethers such as benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; ketals such as benzyldimethyl ketal; thioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, etc. Thioxanthones; anthraquinones such as 2-ethylanthraquinone and 2,3-diphenylanthraquinone; organic peroxides such as benzoyl peroxide and cumene peroxide; 2,4,5-triarylimidazole dimer, riboflavin tetrabuty Thiol compounds such as rate, 2-mercaptobenzoimidazole, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole; 2,4,6-tris- Organic halogen compounds such as triazine, 2,2,2-tribromoethanol, tribromomethylphenylsulfone; (2,6-dimethoxybenzoyl) -2,4,4-pentylphosphine oxide, bis (2,4,6) Acylphosphine oxides such as -trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethyl-2,4,6-trimethylbenzoylphenylphosphinate; 1-phenyl-1,2- Propanedione-2 (o-ethoxycarbonyl) oxime, 1-phenyl-1,2-propanedione-2-o-benzoyloxime, 1,2-octanedione-1- [4- (phenylthio) -2- (o -Oxyme esters such as -benzoyloxime)] It is done. These compounds can be used alone or in combination of two or more. Such a photopolymerization initiator can be used in combination with one or two or more known photopolymerization initiators (or sensitizers) such as benzoic acid type or tertiary amine type.

  The blending amount of such a photopolymerization initiator is suitably 0.2 to 30 parts by mass, preferably 2 to 20 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin. When the blending amount of the photopolymerization initiator is less than 0.2 parts by mass, the photocurability is deteriorated. On the other hand, when it is more than 30 parts by mass, the storage stability of the resin composition is deteriorated.

  In the photocurable thermosetting resin composition of the present invention, the thermosetting component may be any component that thermally reacts with the carboxyl group remaining in the coating film after development in consideration of the coating characteristics after thermosetting. Although not particularly limited, it is preferably a polyfunctional epoxy compound and / or a polyfunctional oxetane compound. These thermosetting components can be used alone or in combination of two or more.

