JPH04353850A - Production of photosensitive resin composition, photosensitive element, and printed circuit board - Google Patents

Abstract

PURPOSE:To offer a photosensitive resin compsn. which can be developed with a diluted alkali aq. soln. and has excellent property for punching, resolution, heat resistance and resistance against gold plating. CONSTITUTION:This photosensitive resin compsn. consists of a photopolymerizable unsatd. compd.(a), a compd.(b) having at least one epoxy group, and a sensitizer or sensitizer system (c) which produces free radicals by active ray. The compd.(a) is obtd. by allowing secondary hydroxyl groups in the reaction product of novolac type epoxy resin and unsatd. carboxylic acid to react with a satd. or unsatd. polybasic acid anhydride with the acid eq./hydroxyl group eq. ratio ranging from 0.1 to 0.8 and then adding satd. or unsatd. monoisocyanate to the residual hydroxyl groups.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to printed wiring board manufacturing,
The present invention relates to a photosensitive resin composition suitable for forming a protective film in the field of metal precision processing, a photosensitive element using the same, and a manufacturing technique for a printed wiring board using the same to form a protective film.

0002

2. Description of the Related Art Conventionally, in the printed wiring board industry, photosensitive resin compositions having excellent properties have been used for solder masks, resists for chemical plating, and the like. The main purpose of a solder mask is to limit the soldering area during soldering, prevent solder bridging, etc., prevent corrosion of bare copper conductors, and maintain electrical insulation between conductors over a long period of time. .

By the way, as a solder mask, one (printed mask) whose main component is a thermosetting resin such as epoxy resin or aminoplast resin is usually used. but,
In recent years, the wiring density of printed wiring boards has increased, and the requirements for electrical insulation between conductors have also become stricter, and the solder masks used for them are also required to be thick and have excellent dimensional accuracy. It is no longer possible to deal with it.

[0004]Also, a punching machine is used to manufacture a printed wiring board having a solder mask into a predetermined shape, but since the solder mask has poor flexibility, when punching on or near the solder mask, the solder mask may crack. This has the disadvantage of reducing reliability. In order to eliminate this drawback, a large clearance is provided between the solder mask part and the cut part, and a router process is applied. However, the former method is disadvantageous for increasing density;
The latter method requires a long time for processing, and has the drawback of reduced productivity and increased costs.

[0005] Therefore, by using a photographic method in which an image is formed by imagewise exposure and development, it is possible to form a highly reliable solder mask with excellent dimensional accuracy and heat resistance and flexibility, for example, on a conductor with a thickness of about 25 μm. There is a desire for the emergence of a photosensitive resin composition that has excellent properties and that can automate the manufacturing process using the photographic method to obtain an inexpensive cover material.

[0006] Furthermore, as a method for electrically connecting a printed wiring board to the outside, many methods are used in which connecting terminals are formed on the outer periphery of the printed wiring board and inserted into an external connector. requires wear resistance and reliability,
To answer this question, nickel and gold plating is applied.
Generally, this terminal plating is performed after forming a solder mask, so a photosensitive resin composition for a solder mask that has excellent plating resistance is desired.

Conventionally, photosensitive resin compositions for forming solder masks include, for example,
3-56018, JP-A-54-1018, etc.); ■ Photosensitive resin compositions containing photoreactive epoxy resins and epoxy resin curing agents as main components (JP-A-54-1018, etc.);
2-37996, JP 58-62636, JP 62-74920, etc.), ■ Isocyanatoethyl methacrylate modified photosensitive resin composition (JP 61-132947, etc.) ■ Polybasic Acid-modified epoxy acrylate photosensitive resin compositions (Japanese Patent Publication No. 1-54390) are known.

However, the above photosensitive resin composition (2) cannot be used in ordinary film-like photosensitive materials for etching and plating (for example, manufactured by DuPont, trade name Riston, manufactured by Hitachi Chemical Co., Ltd., trade name Photec, etc.). It can be developed with flame-retardant 1,1,1-trichloroethane, which is
A highly sensitive solder mask can be formed, but since such a photosensitive resin composition imparts film properties,
Since a large amount of acrylic polymer is used, there is a drawback that the heat resistance of the cured film is insufficient.

[0009] Also, the above (1) (Japanese Patent Laid-Open No. 52-37996
The photosensitive resin composition described in Japanese Patent Application Laid-open No. 58-62636 is based on an epoxy resin and has excellent heat resistance of the cured film, but it is Since it is insoluble in flame-retardant organic solvents, it is necessary to use a flammable organic solvent such as cyclohexanone as a developer, which is disadvantageous in terms of safety.

