JP2802800B2 - Photosensitive thermosetting resin composition and solder resist pattern forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention is a novel photosensitive thermosetting resin composition which is used in the production of printed wiring boards, precision metal processing and the like, and is particularly useful as a solder resist for printed wiring boards. More specifically, in the formation of a solder resist pattern by selectively exposing with an actinic ray through a film on which a pattern is formed and developing an unexposed portion, the method is particularly excellent in developability and exposure. Part has a resistance to the developing solution, has a long pot life,
For solder resist excellent in photosensitivity, adhesion, electrical insulation, electric contact resistance, solder heat resistance, solvent resistance, alkali resistance, acid resistance, and plating resistance such as electrolytic gold, electroless gold, and electroless copper The present invention relates to a photosensitive thermosetting resin composition and a method for forming a solder resist pattern.

(Prior art) Solder resist is intended to prevent the adhesion of solder to unnecessary parts and to protect circuits when soldering printed wiring board parts. Solder heat resistance, solvent resistance, alkali resistance, acid resistance, plating resistance, and the like are required.

As an initial solder resist, an epoxy melamine-based thermosetting type was used. Further, for example, an improved epoxy-based thermosetting type described in JP-B-51-14044 has been used as a mainstream for industrial printed wiring boards.

Further, for example, a quick-curing ultraviolet-curing type described in Japanese Patent Publication No. 61-48800 has been used as a mainstream for consumer printed wiring boards.

In addition, screen printing is used as a method of forming a solder resist. However, in recent years, the density of printed wiring boards has been increased due to the lightness and size reduction of electronic devices, and the formation of solder resist patterns corresponding to the surface mounting of components has been In addition, there is a problem in bleeding and embedding between circuits, and it has become impossible to function as a solder resist film. For this purpose, as a dry film type photo solder resist or liquid photo solder resist, for example,
A photosensitive resin composition for a dry film comprising urethane di (meth) acrylate described in JP-A-57-55914, a cyclic polymer having a specific glass transition temperature, and a sensitizer is used. Was done.

On the other hand, as a liquid photo solder resist, for example, a solid or semi-solid reaction product of a polyepoxide and an ethylenically unsaturated carboxylic acid described in British Patent Application Publication GB-2032939A, an inert inorganic filler and a photopolymerization initiator A photopolymerizable coating composition containing and a volatile organic solvent was used.

As a method for solving the above problems, a liquid photo solder resist in which a thermosetting component is added to an ultraviolet curable component has been proposed. For example, a phenol novolak type epoxy resin described in JP-A-60-208377 has been proposed. A resin composition for a solder resist ink containing a reaction product of a saturated monobasic acid, a partial reaction product of an unsaturated monobasic acid of a cresol novolak type epoxy resin, an organic solvent, a photopolymerization initiator, and an amine-based thermosetting agent. Used. In this case, an epoxy group is left in the molecule, and the epoxy group is cured with an amine-based thermosetting agent, so that thermosetting is also used.

On the other hand, as an example of adding an epoxy resin,
A photosensitive composition comprising an unsaturated compound containing two terminal ethylene groups, a polymerization initiator, a compound containing at least two epoxy groups, and a compound containing at least two carboxyl groups described in JP-A-49-107333. Was used.

Similarly, for example, a reaction product of a novolak type epoxy compound and an unsaturated monocarboxylic acid, a diisocyanate and a poly (meth) acrylate containing one hydroxyl group in one molecule described in JP-A-61-272 are disclosed. An ink composition was used in which an epoxy resin was used in combination with the reaction product, photopolymerization initiator, and organic solvent.

Further, for example, a reaction product of a novolak type epoxy compound and an unsaturated monocarboxylic acid and a reaction product of a saturated or unsaturated polybasic anhydride and a photopolymerization initiator described in JP-A-61-243869 are disclosed. A resist ink composition using a diluent and an epoxy resin in combination has been disclosed.

(Problems to be Solved by the Invention) However, epoxy melamine-based thermosetting types have problems in solder heat resistance, chemical resistance, plating resistance, and the like.

The epoxy-based thermosetting type improved from these has a problem in plating resistance.

The quick-curing ultraviolet-curing type has poor internal curability in a thick film and poor soldering heat resistance, and cannot be used for industrial printed wiring boards.

