JP2008116813A - Alkali developable photosensitive resin composition and printed wiring board using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alkali developable photosensitive resin composition having hole filling property and air bubble resistance, also having such properties as heat resistance, adhesion and electric properties, and excellent in resistance to electroless tin plating and electroless gold plating. <P>SOLUTION: (A) A carboxyl group-containing photosensitive resin obtained by reacting a reaction product of a polyfunctional epoxy compound (a) represented by general formula (I) (wherein X is an aromatic ring residue of an aromatic epoxy resin having two glycidyl groups in one molecule; M is a glycidyl group and/or a hydrogen atom; Z is a residue of an aliphatic or aromatic dibasic acid; and p is an integer of 1-20) and an unsaturated group-containing monocarboxylic acid (b) with a polybasic acid anhydride (c) is combined with (B) a copolymer resin having a carboxyl group obtained by reacting a carboxyl group-containing (meth)acrylic copolymer resin (d) with a compound (e) having an oxirane ring and an ethylenically unsaturated group in one molecule. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is suitable for use as a permanent mask of a printed wiring board. After exposure, an image is formed by developing with an alkaline aqueous solution, and heat-cured to provide heat resistance, adhesion, electroless gold plating resistance, electroless The present invention relates to a photosensitive resin composition capable of alkali development capable of forming a coating film excellent in tin plating resistance.

In general, as a solder resist for printed wiring boards for consumer use and printed wiring boards for industrial use, from the viewpoint of high accuracy and high density, a liquid that forms an image by developing after irradiation with ultraviolet rays and heat cures (main cure). A development type solder resist is used. In consideration of environmental problems, a photo solder resist capable of alkali development using a dilute alkaline aqueous solution as a developer is used.
Examples of the alkali development type solder resist using such a dilute alkaline aqueous solution include, for example, 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 photo A solder resist composition (Patent Document 1) composed of a polymerizable monomer and an epoxy compound has been proposed. Such an alkali development type solder resist is used in large quantities in the production of printed wiring boards.

  In recent years, in Asia, such as Taiwan and China, specifications to fill via holes have been increasing in order to suppress poor appearance due to solder adhesion to via holes and flux wrapping around the back surface. When the development type photo solder resist is used for filling a via hole, a phenomenon (hereinafter simply referred to as “air bubbles”) that the formed solder resist film swells and peels off at the solder leveler is likely to occur. In addition, due to environmental issues, specifications such as electroless tin plating and electroless gold plating are increasing instead of solder levelers, and resistance to electroless tin plating and electroless gold plating is also applied to alkaline development solder resists. It is requested.

As such a solder resist, a prepolymer obtained by reacting a reactive product of a novolac type epoxy compound and an unsaturated monobasic acid with a saturated or unsaturated polybasic acid anhydride, a bisphenol type epoxy compound and an unsaturated type By reaction of a prepolymer obtained by reacting a reactive organism with a monobasic acid with a saturated or unsaturated polybasic acid anhydride, an unsaturated monobasic acid copolymer resin, and an alicyclic epoxy group-containing unsaturated compound. A composition comprising the resulting prepolymer (Patent Document 2) has been proposed.
However, although the alkali development type photo solder resist described above is excellent in hole closing property and air bubble resistance for use in filling holes, electroless tin plating resistance and gold plating resistance are insufficient.
For this reason, it is a photosensitive resin that has pore-sealing properties, air bubble resistance, heat resistance, adhesion, chemical resistance, electrical properties, etc., and excellent electroless tin plating resistance and electroless gold plating resistance. There is a need for the development of compositions.
JP-A 61-243869 Japanese Patent Publication No. WO2003 / 059975

The object of the present invention is to have alkali-developable properties that have pore-sealing properties, air bubble resistance, heat resistance, adhesion, electrical properties, etc., and excellent electroless tin plating resistance and electroless gold plating resistance Is to provide a photosensitive resin composition.
Another object of the present invention is to provide a printed wiring board excellent in reliability using the photosensitive resin composition capable of alkali development.
As a result of intensive studies to achieve the above object, the inventors have (A) a reaction between a polyfunctional epoxy compound (a) represented by the following general formula (1) and an unsaturated group-containing monocarboxylic acid (b). A carboxyl group-containing photosensitive resin obtained by reacting the product with a polybasic acid anhydride (c), (B) (d) a carboxyl group-containing (meth) acrylic copolymer resin, and (e) in one molecule. A copolymer resin having a carboxyl group obtained by a reaction between an oxirane ring and a compound having an ethylenically unsaturated group, (C) a photopolymerization initiator, (D) a reactive diluent, and (E) a compound having an epoxy group. The alkali-developable photosensitive resin composition comprises pore-sealing property, air bubble resistance, excellent properties such as heat resistance, adhesion, chemical resistance, and electrical insulation, and resistance to electroless tin plating. Sees excellent resistance to electroless gold plating However, it has been led to conceive the present invention.



(Wherein X represents an aromatic ring residue of an aromatic epoxy resin having two glycidyl groups in one molecule, M represents a glycidyl group and / or a hydrogen atom, and Z represents an aliphatic or aromatic dibasic group. Represents an acid residue, and p represents an integer of 1 to 20.)

That is, the alkali-developable photosensitive resin composition of the present invention is characterized in that two types of carboxyl group-containing photosensitive resins (A) and (B) contained therein are used in combination.
One carboxyl group-containing photosensitive resin (A) used in the present invention is a reaction product of the polyfunctional epoxy compound (a) represented by the general formula (1) and the unsaturated group-containing monocarboxylic acid (b). Obtained by reacting polybasic acid anhydride (c). That is, the carboxyl group-containing photosensitive resin (A) is obtained by adding an unsaturated group-containing monomer to the linear epoxy compound (a) that regularly and repeatedly contains the aromatic ring represented by X and the aliphatic group or aromatic ring represented by Z. Carboxylic acid (b) is reacted, and the resulting epoxy acrylate compound is reacted with polybasic acid anhydride (c), and appropriately unsaturated groups are arranged at both ends and side chains of the linear oligomer. Resin.