Furthermore, the photosensitive resin composition described in JP-A No. 62-74920 can use a flame-retardant developer such as 1,1,1-trichloroethane, but it is said that cracks are likely to occur during punching. There are drawbacks. Furthermore, the above ■
The photosensitive resin composition can be developed with a developer such as 1,1,1-trichloroethane, has excellent resolution and heat resistance, and is mainly composed of talc as disclosed in JP-A-58-62636. When such a filler is mixed, the adhesion between the printed wiring board and the cured film is improved and a highly reliable solder mask is formed, but there is a drawback that the film surface lacks gloss due to damage during development. For this reason, there is a problem in that the solder mask becomes scratched due to external factors before it is used in final products such as electronic parts, which impairs the commercial value of the solder mask.

[0011] Furthermore, since the cured film of the photosensitive resin composition of items (1) to (3) has poor adhesion to the substrate, plating cracking and peeling of the cured film occur during the terminal plating process, resulting in a decrease in reliability. There is a drawback. In order to solve these problems, we reacted an epoxy resin containing polyhydroxyether with an unsaturated isocyanate, and then mixed it with an unsaturated carboxylic acid-modified epoxy resin (Patent Application No.
No. 2398, Japanese Patent Application No. 1-244153, and Japanese Patent Application No. 2-229241) are known. Since the photosensitive resin compositions disclosed in these patents use chlorinated organic solvents as developing solutions, there is a problem of air pollution.

[0012] Therefore, the photosensitive resin composition mentioned in (1) (Japanese Patent Publication No. 1-54390) is known, but it has the drawback that cracks are likely to occur during punching.

[0013]

[Problems to be Solved by the Invention] The present invention eliminates the drawbacks of the prior art, can be developed with a dilute alkaline aqueous solution, has excellent punching workability, and has excellent resolution, heat resistance, and gold plating resistance even in thick films. The present invention provides a photosensitive resin composition capable of forming an excellent and highly reliable solder mask, a photosensitive element using the same, and a method for manufacturing a printed wiring board using the same.

[0014]

[Means for Solving the Problems] The present invention provides (a) adding a saturated or unsaturated polybasic anhydride acid to the secondary hydroxyl group of a reaction product of a novolac type epoxy resin and an unsaturated carboxylic acid in acid equivalents/
React with a hydroxyl group equivalent ratio in the range of 0.1 to 0.8,
A photopolymerizable unsaturated compound obtained by adding a saturated or unsaturated monoisocyanate to a residual hydroxyl group, (b) a compound having at least one epoxy group, and (c) a sensitizer that generates free radicals when exposed to actinic rays. and/or a photosensitive resin composition containing a sensitizer system, a photosensitive element obtained by coating and drying the photosensitive resin composition on a film, and a printed wiring board on which a conductive pattern is formed. A method for producing a printed wiring board, which comprises forming a layer of the photosensitive resin composition and/or the photosensitive element, and then forming a cured film by irradiation with imagewise actinic light, development, and heat curing. .

In the photosensitive resin composition of the present invention, as an essential component (a), a saturated or unsaturated polybasic anhydride is added to the secondary hydroxyl group of a reaction product of a novolac type epoxy resin and an unsaturated carboxylic acid in an acid equivalent amount. / hydroxyl group equivalent ratio from 0.1 to 0.
8, and contains a photopolymerizable unsaturated compound obtained by adding a saturated or unsaturated monoisocyanate to the remaining hydroxyl group.

The novolac type epoxy resin used in the present invention is obtained by reacting, for example, orthocresol, phenol, halogenated phenol, etc. with an aldehyde in the presence of an acid catalyst. It is obtained by reacting epichlorohydrin and is commercially available.

Examples of the orthocresol novolac type epoxy resin include Araldite E manufactured by Ciba Geigy.
CN1299 (softening point 99°C, epoxy equivalent 230),
ECN1280 (softening point 80°C, epoxy equivalent 230)
, ECN1273 (softening point 73°C, epoxy equivalent 230
), EOCN104 manufactured by Nippon Kayaku Co., Ltd. (softening point 90-1
00℃, epoxy equivalent 225-245), EOCN10
3 (softening point 80~90℃, epoxy equivalent 215~235
), EOCN102 (softening point 70-80°C, epoxy equivalent 215-235), EOCN101 (softening point 65-6
9° C., epoxy equivalent: 205 to 225).

Examples of the phenol novolac type epoxy resin include Epikote 154 (epoxy equivalent weight 176 to 181) manufactured by Shell Co., Ltd. and DEN431 manufactured by Dow Chemical Company.
(Epoxy equivalent: 172-179), DEN438 (Epoxy equivalent: 175-182), YDPN manufactured by Toto Kasei Co., Ltd.
-638 (epoxy equivalent 170-190), YDPN-
601 (epoxy equivalent 180-220), YDPN-6
02 (epoxy equivalent: 180 to 220).

Examples of the halogenated phenol novolak type epoxy resin include BREN manufactured by Nippon Kayaku Co., Ltd. (epoxy equivalent: 270-300, bromine content: 35-37%,
Examples include brominated phenol novolak type epoxy resins having a softening point of 80 to 90°C. Further, as the unsaturated carboxylic acid, acrylic acid, methacrylic acid, β-furylacrylic acid, β-styrylacrylic acid, α-cyanocinnamic acid, cinnamic acid, etc. can be used.

[0020] In the production of the photopolymerizable unsaturated compound which is component (a) in the present invention, the addition reaction between the novolak type epoxy resin and the unsaturated carboxylic acid is carried out by a conventional method as shown in the following formula (I). Thus, the acid equivalent/epoxy equivalent ratio is set in the range of 0.1 to 0.8.

[Chemical formula 1]

If the acid equivalent/epoxy equivalent ratio is less than 0.1, the photocured film is likely to swell during development after image exposure. On the other hand, if the ratio of acid equivalent/epoxy equivalent exceeds 0.8, adhesiveness, heat resistance, etc. will decrease.

The addition reaction between a novolac type epoxy resin and an unsaturated carboxylic acid is a known reaction, and can be easily carried out by appropriately setting the conditions. It is dissolved in an inert organic solvent such as acetate, ethyl cellosolve acetate, cyclohexanone, etc., and as a catalyst triethylamine, tri-n-butylamine,
Tertiary amines such as diethylcyclohexylamine, quaternary ammonium salts such as benzyltrimethylammonium chloride, benzyltriethylammonium chloride, etc.
The addition reaction can be carried out by stirring and reacting with the unsaturated carboxylic acid at 70 to 110°C in the equivalence ratio range described above using hydroquinone, p-methoxyphenol, etc. as a polymerization inhibitor. A precursor A of a photopolymerizable unsaturated compound can be obtained.

Examples of the saturated or unsaturated polybasic anhydride to be reacted with the precursor A include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and methyl 2-substituted butenyltetrahydrophthalic anhydride. Phthalic acid, itaconic anhydride, succinic anhydride, citraconic anhydride, alkenylic anhydride, dodecenylsuccinic anhydride, tricarballylic anhydride, maleic anhydride,
Examples include linoleic acid adducts of maleic anhydride, chlorendic anhydride, maleic anhydride adducts of methylcyclopentadiene, and alkylated endoalkylenetetrahydrophthalic anhydride.

In the present invention, the addition reaction between these polybasic acid anhydrides and precursor A is usually carried out at 100 to 150°C to obtain precursor B. From the viewpoint of developability with an alkaline aqueous solution and swellability of the photocured film, it is preferable to carry out a conventional method with the acid equivalent/hydroxyl group equivalent ratio in the range of 0.1 to 0.8.

A saturated or unsaturated monoisocyanate is added to the hydroxyl groups remaining in the polybasic anhydride reactant of precursor B. Saturated monoisocyanates have at least one isocyanate group in one molecule, such as phenyl isocyanate, parachlorophenylisocyanate, orthochlorophenylisocyanate,
Aromatic isocyanate compounds such as methacryl phenyl isocyanate, 3,4-dichlorophenylisocyanate, 2,5-dichlorophenylisocyanate, polymethylene polyphenylisocyanate; methyl isocyanate, chloromethyl isocyanate, ethyl isocyanate, β-chloroethyl isocyanate, n-propylisocyanate, isopropylisocyanate, n-butyl isocyanate, t-butyl isocyanate, pentyl isocyanate, hexyl isocyanate, cyclohexyl isocyanate, t-octyl isocyanate, decyl isocyanate , undecyl isocyanate,
Dodecyl isocyanate, hexadecyl isocyanate, octadecyl isocyanate, phenyl isocyanate, p-bromophenyl isocyanate, m-chlorophenylisocyanate, o-chlorophenylisocyanate, p-chlorophenylisocyanate, 2,5-dichlorophenylisocyanate, 3,4-dichlorophenylisocyanate, α-methylbenzyl isocyanate, α-naphthyl isocyanate, 1-(1-naphthyl)ethyl isocyanate, m-tolyl isocyanate,
Aliphatic isocyanates such as p-tolyl isocyanate, m-trifluoromethylphenyl isocyanate, and isocyanate acetic acid ethyl ester are used. These saturated isocyanate compounds can be used singly or in combination of two or more. Further, among these compounds, it is preferable to use an aliphatic isocyanate compound in order to impart developability to the composition and flexibility to a cured film.

[0026] Unsaturated monoisocyanates have at least one isocyanate group in one molecule, and examples include methacryloyl isocyanate, isocyanatoethyl acrylate, isocyanatopropyl acrylate, isocyanatobutyl acrylate, and isocyanate. Pentyl acrylate, isocyanatohexyl acrylate, isocyanatooctyl acrylate, isocyanatodecyl acrylate, isocyanatooctadecyl acrylate, isocyanatoethyl methacrylate, isocyanatopropyl methacrylate,
Isocyanatobutyl methacrylate, isocyanatopentyl methacrylate, isocyanatohexyl methacrylate, isocyanatooctyl methacrylate,
Isocyanatodecyl methacrylate, isocyanato octadecyl methacrylate, isocyanatoethyl crotonate, isocyanatopropyl crotonate, isocyanatohexyl crotonate, etc. can be used. These unsaturated isocyanate compounds can be used alone or in combination of two or more.

[0027] Precursor B and saturated or unsaturated monoisocyanate are heated at a temperature of usually 0 to 100°C, preferably 20 to 7°C.
A photopolymerizable unsaturated compound (a
) can be obtained. The isocyanate group equivalent/hydroxyl group equivalent at this time is preferably 0.02 to 0.9, more preferably 0.2 to 0.9.

The compound having at least one epoxy group (b) of the present invention includes, for example, a compound represented by the following formula (II).

[Case 2]

The weight average molecular weight of these compounds is 30
The range is preferably from 00 to 10,000, and from 3,500 to 600
A range of 0 is more preferable. Examples of the compound represented by formula (II) include Epicote 1009 (epoxy equivalent weight 2400-3300, average molecular weight 3750) manufactured by Yuka Shell Epoxy Co., Ltd., Epicote 1010 (epoxy equivalent weight 3000-5000, average molecular weight 5500), etc. can be mentioned.

The photosensitive resin composition of the present invention contains essential components (
As c), it contains a sensitizer and/or a sensitizer system that generates free radicals by actinic radiation. As a sensitizer,
For example, 2-ethylanthraquinone, 2-t-butylanthraquinone, octamethylanthraquinone, 1,2-
Substituted or unsubstituted polynuclear quinones such as benzanthraquinone and 2,3-diphenylanthraquinone, ketoaldonyl compounds such as diacetylbenzyl, α-ketaldonyl alcohols and ethers such as benzoin and pivalone,
α-hydrocarbon-substituted aromatic acyloins such as α-phenyl-benzoin and α,α-diethoxyacetophenone, aromatic ketones such as benzophenone and 4,4'-bisdialkylaminobenzophenone, 2-methylthioxanthone, 2, Thioxanthone such as 4-diethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, 2-ethylthioxanthone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propanone-1, etc. are used. , these can be used alone or in combination. Examples of sensitizer systems include 2,4,5-triallylimidazole dimer, 2-methylcaptobenzoquinazole, leuco crystal violet, and tris(4-diethylamino-
A combination such as 2-methylphenyl)methane is used. Further, additives can be used which do not have photoinitiation properties by themselves, but which, when combined with the above-mentioned substances, improve the photoinitiation performance as a whole. Examples of these additives include tertiary amines such as triethanolamine for benzophenone, isoamyl dimethylaminobenzoate, N-methyldiethanolamine, and bisethylaminobenzophenone for thioxanthone.

In the photosensitive resin composition of the present invention, (a
), (b) and (c) components are (a) component 1
00 parts by weight, component (b) 2 to 20 parts by weight, (c
) component is preferably 1 to 10 parts by weight from the viewpoint of heat resistance, adhesion, solvent resistance, etc.

The photosensitive resin composition of the present invention includes, for example,
Dicyandiamide, guanidine, aminoguanidine, 1
, 1,3,3-tetramethylguanidine, n-dodecylguanidine, 1,6-diguanidinohexane, methylolguanidine, biguanide, 1-phenylguanidine,
Heat resistance and adhesion can be improved by adding guanidine compounds such as 1,3-diphenylguanidine, 1,3-di-o-tolylguanidine, 1-o-tolyl biguanide, and 1-benzyl-2,3-dimethylguanidine. , preferred in terms of solvent resistance. The amount used is preferably 0.1 to 10 parts by weight per 100 parts by weight of component (a).

The photosensitive resin composition of the present invention includes, for example,
2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 2,4-diamino-6
-[2-undecyl-imidazole (1)]-ethyl-
It is preferable to add imidazole compounds such as s-triazine and 2-methylimidazole in terms of heat resistance, adhesion, and solvent resistance. The amount used is (a) 100
It is preferably 0.1 to 10 parts by weight.

[0033] The photosensitive resin composition of the present invention may further contain a fine particulate filler as a secondary component. Examples of fine particulate fillers include talc, silica, titanium oxide, clay, calcium carbonate, hydrated silicic acid, aluminum hydroxide, alumina, barium sulfate, antimony trioxide, magnesium carbonate, mica powder, aluminum silicate,
In addition to inorganic fillers such as magnesium silicate, organic fillers such as polyethylene beads, crosslinked polystyrene beads, and cured epoxy resin beads can be used. The particle size of the particulate filler is preferably 0.01 to 10 μm, more preferably 0.01 to 1.5 μm, from the viewpoint of preventing deterioration of resolution, adhesion of the cured film, and the like. Moreover, it is preferable that the particulate filler is uniformly dispersed in the photosensitive resin composition. In addition, in order to increase the adhesive strength between the filler and the photopolymerizable unsaturated compound, the surface of the filler is coated with a silane coupling agent having a functional group such as a hydroxyl group, an amino group, an epoxy group, or a vinyl group. It can also be processed. Examples of the silane coupling agent include γ-aminopropyltriethoxysilane, β-aminoethyl-γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, etc. can be mentioned.

The photosensitive resin composition of the present invention may also contain other photopolymerizable compounds. As the photopolymerizable compound, for example, trimethylhexamethylene diisocyanate/2-hydroxyethyl acrylate (1/2
Molar ratio) Reactant, isocyanate ethyl methacrylate/water (2/1 molar ratio) Reactant, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, cyclohexyl acrylate, benzyl acrylate, carbitol acrylate, methoxyethyl acrylate, ethoxyethyl acrylate,
Butoxyethyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, butylene glycol monoacrylate, N,N-dimethylaminoethyl acrylate, N,N-diethylaminoethyl acrylate, glycidyl acrylate, tetrahydrofurfuryl acrylate, pentaerythritol monoacrylate, trimethylolpropane Monoacrylate, acrylic acrylate, 1,3-propylene glycol diacrylate, 1,4-butylene glycol diacrylate, 1,6-hexylene glycol diacrylate,
Neopentyl glycol diacrylate, dipropylene glycol diacrylate, 2,2-bis-(4-acryloxydiethoxyphenyl)propane, 2,2-bis-(4-acryloxypropoxyphenyl)propane,
Trimethylolpropane diacrylate, pentaerythritol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, triacryl formal, tetramethylolmethanetetraacrylate, acrylic ester of tris(2-hydroxyethyl)isocyanuric acid,

[Chemical formula 3]

[Chemical 4] Methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, octyl methacrylate, ethylhexyl methacrylate, methoxyethyl methacrylate, ethoxyethyl methacrylate, butoxyethyl methacrylate, hydroxy Ethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, hydroxypentyl methacrylate, N,N-dimethylamino methacrylate, N,N-diethylamino methacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate, methacryloxypropyltrimethoxysilane, allyl methacrylate, trimethylol Propane monomethacrylate, pentaerythritol monomethacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexylene glycol dimethacrylate, neopentyl glycol dimethacrylate, 2,2-bis(4-methacryloxydiethoxyphenyl)propane, Trimethylolpropane dimethacrylate, pentaerythritol dimethacrylate, trimethylolpropane triacrylate, pentaerythritol trimethacrylate, tetramethylolmethanetetramethacrylate, methacrylic acid ester of tris(2-hydroxyethyl)isocyanuric acid,

[C5]

[Chemical 6] Butyl crotonate, glycerin monoclonate, vinyl butyrate, vinyl trimethyl acetate, vinyl caproate, vinyl chloroacetate, vinyl lactate, vinyl benzoate, divinyl succinate, divinyl phthalate, methacrylamide, N-methyl methacrylate Amide, N-ethylmethacrylamide, N-arylmethacrylamide, N-hydroxyethyl-N-methylmethacrylamide, acrylamide, Nt-butylacrylamide, N-methylolacrylamide, N-isobutoxymethylacrylamide, N-butoshiki Methylacrylamide, diacetone acrylamide, hexyl vinyl ether, ethylhexyl vinyl ether, vinyltriether, polyvinyl ether of polyhydric alcohols,
Examples of styrene derivatives include styrene having substituents such as alkyl groups, alkoxy groups, halogens, carboxyl groups, and allyl groups at the ortho and para positions, divinylbenzene, allyloxyethanol, diallyl esters of dicarboxylic acids, N-vinyloxazolidone, Examples include N-vinylimidazole, N-vinylpyrrolidone, and N-vinylcarbazole.

From the viewpoint of heat resistance, the amount of these photopolymerizable compounds used is preferably 20% by weight or less based on the photopolymerizable unsaturated compound (a).

The photosensitive resin composition of the present invention further includes:
It can contain a polymer binder, a thermal polymerization inhibitor, a dye, a pigment, a coatability improver, an antifoaming agent, a flame retardant, an adhesion improver, a latent curing agent for epoxy resin, and the like.

The photosensitive resin composition of the present invention can be prepared by conventional methods such as dip coating, roll coating, flow coating, screen printing, spraying, and electrostatic spraying.
A photosensitive layer having a thickness of 10 to 150 μm can be easily formed by directly coating a substrate or printed wiring board to be processed and protected. When coating, the photosensitive resin composition can be dissolved in a solvent if necessary. Examples of the solvent include methyl ethyl ketone, methyl cellosolve acetate, ethyl cellosolve acetate, cyclohexanone, methyl cellosolve, methylene chloride, 1,1,1
-trichloroethane and the like.

[0038] Further, the above composition or its solution is applied onto a film such as a polyethylene terephthalate film or a polyimide film by a knife coating method, a roll coating method, etc. and dried to prepare a photosensitive element. The photosensitive layer can also be formed by laminating the element on a substrate or printed wiring board under heat and pressure using a hot roll. At this time, if the substrate has irregularities of 10 μm or more, the
It is preferable to laminate under the following vacuum conditions. As this device, for example, a laminating device described in Japanese Patent Publication No. 55-13341 is used. When using a support film that is opaque to actinic light, it is necessary to peel the support film during exposure.

Exposure and development of the photosensitive layer thus formed is carried out by conventional methods. That is, using an ultra-high-pressure mercury lamp, a high-pressure mercury lamp, or the like as a light source, the layer of the photosensitive resin composition is imagewise exposed directly or through a negative mask through a transparent film such as a polyethylene terephthalate film. If a transparent film remains after exposure, it is peeled off and developed.

The image-like protective coating obtained by the above method is
It has properties as a corrosion-resistant film for ordinary etching, plating, etc., but after development, it is exposed to active light and/or
Adhesion is improved by heat treatment at 0 to 200°C.
A permanent protective film that can improve properties such as heat resistance and solvent resistance and satisfies the properties as a solder mask, and a substrate or printed wiring board on which this protective film is formed can be obtained. The order of exposure to active light and heat treatment may be in any order.

[0041]

EXAMPLES Next, the present invention will be explained in detail by examples. In addition, "parts" shall mean "parts by weight."

Example 1 (a) Synthesis of photopolymerizable unsaturated compound A. Orthocresol novolak type epoxy resin (
Nippon Kayaku 230 copies E manufactured by Co., Ltd.
OCN-102, epoxy equivalent weight 230)
Ethyl cellosolve acetate
210 copies B. acrylic acid

72 copies
Benzyltrimethylammonium chloride salt
2
Part p-methoxyphenol

Part 1 C. Tetrahydrophthalic anhydride
Part 76 D. Isocyanate ethyl methacrylate
77 parts dibutyltin dilaurate
0.2 parts
Ethyl cellosolve acetate
7
Part 0 E. methanol

5th part

[0043] Thermometer,
The above A was added to a 1-liter reactor equipped with a stirring device, a cooling tube, and a dropper capable of heating and cooling, and the temperature was raised to 60° C. while stirring to uniformly dissolve the mixture. Reaction temperature to 60
B was added dropwise thereto over 1 hour under a stream of air while maintaining the temperature at °C. After dropping B, the temperature was raised to 100°C and stirring was continued for 30 hours to bring the acid value of the reaction system to 5 or less. Next, while maintaining the reaction temperature at 100°C, C was added and stirring was continued for 5 hours to bring the acid value of the reaction system to 62 (A+B; acid equivalent/epoxy equivalent = 0.5/1, (A+B)+C; acid equivalent/small). Acid group equivalent = 0.5/1).

Next, the reaction temperature was lowered to 60°C, and D was uniformly added dropwise over about 3 hours while maintaining the reaction temperature at 60°C. After dropping D, the reaction temperature was gradually increased to 80°C over about 5 hours.
After raising the temperature to 60°C, the temperature was lowered to 60°C, E was added, and stirring was continued for about 1 hour. In this way, a solution (I) of a photopolymerizable unsaturated compound of orthocresol novolac type epoxy resin/acrylic acid/tetrahydrophthalic anhydride/isocyanatoethyl methacrylate system with a nonvolatile content of 62% was obtained [(A+B)+C]+D; Nato group equivalent/
Small acid group equivalent = 0.5/0.5).

(b) Preparation of photosensitive resin composition - Solution (1) of photopolymerizable unsaturated compound obtained in (a)
160 parts ・50% Epicoat 100g (manufactured by Yuka Shell Co., Ltd., 50% ethyl
20 parts cellosolve acetate solution) ・2,4-diethylthioxanthone

5 parts/Isobutyl benzoate

Part 7/Dicyandiacid

1 part silica powder (
Manufactured by Ryumori Co., Ltd., product name CRS-210-41, average grain
15 part diameter 1.2μm) ・Phthalocyanine green

A photosensitive resin composition (I-1) of the present invention was prepared by blending 0.5 parts and mixing and dispersing with a roll mill.

(c) Formation of cured film and production of printed wiring board The solution of the photosensitive resin composition (I-1) obtained in (b) was applied to a copper-clad laminate (manufactured by Hitachi Chemical Co., Ltd., MCL-E). -67)
It was applied with a bar coater onto a substrate on which a circuit pattern was formed using a subtractive method, and dried at 80°C for 20 minutes.
A photosensitive layer having a thickness of 40 μm (20 μm on the circuit) was formed. Then, through a negative mask, the HMW-68 manufactured by Oak Manufacturing Co., Ltd.
Exposure was carried out at 350 mJ/cm2 using a type 0 exposure machine. After exposure, use 1% sodium carbonate aqueous solution at 30°C for 60°C.
Spray developed for seconds. Thereafter, heat treatment was performed at 150° C. for 45 minutes to obtain a solder mask with excellent dimensional accuracy suitable for a negative mask and a printed wiring board on which the solder mass was formed. This printed wiring board was cut into a press punching machine (manufactured by Yamada Dobby Co., Ltd., C-shaped frame, load: 20 tons) at AST in the United States.
Using the mold shown in M-D61744, punching was performed at 30° C. with a stroke rate of 90 strokes per minute with a clearance between the punch and the die of 0.06 mm, and when visually inspected for crack peeling, no crack peeling was observed at the cut portion. .

In addition, as a heat resistance test, rosin flux M
1 at 260℃ using H-820V (manufactured by Tamura Kaken Co., Ltd.)
After soldering for 0 seconds and washing with 1,1,1-trichloroethane at 25°C for 10 minutes, MIL-STD
-202E 107D Condition B (-65℃/30 minutes →
No cracking or peeling of the coating was observed in the thermal shock test of 50 cycles (at room temperature for 5 minutes or less → 125° C. for 30 minutes), indicating that the product has excellent long-term reliability.

[0048] Separately from the thermal shock test, the above
, 1,1-Trichloroethane at 25°C for 10 minutes, and then gold plating was performed using the following process and conditions, and no liquid leakage or peeling was observed, indicating excellent gold plating resistance. That's what I found out.

Gold plating process and conditions (a) Degreasing process The process was carried out at room temperature for 5 minutes using a degreasing solution containing 7% by volume of Acid Cleaner FR manufactured by Schering Co. and 7% by volume of sulfuric acid. (b) Water washing step for 1 minute; (c) Soft etching step using 25% by weight ammonium persulfate water for 1 minute and 30 seconds. (d) Water washing step Washing was carried out for 1 minute with standing water and then for 1 minute with running water. (e) Sulfuric acid immersion step The sulfuric acid immersion step was carried out for 1 minute at room temperature using 10% by volume sulfuric acid. (f) Water washing step was carried out for 30 seconds. (g) Nickel plating process Watt bath (contains nickel sulfate and nickel chloride) and semi-bright additive (Nical PC-3 manufactured by Meltex)
The test was carried out at 50°C for 10 minutes at 3A/dm2 using (H) Water washing step The washing process was carried out for 1 minute at room temperature. (li) Gold strike process 5A using Aurobond TN (manufactured by Japan Kojundo Kagaku Co., Ltd.)
/dm2 for 20 seconds at 40°C. (v) Water washing step The washing process was carried out at room temperature for 10 seconds. (Le) Gold plating process 1A/d using Autoronex CI (manufactured by EEJA)
plating was carried out at 50° C. for 6 minutes to achieve a plating thickness of 1 μm. (E) Water washing step Washing was carried out at room temperature for 10 seconds with standing water and then for 1 minute with running water.

Example 2 (a) Preparation of photosensitive resin composition 160 parts of solution of photopolymerizable unsaturated compound obtained in Example 1 (a) 50% Epicote 1
010 (manufactured by Yuka Shell Co., Ltd., 50% methi
30 parts lucerosorg acetate solution) ・2-Methyl-1-[4-(methylthio)phenyl]-
2-mol 7 parts holino-propane-1 Michler ketone

0.8 parts 1-o-tolyl biguanide

5 parts/antimony trioxide

3 parts Crystallite 5V (manufactured by Ryumorisha, average particle size 5 μm)
15 parts 2,2-bis [4-
(Methacryloxy, polyethoxy)phenyl] 10
Propane (manufactured by Shin-Nakamura Kasha, product name: NK Ester B)
PE-10) Phthalocyanine green

0.5 parts of 1-cyanoethyl-2-phenylimidazole (manufactured by Shikoku Kasei Co., Ltd., 2 parts, trade name Curazol 2E4MZ-CN) was blended and mixed and dispersed using a roll mill to obtain the photosensitive resin composition (I-2) of the present invention.
adjusted.

(b) Formation of cured film and production of printed wiring board In Example 1(c), photosensitive resin composition (I-1)
A cured film having excellent punching workability, heat resistance, reliability, and gold plating property and a printed wiring board on which this cured film was formed were obtained in the same manner as in Example 1(c), except that . Further, the photosensitive resin composition (I-2) was coated with a thickness of 0.
When a 50 μm thick cured film is formed on both sides of an 8 mm UL94V-0 glass epoxy flame retardant base material (manufactured by Hitachi Chemical Co., Ltd., trade name MCL-E-67), the UL94 V-0
V-0 flame retardancy was maintained.

Example 3 (a) Synthesis of photopolymerizable unsaturated compound A. Orthocresol novolak type epoxy resin (
YDPN- manufactured by Toto Kasei Co., Ltd. 180 copies
638, epoxy equivalent 180) Propylene glycol monoethyl ether acetate
150 copies B. cinnamic acid

44 copies
acrylic acid

44 parts Benzyltrimethylammonium chloride salt
2 parts p-methoxyphenol
Part 1
Ethyl cellosolve acetate
3
Part 0 C. Tetrahydrophthalic anhydride

Part 76 D. Isocyanate ethyl methacrylate
30 parts dibutyltin dilaurate
0.2 parts ethyl cellosolve acetate
50 copies E. methanol

4 parts Using A to E above, others were as in Example 1 (
In the same manner as in a), a solution (II) of a photopolymerizable unsaturated compound of orthocresol novolac type epoxy resin/cinnamic acid/acrylic acid/tetrahydrophthalic anhydride/isocyanatoethyl methacrylate with a nonvolatile content of 62% was obtained. Ta.

(b) Preparation of photosensitive resin composition - Solution (II) of the photopolymerizable unsaturated compound obtained in (a)
) 160 parts/50% Epicote 1
009 (50% methyl ethyl ketone solution)
10 parts ・Benzyl dimethyl ketal (manufactured by Ciba Geigy, trade name Irga 6 parts Cure 651) ・2-Methyl-1-[4-(methylthio)phenyl]-
2-mol 5 parts holinopropane-1 dicyandiamide

5 parts/antimony trioxide

Part 3: Phthalocyanine green
One part of the photosensitive resin composition of the present invention (
II-1) was adjusted.

(c) Formation of cured film and production of printed wiring board In Example 1 (c), photosensitive resin composition (II-1)
After development, 1J/
Same as Example 1(c) except that cm2 irradiation was performed,
A cured film having excellent punching workability, heat resistance, reliability, and gold plating resistance, and a printed wiring board on which the cured film was formed were obtained.

Comparative Examples 1 and 2 Orthocresol novolak type epoxy resin/acrylic acid obtained by excluding D and E in the synthesis of the photopolymerizable unsaturated compounds of Example 1(a) and Example 3(a) /Tetrahydrophthalic anhydride-based photopolymerizable unsaturated compound solution (III) and orthocresol novolac type epoxy resin/cinnamic acid/acrylic acid/tetrahydrophthalic anhydride-based photopolymerizable unsaturated compound solution (IV) A photosensitive resin composition (III-1) was prepared in the same manner as in Example 1(b) using
, (IV-1) was adjusted. Photosensitive resin composition (III
-1), (IV-1) in Example 1(c),
Except for using the photosensitive resin composition (I-1), the same procedure as in Example 1(c) was carried out. As a result, both had excellent punching workability, heat resistance, and reliability, but the gold plating treatment When applied, liquid leakage and peeling were observed, and the gold plating resistance was poor.

[0056]

According to the present invention, it is possible to form a highly reliable solder mask that can be developed with a dilute aqueous alkaline solution and has excellent punching workability, resolution, heat resistance, and gold plating resistance.

Claims (3)

[Claims] Claim 1: (a) A saturated or unsaturated polybasic anhydride is added to the secondary hydroxyl group of the reaction product of a novolac type epoxy resin and an unsaturated carboxylic acid at a ratio of acid equivalent/hydroxyl group equivalent of 0.1 to
A photopolymerizable unsaturated compound obtained by reacting in a range of 0.8 and adding a saturated or unsaturated monoisocyanate to the remaining hydroxyl group, (b) a compound having at least one epoxy group, and (c) actinic rays. A photosensitive resin composition comprising a sensitizer and/or a sensitizer system that generates free radicals. 2. A photosensitive element obtained by applying the photosensitive resin composition according to claim 1 onto a film and drying it. 3. A layer of the photosensitive resin composition according to claim 1 and/or the photosensitive element according to claim 2 is formed on a printed wiring board on which a conductive pattern is formed, and then imagewise irradiation with actinic light is performed. and a method for manufacturing a printed wiring board, characterized by forming a cured film by development and heat curing.