In the case of dry film type photo solder resist, when used for high-density printed wiring boards, it is excellent in forming fine patterns, but solder heat resistance and adhesion are not sufficient, and embedding between circuits is also insufficient Has the disadvantage that

In the case of a liquid photo solder resist, it is excellent in formability of fine patterns and embedding between circuits,
There are problems such as adhesion to a printed wiring board, solder heat resistance, and electrical insulation.

In the case of a solder resist ink composition, since the number of photosensitive groups is reduced by the amount of epoxy groups remaining, curability by ultraviolet rays is reduced, it is difficult to leave a large amount of epoxy groups, and the properties as a solder resist must be satisfied. Can not.

An ink composition containing a diisocyanate can satisfy the properties as a solder resist to some extent, but a photosensitive composition is based on an acrylic cyclic polymer containing (meth) acrylic acid, and has a solder heat resistance and a heat resistance. Low solvent properties. In addition, when the ratio of the epoxy resin is increased, the photocurability, the so-called sensitivity, decreases, and the resistance of the exposed portion to the developer tends to decrease.
There is a problem that undeveloped portions are easily left behind in development.

Since the resist ink composition uses an alkaline aqueous solution as a developing solution, if the ratio of the epoxy resin having no solubility in the alkaline aqueous solution is increased, the sensitivity similarly decreases, and the solubility of the unexposed portion in the developing solution decreases. However, there is a problem in that the exposed portion is liable to be left undeveloped, requires long-term development, and the exposed portion is affected by the developing solution.

In general, epoxy resins have strong properties against alkalis, but have poor acid resistance. The electroless nickel plating solution and the electroless gold plating solution are acidic solutions of PH4 to PH5, and the plating solution is heated to 90 ° C and immersed for 15 to 30 minutes to plate the object. Requires sufficient chemical resistance. In addition, a large amount of hydrogen gas is generated from the metal deposition part during plating, and a force is applied to penetrate the interface between the solder resist and the printed wiring board and try to separate the solder resist from the wiring board. Is required.

Accordingly, an object of the present invention is to provide a photosensitive thermosetting resin composition which has no drawbacks as described above, has excellent developability and sensitivity, has resistance to a developing solution in an exposed portion, and has a long pot life. Is to do.

Further, the object of the present invention, in addition to the above excellent properties, adhesion required for the solder resist, electrical insulation, solder heat resistance, solvent resistance, alkali resistance, acid resistance,
Provided is a photosensitive thermosetting resin composition and a method for forming a solder resist pattern, which can provide a cured coating film having excellent plating resistance and the like, and are particularly suitable for manufacturing consumer printed wiring boards and industrial printed wiring boards. It is in.

(Means for Solving the Problems) As a result of various studies to solve these problems, the present inventors have found that: (A) a photosensitive prepolymer having at least two ethylenically unsaturated bonds in one molecule; (B) a photopolymerization initiator, (C) a photopolymerizable vinyl monomer or oligomer as a diluent and / or an organic solvent, (D) a water-soluble or water-dispersible melamine resin (E) And / or a nitrile-butadiene rubber-modified epoxy resin (II) having a carboxyl group and / or a composition comprising (F) an epoxy curing agent.

Such a photosensitive thermosetting resin composition, for example, on a printed wiring board on which a circuit is formed, screen printing, a curtain coater, a roll coater, or applied over the entire surface by spraying, or a dry film of the composition The coating film can be formed by any method such as laminating directly on a printed wiring board, or applying a liquid by the above-mentioned method, and laminating a dry film thereon in a wet or dried state.

After that, it is exposed to actinic rays such as high-pressure mercury lamp, ultra-high-pressure mercury lamp, metal halide lamp, chemical lamp, and xenon lamp through direct irradiation of laser light or through a patterned photomask. It can be developed to form a pattern.

(Function) In the case of a photosensitive thermosetting resin composition for a solder resist using a thermosetting component together with a photosensitive resin, an epoxy resin and a melamine resin are generally used as the thermosetting component.