The other carboxyl group-containing copolymer resin (B) comprises (d) a carboxyl group-containing (meth) acrylic copolymer resin, and (e) a compound having an oxirane ring and an ethylenically unsaturated group in one molecule. It is a copolymer resin having a carboxyl group obtained by the above reaction.
In order to improve electroless tin plating resistance, in order to prevent the penetration of the plating solution from the interface between the coating film and the copper circuit and the penetration of the plating solution from the coating film surface, adhesion, surface hardening by exposure (high Sensitivity) and chemical resistance must be excellent.

The carboxyl group-containing photosensitive resin (A) of the present invention is excellent in adhesion, flexibility, water resistance and chemical resistance, but is inferior in tackiness and surface curability (high sensitivity) by exposure. The copolymer resin (B) having a carboxyl group is excellent in heat resistance, chemical resistance, tackiness, and surface curability (high sensitivity), but has difficulty in developability. In the present invention, in order to have both of these characteristics, by combining the carboxyl group-containing photosensitive resin (A) and the copolymer resin (B) having a carboxyl group at a suitable ratio, all the characteristics can be balanced in a balanced manner. It can be done.
Therefore, these two types of carboxyl group-containing photosensitive resin (A) and copolymer resin (B) having a carboxyl group are converted into a photopolymerization initiator (C), a reactive diluent (D), an epoxy group-containing compound (E The photosensitive resin composition that can be developed with an alkali according to the present invention has a pore-sealing property, has air bubble resistance by its selective exposure, development, and main curing, and has heat resistance and adhesion. It has excellent properties such as heat resistance, chemical resistance, and electrical insulation, and provides a cured film with excellent electroless tin plating resistance and electroless gold plating resistance.

  Hereinafter, the alkali-developable photosensitive resin composition of the present invention will be described in detail. First, the blending ratio of the carboxyl group-containing photosensitive resin (A) and the carboxyl group-containing copolymer resin (B) constituting the alkali-developable photosensitive resin composition of the present invention is 90:10 to 30:70. It is preferable to mix | blend in a ratio. A more preferable blending ratio is 90:10 to 50:50. When the ratio (A) is higher than 90:10, tackiness is deteriorated. Conversely, when it is lower than 30:70, developability is deteriorated, which is not preferable. The total acid value of these two types of resins is 30 to 150 mgKOH / g, preferably 40 to 120 mgKOH / g. When the total acid value of the two types of resin, that is, the carboxyl group-containing photosensitive resin (A) and the carboxyl group-containing copolymer resin (B) is lower than 30 mgKOH / g, the solubility in an aqueous alkali solution is deteriorated. It becomes difficult to develop the coated film. On the other hand, if it is higher than 150 mgKOH / g, the surface of the exposed area is developed regardless of the exposure conditions, which is not preferable.

Next, the carboxyl group-containing photosensitive resin (A) is obtained by adding a polybasic acid to the reaction product of the polyfunctional epoxy compound (a) represented by the general formula (1) and the unsaturated group-containing monocarboxylic acid (b). Obtained by reacting anhydride (c).
Here, the polyfunctional epoxy compound (a) has an aromatic epoxy resin having two glycidyl groups in one molecule (hereinafter referred to as a bifunctional aromatic epoxy resin) and two carboxyl groups in one molecule. Aliphatic or aromatic dibasic acid having the polymer is alternately polymerized in the presence of a known esterification catalyst such as phosphines, alkali metal compounds, amines, etc., and epihalohydrin is formed on the resulting alcoholic secondary hydroxyl group with dimethyl Presence of alkali metal hydroxides such as caustic soda in known solvents such as aprotic polar solvents such as sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, and aromatic hydrocarbons such as toluene and xylene The reaction is obtained by reaction below (the reaction amount of epihalohydrin is arbitrarily selected from 0 to 1 mol per mol of the hydroxyl group).
The polyfunctional epoxy compound (a) and the unsaturated group-containing monocarboxylic acid (b) are mixed with the unsaturated group-containing monocarboxylic acid (b) with respect to 1 mol of the epoxy group contained in the polyfunctional epoxy compound (a). .9 to 1.2 mol, in the presence or absence of an organic solvent, a polymerization inhibitor such as hydroquinone and oxygen, a tertiary amine such as triethylamine, and a quaternary ammonium such as triethylbenzylammonium chloride In the presence of a reaction catalyst such as a salt, an imidazole compound such as 2-ethyl-4-methylimidazole, and a phosphorus compound such as triphenylphosphine, an epoxy acrylate compound is usually obtained by reaction at about 80 to 140 ° C.

  A carboxyl group-containing photosensitive resin (A) is obtained by reacting the polybasic acid anhydride (c) with the alcoholic hydroxyl group of the epoxy acrylate compound produced by the above reaction. In this reaction, the polybasic acid anhydride ( The amount of c) used is adjusted so that the carboxyl group-containing photosensitive resin (A) to be produced has an acid value of 30 to 150 mgKOH / g. The reaction is usually carried out at about 50 to 130 ° C. in the presence or absence of an organic solvent. At this time, a tertiary amine such as triethylamine, a quaternary ammonium salt such as triethylbenzylammonium chloride, an imidazole compound such as 2-ethyl-4-methylimidazole, or a phosphorus compound such as triphenylphosphine is added as a catalyst. May be.

