JP2000347402A - Resist composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a soldering resist making shock and heat resistances and reliability of electrical insulation compatible, excellent in work efficiency and developable with an aqueous alkali solution by blending a specified reaction product, a photopolymerization initiator, a specified thermosetting component, fine particles of an elastic polymer having carboxyl groups and a volatile organic solvent. SOLUTION: The resist composition is obtained by blending a reaction product of a reactant comprising an epoxy compound and an unsaturated monocarboxylic acid with an anhydrous polybasic acid, a photopolymerization initiator, a thermosetting component having two or more epoxy groups in one molecule, fine particles of an elastic polymer having carboxyl groups and a volatile organic solvent. The resist composition is applied on a printed wiring board by screen printing or another method and irradiated with active energy beams to cure the necessary part and then the unexposed part is dissolved and removed with an aqueous weak alkali solution to form the objective soldering resist as a permanent film having high flexibility and heat resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist composition suitable for producing printed wiring boards,
The present invention relates to a resist composition useful for a solder resist excellent in reliability such as heat resistance, adhesion to copper, electric characteristics, flame retardancy and impact resistance.

[0002]

2. Description of the Related Art As electronic devices have become smaller and more multifunctional,
Currently, printed wiring boards are moving toward higher densities. For example, bare chip or chip size package (C
As for the multi-chip module in which a plurality of SPs are mounted, a multi-chip module based on a resin substrate, which is excellent in mass productivity, from a conventional device base and a ceramic base, is desired. A solder resist excellent in high resolution, high heat resistance and high reliability is required for such a high-density mounting substrate.

As a solder resist, Japanese Patent Publication No. 1-54
No. 390 discloses a resist ink composition. This is (A) an active energy ray-curable resin obtained by reacting a reaction product of a novolak type epoxy compound with an unsaturated monocarboxylic acid and a saturated or unsaturated polybasic acid anhydride, and (B) a photopolymerization. Photocurable and thermosetting liquids containing an initiator, (C) a diluent, and (D) a thermosetting component comprising an epoxy compound having two or more epoxy groups in one molecule and developable with an alkaline solution. It is a resist ink composition.

This composition is excellent in the hardness of the solder resist, but inferior in flexibility. For example, when the above liquid resist is formed on a thin printed wiring board by high-density wiring and used as a solder resist. , Sled,
Cracks were sometimes formed in the solder resist due to torsion or impact during mounting. When cracks occur, the solder may adhere to unnecessary portions during soldering, or the conductor may corrode due to moisture absorption and the insulation between the conductors may decrease.

[0005]

SUMMARY OF THE INVENTION The present inventors have repeatedly studied a composition capable of preventing the occurrence of cracks in the solder resist and a method for imparting good adhesion between the resin layer and copper. That is, an object of the present invention is to provide a solder resist which is compatible with impact resistance, heat resistance, electrical insulation reliability and the like, and which is excellent in workability and which can be developed with an alkaline aqueous solution.

[0006]

The present invention provides (1) a reaction product of a reactant comprising an epoxy compound and an unsaturated monocarboxylic acid with a polybasic anhydride (hereinafter referred to as "first component"), 2) a photopolymerization initiator (hereinafter referred to as "second component"); and (3) a thermosetting component comprising a compound having two or more epoxy groups in one molecule (hereinafter referred to as "third component"). ), (4) a resist comprising a carboxyl group-containing elastic polymer fine particle (hereinafter referred to as “fourth component”), and (5) a volatile organic solvent (hereinafter referred to as “fifth component”). Achievable by the composition

The resist composition of the present invention is applied on a printed wiring board by a screen printing method, a roll coating method, a curtain coating method, or the like, and is irradiated with active energy rays to cure a necessary portion. A resist pattern film is formed by dissolving and removing the unexposed portion, and a solder resist as a permanent film having high flexibility and high heat resistance can be formed by heat curing.

That is, a copolymerization reaction occurs between the epoxy group of the third component and the free carboxyl group present on the side chain of the first component, and the heat resistance, solvent resistance, plating resistance,
Adhesive properties with copper foil, electrical properties, hardness, etc. are obtained, and the elastic polymer fine particles having a carboxyl group, which is the fourth component, enter, causing stress such as thermal shock, mechanical shock, warpage, etc. A resist composition that is less likely to crack can be obtained. Here, the fine particles having a carboxyl group are suitable because the resist composition in the unexposed portion is not easily dissolved in the development after exposure if the polymer fine particles merely have elasticity.