Novolak type epoxy resin, TGIC (triglycidyl isocyanurate) type epoxy resin, etc. are used as the epoxy resin used for this purpose in consideration of heat resistance. Solder resists containing these epoxy resins have low heat resistance. Although they are excellent, they are all poor in acid resistance and adhesion, and cannot withstand electroless nickel plating or electroless gold plating treatment conditions. Therefore, as a result of examining the structure of the epoxy resin and the plating resistance of the solder resist by changing the type of epoxy resin, the epoxy resin having the specific structure described below was converted to the thermosetting component of the photosensitive thermosetting resin composition for solder resist. It has been found that a solder resist composition that can withstand electroless nickel plating and electroless gold plating treatment conditions can be provided only by using as a resist.

The epoxy resin of this specific structure has the general formula And / or a nitrile-butadiene rubber-modified epoxy resin (II) having a carboxyl group.

In addition, melamine resins used for this purpose include:
Water-soluble or water-dispersible ones are used. When the photosensitive thermosetting resin composition using the water-soluble or water-dispersible melamine resin is exposed and an unexposed portion is developed with an alkali developing solution, the developability is extremely good. The characteristics of the melamine resin, such as heat resistance and chemical resistance, are also extremely improved. However, it is difficult to provide a solder resist composition that can completely withstand electroless nickel plating and electroless gold plating processing conditions.

Accordingly, it is an object of the present invention to provide a photosensitive thermosetting resin composition for a solder resist by using an epoxy resin (I) and / or (II) in combination with a water-soluble or water-dispersible melamine resin, and taking advantage of the respective advantages. The biggest feature.

(Aspects of the Invention) Hereinafter, each component of the photosensitive thermosetting resin of the present invention will be described.

Examples of the photosensitive prepolymer having at least two ethylenically unsaturated bonds in one molecule include a novolak-type epoxy compound and esterification of an all-esterified epoxy group (a-1) with an unsaturated monocarboxylic acid. An adduct (a-1-1) of a secondary hydroxyl group generated by the reaction with a saturated or unsaturated polybasic acid anhydride may be mentioned.

The novolak type epoxy compound is obtained, for example, by reacting novolaks obtained by reacting phenols such as phenol, cresol, halogenated phenols and alkylphenols with formaldehyde under an acidic catalyst, and epichlorohydrin and / or methyl epichlorohydrin. Are suitable, YDCN manufactured by Toto Kasei
-701, YDCN-704, YDPN-638, YDPN-602: N-730, N-770, N-865, N-665, N6 manufactured by Dainippon Ink and Chemicals, Inc.
73, N-695, VH-4150, VH-4240, VH-4440, and the like.

In addition, a part of the novolak type epoxy compound is replaced with a glycidyl ether type epoxy compound such as bisphenol A type, bisphenol F type, hydrogenated bisphenol A type, brominated bisphenol A type, amino acid containing, alicyclic, or polybutadiene modified. Can be
It is particularly preferable to use a cresol novolak type epoxy compound.

Next, acrylic acid as the unsaturated monocarboxylic acid,
Methacrylic acid, β-styrylacrylic acid, β-furfurylacrylic acid, crotonic acid, α-cyanocinnamic acid, cinnamic acid, and a saturated or unsaturated dibasic anhydride and one hydroxyl group in one molecule ( (Meth) acrylates, or half esters of a saturated or unsaturated dibasic acid and an unsaturated monoglycidyl compound, such as phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, maleic acid, succinic acid, itaconic acid, chlorendic acid, and methyl Saturated or unsaturated dibasic anhydrides such as hexahydrophthalic acid, methylendomethylenetetrahydrophthalic acid and methyltetrahydrophthalic acid, and hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, polyethylene glycol monoacrylate, glycerin diacryle DOO, trimethylolpropane diacrylate, pentaerythritol triacrylate,
A diacrylate of dipentaerythritol pentaacrylate and triglycidyl isocyanurate, a methacrylate corresponding to the above acrylate, or a half obtained by reacting the above-mentioned saturated or unsaturated dibasic acid with glycidyl (meth) acrylate in an equimolar ratio by a conventional method. Ester or the like may be used alone or as a mixture, and acrylic acid is particularly preferred.

Next, as the saturated or unsaturated polybasic acid anhydride,
Phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, maleic acid, succinic acid, itaconic acid, chlorendic acid, methylhexahydrophthalic acid, methylendomethylenetetrahydrophthalic acid, methyltetrahydrophthalic acid, trimellitic acid, pyromellitic acid, And anhydrides such as benzophenonetetracarboxylic acid, and particularly preferred are tetrahydrophthalic anhydride and hexahydrophthalic anhydride.