  As the bifunctional aromatic epoxy resin, diglycidyl ether such as biphenol type, bixylenol type, bisphenol type or naphthalene type can be used. For example, the product name “Epicoat YL-6056” manufactured by Japan Epoxy Resin Co., Ltd. is used as the biphenol type diglycidyl ether, and the product name “Epicoat YX-4000” manufactured by Japan Epoxy Resin Co., Ltd. is used as the bixylenol type diglycidyl ether. As the bisphenol type diglycidyl ether, bisphenol A type epoxy resins such as “Sumi Epoxy ESA-011” and “Sumi Epoxy ELA-115” manufactured by Sumitomo Chemical Co., Ltd. or Dainippon Ink and Chemicals, Inc. ) Bisphenol F type epoxy resin such as “Epicron 830S”, or bisphenol S type epoxy resin such as “Epicron EXA1514” manufactured by Dainippon Ink and Chemicals, and naphthalene type diglycidyl ether Nippon ink Mention may be made of the trade name of Industry Co., Ltd. "EPICLON HP-4032 (D)" and the like, can be used singly or in combination of two or more.

Examples of the dibasic acid having two carboxyl groups in one molecule include 1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic acid, hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, phthalic acid, isophthalic acid, Although terephthalic acid, itaconic acid, succinic acid, adipic acid, muconic acid, sebacic acid and the like can be used, an aliphatic or cycloaliphatic dicarboxylic acid compound is preferred from the viewpoint of imparting ultraviolet transparency and flexibility. . These can be used alone or in combination of two or more.
Representative examples of the unsaturated group-containing monocarboxylic acid (b) include acrylic acid, methacrylic acid, or further, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, Unsaturated dihydroxy-containing acrylates such as trimethylolpropane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, phenylglycidyl (meth) acrylate, (meth) acrylic acid caprolactone adduct Examples include basic acid anhydride adducts. Particularly preferred here are acrylic acid and / or methacrylic acid. These unsaturated group-containing monocarboxylic acids can be used alone or in combination of two or more.
In the present specification, (meth) acrylate is a term that collectively refers to acrylate and methacrylate, and the same applies to other similar expressions.

  The polybasic acid anhydride (c) is reacted with the alcoholic hydroxyl group of the epoxy acrylate compound produced by the reaction to obtain a carboxyl group-containing photosensitive resin (A). In this reaction, the polybasic acid anhydride (c) ) Is adjusted so that the acid value of the resulting carboxyl group-containing photosensitive resin (A) is in the range of 30 to 150 mgKOH / g, preferably 40 to 120 mgKOH / g. When the acid value of the carboxyl group-containing photosensitive resin (A) is lower than 30 mgKOH / g, the solubility in an alkaline aqueous solution is deteriorated, and development of the formed coating film becomes difficult. On the other hand, if it is higher than 150 mgKOH / g, the surface of the exposed area is developed regardless of the exposure conditions, which is not preferable.

The reaction is usually carried out at about 50 to 130 ° C. in the presence or absence of an organic solvent and in the presence of a polymerization inhibitor such as hydroquinone or oxygen. At this time, if necessary, a tertiary amine, a quaternary ammonium salt, an imidazole compound, a phosphorus compound, or the like may be added as a catalyst.
Examples of the polybasic acid anhydride (c) include methyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, nadic anhydride, 3,6-endomethylenetetrahydrophthalic anhydride, Cycloaliphatic dibasic anhydrides such as methylendomethylenetetrahydrophthalic anhydride and tetrabromophthalic anhydride; succinic anhydride, maleic anhydride, itaconic anhydride, octenyl succinic anhydride, pentadodecenyl succinic anhydride, phthalic anhydride, anhydrous Aliphatic or aromatic polybasic acid anhydrides such as trimellitic acid can be mentioned, and one or more of these can be used.

Next, the copolymer resin (B) having a carboxyl group includes (d) a carboxyl group-containing (meth) acrylic copolymer resin, and (e) a compound having an oxirane ring and an ethylenically unsaturated group in one molecule. It is a copolymer resin having a carboxyl group obtained by the reaction.
The carboxyl group-containing (meth) acrylic copolymer resin (d) is obtained by copolymerizing a (meth) acrylic acid ester and a compound having one unsaturated group and at least one carboxyl group in one molecule. Obtained. As the (meth) acrylic acid ester constituting the carboxyl group-containing (meth) acrylic copolymer resin (d), methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, (Meth) acrylic acid alkyl esters such as pentyl (meth) acrylate and hexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, caprolactone-modified 2-hydroxy Hydroxyl group-containing (meth) acrylic esters such as ethyl (meth) acrylate, methoxydiethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, isooctyloxydiethylene glycol Lumpur (meth) acrylate, phenoxy triethyleneglycol (meth) acrylate, methoxy triethylene glycol (meth) acrylate, glycol-modified (meth) acrylates such as methoxy polyethylene glycol (meth) acrylate. These may be used alone or in combination of two or more.
In addition, examples of the compound having one unsaturated group and at least one carboxyl group in one molecule include acrylic acid, methacrylic acid, and a modified unsaturated monocarboxylic acid in which a chain is extended between the unsaturated group and the carboxylic acid. For example, β-carboxyethyl (meth) acrylate, 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, unsaturated monocarboxylic acid having an ester bond due to lactone modification, etc., modified unsaturated having an ether bond Examples thereof include monocarboxylic acids, and those containing two or more carboxyl groups in the molecule, such as maleic acid. These may be used alone or in combination of two or more.

The compound having an oxirane ring and an ethylenically unsaturated group in one molecule of (e) may be any compound having an ethylenically unsaturated group and an oxirane ring in one molecule, such as glycidyl (meth) acrylate, α-methylglycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, 3,4-epoxycyclohexylethyl (meth) acrylate, 3,4-epoxycyclohexylbutyl (meth) acrylate, 3,4-epoxy Examples thereof include cyclohexylmethylamino acrylate. Among these, 3,4-epoxycyclohexylmethyl (meth) acrylate is preferable. These compounds (e) having an oxirane ring and an ethylenically unsaturated group in one molecule may be used alone or in admixture of two or more.