Examples of the polyfunctional epoxy compound include Epicoat 828, Epicoat 834, Epicoat 1001, Epicoat 1004, Epicron 840, Epicron 850, Epicron 1050, Epicron 2055, and Toto, manufactured by Dainippon Ink & Chemicals, Inc. Epototo YD-011, YD-013, YD-127, YD-128 manufactured by Kasei Co., Ltd., D.C. E. R. 317, D.E. E. R. 331, D.D. E. R. 661, D.E. E. R. 664, Ciba Specialty Chemicals' Araldide 6071, Araldide 6084, Araldide GY50, Araldide GY260, Sumitomo Chemical Industries Sumi-Epoxy ESA-011, ESA-014, ELA-115, ELA-128, Asahi Kasei Kogyo Co., Ltd. A. E. R. 330, A.I. E. R. 331, A.I. E. R. 661, A.I. E. R. Bisphenol A type epoxy resin such as 664 (all trade names); Epicoat YL903 manufactured by Japan Epoxy Resin, Epicron 152, Epicron 165 manufactured by Dainippon Ink and Chemicals, Epototo YDB-400, YDB- manufactured by Tohto Kasei Co., Ltd. 500, D.C. E. R. 542, Araldide 8011 manufactured by Ciba Specialty Chemicals, Sumi-epoxy ESB-400, ESB-700 manufactured by Sumitomo Chemical Co., Ltd., and A.D. E. R. 711, A.I. E. R. Brominated epoxy resins such as 714 (all trade names); Epicoat 152 and Epicoat 154 manufactured by Japan Epoxy Resin Co., Ltd., D.C. E. N. 431, D.E. E. N. 438, Epicron N-730, Epicron N-770, Epicron N-865, Etototo YDCN-701, YDCN-704 from Toto Kasei Co., Ltd., Araldide ECN1235 from Ciba Specialty Chemicals, Araldide ECN1273, Araldide ECN1299, Araldide XPY307, EPPN-201, EOCN-1025, EOCN-1020, EOCN-104S, RE-306 manufactured by Nippon Kayaku Co., Ltd., Sumi-epoxy ESCN-195X, ESCN- manufactured by Sumitomo Chemical Co., Ltd. 220, manufactured by Asahi Kasei Corporation. E. R. Novolak type epoxy resins such as ECN-235, ECN-299, etc. (both trade names); Epicron 830 manufactured by Dainippon Ink & Chemicals, Epicoat 807 manufactured by Japan Epoxy Resin, Epototo YDF-170 manufactured by Toto Kasei Co., YDF -175, YDF-2004, bisphenol F type epoxy resin such as Araldide XPY306 manufactured by Ciba Specialty Chemicals (all are trade names); Epotot ST-2004, ST-2007, ST-3000 manufactured by Tohto Kasei Hydrogenated bisphenol A type epoxy resin, such as Epicoat 604 manufactured by Japan Epoxy Resin Co., Ltd., Epotot YH-434 manufactured by Toto Kasei Co., Ltd., Araldide MY720 manufactured by Ciba Specialty Chemicals Co., Ltd., Sumitomo Chemical Co., Ltd. Epoxy ELM-120 etc. ( Glycidylamine type epoxy resin (trade name); Hydantoin type epoxy resin such as Araldide CY-350 (trade name) manufactured by Ciba Specialty Chemicals; Celoxide 2021 manufactured by Daicel Chemical Industries, Ciba Specialty Chemicals Alicyclic epoxy resins such as Araldide CY175, CY179, etc. (both trade names) manufactured by YL-933 manufactured by Japan Epoxy Resin Co., Ltd. E. N. , EPPN-501, EPPN-502, etc. (all trade names) trihydroxyphenylmethane type epoxy resin; Japan Epoxy Resin YL-6056, YX-4000, YL-6121 (all trade names), etc. Xylenol type or biphenol type epoxy resin or a mixture thereof; bisphenol S type such as EBPS-200 manufactured by Nippon Kayaku Co., Ltd., EPX-30 manufactured by Asahi Denka Kogyo Co., Ltd., EXA-1514 (trade name) manufactured by Dainippon Ink & Chemicals, Inc. Epoxy resin; Bisphenol A novolac type epoxy resin such as Epicoat 157S (trade name) manufactured by Japan Epoxy Resin; Epicoat YL-931 manufactured by Japan Epoxy Resin, Araldide 163 manufactured by Ciba Specialty Chemicals, etc. Name) Tetraphenylolethane type Poxy resin; Araldide PT810 manufactured by Ciba Specialty Chemicals, TEPIC manufactured by Nissan Chemical Industries, Ltd. (both are trade names); Diglycidyl phthalate resin such as Bremer DGT manufactured by Nippon Oil &Fats; Tetraglycidyl xylenoyl ethane resin such as ZX-1063 manufactured by Nippon Steel; containing naphthalene groups such as ESN-190 and ESN-360 manufactured by Nippon Steel Chemical Co., Ltd., HP-4032, EXA-4750, and EXA-4700 manufactured by Dainippon Ink & Chemicals, Inc. Epoxy resin; Epoxy resin having dicyclopentadiene skeleton such as HP-7200 and HP-7200H manufactured by Dainippon Ink &Chemicals; Glycidyl methacrylate copolymer epoxy resin such as CP-50S and CP-50M manufactured by Nippon Oil &Fats; In addition, cyclohexylmaleimide and glycidyl Methacrylate copolymerized epoxy resins; epoxy-modified polybutadiene rubber derivatives (for example, PB-3600 manufactured by Daicel Chemical Industries, Ltd.), CTBN-modified epoxy resins (for example, YR-102, YR-450 manufactured by Tohto Kasei Co., Ltd.), etc. However, it is not limited to these.
These epoxy resins can be used alone or in combination of two or more. Among these, a novolac type epoxy resin, a heterocyclic epoxy resin, a bisphenol A type epoxy resin or a mixture thereof is particularly preferable.

  Examples of the polyfunctional oxetane compound include bis [(3-methyl-3-oxetanylmethoxy) methyl] ether, bis [(3-ethyl-3-oxetanylmethoxy) methyl] ether, 1,4-bis [(3-methyl -3-Oxetanylmethoxy) methyl] benzene, 1,4-bis [(3-ethyl-3-oxetanylmethoxy) methyl] benzene, (3-methyl-3-oxetanyl) methyl acrylate, (3-ethyl-3-oxetanyl) In addition to polyfunctional oxetanes such as methyl acrylate, (3-methyl-3-oxetanyl) methyl methacrylate, (3-ethyl-3-oxetanyl) methyl methacrylate and oligomers or copolymers thereof, oxetane and novolac resins, poly (P-hydroxystyrene), cardo-type bisphenols, calix array And etherified products with resins having hydroxyl groups such as silsesquioxane, calixresorcinarenes, and the like. In addition, a copolymer of an unsaturated monomer having an oxetane ring and an alkyl (meth) acrylate is also included.