Next, the total esterified product of the epoxy group of the novolak type epoxy compound and the unsaturated monocarboxylic acid has an epoxy equivalent / carboxylic acid equivalent of 0.8 to 3.3, preferably 0.9 to 1.1.
The reaction is carried out according to a conventional method within the range described above. This equivalent ratio is 0.
When the value is 8 or less, the free acid remains, and the solder heat resistance decreases. When the value exceeds 3.3, the photosensitivity decreases, which is not preferable.

For example, the novolak type epoxy compound is dissolved in an organic solvent such as cellosolve acetate, carbitol acetate, and ethyl methyl ketone, and a thermal polymerization inhibitor such as hydroquinone, catechol, and pyrogallol, and tertiary amines such as benzyldimethylamine and triethylamine or benzyl. The unsaturated monocarboxylic acid and / or unsaturated phenol compound is mixed with a quaternary ammonium salt such as trimethylammonium chloride and benzyltriethylammonium bromide as a catalyst, and the mixture is reacted by heating and stirring at 70 to 140 ° C.

Next, the ratio of the addition reaction between the secondary hydroxyl group generated by the reaction of all the esterified products of the novolak type epoxy compound and the polybasic acid anhydride is such that the acid anhydride equivalent is 0.3 with respect to the secondary hydroxyl group equivalent of the esterified product. The above is preferable, and the range of the acid value of the formed resin is 30 to 160 mgKOH / g, preferably
It is 45 to 120 mgKOH / g. When the acid value is 30 or less, the solubility in an alkali developing solution is deteriorated. On the other hand, when the acid value is 160 or more, it becomes a factor of deteriorating various properties as a solder resist such as alkali resistance and electric properties of the cured film.

The photosensitive prepolymer used in the present invention can be obtained by selecting at least one kind from the total esterified product of the epoxy resin and the polybasic acid anhydride, mixing, and reacting by heating and stirring at 70 to 120 ° C. by a conventional method.

Next, typical examples of the photopolymerization initiator (B) include benzoins such as benzoin, benzyl and benzoin methyl ether, and benzoin alkyl ethers: acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-dichloroacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-
[4- (methylthio) phenyl] -2-morpholino-
Acetophenones such as propan-1-one and N, N-dimethylaminoacetophenone: 2-methylanthraquinone, 2-ethylanthraquinone, anthraquinones such as 2-amylanthraquinone, and the like: 2,4-dimethylthioxanthone, 2-chlorothioxanthone, Thioxanthones such as 2,4-diisopropylthioxanthone: ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal: benzophenones such as benzophenone, methylbenzophenone, 4,4-dichlorobenzophenone, 4,4'-bisdiethylaminobenzophenone, and Michler's ketone; , Xanthones and the like, and these can be used alone or in combination of two or more. Further, the photopolymerization initiator (B) is a benzoic acid ester such as ethyl 4-dimethylaminobenzoate or 2- (dimethylamino) ethylbenzoate, or triethylamine.
Known and commonly used photosensitizers such as tertiary amines such as triethanolamine can be used alone or in combination of two or more.

The preferred range of the amount of the photopolymerization initiator (B) used is 0.2 to 30 parts by weight, preferably 2 to 20 parts by weight, based on 100 parts by weight of the photosensitive prepolymer (A).

Next, a photopolymerizable vinyl monomer and / or an organic solvent can be used as the diluent (C).

Representative examples of the photopolymerizable vinyl monomer include:
Hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxybutyl acrylate: Mono- or diacrylates of glycols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol, and propylene glycol:
Acrylamides such as N, N-dimethylacrylamide and N-methylolacrylamide: aminoalkyl acrylates such as N, N-dimethylaminoethyl acrylate: hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, tris-
Polyhydric alcohols such as hydroxyethyl isocyanurate or polyhydric acrylates of these ethylene oxide or propylene oxide adducts: phenoxy acrylate, bisphenol A diacrylate, and ethylene oxide or propylene oxide adducts of these phenols Acrylates of:
Acrylates of glycidyl ether such as glycerin dichridyl ether, trimethylolpropane triglycidyl ether and triglycidyl isocyanurate:
And melamine acrylates and / or methacrylates corresponding to the above acrylates.