Next, examples of the photopolymerization initiator (C) constituting the photocurable / thermosetting resin composition of the present invention include benzoin and benzoin alkyl ethers such as benzoin, benzoin methyl ether, and benzoin isopropyl ether; acetophenone 2,2-dimethoxy-
Acetophenones such as 2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 1-hydroxycyclohexylpheniketone; 2-methyl-1- (4-methylthiophenyl) -2-morpholino Propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [ Aminoacetophenones such as 4- (4-morpholinyl) phenyl] -1-butanone and N, N-dimethylaminoacetophenone; 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone, 2 -Amylanthraquinone, 2-aminoanthraquino Anthraquinones such as 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, thioxanthones such as 2,4-diisopropylthioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal; benzophenone, methyl Benzophenones such as benzophenone, 4,4′-dichlorobenzophenone, 4,4′-bisdiethylaminobenzophenone, 4-benzoyl-4′-methyldiphenyl sulfide; 2,4,6-trimethylbenzoyldiphenylphosphine oxide and the like . These photopolymerization initiators can be used alone or in combination of two or more.

  Further, the photopolymerization initiator (C) includes N, N-dimethylaminobenzoic acid ethyl ester, N, N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine, triethanolamine and the like. It can be used in combination with one kind or two or more kinds of photosensitizers or photoinitiating aids such as a secondary amine.

  The blending amount of the photopolymerization initiator (C) (the total amount when a photosensitizer or photoinitiator aid is used) is the total amount of carboxyl group-containing photosensitive resins (A) and (B) of 100. A ratio of 1 to 30 parts by mass, preferably 5 to 25 parts by mass is preferred with respect to parts by mass (the same applies hereinafter as solid content). When the blending amount of the photopolymerization initiator (C) is less than the above range, it is not cured even when active energy rays are irradiated, or it is necessary to increase the irradiation time, and it becomes difficult to obtain appropriate film characteristics. On the other hand, even if a photopolymerization initiator is added in a larger amount than the above range, there is no change in photocurability, which is economically undesirable.

  Next, the reactive diluent (D) constituting the photocurable / thermosetting resin composition of the present invention is a liquid, solid or semi-liquid at room temperature having one or more (meth) acryloyl groups in one molecule. Solid photosensitive (meth) acrylate compounds can be used. For example, hydroxyl group-containing (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate; polyethylene glycol di Water-soluble (meth) acrylates such as (meth) acrylate and polypropylene glycol di (meth) acrylate; such as trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate and dipentaerythritol hexa (meth) acrylate Polyfunctional polyester (meth) acrylates of polyhydric alcohols; polyfunctional alcohols such as trimethylolpropane and hydrogenated bisphenol A or bisphenol A, biphenol (Meth) acrylates of polyhydric phenols such as ethylene oxide and / or propylene oxide adducts; polyfunctional or monofunctional polyurethane (meth) acrylates which are isocyanate modified products of the above hydroxyl group-containing (meth) acrylates; bisphenols A diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, or epoxy (meth) acrylates that are (meth) acrylic acid adducts of phenol novolac epoxy resins, etc., are used alone or in combination of two or more. can do. The purpose of using these photosensitive (meth) acrylate compounds is to increase the photoreactivity of the composition. However, when a large amount of photosensitive (meth) acrylate compound that is liquid at room temperature is used, it is preferable because the touch-drying property of the coating film cannot be obtained, and the photocrosslinking tends to proceed excessively, and the bubble resistance tends to deteriorate. Absent.

  The compounding quantity of photosensitive (meth) acrylate compound (D) is 5-40 mass parts with respect to 100 mass parts of total amounts of the said carboxyl group-containing photosensitive resin (A) and (B), Preferably it is 5-30 masses. The proportion of parts is preferred. When the blending amount of the photosensitive (meth) acrylate compound (D) is smaller than the above range, it is necessary to cure the active energy ray or not to cure or to increase the irradiation time, and an appropriate film characteristic can be obtained. It becomes difficult. On the other hand, when the amount is larger than the above range, it is not preferable because photocrosslinking proceeds excessively and air bubble resistance tends to deteriorate.