The compounding quantity of such a thermosetting component is 0.5-2.0 equivalent with respect to 1 equivalent of the total amount of the carboxyl group of the said carboxyl group-containing photosensitive resin, Preferably, 0.8-1.5 It is a range that is equivalent. When the blending amount of the thermosetting component is less than 0.5 equivalent, a carboxyl group remains, which is not preferable because heat resistance, alkali resistance, electrical insulation, and the like are deteriorated. On the other hand, if it exceeds 2.0 equivalents, the low molecular weight thermosetting component remains, which is not preferable because the strength of the coating film is lowered.

Moreover, the photocurable thermosetting resin composition of this invention can mix | blend an organic solvent as needed for the purpose of viscosity adjustment.
Examples of the organic solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; cellosolve, methyl cellosolve, butyl cellosolve, carbitol, methyl carbitol, butyl carbitol, propylene glycol monomethyl Glycol ethers such as ether, dipropylene glycol monomethyl ether, dipropylene glycol diethyl ether, tripropylene glycol monomethyl ether; ethyl acetate, butyl acetate, butyl lactate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, propylene Glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate Esters such as propylene carbonate; octane, aliphatic hydrocarbons decane; petroleum ether, petroleum naphtha, an organic solvent conventionally known, such as petroleum-based solvents such solvent naphtha may be used. These organic solvents can be used alone or in combination of two or more.

The photocurable thermosetting resin composition of the present invention may contain a curing catalyst in order to accelerate the curing reaction between the carboxyl group of the carboxyl group-containing photosensitive resin and the thermosetting component.
Examples of the curing catalyst include imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 4-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, 1- Imidazole derivatives such as (2-cyanoethyl) -2-ethyl-4-methylimidazole; dicyandiamide, benzyldimethylamine, 4- (dimethylamino) -N, N-dimethylbenzylamine, 4-methoxy-N, N-dimethylbenzyl Examples of commercially available amine compounds such as amines, amine compounds such as 4-methyl-N, N-dimethylbenzylamine, hydrazine compounds such as adipic acid hydrazide and sebacic acid hydrazide; Made by Kasei Kogyo Co., Ltd. 2MZ-A, 2MZ-OK, 2PHZ, 2P4BHZ, 2P4MHZ (all are trade names of imidazole compounds), U-CAT3503N and U-CAT3502T (all are trade names of dimethylamine blocked isocyanate compounds), manufactured by San Apro, DBU, DBN, U-CATSA102, U-CAT5002 (both bicyclic amidine compounds and salts thereof), and the like. In particular, it is not limited to these, as long as it is a thermosetting catalyst for epoxy resins or oxetane compounds, or a catalyst that promotes the reaction of epoxy groups and / or oxetanyl groups with carboxyl groups, either alone or in combination of two or more. Can be used. Guanamine, acetoguanamine, benzoguanamine, melamine, 2,4-diamino-6-methacryloyloxyethyl-s-triazine, 2-vinyl-2,4-diamino-s-triazine, 2 which also functions as an adhesion-imparting agent S-triazine derivatives such as vinyl-4,6-diamino-s-triazine isocyanuric acid adduct, 2,4-diamino-6-methacryloyloxyethyl-s-triazine isocyanuric acid adduct, Preferably, a compound that also functions as an adhesion promoter is used in combination with the thermosetting catalyst.

  The amount of such a curing catalyst is sufficient at a normal quantitative ratio. The ratio of parts. When the amount of the curing catalyst is less than 0.1 parts by mass, the curing time becomes long, workability is lowered, and oxidation of the copper foil or the like becomes intense, which is not preferable. On the other hand, when the blending amount of the curing catalyst exceeds 20 parts by mass, it is not preferable because the electrical characteristics are deteriorated or the standing life after temporary drying is shortened.

  Moreover, the photocurable thermosetting resin composition of this invention can mix | blend an inorganic filler in order to improve characteristics, such as adhesiveness of a hardened | cured material, mechanical strength, and a linear expansion coefficient further. For example, known and commonly used inorganic fillers such as barium sulfate, barium titanate, silicon oxide powder, finely divided silicon oxide, amorphous silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, mica powder, etc. Can be used. The blending ratio is 0 to 80% by mass of the resin composition.

  The photo-curable thermosetting resin composition of the present invention may be used in a known and conventional manner such as phthalocyanine blue, phthalocyanine green, iodin green, disazo yellow, crystal violet, titanium oxide, carbon black, and naphthalene black. Colorants, hydroquinone, hydroquinone monomethyl ether, t-butylcatechol, pyrogallol, phenothiazine and other known conventional thermal polymerization inhibitors, fine silica, organic bentonite, montmorillonite and other known conventional thickeners, silicone-based, fluorine-based, Known and commonly used additives such as a defoaming agent and / or a leveling agent such as a polymer, and a silane coupling agent such as an imidazole, thiazole or triazole can be blended.

The photocurable thermosetting resin composition of the present invention as described above is adjusted to a viscosity suitable for the coating method using, for example, the above organic solvent, and is applied to the entire surface of the circuit-formed substrate, and is about 60-100. A tack-free coating film can be formed by volatile drying (temporary drying) of the organic solvent contained in the composition at a temperature of ° C.
Examples of the coating method include a dip coating method, a flow coating method, a roll coating method, a bar coater method, a screen printing method, and a curtain coating method.

  Base materials used for circuit-formed substrates include paper phenol, paper epoxy, glass cloth epoxy, glass polyimide, glass cloth / non-woven cloth epoxy, glass cloth / paper epoxy, synthetic fiber epoxy, and copper such as FR-4. Examples thereof include a tension laminate, other polyimide films, PET films, glass substrates, ceramic substrates, and wafer plates.

After coating on these substrates to form a coating film, selective exposure is performed using an active energy ray through a photomask having a pattern formed by a contact method or a non-contact method. Examples of the irradiation light source used for the active energy ray irradiation at the time of exposure include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp, and a metal halide lamp. In addition, laser beams can be used as active energy rays.
Thereafter, the unexposed portion is developed with an aqueous alkaline solution to form a resist pattern. Examples of the developing method include a dipping method, a shower method, a spray method, and a brush method. As the developer, an alkaline aqueous solution such as potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, amines and the like can be used.

  Furthermore, for example, by heating to a temperature of about 120 to 180 ° C. and thermosetting, the carboxyl group of the carboxyl group-containing photosensitive resin reacts with the thermosetting component, resulting in heat resistance, chemical resistance, and moisture absorption resistance. A cured coating film excellent in various properties such as adhesion and electrical properties can be formed.

The photocurable thermosetting composition of the present invention can also be used as a dry film.
In the present invention, a photocurable thermosetting dry film is obtained by applying and drying a photocurable thermosetting resin composition on a film such as a polyester film such as PET or a polyimide film having a thickness of 10 to 150 μm. can get. The dry film thus obtained may be protected by coating a film (protective film) such as a polyethylene film or a polypropylene film on the photocurable thermosetting resin composition layer.

  Such a dry film is peeled off the protective film as necessary, laminated on a circuit-formed substrate, and then exposed and developed in the same manner as the liquid composition to form a resist pattern.

  EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

Synthesis Example 1: Synthesis of carboxyl group-containing photosensitive resin (varnish (A))
First, 330 g of cresol novolac type epoxy resin (Epiclon N-695, manufactured by Dainippon Ink & Chemicals, epoxy equivalent 220) was placed in a flask equipped with a gas introduction tube, a stirrer, a cooling tube and a thermometer, and carbitol was added. 340 g of acetate was added and dissolved by heating, and 0.46 g of hydroquinone and 1.38 g of triphenylphosphine were added.
Next, this mixture was heated to 95 to 105 ° C., and 108 g of acrylic acid was gradually added dropwise to react for 16 hours. The reaction product was cooled to 80 to 90 ° C., 68 g of tetrahydrophthalic anhydride was added, reacted for 8 hours, and cooled.
As a result, a carboxyl group-containing photosensitive resin having a solid acid value of 50 mgKOH / g and a nonvolatile content of 60% was obtained.
Hereinafter, this reaction solution is referred to as varnish (A).

Synthesis Example 2: Synthesis of carboxyl group-containing photosensitive resin (varnish (B))
First, in a 5 L separable flask equipped with a thermometer, a stirrer, and a reflux condenser, 1,245 g of a polycaprolactone diol (PLACCEL 208, molecular weight 830, manufactured by Daicel Chemical Industries, Ltd.) as a polymer polyol, and a dihydroxyl compound having a carboxyl group 201 g of dimethylolpropionic acid, 777 g of isophorone diisocyanate as a polyisocyanate, 119 g of 2-hydroxyethyl acrylate as a (meth) acrylate having a hydroxyl group, p-methoxyphenol and di-tert-butyl-hydroxytoluene 0.5 g each was added.
Next, it was stopped by heating to 60 ° C. while stirring, and 0.8 g of dibutyltin dilaurate was added. When the temperature in the reaction vessel starts to decrease, the mixture is heated again and stirred at 80 ° C., and the reaction is terminated after confirming that the absorption spectrum of the isocyanate group (2280 cm ⁻¹ ) has disappeared in the infrared absorption spectrum. A viscous liquid urethane acrylate compound was obtained.
Furthermore, the non-volatile content was adjusted to 50% by mass using carbitol acetate to obtain a carboxyl group-containing urethane (meth) acrylate compound having a solid acid value of 47 mgKOH / g and a non-volatile content of 50%.
Hereinafter, this reaction solution is referred to as varnish (B).