On the other hand, as organic solvents, 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 monetyl ether , Dipropylene glycol monoethyl ether,
Glycol ethers such as triethylene glycol monoethyl ether: esters such as ethyl acetate, butyl acetate and acetic acid ester of the above glycol ethers: ethanol, prohanol, ethylene glycol;
Alcohols such as propylene glycol: octane,
Aliphatic hydrocarbons such as decane: petroleum solvents such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solevent naphtha, and those having good compatibility with the photosensitive prepolymer (A) are preferable.

The diluent (C) as described above is used alone or as a mixture of two or more kinds. A preferable range of the amount used is 20 to 300 parts by weight, based on 100 parts by weight of the photosensitive prepolymer (A). Preferably it is 30 to 200 parts by weight.

The purpose of use of the diluent is, in the case of a photopolymerizable vinyl monomer, to dilute the photosensitive prepolymer to make it easy to apply, and to enhance photopolymerizability, and in the case of an organic solvent, The photosensitive prepolymer is prepared by dissolving and diluting the photosensitive prepolymer, thereby applying it as a liquid, and then drying it to form a film. Therefore, depending on the diluent to be used, either a contact type or a non-contact type in which a photomask is brought into contact with a coating film is used.

As the water-soluble or water-dispersible melamine resin (D),
Methylated melamine resins and mixed etherified melamine resins are used.

The melamine resin is obtained by etherifying methylolated melamine produced by the reaction between melamine and formalin with alcohol.

Many products having different degrees of methylolation and etherification, different types of alcohols used for etherification, and different degrees of condensation are commercially available.

The solubility of a melamine resin varies greatly depending on the type of alcohol used for alkyl etherification.

The methylated melamine resin is a melamine resin alkyl-etherified with methanol (generally, bound formaldehyde is about 3 to 6 moles and the remaining methylol group is about 0 to 2 moles), and has both water solubility and oil solubility. The mixed etherified melamine resin is a melamine resin etherified with two or more alcohols (for example, methanol and butanol), and has both water dispersibility and oil solubility. Butylated melamine resin is a melamine resin alkyl-etherified with n-butanol or iso-butanol, which has more residual methylol groups than all the two, condenses into a polynuclear, has a large molecular weight, and is soluble in various organic solvents. , Insoluble in water.

Since the melamine resin in the present invention needs to have water solubility or water dispersibility, it is preferable to use a methylated melamine resin and a mixed etherified melamine resin.

From the above, as the melamine resin (D) used in the present invention, water sol S-683 IM manufactured by Dainippon Ink and Chemicals, Nikarac MW-22, MW- manufactured by Sanwa Chemical Co., Ltd.
12LF, MW-30, MX-031, MS-21, MX-730, MX-705,
Melamine 620 manufactured by Hitachi Chemical, Sumimar M manufactured by Sumitomo Chemical
Methylated melamine resins such as -30W, M-40W, M-50W, M-55, M-100C; Nikalac MX-4 manufactured by Sanwa Chemical
0, NX-470, Sumitomo Chemical Co., Ltd. Sumimar M-66B, and the like, and mixed etherified melamine resins.

The preferred range of the amount used depends on the structure of the photosensitive prepolymer and the melamine resin used, but generally the ratio of the photosensitive prepolymer and the melamine resin is 95: 5 to 10:90.
(Weight ratio of resin solids), more preferably 80:20 to 70:
30. If the melamine resin is less than this ratio, the heat resistance of the coating film is reduced, and if it is larger, the photosensitivity is reduced.

In the present invention, the melamine resin causes a crosslinking reaction by the following ester reaction with the photosensitive prepolymer, It is considered that a strong network structure is formed by the following condensation reaction (methyleneation reaction, dimethylene etherification reaction) to improve the heat resistance and chemical resistance of the coating film.

The epoxy resin (E) has the general formula And an NBR-modified epoxy resin (II) having a carboxyl group are used alone or as a mixture. Examples of the epoxy resin (I) include EPPN501, EPPN502, EPPN504, and Nippon Kayaku. As an example of epoxy resin (II), R130 manufactured by AC R
9, R1415-1, R1437-2, and R1508.

The preferred range of the amount used is such that the mixing ratio of the photosensitive prepolymer (A) and the epoxy resin (D) is 50-95: 50-5.
If the amount of the component (D) is less than 50:50 (weight basis), preferably 60:90:40 to 10, heat resistance and plating resistance will be reduced.

