JPH03121154A - Photosensitive thermoset resin composition and method for forming solder resist pattern therewith - Google Patents

Abstract

PURPOSE:To improve the developability, sensitivity, and resistance to soldering heat, chemicals, and plating by compounding a specific photosensitive prepolymer, a photopolumn. initiator, a diluent, and a water-sol. or water- dispersible melamine resin. CONSTITUTION:The title resin compsn. is prepd. by compounding: 100 pts.wt. photosensitive prepolymer having at least two ethylenically unsatd. bonds [e.g. a reaction product of an (un)satd. polybasic acid anhydride with secondary hydroxyl groups of an ester obtd. by the esterification of a novolak epoxy compd. with an unsatd. monocarboxylic acid]; a water-sol. or water-dispersible melamine resin in a wt. ratio of the melamine resin to the photosensitive prepolymer of (5:95)-(90:10); 0.2-30 pts.wt. photopolymn. initiator (e.g. benzoin); and 20-300 pts.wt. diluent comprising a photopolymerizable vinyl monomer (e.g. 2-hydroxyethyl acrylate) and/or an org. solvent (e.g. cyclohexanone).

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a novel photosensitive thermosetting resin composition that is used in printed wiring board manufacturing, metal precision processing, etc., and is particularly useful as a solder resist for printed wiring boards. Regarding the product and the method of forming a solder resist pattern, more specifically, in the formation of a solder resist pattern by selectively exposing a patterned film to actinic rays and developing the unexposed portions, it has particularly excellent developability and a method for forming a solder resist pattern. It has resistance to some developing solutions, long pot life, photosensitivity, adhesion, electrical insulation, electrical contact resistance, soldering heat resistance,
The present invention relates to a photosensitive thermosetting resin composition for a solder resist having excellent solvent resistance, alkali resistance, acid resistance, and plating resistance of electrolytic gold, electroless gold, electroless copper, etc., and a method for forming a solder resist pattern.

(Prior art) Solder resist is used to prevent solder from adhering to unnecessary parts and to protect circuits when soldering printed wiring board components.
Electrical insulation, soldering heat resistance, solvent resistance, alkali resistance,
Acid resistance and plating resistance are required.

Early solder resists used were epoxy melamine thermosetting types. Further, for example, an improved epoxy thermosetting type described in Japanese Patent Publication No. 51-14044 has been mainly used for industrial printed wiring boards.

Further, for example, a fast-curing ultraviolet curing type described in Japanese Patent Publication No. 61-48800 was mainly used for consumer printed wiring boards.

In addition, screen printing was used as a method for forming solder resist, but it is not suitable for forming solder resist patterns that correspond to the increased density of printed wiring boards and the surface mounting of components as electronic devices become lighter, thinner, and smaller. There were problems with bleeding and embedding between circuits, and it became impossible to fulfill the function as a solder resist film.

For this reason, dry film type photo solder resists and liquid photo solder resists are made using, for example, urethane di(meth)acrylate and a cyclic polymer compound having a specific glass transition temperature as described in JP-A-57-55914. A photosensitive resin composition for dry film containing a sensitizer was used.

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, an inert inorganic filler, a photopolymerization initiator, and a volatile organic solvent, as described in British Patent Application Publication No. GB-2032939A. A photopolymerizable coating composition containing the following was used.

In addition, as a method to solve the above-mentioned problems, a liquid photoresist in which a thermosetting component is added to an ultraviolet curable component has been proposed. A resin composition for solder resist ink containing a reaction product of a cresol novolac type epoxy resin with an unsaturated basic acid, a partial reaction product of a cresol novolak type epoxy resin with an unsaturated basic acid, an organic solvent, a photopolymerization initiator, and an amine thermosetting agent. things were used. In this case, thermosetting was also used by leaving an epoxy group in one molecule and curing it with an amine thermosetting agent.

On the other hand, as an example of adding epoxy resin, for example,
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, as described in Publication No. 9-107333. was used.

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

Furthermore, for example, a reaction product of a novolak type epoxy compound and an unsaturated monocarboxylic acid, a reaction product of a saturated or unsaturated polybasic acid anhydride, and a photopolymerization initiator described in JP-A No. 61-243869. A resist ink composition that uses a diluent and an epoxy resin in combination has been disclosed.

(Problems to be Solved by the Invention) However, the thermosetting epoxy melamine type has problems in soldering heat resistance, straw resistance, plating resistance, etc.

Epoxy-based heat-curable products that are improved from these have problems with plating resistance.

Fast-curing ultraviolet curing types have poor internal curing properties in thick films and poor solder heat resistance, so they cannot be used for industrial printed wiring boards.

Dry film type photo solder resists have excellent ability to form fine patterns when used in high-density printed wiring boards, but they do not have sufficient solder heat resistance or adhesion, and are not easy to embed between circuits. It has the disadvantage of being

Liquid photo solder resist has excellent ability to form fine patterns and embed between circuits, but
There are problems with adhesion to printed wiring boards, solder heat resistance, electrical insulation, etc.

In the case of a solder resist ink composition, as the epoxy groups remain, the number of photosensitive groups decreases, so the curability with ultraviolet rays decreases, and it is difficult to leave a large number of epoxy groups, so that the composition satisfies the properties as a solder resist. I can't.

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 compound containing (meth)acrylic acid, and has poor soldering heat resistance and resistance. In both cases, increasing the ratio of epoxy resin lowers the photocurability, so-called sensitivity, and the resistance of exposed areas to developer tends to decrease, making it impossible to develop for a long time, and leaving undeveloped areas in unexposed areas. There are problems such as easy to occur.

Resist ink compositions use an alkaline aqueous solution as a developer, so increasing the ratio of epoxy resin that is not soluble in the alkaline aqueous solution will similarly reduce the sensitivity and also reduce the solubility of unexposed areas in the developer. However, there are problems such as residual development occurs, long-term development is required, and exposed areas are eroded by the developer.

Therefore, an object of the present invention is to provide a photosensitive thermosetting resin composition that does not have the various drawbacks mentioned above, has excellent developability and sensitivity, is resistant to developing solutions in exposed areas, and has a long pot life. It's about doing.

A further object of the present invention is to achieve the adhesion, electrical insulation, and
A photosensitive thermosetting product that produces cured coatings with excellent solder heat resistance, solvent resistance, alkali resistance, acid resistance, plating resistance, etc., and is particularly suitable for manufacturing consumer printed wiring boards and industrial printed wiring boards. An object of the present invention is to provide a synthetic resin composition and a method for forming a solder resist pattern.

(Means for Solving the Problems) The present inventors have made various studies to solve these problems.

(Photosensitive prepolymer (B) photopolymerization initiator having at least two ethylenically unsaturated bonds in one Al molecule.

(Photopolymerizable vinyl monomer as C1 diluent and/or
Alternatively, the problem was solved by creating a composition comprising an organic solvent, (D) a water-soluble or water-dispersible melamine resin, and a finely divided epoxy compound that is poorly soluble in the diluent used.

For example, such a photosensitive thermosetting resin composition is applied to the entire surface of the circuit-formed printed circuit board by screen printing, a curtain coater, a roll coater spray, or the like, or the composition is formed into a dry film. A coating film can be formed by any method, such as directly laminating it on a printed wiring board, or applying it in liquid form by the method described above, and then laminating a dry film thereon in a wet or dry state.

After that, it is selectively exposed to active light from a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a chemical lamp, a xenon lamp, etc. through direct laser light irradiation or a patterned photomask, and the unexposed areas are treated with a developer. It can be developed to form a pattern.

(Function) In the case of a photosensitive thermosetting resin composition for a solder resist that uses a thermosetting component together with a photosensitive resin, an epoxy resin has conventionally been generally used as the thermosetting component. When a photosensitive thermosetting resin composition is prepared using such an epoxy resin, the epoxy resin is intertwined with the photosensitive resin (the chain length portions of each resin are intertwined). It is estimated to be. As a result, when exposed and unexposed areas are developed with an alkaline aqueous solution, the epoxy resin does not dissolve in the alkaline aqueous solution, and since the epoxy resin and photosensitive resin are intertwined, the photosensitive resin in the unexposed areas In addition, since the epoxy resin is molten, it reacts quickly with the curing agent, which tends to cause residual development during development, ie, so-called thermal fogging, resulting in poor developability.

On the other hand, when a water-soluble or water-dispersible melamine resin is used as in the present invention, both the photosensitive resin and thermosetting resin in the unexposed areas are easily removed when developed with an alkaline aqueous solution, and the heat The curable melamine resin does not adversely affect the elution of the photosensitive prepolymer, and the developability is extremely improved.

That is, the photosensitive thermosetting resin composition of the present invention is characterized in that a melamine resin that is soluble or dispersed in an alkaline aqueous solution is used as a thermosetting component.

(Aspects of the Invention) Each component of the photosensitive thermosetting resin of the present invention will be explained below.

The above-mentioned photosensitive prepolymer fA) having at least two ethylenically unsaturated bonds in the molecule includes (al novolak type epoxy compound and total esterification product of epoxy groups with unsaturated monocarboxylic acid (a-1))
(a-1-1
1, and/or a novolac-type epoxy compound and a secondary hydroxyl group produced by an esterification reaction of a partially esterified product (a-2) of an epoxy group with an unsaturated monocarboxylic acid, and a saturated or unsaturated polybasic acid anhydride. adduct 1a-2-11 with a substance, and/or.

b) Total etherification of epoxy groups with a novolac type epoxy compound and an unsaturated phenol compound (adduct of b-11, secondary hydroxyl group produced by the etherification reaction and saturated or unsaturated polybasic acid anhydride) b-1-11
, and/or a novolak-type epoxy compound and a partially etherified epoxy group with an unsaturated phenol compound (b-21, a secondary hydroxyl group produced by the etherification reaction and a saturated or unsaturated polybasic acid anhydride) Examples include adducts (b-2-1), and at least one of these is mentioned.

The above-mentioned novolak type epoxy compound is 1. For example, a compound obtained by reacting a novolak obtained by reacting phenols such as phenol, cresol, halogenated phenol, and alkylphenol with formaldehyde under an acidic catalyst and epichlorohydrin and/or methylepichlorohydrin. YDC manufactured by Tobu Kasei is suitable.
N-701, YDCN-704, YDPN-638, Y
DPN-602 + Dainippon Ink & Chemicals N-730,
N-770, N-865, N-665, N-673, N
-695, VH-4150, Vll-4240, VH-
4440, etc.

In addition, some of the novolac type epoxy compounds are bisphenol A type, bisphenol F type, and hydrogenated bisphenol A.
Although the epoxy compound can be replaced by a glycidyl ether type epoxy compound such as brominated bisphenol A type, amino acid-containing, alicyclic type, or polybutadiene-modified epoxy compound, it is particularly preferable to use a Talesol novolac type epoxy compound.

Next, the unsaturated monocarboxylic acids include acrylic acid, methacrylic acid, β-styrylacrylic acid, β-furfurylacrylic acid, crotonic acid, α-cyanocinnamic acid, cinnamic acid, and saturated or unsaturated dibasic acids. Half esters of anhydrides and (meth)acrylates having one hydroxyl group in one molecule, or saturated or unsaturated dibasic acids and unsaturated monoglycidyl compounds 1 For example, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid , saturated or unsaturated dibasic acid anhydrides such as maleic acid, succinic acid, itaconic acid, chlorendic acid, methylhexahydrophthalic acid, methylendomethylenetetrahydrophthalic acid and methyltetrahydrophthalic acid, and hydroxyethyl acrylate, hydroxypropyl acrylate. , hydroxybutyl acrylate, polyethylene glycol monoacrylate, glycerin diacrylate, trimethylolpropane diacrylate, pentaerythritol triacrylate,
Diacrylates of dipentaerythritol pentaacrylate and triglycidyl isocyanurate, methacrylates corresponding to the above acrylates, or half-forms obtained by reacting the above-mentioned saturated or unsaturated dibasic acids with glycidyl (meth)acrylate in an equimolar ratio by a conventional method. Esters and the like can be used alone or in combination, with acrylic acid being particularly preferred.

Next, the saturated or unsaturated polybasic acid anhydrides include phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, maleic acid, succinic acid, itaconic acid, chlorendic acid,
Anhydrides such as methylhexahydrofucric acid, methylendomethylenetetrahydrophthalic acid, methyltetrahydrophthalic acid, trimellitic acid, pyromellitic acid, and benzophenonetetracarboxylic acid are used, with tetrahydrophthalic anhydride or hexahydrofucric anhydride being particularly preferred. .

Next, the unsaturated phenol compounds include 4°-hydroxychalcone, 2°-hydroxychalcone, and 4.4°-hydroxychalcone.
Dihydroxychalcone and the like are used, with 4'-hydroxychalcone being particularly preferred.

Next, a total esterification product (a-1) of an epoxy group using the novolac type epoxy compound, an unsaturated monocarboxylic acid, and an unsaturated phenol compound, and a total etherification product fb-1.
1 and partially esterified product fa-2), partially etherified product [b-21 is an epoxy equivalent/carboxylic acid equivalent or an epoxy equivalent/phenolic hydroxyl equivalent of 0.8 to 3]
．． 3 Preferably 0.9 to 1 for all esterified products (a-1) and all etherified products (b-1).

1. For the partially esterified product fa-21 and the partially etherified product fb-21, the reaction is carried out in a conventional manner in the range of 1.1 to 2.5. If this equivalent ratio is less than 0.8, the free acid or free phenol remains, resulting in a decrease in soldering heat resistance, and if it exceeds 3.3, the photosensitivity decreases, which is not preferable.

For example, the above-mentioned novolac type epoxy compound is dissolved in an organic solvent such as cellosolve acetate, carpitol acetate, or ethyl methyl ketone, and then a thermal polymerization inhibitor such as hydroquinone, catechol, or pyrogallol and a tertiary amine such as benzyldimethylamine or triethylamine or benzyl The unsaturated monocarboxylic acid and/or unsaturated phenol compound are mixed using a quaternary ammonium salt such as trimethylammonium chloride or benzyltriethylammonium bromide as a catalyst, and the mixture is heated at 70 to 140°C.
It is obtained by reacting with heating and stirring.

Next, the secondary hydroxyl group produced by the reaction of the total esterification product (a-11, the total etherification product (b-11), and the partial esterification product (a-21, partial etherification product fb-21) of the novolak type epoxy compound and the polyester The ratio of the addition reaction of the basic acid anhydride to the secondary hydroxyl equivalent of the above (a-1) to (b-2) is preferably 0.3 or more, and the acid value of the resulting resin is Range is 30-160mgKO
H/g is preferably 45 to 120 mgKOH/g.

If the acid value is less than 30, the solubility in an alkaline developer will be poor, and if it is more than 160, it will be a factor that reduces the properties of the cured film as a solder resist, such as alkali resistance and electrical properties. In this case, (a-11 to (b-2)) tend to gel when reacted with saturated or unsaturated polybasic acid anhydride if there are many remaining epoxy groups, so the remaining rate of epoxy groups is 20% or less. is suitable, preferably 15% or less.

For example, it can be obtained by selecting at least one of the resins (a-11 to b-21) and at least one of the polybasic acid anhydrides, mixing them, and reacting them by heating and stirring at 70 to 120°C in a conventional manner.

Next, a photopolymerization initiator (typical examples of Bl include benzoins such as benzoin, benzyl, benzoin methyl ether, and benzoin alkyl ethers: acetophenone, 2.2-dimethoxy-2-phenylacetophenone, 1.1 -dichloroacetophenone, ■-hydroxycyclohexylphenylketone, 2-methyl-
Acetophenones such as 1-(4-(methylthio)phenyl]-2-morpholino-propan-1-one, N,N-dimethylaminoacetophenone: 2-methylanthraquinone, 2-ethylanthraquinone, 2-amylanthraquinone, etc. Anthraquinones: 2.4-dimethylthioxanthone, 2-chlorothioxanthone, 2.4
- Thioxanthone such as diisopropylthioxanthone: Ketal such as acetophenone dimethyl ketal, benzyl dimethyl ketal: benzophenone, methylbenzophenone, 4,4-dichlorobenzophenone,
Examples include benzophenones such as 4.4°-bisdiethylaminobenzophenone and Michler's ketone, and xanthones, which can be used alone or in combination of two or more. Furthermore, the photopolymerization initiator t83 is ethyl 4
- Known and commonly used photosensitizers such as benzoic acid esters such as dimethylaminobenzoate and 2-(dimethylamino)ethylbenzoate, or tertiary amines such as triethylamine and triethanolamine, either alone or in combination of two or more. It can be used as

The suitable 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 tA). .

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

Typical photopolymerizable vinyl monomers include 2
-Hydroxyalkyl acrylates such as hydroxyethyl acrylate and 2-hydroxybutyl acrylate: mono- or diacrylates of glycols such as ethylene glycol, methoxytetraethylene golicol, polyethylene golicol, and propylene glycol IN
, N-dimethylacrylamide, N-methylolacrylamide, and other acrylamides; N,N-dimethylaminoethyl acrylate and other aminoalkyl acrylates; hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol,
Polyhydric alcohols such as tris-hydroxyethyl isocyanurate, or their adducts of ethylene oxide or propylene oxide, polyhydric acrylates:
Acrylates such as phenoxy acrylate, bisphenol A diacrylate, and adducts of these phenols with ethylene oxide or propylene oxide; Acrylates of glycidyl ethers such as glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, and triglycidyl isocyanurate: and melamine acrylate and/or methacrylates corresponding to the above acrylates.

On the other hand, organic solvents include ketones such as ethyl methyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; methyl cellosolve, butyl cellosolve, methyl calpitol, butyl calpitol, propylene glycol monoethyl ether; , dipropylene glycol monoethyl ether, tonoethylene glycol monoethyl ether, and other glycol ethers: ethyl acetate, butyl acetate, and acetate esters of the above glycol ethers, and other esters: ethanol, prohanol, ethylene glycol, propylene glycol, etc. Alcohols: include aliphatic hydrocarbons such as octane and decane, petroleum solvents such as dipetroleum ethers, petroleum naphtha, hydrogenated petroleum naphtha, and trebento naphtha, and those having good compatibility with the photosensitive prepolymer iAl. preferable.

The diluent (C) as described above may be used alone or as a mixture of two or more, and the preferred range of usage is 20 to 30 parts by weight based on the photosensitive prepolymer (A1100 parts by weight).
0 parts by weight, preferably 30 to 200 parts by weight.

In the case of photopolymerizable vinyl monomers, the diluent is used to dilute the photosensitive prepolymer to make it easier to apply, and to enhance photopolymerizability; in the case of organic solvents, the diluent is used to This is because the photosensitive prepolymer is dissolved and diluted, applied as a liquid, and then dried to form a film. Therefore, depending on the diluent used, either a contact exposure method in which a photomask is brought into contact with the coating film or a non-contact exposure method is used.

As the water-soluble or water-dispersible melamine resin TD), a methylated melamine resin or a mixed etherified melamine resin is used.

Melamine resin is produced by etherifying methylolated melamine, which is produced by the reaction of melamine and formalin, with alcohol.

Many products with different degrees of methylolization and etherification, different types of alcohol used for etherification, and different degrees of condensation are synthesized and commercially available.

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

Methylated melamine resin is a melamine resin that has been alkyl etherified with methanol (generally, bound formaldehyde is 3 to 6 moles and residual methylol group is about 0 to 2 moles), and has both water solubility and oil solubility.

Further, mixed etherified melamine resin is a melamine resin etherified with two or more types of alcohols (for example, methanol and butanol), and has both water dispersibility and oil solubility. Butylated melamine resin is a melamine resin that has been alkyl etherified with n-butanol or iso-butanol, and has more residual methylol groups than all three, and it condenses to form a polynuclear substance with a large molecular weight and is soluble in various organic solvents. , insoluble in water.

Since the melamine resin in this invention needs to be water-soluble or water-dispersible, it is preferable to use methylated melamine resins and mixed etherified melamine resins.

From the above, the melamine resin fD used in the present invention
Watersol S-6831M manufactured by Dainippon Ink and Chemicals, Nikaratsuk MIS-2 manufactured by Sansho Chemical Co., Ltd.
2, MW-12LF, MW-30, &1X-031. M
S-21. MX-730, MX-705, Hitachi Chemical Melamine 620, Sumitomo Chemical Co., Ltd. -JL, IJ
-301, M-40W, M-50W, M-55, M
Methylated melamine resins such as -10-C: Nikaratsuku MX-40 and NX-470 manufactured by Sansho Chemical Co., Ltd., Sumitomo Chemical Co., Ltd. -LM-66B, mixed etherified melamine resins, etc.

In addition, the suitable range of the amount used varies depending on the structure of the photosensitive prepolymer and melamine resin used, but generally the ratio of the photosensitive prepolymer and melamine resin is 95 = 5 to 10.
:90 (weight ratio of resin solid content), more preferably,
It is 90:10 to 20:80. If the amount of melamine resin is less than this ratio, the heat resistance of the coating film will be reduced, and if it is more than this ratio, the photosensitivity will be reduced.

In the present invention, the melamine resin undergoes a crosslinking reaction with the photosensitive prepolymer through the following ester reaction, and also forms a strong network structure through the following condensation reaction (methyleneation reaction, dimethylene etherification reaction). This is thought to improve the heat resistance and straw resistance of the coating film.

M NHCHOH+ M NH -M-NH-CH-HN-M + H0 Furthermore, the photosensitive thermosetting resin composition of the present invention may optionally contain barium sulfate, Known and commonly used inorganic fillers such as barium titanate, silicon oxide powder, finely powdered silicon oxide, amorphous silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, and mica powder can be used, and their formulations The ratio is 0 to 60% by weight of the photosensitive thermosetting resin composition, preferably 5 to 40% by weight.

Furthermore, if necessary, known and commonly used coloring agents such as phthalocyanine blue, phthalocyanine green, crystal violet, titanium oxide, carbon black, and naphthalene black, and known and commonly used colorants such as hydroquinone, hydroquinone monomethyl ether, tert-butylcatechol, pyrogallol, and phenothiazine are added. thermal polymerization inhibitors, known and commonly used thickeners such as orbenes, bentones, montmorillonites, antifoaming agents and/or leveling agents such as silicone-based, fluorine-based, polymer-based, imidazole-based, thiazole-based, triazole-based, Known and commonly used additives such as adhesion imparting agents such as silane coupling agents can be used.

In addition, known and commonly used binder resins such as copolymers of ethylenically unsaturated compounds such as acrylic acid esters, polyester resins synthesized from polyhydric alcohol Zn and saturated or unsaturated polybasic acid compounds, Polyester (meth)acrylates are synthesized from alcohols and the saturated or unsaturated polybasic acid compound glycidyl (meth)acrylate, and polyesters (meth)acrylates are synthesized from polyhydric alcohols, diisocyanates, and hydroxyl group-containing (meth)acrylates. Known and commonly used photosensitive oligomers such as urethane (meth)acrylates can also be used as long as they do not affect the properties of the solder mask.

The developing solution for forming a solder resist pattern after exposing the photosensitive thermosetting resin composition through a photomask includes potassium hydroxide, sodium hydroxide,
Alkaline aqueous solutions such as sodium carbonate, potassium carbonate, sodium phosphate, sodium silicate, ammonia, and amines can be used.

(Example) The present invention will be specifically explained below by showing production examples, examples, and comparative examples, but the present invention is not limited thereto. All figures are by weight unless otherwise specified.

Example-1 1090 parts of a Talesol novolak type epoxy resin (YDCN-702 manufactured by Tobu Kasei Co., Ltd.) with an epoxy equivalent of 218 was placed in a three-loaf flask equipped with a stirrer and a condenser, and the epoxy equivalent was 218.
A mixture of 396 parts of acrylic acid, 0.6 parts of hydroquinone, and 7.0 parts of benzyldimethylamine was heated and stirred at 100° C.
The temperature was raised to °C, the reaction was stirred for 12 hours, and the acid value was 4.511 parts gK when taken out from the reactor and cooled to room temperature.
A total esterification product of a novolak-type epoxy compound with acrylic acid was obtained at OH/g.

Next, 450 parts of the obtained total esterified product, 125 parts of cellosolve acetate, and 125 parts of Ibusol #150 (petroleum solvent mainly composed of tetramethylbenzene, manufactured by Izumi Petrochemical) were placed in the same reaction apparatus as in Production Example-1 for 70 minutes. ~80°
Next, 120 parts of phthalic anhydride was mixed with 120 parts of phthalic anhydride, heated to 95-100°C, stirred and reacted for 8 hours, taken out from the reactor and cooled to room temperature. An organic solvent solution of an acid anhydride adduct of a total ester compound (photosensitive blur (solid content 70%) Polymer 1) with acrylic acid of a novolac type epoxy compound having an acid value of 50 mg KO1 l/g was prepared.

Example-1 Solution of photosensitive prepolymer 1 obtained in Production Example-1 Calpitol acetate/dibetaerythritol hexaacrylate 2-amyl anthraquinone benzoin barium sulfate silica phthalocyanine green 7 two-carat M-22 (three-phase chemical 45.0 parts 5.0 parts 5.0 parts 4.0 parts 0.5 parts 10.0 parts 1000 parts 0.5 parts 20.0 parts Total 100.0 parts Above formulation After premixing the components, they were kneaded twice using a three-roll mill to prepare a photosensitive thermosetting resin composition. This photosensitive thermosetting resin composition was applied to the entire surface of the copper/gala Evo printed wiring by a screen printing method, and placed in a hot air circulation oven for 80'
After drying at C for 20 minutes, the coating was cooled to room temperature to obtain a dry coating.

Next, the patterned photomask was brought into contact with the coating surface, exposed using a metal halide lamp exposure device manufactured by Oak Seisakusho, and then a 1% aqueous sodium carbonate solution was used as a developer.
It was developed with a spray pressure of 2.0 kg/cm'', washed with water, and dried.Then, it was placed in a hot air circulation oven heated to 150°C for 30 minutes to post-cure (thermally harden) to form a solder resist pattern.

Example-2 Solution of photosensitive prepolymer-1 obtained in Production Example-1 32.0 parts Carpitol acetate 6.0 parts Dipentaerythritol hexaacrylate 5.0 parts 2-amyl anthraquinone 4.0 parts Benzoin 0 .5 parts barium sulfate 1000 parts silica
to, 0 parts Phthalocyanine Green 0.5 parts "Nikaratsuku LAN-2
2Jl + methylated melamine resin manufactured by Sanphase Chemical)
32.0 parts "Evicron N-680Jl (cresol novolac type epoxy resin manufactured by Dainippon Ink Chemical Industries) 2
5.0 parts total 1001 parts After preparing a photosensitive thermosetting composition in the same manner as in Example-1 except for changing the above-mentioned ingredients, a solder resist pattern was formed.

Comparative Example-1 Solution of photosensitive prepolymer-1 obtained in Production Example-1 40.0 parts Carpitol acetate 5.0 parts Dipentaerythritol hexaacrylate 5.0 parts 2-Methyl-1-(4-( methylthio)phenyl]-2
-Morpholino-propan-1-one 4.0 parts 2-
Ethylanthraquinone 0.5 parts Barium sulfate 1090 parts Silica
10.0 parts Phthalocyanine green 0.5 parts total
A photosensitive thermosetting composition was prepared in the same manner as in Example 1 except that the above ingredients were changed to 100.0 parts, and then a solder resist pattern was formed.

Comparative Example-2 Solution of photosensitive prepolymer-1 obtained in Production Example-1 45.0 parts Carpitol acetate 5.0 parts Dipentaerythritol hexaacrylate 5.0 parts 2-ethylthioxanthone 4.0 parts Benzoin 0 .5 parts barium sulfate 10 parts silica
10 parts Phthalocyanine green 0.5 parts Melan 28J (butylated melamine resin manufactured by Hitachi Chemical) 20.0 parts Total 100.0 parts Photosensitive heat in the same manner as in Example 1 except that the above ingredients were changed. After preparing the curable composition, a solder resist pattern was formed.

Table 1 shows the results of testing the properties of the solder resist resin compositions and solder resist patterns obtained in Examples 1 and 2 and Comparative Examples 1 and 2.

The test method and evaluation judgment for each performance in Table 1 below are as follows.

I) Photosensitivity test After irradiating with ultraviolet rays with a wavelength of 365 nm at a dose of 700 mJ/cm'' using an integrated photometer manufactured by Oak Seisakusho, and developing with each developer at a spray pressure of 2 Kg/cm'' for 60 seconds. The condition of the coating film was visually judged.

0: No change observed at all ○: Slight change on the back surface Δ: Significant change on the surface ×: The coating film falls off 2) Developability test Each sample was passed through a photomask at 365r+m The amount of ultraviolet irradiation with a wavelength of 75
0 + iJ/co+'' irradiated test pieces were used, and after developing with each developer at a spray pressure of 2 Kg/cn+'' for 60 seconds, the state in which the unexposed areas were removed was visually determined.

0: Completely developed ○: There is a thin undeveloped area on the back surface Δ: There is some undeveloped area on the entire surface X: Barely developed 3) Adhesion test The amount of irradiated ultraviolet light with a wavelength of 365 nm was measured at 700 nm using an integrated light meter manufactured by Seisakusho.
mJ/c+s" irradiated material was developed with each developer at a spray pressure of 2 g/cm" for 60 seconds, and then post-cured under each condition to make a test piece.
A cross cut was made in the pattern of the substrate according to the test method of JIS D 0202, and then the state of peeling after a peeling test with cellophane tape was visually judged.

0: 100/l with no peeling at all 0:
100/100 with a slight peeling of the cross cut Δ: 50/100 to 90/100x: 0/1
00~50~100 4) Pencil hardness test The same test pieces as the adhesion test were tested according to JIS 54.
Hardness was measured according to the test method of 00 under a load of IKg.

5) Solder resistance test Each test piece is the same as the adhesion test.

According to the test method of JIS C6481, 260 @
The state of the coating film was evaluated after being immersed in the solder bath C for 10 seconds once, three times, and five times.

6) Insulation Resistance Measurement Using a comb-shaped test pattern of 0.318 mm, test pieces were prepared under the same conditions as in the adhesion test, and the insulation resistance was measured initially and after boiling for 1 hour and absorbing moisture.

Table 1 As is clear from the results shown in Table 1, the photosensitive thermosetting resin compositions using the methylated melamine resins obtained in the Examples of the present invention were excellent in both photosensitivity and developability. The resulting solder resist pattern had superior adhesion, hardness, and solder resistance compared to conventional epoxy resin patterns. Further, when a butylated melamine resin was used as in Comparative Example 2, the developability decreased.

Production Example-2 Phenol novolac type epoxy resin with an epoxy equivalent of 210 (Evicron N-865 manufactured by Dainippon Ink and Chemicals)
1105 parts and 130 parts of cellosolve acetate were heated (170 to 80°C) in the same apparatus as in Production Example-1, and dissolved.
To this, 120 parts of 4°-hydroxychalcone and 3.5 parts of benzyltrimethylammonium bromide (catalyst) were added and reacted at 125-130'C for 15 hours.Next, the reaction system was cooled to 80°C. Add 40 parts of hexahydrophthalic anhydride and react at 90 to 95°C for 10 hours, and the acid value of the solid content is 60 mg K, OH/g. An organic solvent solution (solid content: 67%) of the adduct (photosensitive prepolymer 2) was obtained.

Examples 3 to 8, Comparative Example 3 Solution of photosensitive prepolymer 1 obtained in Production Example-1 Solution of photosensitive prepolymer 2 obtained in Production Example-2 Carpitol Acetate Pentaerythritol Tetraacrylate Dimethyl Benzyl Ketal 2 -Ethylanthraquinone Aerosil #200 Talc sulfate barium phthalocyanine 15.0 parts 1000 parts 35.0 parts 1000 parts 3.0 parts 2.0 parts 1.5 parts 10.0 parts 13.0 parts 0.5 parts J- 5 parts (Example 3), 10 parts (Example 4), 20 parts (Example 5), 40 parts (Example 6), 60 parts (Example 7),
A formulation containing 100 parts (Example 8) was prepared and evaluated in the same manner as in Example 1. The results are summarized in Table 2.

Total: 100.0 parts In the above table (Comparative Example 3), methylated melamine Table 2 1) to 5) As is clear from the results shown in Table 2, which is the same as Table 1, the present invention The photosensitive thermosetting resin composition has excellent photosensitivity, developability, adhesion, hardness, and heat resistance.

(Effects) As described above, the photosensitive thermosetting resin composition according to the present invention has resistance to developer in the exposed area due to the use of water-soluble or water-dispersible melamine resin as the thermosetting resin component. It is a photosensitive thermosetting resin composition that has excellent photosensitivity and has good developability in unexposed areas. Furthermore, by using such a photosensitive thermosetting resin composition, it is possible to form a solder resist pattern with excellent adhesion, hardness, soldering heat resistance, and electrical insulation by exposing, developing, and then thermally curing. can do.

Claims (1)

[Claims] 1. (A) a photosensitive prepolymer having at least two ethylenically unsaturated bonds in one molecule (B) a photopolymerization initiator (C) a photopolymerizable vinyl polymer as a diluent as well as/
Alternatively, a photosensitive thermosetting resin composition comprising an organic solvent and (D) a water-soluble or water-dispersible melamine resin. 2. The composition according to claim 1, wherein the blending ratio of the photosensitive prepolymer and melamine resin is 95:5 to 10:90 (solid content ratio on a weight basis). 3. Claim 1, wherein the amount of the diluent is 20 to 300 parts by weight per 100 parts by weight of the photosensitive prepolymer.
The composition described in Section. 4. The composition according to claim 1, which contains an inorganic filler. 5. The photosensitive prepolymer is (a) a reaction product of a secondary hydroxyl group of an esterified product produced by an esterification reaction between a novolac type epoxy compound and an unsaturated monocarboxylic acid and a saturated or unsaturated polybasic acid anhydride. (b) a reaction product of a secondary hydroxyl group of an etherified product produced by the etherification reaction of a novolak-type epoxy compound and an unsaturated phenol compound and a saturated or unsaturated polybasic acid anhydride. Claim 1, which is at least one photosensitive prepolymer.
The composition described in Section. 6. (A) a photosensitive prepolymer having at least two ethylenically unsaturated bonds in one molecule; (B) a photoinitiator; (C) a photopolymerizable vinyl monomer as a diluent; and/or
or an organic solvent; (D) A photosensitive thermosetting resin composition containing a water-soluble or water-dispersible melamine resin is applied to the entire surface of a printed wiring board, and actinic light is selectively applied through a patterned photomask. 1. A method for forming a solder resist pattern for a printed wiring board, the method comprising exposing the melamine resin to light, developing the unexposed portions with a developer to form a pattern, and then heating the melamine resin to thermally cure the melamine resin.