As an epoxy compound (E) used as a thermosetting component in the photo-curable / thermosetting resin composition of the present invention, Epicoat 828, Epicoat 834, Epicoat 1001, Epicoat 1004, large size manufactured by Japan Epoxy Resin Co., Ltd. Epicron 840, Epicron 850, Epicron 1050, Epicron 2055, Etototo YD-011, YD-013, YD-127, YD-128, manufactured by Nippon Ink Chemical Co., Ltd., Sumitomo Chemical Co., Ltd. ) Sumi-Epoxy ESA-011, ESA-014, ELA-115, ELA-128 (all trade names) and other bisphenol A type epoxy resins; Japan Epoxy Resin Co., Ltd. Epicoat YL903, Dainippon Ink & Chemicals, Inc. Epicron 152, Epicron 16 manufactured by Kogyo Co., Ltd. Brominated epoxy resins such as Etototo YDB-400, YDB-500 manufactured by Toto Kasei Co., Ltd., 2 Sumi-epoxy ESB-400, ESB-700 (all trade names) manufactured by Sumitomo Chemical Co., Ltd .; Japan Epoxy Resin Co., Ltd. Epicoat 152, Epicoat 154, Dainippon Ink & Chemicals, Inc. Epicron N-730, Epicron N-770, Epicron N-865, Toto Kasei Co., Ltd. Epototo YDCN-701, YDCN-704, Nippon Kayaku Co., Ltd. EPPN-201, EOCN-1025, EOCN-1020, EOCN-104S, RE-306, Sumitomo Chemical Co., Ltd. Sumi-epoxy ESCN-195X, ESCN-220 Novolak type epoxy resin (all are trade names); Epiku made by Dainippon Ink & Chemicals, Inc. 830, Epicote 807 manufactured by Japan Epoxy Resin Co., Ltd., Etototo YDF-170, YDF-175, YDF-2004 (all trade names) manufactured by Toto Kasei Co., Ltd .; Toto Kasei Co., Ltd. Hydrogenated bisphenol A type epoxy resin such as Epototo ST-2004, ST-2007, ST-3000 (all trade names) manufactured by EPOCOAT 604 manufactured by Japan Epoxy Resin Co., Ltd. Epototo YH manufactured by Toto Kasei Co., Ltd. -434, Glycidylamine type epoxy resins such as Sumi-epoxy ELM-120 (all trade names) manufactured by Sumitomo Chemical Co., Ltd .; Cycloside 2021 (trade names) manufactured by Daicel Chemical Industries, Ltd. Epoxy resin; YL-933 manufactured by Japan Epoxy Resin Co., Ltd., EPPN-50 manufactured by Nippon Kayaku Co., Ltd. 1, trihydroxyphenylmethane type epoxy resin such as EPPN-502 (all trade names); xylenol such as YL-6056, YX-4000, YL-6121 (all trade names) manufactured by Japan Epoxy Resins Co., Ltd. Type or biphenol type epoxy resin or a mixture thereof; EBPS-200 manufactured by Nippon Kayaku Co., Ltd., EPX-30 manufactured by Asahi Denka Kogyo Co., Ltd., EXA-1514 manufactured by Dainippon Ink & Chemicals, Inc. Bisphenol S type epoxy resin such as EPOCOAT 157S (trade name) manufactured by Japan Epoxy Resin Co., Ltd .; Epicoat YL-931 manufactured by Japan Epoxy Resin Co., Ltd. (trade name) Tetraphenylol ethane type epoxy resin such as TEPIC manufactured by Nissan Chemical Co., Ltd. Name), etc .; diglycidyl phthalate resin such as Bremer DGT (trade name) manufactured by NOF Corporation; tetraglycidyl xyleno such as ZX-1063 (trade name) manufactured by Tohto Kasei Co., Ltd. Irethane resin; 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 and Chemicals, Inc. (all trade names) Containing epoxy resin; Epoxy resin having dicyclopentadiene skeleton such as HP-7200, HP-7200H (both trade names) manufactured by Dainippon Ink and Chemicals, Inc .; CP-50S, CP manufactured by Nippon Oil & Fats Co., Ltd. -50M (all trade names) glycidyl methacrylate copolymer epoxy resin; cyclohexylmaleimide and glycidyl methacrylate It includes such copolymerizable epoxy resin, these epoxy compounds may be used alone or in combination of two or more.

  The compounding quantity of an epoxy compound (E) is 10-70 mass parts with respect to 100 mass parts of total amounts of the said carboxyl group-containing photosensitive resin (A) and (B), More preferably, the ratio of 10-60 mass parts is. Is appropriate.

  The inorganic filler (F) is used for the purpose of improving properties such as adhesion and hardness, barium sulfate, barium titanate, silicon oxide powder, finely divided silicon oxide, amorphous silica, talc, clay, magnesium carbonate, calcium carbonate. Well-known inorganic fillers such as aluminum oxide, aluminum hydroxide, and mica powder can be used alone or in combination of two or more.

In the present invention, in order to suppress the adhesion of solder balls of the cured coating film, it may be necessary to suppress the gloss value of the cured coating film to a value of ASTM 60 ° from 1 to 50. For such purposes, it is preferable to select so as to include silica such as silicon oxide powder, finely divided silicon oxide, and amorphous silica.
The compounding quantity of an inorganic filler (F) is 60-200 mass parts with respect to 100 mass parts of total amounts of the said carboxyl group-containing photosensitive resin (A) and (B), More preferably, the ratio of 80-200 mass parts is. Is appropriate.

In the present invention, an organic solvent can be used to adjust the viscosity to be suitable for the coating method.
Examples of the organic solvent include ketones such as ethyl methyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; methyl cellosolve, butyl cellosolve, methyl carbitol, butyl carbitol, propylene glycol monomethyl ether, Glycol ethers such as dipropylene glycol monoethyl ether, dipropylene glycol diethyl ether, and triethylene glycol monoethyl ether; esters such as ethyl acetate, butyl acetate, butyl cellosolve acetate, and carbyl acetate; ethanol, propanol, ethylene glycol, propylene Alcohols such as glycol; aliphatic hydrocarbons such as octane and decane; petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtho , And the like petroleum solvents like.

  In the present invention, a curing catalyst can be used in order to improve properties such as toughness, adhesion, heat resistance and electroless gold plating resistance of the coating film. As the curing catalyst, known conventional curing such as imidazole derivatives such as 2E4MZ-AZINE, C11Z-AZINE and 2PHZ, guanamines such as acetoguanamine and benzoguanamine, polyamines such as dicyandiamide, urea, urea derivative, melamine and polybasic hydrazide, etc. Agents or curing accelerators can be used alone or in combination of two or more.

Furthermore, in this invention, it can color with a well-known and usual inorganic pigment, an organic pigment, etc. as needed. Examples thereof include phthalocyanine / blue, phthalocyanine / green, disazo yellow, anthraquinone yellow pigment, benzimidazolone, titanium oxide, and carbon black.
Furthermore, known conventional flow control agents such as finely divided silica, organic bentonite, montmorillonite, silicone-based, fluorine-based and polymer-based antifoaming or leveling agents, imidazole-based, thiazole-based, and triazole as necessary. System, adhesion imparting agents such as silane coupling agents, known and usual matting agents and the like can be blended.

The alkali-developable photosensitive resin composition of the present invention is obtained by blending the above-described blending components preferably in the above proportions and uniformly mixing and dispersing with a roll mill or the like.
The alkali-developable photosensitive resin composition of the present invention as described above becomes a photosensitive resin film closed in via holes through the steps described below. That is, the photosensitive resin composition of the present invention is filled in via holes, coated on the surface and dried, and a coating film obtained through the coating film forming process is selectively irradiated with active energy rays. After the photo-curing treatment step, the photo-curing treatment step, the alkali developing solution is used to remove the unirradiated portion to obtain a pattern, and the pattern obtained in the alkali developing step is heated and cured to be cured. An object pattern is formed.

(1) Coating film forming step In this step, the photosensitive resin composition of the present invention is first filled by printing in a via hole portion of a printed wiring board on which a circuit is formed. Filling is usually done from one side using a screen that can selectively fill the via hole portion. After filling, the photosensitive resin composition of the present invention is applied to both sides by screen printing, curtain coating, spray coating, or roll coating. When applying by screen printing, the step of filling the via hole described above can be omitted and the application and filling of the via hole can be performed simultaneously.
After coating, the volatile components contained in the composition are removed at a temperature of 60 ° C. to 90 ° C. and dried to form a dry coating film filled in the via hole. At this time, it is important to select the temperature and time so that the solvent in the via hole can be volatilized.

(2) Photocuring treatment (exposure) step In this step, the dried coating film obtained in the step (1) is selectively irradiated with active energy rays. Here, for the exposure, active energy rays may be selectively irradiated through a photomask on which a pattern is formed. As the exposure light source, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a xenon lamp, a metal halide lamp, or the like is usually suitable.
The amount of light irradiation in the exposure is the weight average molecular weight of the binder polymer, the monomer ratio, the content, the type and content of the photopolymerizable compound, the type and content of the photopolymerization initiator, and the type of photopolymerization initiation aid. It is appropriately selected depending on the content and the like.

(3) Alkali development process The coating film after exposure which completed the process of said (2) is developed. In the development, a developer is sprayed on the exposed coating film with a shower to remove the unexposed film. Examples of the developer include dilute alkaline aqueous solutions such as sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, and organic amines. By developing, an unexposed part is removed and a coating film pattern is formed. After development, it is usually washed with water and dried.

(4) Curing step The coating film pattern on the substrate after the step (3) is heated and thermally cured.
In heat curing, step cure is performed for the purpose of suppressing curing shrinkage of the coating film in the via hole and suppressing bleeding of the coating film and air bubbles.
Step cure is a method of heat-curing by dividing temperature and time into two or three stages. Usually, the temperature and time are appropriately selected and used at 60 to 80 ° C. for 30 to 60 minutes, 100 to 120 ° C. for 0 to 40 minutes, and then 150 to 160 ° C. for 40 to 90 minutes. In order to obtain sufficient electroless tin plating resistance and electroless gold plating resistance, it is preferable to shorten the condition of the step cure as much as possible within the range where no air bubbles are generated.

  By the process described above, it has a pore-sealing property, air bubble resistance, excellent properties such as heat resistance, adhesion, chemical resistance, and electrical insulation properties, and excellent electroless tin plating resistance and electroless gold plating resistance. A cured coating is formed.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated further more concretely, it cannot be overemphasized that this invention is not limited to the following Example. In the following, “parts” and “%” are all parts by mass and mass% unless otherwise specified.

Synthesis example 1
A reaction vessel equipped with a gas introduction tube, a stirrer, a cooling tube, a thermometer, and a dropping funnel for continuous dripping, 86 parts of 1,4-cyclohexanedicarboxylic acid with a carboxylic acid equivalent of 86 g / equivalent and a bisphenol A type epoxy resin (Japan) 378 parts of Epoxy Resin Co., Ltd., Epicoat 828, epoxy equivalent 189 g / equivalent) were charged and dissolved at 110 ° C. under stirring in a nitrogen atmosphere. Thereafter, 0.3 part of triphenylphosphine was added, the temperature in the reaction vessel was raised to 150 ° C., and the reaction was allowed to proceed for about 90 minutes while maintaining the temperature at 150 ° C. to obtain an epoxy equivalent of 464 g / equivalent of an epoxy compound. Obtained. Next, the temperature in the flask is cooled to 40 ° C., 390 parts of carbitol acetate is added, heated and dissolved, 0.46 parts of methylhydroquinone and 1.38 parts of triphenylphosphine are added, and heated to 95 to 105 ° C. Then, 72 parts of acrylic acid was gradually added dropwise and reacted for 16 hours. The reaction product was cooled to 80 to 90 ° C., 190 parts of tetrahydrophthalic anhydride was added and reacted for 8 hours. The carboxyl group-containing photosensitive resin thus obtained had a nonvolatile content of 65% and a solid acid value of 100 mgKOH / g. Hereinafter, this resin solution is referred to as A-1 varnish.

Synthesis example 2
A reaction vessel equipped with a gas introduction tube, a stirrer, a cooling tube, a thermometer, and a dropping funnel for continuous dropping of an aqueous alkali metal hydroxide solution, 130 parts of itaconic acid with a carboxylic acid equivalent of 65 g / equivalent and a bisphenol A type epoxy resin (Japan Epoxy Resin Co., Ltd. product, Epicoat 828, epoxy equivalent 189g / equivalent) 776 parts was prepared, and it was made to melt | dissolve at 110 degreeC under stirring in nitrogen atmosphere. Thereafter, 0.65 part of triphenylphosphine was added, the temperature in the reaction vessel was raised to 150 ° C., and the reaction was allowed to proceed for about 90 minutes while maintaining the temperature at 150 ° C. to obtain an epoxy equivalent of 443 g / epoxy equivalent. Obtained. Next, the temperature in the flask is cooled to 40 ° C., 1800 parts of epichlorohydrin and 1690 parts of dimethyl sulfoxide are added, and the temperature is raised to 45 ° C. with stirring and maintained. Thereafter, 364 parts of a 48% aqueous sodium hydroxide solution was continuously added dropwise over 60 minutes, and then reacted for another 6 hours. After completion of the reaction, most of the excess epichlorohydrin and dimethyl sulfoxide were recovered by distillation under reduced pressure, and the reaction product containing the by-product salt and dimethyl sulfoxide was dissolved in methyl isobutyl ketone and washed with water. After the organic solvent layer and the aqueous layer were separated, methyl isobutyl ketone was distilled from the organic solvent layer under reduced pressure to obtain a polyfunctional epoxy resin having an epoxy equivalent of 245 g / equivalent. Next, 245 parts of this polyfunctional epoxy resin is put into a flask equipped with a stirrer, a cooling tube and a thermometer, 240 parts of carbitol acetate is added, dissolved by heating, 0.46 parts of methylhydroquinone and triphenylphosphine 1 .38 parts were added and heated to 95-105 ° C., and 72 parts of acrylic acid was gradually added dropwise to react for 16 hours. The reaction product was cooled to 80 to 90 ° C., and 129 parts of tetrahydrophthalic anhydride was added and reacted for 8 hours. The carboxyl group-containing photosensitive resin thus obtained had a nonvolatile content of 65% and a solid acid value of 100 mgKOH / g. Hereinafter, this resin solution is referred to as A-2 varnish.

Synthesis example 3
In a flask equipped with a thermometer, stirrer, dropping funnel, and reflux condenser, 700.0 g of dipropylene glycol monomethyl ether as a solvent is heated to 110 ° C., and 270.0 g of methacrylic acid, 153.0 g of methyl methacrylate, A mixture of 294.0 g of propylene glycol monomethyl ether and 10.0 g of t-butylperoxy-2-ethylhexanoate (Nippon Yushi Co., Ltd., Perbutyl O) as a polymerization catalyst was added dropwise over 3 hours. The polymerization catalyst was deactivated by stirring for a time to obtain a copolymer resin solution. After cooling this resin solution, 390.0 g of 3,4-epoxycyclohexylmethyl acrylate (Daicel Chemical Industries, Ltd. Cyclomer A400), 5.0 g of triphenylphosphine, and 1.5 g of hydroquinone monomethyl ether were added, and the mixture was heated to 100 ° C. Epoxy ring-opening addition reaction was carried out by heating and stirring. The carboxyl group-containing photosensitive resin thus obtained had a weight average molecular weight of 22,000, a non-volatile content of 45 wt%, and a solid content acid value of 70 mg KOH / g. Hereinafter, this reaction solution is referred to as B-1 varnish.

Synthesis example 4
In a flask equipped with a thermometer, a stirrer, a dropping funnel, and a reflux condenser, 210 parts of cresol novolac type epoxy resin (Epiclon N-680, manufactured by Dainippon Ink and Chemicals, epoxy equivalent = 210) and carbitol acetate 96 4 parts were weighed and dissolved by heating. Next, 0.1 part of hydroquinone as a polymerization inhibitor and 2.0 parts of triphenylphosphine as a reaction catalyst were added. This mixture was heated to 95 to 105 ° C., 72 parts of acrylic acid was gradually added dropwise, and the mixture was reacted for about 16 hours until the acid value became 3.0 mgKOH / g or less. The reaction product was cooled to 80 to 90 ° C., 60.1 parts of tetrahydrophthalic anhydride was added, and about 6 hours until the absorption peak (1780 cm ⁻¹ ) of the acid anhydride disappeared by infrared absorption analysis. Reacted. To this reaction liquid, 96.4 parts of aromatic solvent ipsol # 150 manufactured by Idemitsu Petrochemical Co., Ltd. was added, diluted, and taken out. The carboxyl group-containing photosensitive resin thus obtained had a non-volatile content of 65% and a solid acid value of 66 mgKOH / g. Hereinafter, this reaction solution is referred to as R-1 varnish.

Examples 1-7 and Comparative Examples 1-3
Each component was blended according to the blending composition shown in Table 1 (the numerical value is part by mass), and kneaded separately with a three-roll mill to prepare an alkali-soluble photosensitive resin composition. This was printed by a screen printing method using a pin stand using a 90 mesh polyester screen in which a pattern that can be filled in the via hole portion was used so that the via hole of the patterned copper through hole printed wiring board was sufficiently filled. . Further, a 90-mesh polyester screen was used to coat the entire surface, and the coating film was dried for 40 minutes using a 70 ° C. hot air dryer. Next, a negative film having a resist pattern is brought into close contact with the coating film, and irradiated with ultraviolet rays (exposure amount: 500 mJ / cm @ 2) using an ultraviolet exposure device (Oak Manufacturing Co., Ltd., model HMW-680GW), and 1% potassium carbonate. 2.0kg / c for 90 seconds with aqueous solution
The unexposed portion was dissolved and removed by development with a spray pressure of m2. Then, 80 degreeC x 30 minutes, 110 degreeC x 30 minutes, and 160 degreeC x 40 minutes heat-cured with the hot air dryer, and produced the test board | substrate. For the test substrate having the obtained cured film, tackiness, adhesion, solder heat resistance, solvent resistance, electroless gold plating resistance, electroless tin plating resistance, and air bubble resistance are tested and tested as described below. A test was conducted. Table 2 shows the evaluation results of the above tests.

The evaluation method of each characteristic test in Table 2 is as follows.
(1) Tackiness: The method of peeling off the negative film after exposure in the test substrate production process was visually evaluated according to the following criteria.
○: The film has no tack mark.
Δ: Tack marks are slightly seen on the film.
×: A tack mark is seen on the entire surface of the film

(2) Adhesion: according to the test method of JIS D 0202, the cured film of the test substrate was cross-cut in a grid pattern, and then the peelability after the peeling test with a cellophane adhesive tape was evaluated according to the following criteria. .
○: 100/100 with no peeling Δ: 100/100 with a slight cross-cut part ×: 0/100 to 90/100 with peeling

(3) Solder heat resistance: In accordance with the test method of JIS C 6481, the test substrate was immersed in a 260 ° C. solder bath three times for 10 seconds using a rosin-based flux and a non-cleaning flux. evaluated.
○: There is no abnormality such as peeling on the cured film. Δ: Discoloration is observed on the cured film. ×: Floating and peeling on the cured film.

(4) Solvent resistance: The cured film of the previous test substrate was immersed in propylene glycol monomethyl ether acetate at 20 ° C. for 30 minutes to confirm the state of the cured film. The evaluation criteria are as follows.
○: The cured film has no discoloration such as peeling or whitening.
Δ: The cured film has a slight discoloration such as whitening.
X: It peels off to a cured film and has discoloration, such as whitening.

(5) Resistance to electroless gold plating: Using a commercially available electroless nickel solution and electroless gold plating solution as the cured film of the test substrate, the plating thickness is 3 μm and gold is 0.03 μm at a temperature of 85 ° C. to 90 ° C. Electroless plating was performed so that the discoloration and the peeled state of the cured film were evaluated according to the following criteria.
○: No abnormality such as discoloration or peeling on the cured film.
Δ: The cured film is not peeled off, but has a discoloration such as whitening. X: The cured film is lifted or peeled off, and plating burrs are observed.

(6) Electroless tin plating resistance: The cured film of the test substrate is pretreated (acid degreasing + soft etch + sulfuric acid treatment), and the plating thickness is 1 μm using a commercially available electroless tin plating solution. Electroless tin plating was performed under various conditions (70 ° C., 12 minutes). About the evaluation board | substrate after this plating, the peel test by a cellophane adhesive tape was done, and peeling of the resist layer was evaluated.
○: No abnormality such as discoloration or peeling on the cured film.
Δ: Slightly peeled off and some penetration of the cured film ×: Floating or peeling of the cured film was observed, and plating stagnation was observed.

(7) Air bubble resistance: The test substrate was subjected to a solder leveler treatment with a horizontal leveler, and after the tape peel, the state of peeling of the coating at the via hole portion was confirmed.
○: In the via hole 500 hole, no peeling occurred Δ: In the via hole 500 hole, peeling occurred 10 or less ×: In the via hole 500 hole, peeling occurred 10 or more

(8) Glossiness: The surface of the test substrate was measured for 60 ° glossiness (gloss value) using microtrigloss (manufactured by Big Chemie Japan). The glossiness at 60 ° was measured at five points, and the average value was rounded off to the first decimal place and displayed as an integer.

  As described above, according to the present invention, it has a pore-sealing property and air bubble resistance, has various properties such as tackiness, heat resistance, adhesion, and electrical properties, and has an electroless tin plating resistance and an electroless property. A photosensitive resin composition with excellent gold plating resistance and capable of alkali development can be obtained.

Claims (8)

(A) Obtained by reacting a polybasic acid anhydride (c) with a reaction product of a polyfunctional epoxy compound (a) represented by the following general formula (1) and an unsaturated group-containing monocarboxylic acid (b). Obtained by reaction of a carboxyl group-containing photosensitive resin, (B) (d) a carboxyl group-containing (meth) acrylic copolymer resin, and (e) a compound having an oxirane ring and an ethylenically unsaturated group in one molecule. A photosensitive resin composition capable of alkali development, comprising a copolymer resin having a carboxyl group, (C) a photopolymerization initiator, (D) a reactive diluent, and (E) a compound having an epoxy group. object.


(Wherein X represents an aromatic ring residue of an aromatic epoxy resin having two glycidyl groups in one molecule, M represents a glycidyl group and / or a hydrogen atom, and Z represents an aliphatic or aromatic dibasic group. Represents an acid residue, and p represents an integer of 1 to 20.) The carboxyl group-containing copolymer resin (B) is (d) a carboxyl group-containing (meth) acrylic copolymer resin, and (e) a compound having an alicyclic epoxy group and an ethylenically unsaturated group in one molecule; 2. The alkali-developable photosensitive resin composition according to claim 1, which is a copolymer resin having a carboxyl group obtained by the above reaction. 2. The alkali-developable photosensitive resin according to claim 1, wherein a blending ratio of the carboxyl group-containing photosensitive resin (A) and the carboxyl group-containing copolymer resin (B) is 90:10 to 50:50. Resin composition. The blending amount of the photopolymerization initiator (C) is in the range of 1 to 30 parts by mass with respect to 100 parts by mass in total of the carboxyl group-containing photosensitive resin (A) and the copolymer resin (B) having a carboxyl group, The amount of the reactive diluent (D) is in the range of 5 to 40 parts by mass, and the amount of the compound (E) having the epoxy group is in the range of 10 to 70 parts by mass. The photosensitive resin composition in which alkali development is possible. Furthermore, (F) 50-200 mass parts is included with respect to a total of 100 mass parts of carboxyl group-containing photosensitive resin (A) and (B), and an inorganic filler is characterized by the above-mentioned. A photosensitive resin composition capable of alkali development as described in 1. The photosensitive resin composition capable of alkali development according to claim 5, wherein the inorganic filler (F) contains silica. The alkali-developable photosensitive resin composition according to claim 1, wherein an ASTM 60 ° value of the coating film obtained by coating and drying, irradiation with active energy rays, development, and heat curing is in the range of 1-60. . Applying the alkali-developable photosensitive resin composition according to any one of claims 1 to 6, forming a solder resist film obtained by drying, irradiation with active energy rays, development, and heat curing. Printed wiring board.