The photosensitive thermosetting resin composition thus obtained contains a hydroxyl group and / or a carboxyl group in the photosensitive prepolymer (A), and the hydroxyl group and / or the carboxyl group in the photosensitive prepolymer (A) is an epoxy resin. Since it works as a resin resin curing agent, it functions sufficiently as a solder resist without newly using an epoxy resin curing agent. Further, as the photopolymerization initiator (B), the amino group-containing photopolymerization initiator used for increasing photosensitivity,
When a photosensitizer is contained, the epoxy compound (D) may be used due to the effects of a photopolymerization initiator and an amino group in the photopolymerization sensitizer.
Effect is further promoted. However, it is preferable to newly use an epoxy resin curing effect agent (F) in order to further improve properties such as adhesion, chemical resistance, and heat resistance.

Examples of such epoxy resin curing agent (F), manufactured by Shikoku _{Chemicals, 2E4MZ, C 17 Z, 2PZ} , 2E4MZ, 2PHZ-CN, 2E
4MZ-CNS, 2E4MZ-AZINE, 2MA-OK, 2P4MHZ, 2PHZ, 4BH
Imidazole derivatives such as Z: guanamines such as acetoguanamine and benzoguanamine: diaminodiphenylsulfone, cyclohexylamine, N-aminoethylpiperazine, isophoronediamine, dicyandiamide, urea, urea derivatives, melamine, polybasic hydrozide,
Polyamines, such as their organic acid salts, and / or epoxy adducts: amine complexes of boron trifluoride: triethanolamine, N, N-dimethyloctylamine, N
-Tertiary amines such as methylmorpholine and hexa (N-methyl) melamine: Polyphenols such as polyvinylphenol, polyvinylphenol bromide, phenol novolak, and alkylphenol novolak: tributylphosphine, triphenylphosphine, and tris-
Organic phosphines such as 2-cyanoethylphosphine:
Phosphonium salts such as tri-n-butyl (2,5-dihydroxyphenyl) phosphonium bromide and hexiodecyltolubutyl osphonium chloride: quaternary ammonium salts such as benzyltrimethylammonium bromide: the polybasic anhydride: diphenyl Photocationic polymerization catalysts such as iodonium tetrafluoroboroate, triphenylsulfonium hexafluoroantimonate, 2,4,6-triphenylthiobrillium hexafluorophosphate, CG-24-61 manufactured by Ciba-Gaiky, etc .: Styrene-malein Known and commonly used curing agents and curing accelerators such as acid resins can be used alone or in combination of two or more.

Further, the photosensitive curable resin composition of the present invention has, as necessary, barium sulfate, barium titanate, silicon oxide powder, finely divided silicon oxide, amorphous silica, for the purpose of improving properties such as hardness, Known and commonly used inorganic fillers such as talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, and mica powder can be used, and the compounding ratio is 0 to 0 of the photosensitive thermosetting resin composition.
It is 60% by weight, preferably 5 to 40% by weight. If necessary, phthalocyanine blue, fullerocyanine green, crystal violet, titanium oxide, carbon black, naphthalene black, etc., known and commonly used coloring agents, hydroquinone, hydroquinone monomethyl ether, tert-butyl catechol, pyrogallol, phenochazine, etc. Thermal polymerization inhibitor, orben,
Benton, known and conventional thickeners such as montmorillonite,
Defoaming agents of silicone type, fluorine type, polymer type and / or
Alternatively, known and commonly used additives such as an adhesion-imparting agent such as a leveling agent, imidazole-based, thiazole-based, triazole-based, and silane coupling agents can be used.

Further, known and commonly used binder resins such as copolymers of ethylenically unsaturated compounds such as acrylates and polyester resins synthesized from polyhydric alcohols and saturated or unsaturated polybasic acid compounds; Polyester (meth) acrylates synthesized from polyhydric alcohols and saturated or unsaturated polybasic oxides glycidyl (meth) acrylate, and urethanes synthesized from polyhydric alcohols, diisocyanates, and hydroxyl group-containing (meth) acrylates ( Known and commonly used photosensitive oligomers such as meth) acrylates can also be used as solder masks within a range that does not affect these properties.

As a developer for forming a solder resist pattern after exposing the photosensitive thermosetting resin composition through a photomask, potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, sodium phosphate, silica An aqueous alkali solution such as sodium acid, ammonia, and amines can be used.