The first component of the present invention is a base material for obtaining solubility in an alkaline solution. The second component is a component that crosslinks the resin by irradiation with active energy rays such as ultraviolet rays. The third component is used for curing the resin by heat and reinforcing the resin. The fourth component is for obtaining flexibility of the resin. The fifth component is an organic solvent for coating the resist composition.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The first component is a reaction product of a reactant composed of an epoxy compound and an unsaturated monocarboxylic acid with a polybasic anhydride, and is a component having a carboxyl group and being alkali-soluble. Among them, those that are solid at room temperature,
The resist composition of the present invention is suitable in that the surface of the coating film can be tack-free. Among the first components that are solid at room temperature,
The softening point is preferably 20 to 120 ° C, more preferably 4 ° C.
Those in the range of 0 to 100 ° C are more suitable.

The reactant composed of the epoxy compound and the unsaturated monocarboxylic acid, which are the raw materials of the first component, generally has a compound having at least one epoxy group in one molecule and a compound having an unsaturated bond and a carboxyl group in one molecule. A compound having an unsaturated bond and a hydroxyl group in the molecule. The reactant comprising the epoxy compound and the unsaturated monocarboxylic acid used in the present invention preferably contains substantially no unreacted epoxy group and at least two unsaturated bonds. When a reactant comprising an epoxy compound and an unsaturated monocarboxylic acid containing an unreacted epoxy group is used as a raw material of the first component, when the hydroxyl group is reacted with a polybasic anhydride, the reaction with the epoxy group may occur. The possibility of gelling due to concurrent reactions increases, and the possibility of gelling during storage increases. Those containing only one unsaturated bond have low mechanical strength of the coating film obtained by exposure, and the cured product may peel off or meander during development.

The compound having at least one epoxy group, which is one raw material of a reaction product comprising an epoxy compound and an unsaturated monocarboxylic acid, includes bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, and phenol Novolak-type epoxy resins, cresol novolak-type epoxy resins, glycidylamine-type epoxy resins such as tetraglycidylaminodiphenylmethane, and alicyclic epoxy resins. The unsaturated monocarboxylic acids to be reacted therewith include acrylic acid, methacrylic acid, acid anhydrides such as phthalic anhydride, tetrahydrophthalic anhydride or succinic anhydride, and hydroxyethyl acrylate and / or hydroxyethyl methacrylate. (Hereinafter, “acrylate and / or methacrylate” will be referred to as “(meth) acrylate”.), A reaction product with a hydroxyl group-containing (meth) acrylate such as pentaerythritol (meth) acrylate, acrylic acid dimer, crotonic acid and cinnamic acid And the like. From the viewpoints of curability at the time of exposure, heat resistance of the final coating film, etc., the compound having at least one epoxy group is a phenol novolak type epoxy resin or a cresol novolak type epoxy resin, and the unsaturated monocarboxylic acid is acrylic. Acid and / or methacrylic acid (hereinafter referred to as “(meth) acrylic acid”) are preferred.

The reaction between the reactant comprising the epoxy compound and the unsaturated monocarboxylic acid and the polybasic anhydride can be performed under the conditions known for the reaction between the compound having a hydroxyl group and the polybasic anhydride. The polybasic anhydride is preferably 0.1 mol or more and 1.0 mol or less, more preferably 0.2 mol or more and 0.1 mol or less with respect to 1 mol of the hydroxyl group of the reactant comprising the compound and the unsaturated monocarboxylic acid.
The reaction is performed in a proportion of 9 mol or less. 0.1 polybasic anhydride
When the amount is less than mol, the developability of the resist composition of the present invention with an alkaline aqueous solution is likely to be reduced. on the other hand,
When an amount of the polybasic anhydride exceeding 1.0 mol is reacted,
Unreacted polybasic anhydride will remain in the first component,
Crystallization of unreacted polybasic anhydride or, in many cases, reaction between the hydroxyl group remaining in the first component and unreacted polybasic anhydride occurs during storage, so that the storage stability of the resist composition of the present invention is improved. There is a possibility that the property is reduced.

The polybasic anhydride as the other raw material of the first component includes maleic anhydride, phthalic anhydride, succinic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, and hexahydrophthalic anhydride. Acid, 2,6-endomethylenetetrahydrophthalic anhydride, dodecylsuccinic anhydride, nonylsuccinic anhydride, trimellitic anhydride and the like. The reactant comprising the epoxy compound and the unsaturated monocarboxylic acid and the polybasic anhydride are preferably at 50 to 150 ° C, more preferably at 80 to 12 ° C.
The reaction is carried out at a temperature of 0 ° C. for usually 0.1 to 10 hours, preferably 0.5 to 5 hours. Further, in this reaction, known catalysts such as tertiary amines, quaternary ammonium salts, triethylamine and tetrabutylammonium bromide can be used.

The second component, a photopolymerization initiator, is known to initiate radical polymerization by irradiation with ultraviolet light or the like. Specifically, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin Benzoin and benzoin alkyl ethers such as isopropyl ether; acetophenol, 2,2-dimethoxy-2-acetophenone, 2,2-diethoxy-
Acetophenones such as 2-acetophenone and 1,1-dichloroacetophenone; 2-methylanthraquinone, 2
-Anthraquinones such as -ethylanthraquinone, 2-tert-butylanthraquinone, 1-chloroanthraquinone and 2-amylanthraquinone; 2,4-dimethylthioxane, 2,4-diethylthioxanthone, 1-chlorothioxanthone and 2,4-diisopropyl Thioxanthones such as thioxanthone; ketals such as acetophenone dimethyl ketal and benzyl dimethyl ketal;
Benzophenones such as benzophenone, xanthone, 2
And carbonyl compounds such as -methyl- (4- (methylthio) phenyl) -2-morpholino-1-propanone. The preferred amount of the second component is the solid content of the resist composition of the present invention, that is, the first component, the third component and the fourth component.
0.2 to 20 parts by weight per 100 parts by weight of the total components,
More preferably, it is 2 to 10 parts by weight. If less than 0.2 parts by weight, the mechanical strength of the coating film obtained by exposure is weak, and the cured product may peel or meander during development,
On the other hand, when the amount exceeds 20 parts by weight, a large amount of the photopolymerization initiator not used at the time of exposure remains in the coating film, and the physical properties such as heat resistance of the coating film may be deteriorated. The second component is preferably used in combination with one or more known photopolymerization accelerators such as benzoic acid or tertiary amine.

Specific examples of the thermosetting component comprising a compound having two or more epoxy groups in one molecule, which is the third component of the resist composition of the present invention, include bisphenol A epoxy resin and bisphenol F epoxy resin. Resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin,
A glycidylamine type epoxy resin such as tetraglycidylaminodiphenylmethane or an alicyclic epoxy resin is exemplified. Further, a small amount of a curing accelerator such as an amine compound, an imidazole compound, a carboxylic acid, a phenol, a quaternary ammonium salt or a methylol group-containing compound may be used in combination therewith to promote the reaction. The epoxy group of the third component easily reacts with the carboxyl group of the reaction product of the reaction product of the first component epoxy compound and the unsaturated monocarboxylic acid with the polybasic anhydride to form the resist composition of the present invention. This has the effect of reducing the water absorption of the material and increasing the adhesion to copper. The amount of the third component is
10 to 6 parts by weight per 100 parts by weight of the resist composition of the present invention
The amount is preferably 0 parts by weight, more preferably 20 to 50 parts by weight. The amount of the curing accelerator is preferably 1 to 20 parts by weight based on 100 parts by weight of the third component.

Elastic polymer fine particles containing a carboxyl group as the fourth component are uniformly dispersed in the cured product of the resist composition of the present invention to form a structure corresponding to an island having a sea-island structure. It is blended mainly for imparting crack resistance to the cured resist composition of the present invention. That is, even if the resist composition of the present invention is subjected to an impact at room temperature or a stress at the time of heating to cause partial destruction of the resin, the destruction occurs at the island portion of the sea-island structure, that is, at the interface of the elastic polymer fine particles. It is considered that the fracture does not extend to stop the crack, and the crack hardly occurs.

The average particle size of the elastic polymer fine particles is preferably less than 1 μm by a volume standard method. At 1 μm or more,
In the resist composition of the present invention, the dispersibility of the component becomes poor. More preferably, it is 0.1 μm or less.

The fourth component is a crosslinked acrylic rubber having a carboxyl group, a crosslinked NB having a carboxyl group.
A crosslinked MBS resin having R and a carboxyl group is exemplified. Among them, a crosslinked acrylic rubber having a carboxyl group and a crosslinked NBR having a carboxyl group, which are soluble in an alkaline solution, are preferred because they are easily available and contribute to improving the adhesion between the solder resist and the copper foil. In addition, a crosslinked acrylic rubber is more preferable because the resist composition of the present invention improves both the insulating property when cured and the alkali solubility when uncured. The amount of the fourth component is preferably in the range of 5 to 40% by weight of the entire resist composition of the present invention so that the resist composition of the present invention can obtain sufficient impact resistance. When the amount is more than 40% by weight, there is no problem in terms of impact resistance. However, when the resist composition of the present invention is applied and dried on the inner layer panel, coating unevenness and air bubbles are apt to occur. Absent.

In the case where the resist composition of the present invention is mixed with a solvent to produce an ink, if the fourth component is soluble in the solvent in the ink, it becomes difficult for the fourth component to aggregate and disperse uniformly in the solvent. When the alkali is dissolved, the aggregates are likely to remain without being dissolved. Further, when the fourth component is completely dissolved in the ink, a portion corresponding to the island having the above-mentioned sea-island structure is not formed, so that cracks are easily generated. In addition, since the soft component attributed to the fourth component remains in the sea portion of the sea-island structure, the resist composition of the present invention lowers the glass transition temperature (Tg) of the cured product, resulting in high-temperature physical properties. Is undesirably reduced. For this reason, the fourth component is preferably insoluble or hardly soluble in a solvent used for producing the ink. Specifically, the fourth component can be made insoluble or hardly soluble by forming a crosslinked structure. In addition, the effect of increasing the stability in the ink is exhibited by forming a crosslinked structure.

By combining a reaction product of a first component, a reaction product comprising an epoxy compound and an unsaturated monocarboxylic acid, with a polybasic anhydride, and a fourth component, a crosslinked elastic polymer fine particle having a carboxyl group, The solubility of the uncured resist composition of the present invention when dissolved and removed with an alkaline aqueous solution or the like is remarkably improved. This is thought to be due to the fact that the fourth component has a carboxyl group and thus is originally excellent in alkali solubility, and because it is crosslinked, it is easily dispersed in a sea-island state in the resist composition of the present invention. Can be

The uncrosslinked elastic polymer fine particles having a carboxyl group do not form a sea-island shape because they are mixed with a reactant composed of an epoxy compound and an unsaturated monocarboxylic acid and other components such as a crosslinking agent, and are dissolved and removed with an alkaline aqueous solution or the like. When the resin composition of the present invention is cured, cracks are likely to occur when the resin composition of the present invention is cured.

Even when a crosslinked elastic polymer containing no carboxyl group is used, the uncured resist resin layer can be removed by the carboxyl group contained in the first component, but it is difficult to dissolve it uniformly. Then, the resin swollen by the spraying force of the alkali developing machine is removed so as to be peeled off. For this reason, when developing with alkali,
If crosslinked elastic polymer fine particles containing no carboxyl group are used in place of the fourth component, there is a problem that the shape of the resist wall surface is extremely deteriorated and the resolution of the resist is significantly reduced.

As a method of dispersing the fourth component in the resist composition of the present invention, each component is previously added to a solvent such as methyl ethyl ketone and dispersed by a homomixer or the like, and then the resist composition of the present invention is constituted. It is preferable that secondary aggregation of the fine particles is loosened by blending other components or blending the fourth component, the solvent, and the other components, and then dispersing with a homomixer. Further, as another method, a three-roll, ball mill or the like is also suitable. When the resist composition of the present invention is used as an ink while secondary aggregation is not sufficiently loosened, the fourth component is separated in the ink and storage stability of the ink is significantly reduced. Even when coated on an inner layer panel having a circuit pattern, it is difficult to obtain a uniform coating film, insulation reliability is reduced, and the formation of fine circuits formed on the surface may be significantly impaired.

In order to make the resist composition of the present invention have a viscosity suitable for printing, a volatile organic solvent is added as a fifth component. Here, the term “volatile” means that the organic solvent concentration in the applied resist layer becomes 1% or less by heating at 60 to 100 ° C. for 10 to 30 minutes. Specific examples of the volatile organic solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene and xylene; cellosolve;
Cellosolves such as butyl cellosolve; sorbitols such as carbitol and butyl carbitol; and acetates such as ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, power rubitol acetate and futyl carbitol acetate. Can be used alone or in combination of two or more.

In order to impart flame retardancy to the resist composition of the present invention, as a sixth component, a reaction product of glycidyl ether of a halogenated phenol compound with (meth) acrylic acid and / or a seventh component It is preferable to add phosphorus or a phosphorus-based flame retardant.

Specific examples of the reaction product of the glycidyl ether of the halogenated phenol compound, which is the sixth component, and (meth) acrylic acid include a reaction product of tetrabromobisphenol A diglycidyl ether and (meth) acrylic acid.
A reaction product of a tetrabromobisphenol A skeleton and an epoxy resin (for example, DER514 manufactured by Dow) containing both bromine-free bisphenol A and (meth) acrylic acid may be used. If desired, two or more kinds may be used. it can. Further, compounds having different bromine substitution numbers per bisphenol A skeleton, such as a monobromo compound and a dibromo compound, contained as by-products of tetrabromobisphenol A may be present. Further, a reaction product of a monofunctional brominated epoxy resin (for example, BROC series manufactured by Nippon Kayaku Co., Ltd.) and (meth) acrylic acid or a polyfunctional brominated epoxy resin (for example, BREN series manufactured by Nippon Kayaku Co., Ltd.) A reaction product of (meth) acrylic acid and (meth) acrylic acid can also be used. Among them, a bifunctional compound which can impart both strength and appropriate flexibility when incorporated into the resist composition of the present invention is preferable, and bromine as a type of halogen has excellent flame retardancy. Therefore, it is particularly preferable. The compounding amount of the sixth component is preferably such that the bromine content is 5 to 25% by weight in the resist composition of the present invention.

If the bromine content is less than 5% by weight, the flame retardancy of the cured product cannot be sufficiently obtained with the resist composition of the present invention unless 2% by weight or more of phosphorus derived from the seventh component described below is added. It is not preferable to mix a large amount of phosphorus because the insulating property is reduced. When the amount of bromine is more than 25% by weight, flame retardancy can be obtained, but the halogen compound is liable to be removed during heating, and solder heat resistance and long-term reliability are undesirably reduced. For this purpose, the following phosphate esters are used in combination.

Specific examples of the phosphate ester as the seventh component include tricresyl phosphate, tri (2,6-dimethylphenyl) phosphate (PX130 manufactured by Daihachi Chemical Industry Co., Ltd.), and triaryl phosphate (Ajinomoto ( Reophos) available from Co., Ltd. can be used, and if desired, two or more kinds can be added. Red phosphorus, which is a simple substance of phosphorus, also has a high flame-retardant effect, and its fine powder such as Hishigard CP manufactured by Nippon Chemical Industry Co., Ltd. can be used.

The compounding amount of the seventh component is preferably such that the phosphorus content in the resist composition of the present invention is in the range of 0.1 to 2% by weight. When the phosphorus content is less than 0.1% by weight, flame retardancy cannot be obtained unless a larger amount of a bromine compound is added, so that a large amount of halide decomposed products are generated during soldering, and heat resistance is reduced. Not enough, 2% by weight
If it exceeds, the electrical insulation tends to deteriorate.

Further, the resist composition of the present invention may contain an acryloyl group and / or a methacryloyl group (hereinafter referred to as “(meth) acryloyl group”) as a desired component in order to adjust the viscosity or increase the curability by irradiation with ultraviolet rays. ) May be added.

Specific examples of the compound having at least one (meth) acryloyl include β-hydroxyethyl (meth)
Acrylate, β-hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol Di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, trimethylol Propane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) a Relate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate and tris-2-acryloyloxyethyl isocyanurate, polybasic acid And hydroxylacryl (meth) acrylate having a condensation degree of 1 or more, epoxy (meth) acrylate and urethane (meth) acrylate having at least one (meth) acryloyl group in a molecule, and the like.

Further, a thermal polymerization initiator may be added to the resist composition of the present invention in order to enhance thermosetting properties. Examples of the thermal polymerization initiator include an organic peroxide type and an azobis type. Among these, dialkyl peroxides are preferred from the viewpoint that storage stability is good due to a high decomposition initiation temperature, and the generation of low-molecular-weight volatile components is small when decomposed.Specifically, dicumyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexine and the like. . The amount is preferably 0.5 to 5 parts by weight based on 100 parts by weight of the resist composition of the present invention. If the amount is less than 0.5 part by weight, the polymerization is insufficient. If the amount exceeds 5 parts by weight, the shelf life is shortened and the amount of the decomposition product of the initiator is increased, so that the heat resistance may be impaired.

In the resist composition of the present invention, if necessary, fillers such as barium sulfate, silicon oxide, talc, silica, and calcium carbonate that are conventionally widely used in this type of composition; phthalocyanine green And various additives such as color pigments such as phthalocyanine blue, titanium oxide and carbon black; dyes; defoamers; adhesion-imparting agents or leveling agents. Further, a polymerization inhibitor such as hydroquinone, hydroquinone monomethylethyl, pyrogallol, tert-butylcatechol, and phenothiazine may be added.

When the resist composition of the present invention is used as a solder resist, it is applied to the entire surface of a printed wiring board by a screen printing method, a roll coating method, a curtain coating method, or the like, and the coated film surface is covered with a photomask and irradiated with ultraviolet rays. To cure the coating by radical polymerization. Since the resist composition of the present invention uses an organic solvent as a diluent, it is desirable to remove the solvent by performing preliminary drying before irradiating with ultraviolet rays. When the surface of the coating film becomes tack-free due to the preliminary drying, the photomask is brought into close contact with the coating film surface and irradiated with ultraviolet rays. As a light source for irradiating ultraviolet rays, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, or a metal halide lamp is suitable, and irradiation conditions may be in accordance with ordinary methods. After irradiating with ultraviolet rays as described above, by using an aqueous solution of an alkali such as sodium carbonate or sodium hydroxide as a developing solution, fine particles in an uncured state without being exposed to ultraviolet rays can be easily dissolved and removed. be able to.
Thereafter, if necessary, the curing reaction in the composition is completed by heating to form a resist pattern. Preferred conditions for such heat curing are temperatures of 100 ° C to 200 ° C, more preferably 120 ° C to 180 ° C,
The heating time is between 10 minutes and 2 hours.

[0036]

Next, the present invention will be described more specifically with reference to examples and comparative examples.

Example 1 In a four-necked flask equipped with a thermometer, a stirrer, and a cooler, 850 phenol novolak epoxy resin YDPN-704 manufactured by Toto Kasei KK was added.
g (4.08 epoxy equivalent) and 624 g of butyl cellosolve acetate as a solvent were mixed and heated to 110 ° C. to obtain a uniform solution. 0.52 g of phenothiazine as a polymerization inhibitor, 10.4 g of tetrabutylammonium bromite as a catalyst and 294 g of acrylic acid were added to this liquid.
(4.08 carboxy equivalents) were added, and the mixture was reacted at 110 ° C. while blowing air to produce an epoxy acrylate. When the consumption rate of acrylic acid was measured by measuring the acid value of the reaction solution, the decrease in the acid value disappeared in about 9 hours, and the consumption rate of acrylic acid calculated from the acid value became almost 100%. Was. To the epoxy acrylate solution obtained above, 302 g of phthalic anhydride (2
Mol) and the reaction was carried out at 110 ° C. After the phthalic anhydride in the reaction solution was completely dissolved, the reaction was further performed for 3 hours. To this solution was added 159 g of butyl cellosolve acetate,
A reaction product (first component) of the epoxy acrylate and the polybasic anhydride was obtained as a solution having a solid content of 65%.

With respect to 100 parts by weight (solid content) of the first component, the following components are used in accordance with the following compounding ratio and kneaded with these three rolls to obtain a resist composition having a solid content of 66%. It was adjusted. Second component (photopolymerization initiator): 2-methyl (4- (methylthio) phenyl) -2-morpholino-1-propanone (trade name “Irgacure 907” manufactured by Ciba Geigy) 5
2 parts by weight and 2,4-diethylthioxanthone (trade name "Kayacure DETEX" manufactured by Nippon Kayaku Co., Ltd.) Third component (thermosetting component): Yuka Shell Epoxy Co., Ltd.
80 parts by weight of Bisphenol A type epoxy resin trade name "Epicoat 1001" 4th component (elastic polymer fine particles): 40 parts by weight of acrylic rubber fine particles "DHS2" manufactured by Nippon Synthetic Chemical Co., Ltd. 5th component: 20 parts by weight of butyl cellosolve acetate Sixth component (flame retardant): brominated epoxy methacrylate
40 parts by weight Component 7 (flame retardant aid): Phosphate ester 6 parts by weight

This resist composition is applied to a copper through-hole printed wiring board by screen printing to a thickness of 20 to
The coating was applied at 30 μm and the coating was dried at 75 ° C. for 30 minutes.
A photomask was applied to the coating film thus prepared, and the coating film was exposed to light at a light amount of 500 mJ / cm ² by a photo solder double-side printing machine.

(Comparative Example 1) The following components were used according to the following mixing ratio with respect to 100 parts by weight (solid content) of the first component prepared in Example 1, and these were kneaded with a three-roll mill. To prepare a curable composition having a solid content of 66%. Second component (photopolymerization initiator): 5 parts by weight of 2-methyl (4- (methylthio) phenyl) -2-morpholino-1-propanone (trade name “Irgacure 907” manufactured by Ciba Geigy) and 2,4-diethylthioxanthone [Nippon Kayaku Co., Ltd. product name "Kaya Cure DETEX" 2 parts by weight Third component (thermosetting component): Yuka Shell Epoxy Co., Ltd. product name "Epicoat 1001" 80 parts by weight Fifth component: butyl cellosolve acetate 20 Parts by weight Component 6 (flame retardant): Brominated epoxy methacrylate
40 parts by weight Component 7 (flame retardant aid): Phosphate ester 6 parts by weight

The curable composition is applied to a printed wiring board based on a glass epoxy laminate having a thickness of 0.4 mm by a screen printing method to a thickness of 20 to 30 μm.
Dry at 5 ° C. for 30 minutes. A photomask was applied to the coating film thus prepared, and the coating film was exposed to light at a light amount of 500 mJ / cm ² by a photo solder double-side printing machine.

(Various Evaluations) Next, the printed wiring board samples prepared as described above were subjected to a pencil hardness test and a cross-cut test according to JIS D0202, and were placed in a molten solder bath at a bath temperature of 260 ° C. for 60 seconds. As a result of checking whether the solder resist floated or peeled off, no abnormality was found in both Example 1 and Comparative Example 1. The surface insulation resistance was measured using the J pattern of the test pattern for a multilayer printed wiring board specified in JIS-C5012. As a result, the initial value was 10 ¹² Ω to 10 ¹³ Ω.
And after moisture resistance (C-96 / 850/85, BIAS 50
VDC) is 10 ¹¹ to 10 ¹² Ω in both the example and the comparative example.
Met.

The cured product of each composition was set on a mini desk press manufactured by Kamekura Seiki Co., Ltd. so that the male mold first hit it, and the substrate was punched out with a 2 cm square punching die and dropped out (2 cm square).
Was observed under a microscope to check for cracks. FIG. 1 (Example 1) and FIG. 2 (Comparative Example 1) show micrographs of corners of the punched test piece. In FIG. 1, the resist portion was good without cracks, but in FIG. 2, several arc-shaped streaks (cracks) were observed in the resist portion centered on the corners. In each of the drawings, a black portion seen around the substrate is a defective portion generated at the time of punching.

[0044]

The resist composition according to the present invention is a resin composition having crack-free flexibility, impact resistance, heat resistance, flame retardancy and insulation reliability. From the above, the present invention can provide a resist composition which can be used for an electronic device mounting board having excellent reliability, and therefore has great industrial utility value.

[Brief description of the drawings]

FIG. 1 is a photomicrograph of a corner of a substrate on which a punching test of Example 1 was performed.

FIG. 2 is a micrograph of a corner portion of a substrate on which a punching test of Comparative Example 1 was performed.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03F 7/004 501 G03F 7/004 501 7/028 7/028 F-term (Reference) 2H025 AA00 AA10 AA14 AA20 AB15 AC01 AD01 BC74 BC85 CC03 CC08 CC20 FA03 FA17 4J011 QA37 QB19 QB20 QB22 QC05 RA05 RA11 RA12 SA01 SA21 SA51 SA63 SA64 SA90 TA07 UA01 4J036 AD08 AD20 AF01 AF06 AH18 CA20 CA21 HA02 JA09 4J039 AE05 CA07 EA05 GA17

Claims (1)

[Claims] 1. A reaction product of (1) a reaction product comprising an epoxy compound and an unsaturated monocarboxylic acid with a polybasic anhydride, (2) a photopolymerization initiator, and (3) two or more compounds per molecule. A thermosetting component comprising an epoxy compound having an epoxy group,
(4) elastic polymer fine particles having a carboxyl group, and
(5) A resist composition comprising a volatile organic solvent.