Examples 1-3 and Comparative Examples 1-2:
The composition shown in Table 1 using the varnish (A) and the varnish (B) obtained in Synthesis Examples 1 and 2 were kneaded with a three-roll mill to obtain a photocurable thermosetting resin composition. .

Performance evaluation:
After buffing the FR-4 substrate on which the circuit was formed, the photocurable thermosetting resin composition having thermosetting properties in the alkali development types of Examples 1 to 3 and Comparative Examples 1 and 2 was screen-printed. The whole surface was printed by the method and dried at 80 ° C. for 30 minutes to prepare an evaluation substrate.

(1) Developability The evaluation substrate produced by the above method was developed with a 1 wt% Na ₂ CO ₃ aqueous solution, 30 ° C., and a spray pressure of 0.2 MPa, and the time until development was measured.

(2) Sensitivity To a substrate manufactured in the same manner as described above, Kodak No. No. 2 step tablet was applied and exposed at various exposure amounts, and then developed at each desired time using a 1 wt% Na ₂ CO ₃ aqueous solution at a spray pressure of 0.2 MPa, and the coating film was completely removed. The number of plates was evaluated. A larger number of steps indicates higher sensitivity.

(3) Solder heat resistance A negative pattern on which a pattern is drawn is applied to each of the above-described evaluation substrates, and the exposure amount of 4 steps is irradiated with the above sensitivity. Development was performed at each desired time with a 2 MPa developing machine to form a pattern. Then, it hardened | cured for 60 minutes at 150 degreeC, and the cured coating film was obtained.
A rosin flux was applied to the cured coating film and immersed in a solder bath at 260 ° C. for 30 seconds, and the state of the cured coating film was evaluated according to the following criteria.
○: The cured coating has no blistering, peeling or discoloration
Δ: Slightly blistered, peeled, or discolored on the cured coating film
X: The cured coating has blistering, peeling, or discoloration

(4) Evaluation of warpage In the same manner as described above, the photocurable thermosetting resin composition is printed on the entire surface of a FR-4 substrate having a substrate thickness of 60 μm, exposed and developed, and then thermally cured to obtain an evaluation substrate. Created. Using this evaluation substrate (400 mm × 300 mm) as a test piece, four corners of the test piece were measured on a plane, and the total of the values was measured as the amount of warpage deformation.
○: 20 mm or less △: 20 mm to 40 mm
×: 40 mm or more

The results of evaluating the photocurable thermosetting resin compositions of Examples 1 to 3 and Comparative Examples 1 and 2 as described above are shown in Table 2 below.

As is clear from the results shown in Table 2, the composition of Example 1 according to the present invention using only a carboxyl group-containing photosensitive resin without using a low molecular (meth) acrylate was mixed with a low molecular acrylate. Although the sensitivity is inferior to those of Comparative Examples 1 and 2, it is possible to suppress warpage and to provide a photocurable thermosetting resin composition that is balanced in all characteristics.
Example 2 and Example 3 according to the present invention using a carboxyl group-containing urethane (meth) acrylate compound as a carboxyl group-containing photosensitive resin can suppress the occurrence of warp without degrading developability and sensitivity. Excellent solder heat resistance required for solder resists and resists for package substrates. As a result, it can also be used for thin plate substrates for package substrates such as QFP, BGA, and CSP.

Claims (5)

The photosensitive component is
A compound having a (meth) acryloyl group and a carboxyl group in one molecule and a weight average molecular weight of 2,000 to 50,000,
Consists of a photopolymerization initiator,
A photocurable thermosetting resin composition capable of alkali development and containing no monomer having an unsaturated double bond, characterized by containing a thermosetting component. A compound having a (meth) acryloyl group and a carboxyl group in one molecule and a weight average molecular weight of 2,000 to 50,000,
A photosensitive component composed solely of a combination with a photopolymerization initiator;
A photocurable thermosetting resin composition capable of alkali development, comprising a thermosetting component.   The photocurable thermosetting resin composition according to claim 1 or 2, wherein the compound having both a (meth) acryloyl group and a carboxyl group in one molecule is a carboxyl group-containing urethane (meth) acrylate compound. object.   The dry film which has a photocurable thermosetting resin composition layer obtained by apply | coating and drying the photocurable thermosetting resin composition as described in any one of Claims 1-3 on a film.   Hardened | cured material obtained by hardening | curing the photocurable thermosetting resin composition as described in any one of Claims 1-3, or the dry film of Claim 4 by active energy ray irradiation and heating.