(Examples) Hereinafter, the present invention will be specifically described with reference to Production Examples, Examples, and Comparative Examples, but the present invention is not limited thereto. Note that “parts” and “%” are based on weight unless otherwise specified.

Production Example-1 1090 parts of cresol novolak type epoxy resin having an epoxy equivalent of 218 (YDCN-702 manufactured by Toto Kasei) is placed in a three-necked flask equipped with a stirrer and a condenser, heated and melted at 90 to 100 ° C., and stirred. . Next, 396 parts of acrylic acid, 0.6 parts of hydroquinone and 7.0 parts of benzyldimethylamine were added. Next, the mixture was heated to 110 to 115 ° C., and reacted with stirring for 12 hours, taken out of the reactor and cooled to room temperature.
A total esterified product of the novolak-type epoxy compound of gKOH / g with acrylic acid was obtained.

Next, 450 parts of the obtained total esterified product, 125 parts of cellosolve acetate, and 125 parts of Ibusol # 150 (a petroleum-based solvent mainly composed of tetramethylbenzene: manufactured by Idemitsu Petrochemical) were charged into the same reactor as in Production Example-1. Heat to ~ 80 ° C to dissolve. Next, 120 parts of phthalic anhydride was mixed, the temperature was raised to 95 to 100 ° C., and the mixture was stirred and reacted for 8 hours. After taking out from the reactor and cooling to room temperature, a novolak-type epoxy compound having an acid value of solid of 50 mgKOH / g was obtained. An organic solvent solution (solid content 70%) of an acid anhydride adduct of all ester compounds with acrylic acid (photosensitive prepolymer 1) was obtained.

Production Example-2 Solution of photosensitive prepolymer 1 obtained in Production Example-1 50.0 parts Carbitol acetate 2.0 parts Dipentaerythritol hexaacrylate 3.0 parts 2-methyl-1- [4- (methylthio) phenyl] -2
Morpholino-1-propanone 3.0 parts Benzoin 0.5 parts Barium sulfate 40.0 parts Phthalocyanine green 0.5 parts Dicyandiamide 1.0 parts Total 100.0 parts After the above components were premixed, they were kneaded twice with a three-roll mill to obtain a green viscous liquid.

The components of Examples 1 to 6 and Comparative Examples 1 and 2 were mixed based on the composition table in Table 1 to prepare a photosensitive thermosetting resin composition.

Each of these photosensitive thermosetting resin compositions is applied to the entire surface of a copper / glass epoxy printed circuit board by a screen printing method, placed in a hot air circulating furnace, dried at 80 ° C. for 30 minutes, cooled to room temperature, and dried. Obtained.

Next, a patterned photomask is brought into contact with the coating film surface, and exposed using a metal halide lamp exposure device manufactured by Oak Manufacturing Co., Ltd., and then a 1% aqueous solution of sodium carbonate is used as a developing solution at a spray pressure of 2.0 kgf / cm ^2. It was developed, washed with water and dried.
Next, it was placed in a hot-air circulating furnace heated to 150 ° C. for 30 minutes, and post-cured (heat-cured) to form a solder resist pattern.

Table 2 shows the results of tests on various properties of the solder resist resin composition and the solder resist pattern obtained in Examples 1 to 6 and Comparative Examples 1 and 2.

 The test method and evaluation criteria are as follows.

1) Adhesion test 700mJ / cm using an integrated light meter manufactured by Oak Manufacturing Co., Ltd.
^{(2) After} irradiation, each developing solution was developed at a spray pressure of ² kg / cm ² for 60 seconds, and then post-cured under each condition to form a test piece, and in a grid pattern according to the test method of JIS D 0202. A cross cut was made, and then the peeling state after the peeling test with a cellophane tape was visually judged.

◎: 100/100 with no peeling ○: 100/100 with slightly peeled cross cut △: 50 / 100-90 / 100 ×: 0 / 100-50-100 2) Pencil hardness test The hardness of each test piece as in the adhesion test was measured under a load of 1 kg according to the test method of JIS K 5400.

3) Sulfuric acid resistance test After heating 20 vol% H ₂ SO ₄ to 80 ° C. and immersing the test piece in this solution for 1 hour, a cellophane peeling test is performed to evaluate the presence or absence of peeling.

4) Electroless nickel plating and electroless gold plating test A test piece, which had been subjected to electroless nickel plating or electroless gold plating under the above conditions, was subjected to a healing test using a cellophane tape, and the peeled state was measured.

◎: No peeling at all △: Slight peeling ○: A peeling is remarkably confirmed ×: A coating is peeled off as a whole The practice of the present invention is clear from the results shown in Table 1. Since the photosensitive thermosetting resin composition obtained in the example contains a specific epoxy resin as a thermosetting component, adhesion,
Excellent sulfuric acid resistance, electroless nickel plating resistance and electroless gold plating resistance.

5) Solder resistance test JIS C 6481
According to the test method described above, the state of the coating film after immersion in a 260 ° C. solder bath for 15 seconds for 2 to 8 times was evaluated.

(Effect) The photosensitive thermosetting resin composition according to the present invention has excellent resistance to a developing solution in an exposed part by using an epoxy resin and a melamine resin having a specific structure as a thermosetting resin component, and It is a photosensitive thermosetting resin composition having good developability of unexposed portions, excellent photosensitivity, adhesion, sulfuric acid resistance, electroless nickel plating resistance, and electroless gold plating resistance.

Further, by using such a photosensitive thermosetting resin composition, by exposure, development, and then thermosetting,
A solder resist pattern having excellent adhesion, sulfuric acid resistance, electroless nickel plating resistance, electroless gold plating resistance, hardness, solder heat resistance, and electrical insulation can be formed.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kouji Miyabe 251 Suwa-cho, Hachioji-shi, Tokyo Inside the Asahi Chemical Laboratory, Inc. (72) Inventor Yoichi Oba 251 Suwa-cho, Hachioji-shi, Tokyo Asahi Chemical Research Inc. In-house (72) Isao Shirooka, Inventor 251 Suwa-cho, Hachioji-shi, Tokyo Inside the Asahi Chemical Laboratory Co., Ltd. (72) Inventor Iwasa Yamada 251, Suwa-cho, Hachioji-shi, Tokyo Asahi Chemical Laboratory Co., Ltd. (56) References JP-A-3-172317 (JP, A) JP-A-2-173747 (JP, A) JP-A-2-97513 (JP, A) JP-A-2-43551 (JP, A) JP-A-1-203424 (JP, A) JP-A-1-174522 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03F 7/032 G03F 7/004 C08G 59/32

Claims (6)

(57) [Claims] (A) a photosensitive prepolymer having at least two ethylenically unsaturated bonds in one molecule; (B) a photopolymerization initiator; (C) a photopolymerizable vinyl monomer or oligomer as a diluent; (D) water-soluble or water-dispersible melamine resin (E) general formula And / or a nitrile-butadiene rubber-modified epoxy resin (II) having a carboxyl group, and / or (F) an epoxy curing agent. Composition. 2. The composition according to claim 1, wherein the compounding ratio of the photosensitive prepolymer to the melamine resin is 95: 5 to 10:90 (solid content ratio on a weight basis). 3. The photosensitive prepolymer as claimed in claim 1, wherein the compounding amount of the diluent is
Claims 1 to 20 to 300 parts by weight per 100 parts by weight
The composition according to Item. 4. The method according to claim 1, wherein the composition contains an inorganic filler.
The composition according to Item. 5. A reaction product of the photosensitive prepolymer, wherein a secondary hydroxyl group of an esterified product produced by an esterification reaction between a novolak type epoxy compound and an unsaturated monocarboxylic acid and a saturated or unsaturated polybasic acid anhydride. The composition according to claim 1, which is a product. (A) a photosensitive prepolymer having at least two ethylenically unsaturated bonds in one molecule, (B) a photopolymerization initiator, and (C) a photopolymerizable vinyl monomer or oligomer as a diluent. And / or an organic solvent; (D) a water-soluble or water-dispersible melamine resin (E) a general formula A photosensitive thermosetting resin composition containing an epoxy resin (I) and / or a nitrile-butadiene rubber-modified epoxy resin (II) having a carboxyl group (F) an epoxy curing agent The entire surface is coated on a plate, selectively exposed to actinic rays through a patterned photomask, and the unexposed portion is developed with a developer to form a pattern, and then heated to thermally cure the melamine resin. A method for forming a solder resist pattern on a printed wiring board, the method comprising: