JPS61264341A - Photosensitive resin composition - Google Patents

Abstract

PURPOSE:To enable a solder mask developable with an inflammable developing soln., superior in resolution and heat resistance and high in reliability to be formed by incorporating a specified photopolymerizable unsatd. compound. CONSTITUTION:The photopolymerizable unsatd. compound is obtained by reacting isocyanatoethyl methacrylate in an isocyanato equivalent/hydroxyl equivalent ratio of 0.1-1.2, with the secondary hydroxyl group of an unsatd. compd. obtained by additionally reacting unsatd. carboxylic acid in an acid equivalent/epoxy equivalent ratio of 0.1-0.98, with a novolak type epoxy resin selected from a group composed of o-cresol-, phenol-, and halogenated phenol- novolak type epoxy resins. The photosensitive resin compsn. contains said unsatd. compd., a sensitizer or its system to be allowed to produce a free radical by actinic rays, and fine filler particles. The use of this photosensitive resin compsn. permits it to be developed with an inflammable developing soln., such as 1,1,1-trichloroethane, and a solder mask superior in resolution and durability to be formed.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a photosensitive resin composition, and more specifically, a photosensitive resin composition for forming a protective film that can be used in printed wiring board manufacturing, metal precision processing, etc. Regarding.

(Conventional technology) Traditionally, solder masks have been used in the printed wiring board industry.

Photosensitive resin compositions having excellent properties that can be used as resists for chemical plating and the like are known. The main purpose of a solder mask is to limit the area during soldering and prevent solder bridging.

The purpose is to prevent corrosion of bare copper conductors and to maintain electrical insulation between conductors over a long period of time. Epoxy resin is usually used as a solder mask.

A mask whose main component is a thermosetting resin such as aminoplast resin (printed mask) is used.

However, in recent years, the wiring density of printed wiring boards has increased.

In addition, requirements for electrical insulation between conductors have become stricter, and the solder mask used therefor has also been required to have a thick film and excellent dimensional accuracy, making it no longer possible to meet the requirements with screen printing methods.

Therefore, the photographic method (forming an image by imagewise exposure followed by development)
It is desired to develop a photosensitive resin composition that can form a highly reliable solder mask that is thin (usually 15 μm thick on a conductor) and has excellent dimensional accuracy.

Conventionally, as a photosensitive resin composition for forming a solder mask,
(1) Photosensitive resin compositions containing acrylic polymers and photopolymerizable monomers as main components (JP-A-53-56018, JP-A-54-1018, etc.), (21 photoreactivity imparted) A photosensitive resin composition containing an epoxy resin and an epoxy resin curing agent as main components (Japanese Patent Application Laid-Open No. 52-3799
6, Japanese Unexamined Patent Publication No. 58-62636, etc.) are known.

However, the photosensitive resin composition of t1) is a flame-retardant material used in ordinary film photosensitive materials for etching and plating (for example, manufactured by DuPont, trade name Riston, manufactured by Hitachi Chemical Co., Ltd., trade name Fotec, etc.). Sex 1.1.
1-) Although it is possible to develop with 'J dichlorothane and form a high-resolution solder mask, such photosensitive resin compositions use a large amount of acrylic polymer to impart film properties. However, there is a drawback that the heat resistance of the cured film is not sufficient.

On the other hand, the photosensitive resin composition of (2) is based on an epoxy resin, and although it has excellent heat resistance of the cured film, it is insoluble in flame-retardant organic compounds such as e1+L1-trichloroethane. , as a developer.

This method has the drawback of requiring the use of a flammable organic solvent such as cyclohexanone, which is not desirable from a safety standpoint.

(Problems to be Solved by the Invention) It is an object of the present invention to eliminate the drawbacks of the prior art described above.
1- It is an object of the present invention to provide a photosensitive resin composition which can be developed with a flame-retardant developer such as trichloroethane and which can form a highly reliable solder mask having excellent resolution and heat resistance.

(Means for Solving the Problems) The present invention provides at least one novolak-type epoxy resin selected from the group consisting of +al orthocresol novolac-type epoxy resins, phenol novolac-type epoxy resins, and halogenated phenol novolac-type epoxy resins. and an unsaturated carboxylic acid.

Incyanate ethyl methacrylate is added to the secondary hydroxyl group of an unsaturated compound obtained by addition reaction at an acid equivalent/epoxy equivalent ratio of 0.1 to 0.98.

A photopolymerizable unsaturated compound obtained by reacting at an isocyanate equivalent/hydroxyl group equivalent ratio of 0.1 to 1.2.

[b) Sensitizers and sensitizer systems that generate free radicals by actinic light.

and (c1 fine granular filler.

The present invention relates to a photosensitive resin composition containing the following.

The photosensitive resin composition of the present invention has as an essential component (a).

At least one novolak epoxy resin selected from the group consisting of orthocresol novolak epoxy resin, phenol novolak epoxy resin, and halogenated phenol novolak epoxy resin and an unsaturated carboxylic acid, acid equivalent/epoxy equivalent The ratio is 0.1-0.
2 of unsaturated compounds obtained by addition reaction in the range of 98
to the grade hydroxyl group.

Contains a photopolymerizable unsaturated compound obtained by reacting inocyanate ethyl methacrylate with an isocyanate equivalent/hydroxyl group equivalent ratio in the range of 0.1 to 1.2.

The novolac type epoxy resin used in the present invention is obtained by reacting an aldehyde with, for example, olincresol, phenol, 10-genated phenol, etc. in the presence of an acid catalyst. It is obtained by reacting epichlorohydrin and is commercially available.

9 for orthocresol novolac type epoxy resin
For example, Araldite ECN129 manufactured by Ciba Geigy.
9 (softening point 99°C, epoxy equivalent 230), ECN1
280 (softening point 80°C, epoxy equivalent 230), EC
N1273 (softening point 73°C, epoxy equivalent 230),
Made by Nippon Kayaku ■, EOCN104 (softening point 90-1
00°C, epoxy equivalent 225-245), EOCN
IO3 (softening point 80-90℃, epoxy equivalent 215-2
35), EOCNIO2 (softening point 70-80°C, epoxy equivalent 215-235), EOCNIO1 (softening point 65-69°C, epoxy equivalent 205-225).

As a phenol novolac type epoxy resin.

For example, Epikote 154 (epoxy equivalent: 1
76-181), manufactured by Dow Chemical Company, DEN431 (epoxy equivalent weight 172-179), DEN438 (epoxy equivalent weight 175-182), manufactured by Tobu Kasei ■, YDPN-63
8 (epoxy equivalent 170-190), YDPN-60
1 (epoxy equivalent 180-220), YDPN-60
2 (epoxy equivalent: 180 to 220).

Examples of halogenated phenol novolak epoxy resins include 9, manufactured by Nippon Kayaku ■, and BREN (epoxy equivalent: 27
0-300. Bromine content 35-37chi, softening point 80-9
Examples include brominated phenol novolac type epoxy resins such as 0°C). As the unsaturated carboxylic acid, acrylic acid, methacrylic acid, β-furylacrylic acid, β-styrylacrylic acid, α-cyanocinnamic acid, cinnamic acid, etc. are used.

In the present invention, the addition reaction between these novolac type epoxy resins and unsaturated carboxylic acids is as shown in formula (1), and is carried out by a conventional method when the acid equivalent/epoxy equivalent ratio is in the range of 0.1 to 0.98. This is done by When the acid equivalent/epoxy equivalent ratio is less than 0.1, the photocured film is likely to swell during development treatment after image exposure. Acid equivalent/epoxy equivalent ratio is 0.9
If it exceeds 8.

Adhesion, heat resistance, etc. decrease.

H... (1) For example, the novolak type epoxy resin is dissolved in an inert organic solvent such as methyl ethyl ketone, methyl cellosolve acetate, ethyl cellosolve acetate, cyclohexanone, etc., and 3 such as triethylamine, tri-n-butylamine, diethylcyclohexylamine, etc. are used as a catalyst. quaternary ammonium salts such as benzyltrimethylammonium chloride and benzyltriethylammonium chloride.

Further, an unsaturated compound can be obtained by stirring and reacting with the unsaturated carboxylic acid at 70 to 110° C. in the equivalent ratio range described above using hydroquinone, p-methoxyphenol, etc. as a polymerization inhibitor.

The reaction of incyanatoethyl methacrylate with the secondary hydroxyl group of the unsaturated compound obtained by addition-reacting a novolac type epoxy resin with an unsaturated carboxylic acid as described above is as shown in formula (II), and the diisocyanate equivalent is /
When the isocyanate equivalent/hydroxyl equivalent ratio is less than 0.1, flame retardant materials such as 1,1゜1-trichloroethane, etc. Development with organic solvents becomes difficult, and photocurability also decreases. Isocyanate equivalent/hydroxyl equivalent ratio is 1.2
If it exceeds tl, gelation will not occur during one reaction.
In addition, properties such as heat resistance are also reduced. After reaction, methanol.

It is desirable to urethane and deactivate the remaining isocyanatoethyl methacrylate using a primary alcohol such as ethanol or 2-hydroxyethyl methacrylate from the viewpoint of safety and improving storage stability. The one manufactured by Dow Chemical Company is used.

H For example, an addition reaction between the above-mentioned novolanc type epoxy resin and an unsaturated carboxylic acid is carried out.Next, a urethanization catalyst such as dibutyl tin dilaurate or dibutyl rank 2 ethyl hexoate is added to the product, and the above equivalent ratio is Incyanate ethyl methacrylate in the range of 50 to 11
A photopolymerizable unsaturated compound is obtained by stirring and reacting at 0°C. Under such reaction conditions, side reactions such as the reaction between urethane bonds and epoxy groups and thermal polymerization of unsaturated bonds can be prevented, and as a result, photopolymerizable unsaturated compounds can be formed without forming gel-like substances. can be obtained.

In the present invention, particularly preferred photopolymerizable unsaturated compounds include orthocresol novolak epoxy resin/
Acrylic acid/isocyanate ethyl methacrylate (acid equivalent/epoxy equivalent ratio 0.1 to 0.98, incyanato equivalent/hydroxyl equivalent ratio 0.1 to 1.2) Unreacted material, orthocresol novolanc type epoxy resin/methacrylic acid /isocyanate ethyl methacrylate (acid equivalent/epoxy equivalent ratio 0.1 to 0.98; isocyanate equivalent/hydroxyl group equivalent ratio 0.1 to 1.2) type reactants.

The photosensitive resin composition of the present invention contains as an essential component (b) a sensitizer and/or a sensitizer system that generates free radicals by actinic light.

Examples of the sensitizer include substituted or unsubstituted polynuclear quinones 1, such as 2-ethylanthraquinone, 2-t-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, 3-diphenylanthraquinone, diacetylbenzyl, etc. α-ketaldonyl alcohols and ethers such as butaldonyl compounds, benzoin and biparone, and α-hydrocarbon-substituted aromatic acyloins.

For example, aromatic ketones such as α-phenyl-benzoin, α, α-jethoxyacetophenone, benzophenone, 4,4′-bisdialkylaminobenzophenone, etc.
Thioxanthone such as methylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2-inopropylthioxanthone, and 2-ethylthioxanthone are used, and these may be used alone or in combination.

As a sensitizer system, 9 (for example, 2,4.5-)! J allylimidazole dimer and 2-mercaptobenzoquinazole,
A combination with leuco crystal violet, tris(4-diethylamino-2-methylphenyl)methane, etc. is used. Also, additives which do not have photoinitiating properties by themselves, but which, when used in combination with the above-mentioned substances, result in a sensitizer system with better photoinitiating properties as a whole, such as triethanolamine for benzophenone, etc.
It is also possible to use isoamyl dimethylaminobenzoate, N-methyldietalamide, bisethylaminobenzophenone, etc. for thioxanthones.

The photosensitive resin composition of the present invention contains a fine particulate filler as an essential component (
Contained as c1.

Examples of fine particulate fillers include talc and silica.

Titanium oxide, clay, calcium carbonate, hydrated silicic acid.

Aluminum hydroxide, alumina, barium sulfate.

Antimony trioxide, magnesium carbonate, mica powder.

Aluminum silicate, magnesium silicate, etc. are 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. It is preferable that the particulate filler is uniformly dispersed in the photosensitive resin composition. In order to increase the adhesive force between the filler and the photopolymerizable unsaturated compound, the surface of the filler is treated with a silane camping agent having a functional group such as a hydroxyl group, an amino group, an epoxy group, or a vinyl group. You can also do that. Examples of silane camping agents include γ-7minopropyltriethoxysilane, β-aminoethyl-r-aminopropyltrimethoxysilane, γ-glycidoxyglobiltrimethoxysilane, and r-methacryloxyglobiltrimethoxysilane. Examples include methoxysilane.

The photosensitive resin composition of the present invention contains a photopolymerizable unsaturated compound (
Using 0.1 to 30 parts by weight of the sensitizer and/or sensitizer system (bl) and 3 to 100 parts by weight of the particulate filler (c1) to improve resolution and This is preferable for forming a solder mask having excellent solder heat resistance.Furthermore, the composition of the present invention may contain other photopolymerizable compounds.

Other photopolymerizable compounds include 1, such as trimethylolpropane triacrylate, pentaerythritol triacrylate, trimethylhexamethylene diinocyanate/2-hydroxyethyl acrylate (1/2 molar ratio) reaction product incyanatoethyl methacrylate /water (2
/1 molar ratio) reactants, etc. Also, JP-A-53-
Photopolymerizable compounds disclosed in Japanese Patent No. 56018 can also be used. However, from the viewpoint of maintaining heat resistance, the content of these other photopolymerizable compounds is preferably 10% by weight or less based on (a) the photopolymerizable unsaturated compound.

Furthermore, the photosensitive resin composition of the present invention may contain other subsidiary components. As a secondary ingredient.

Examples include polymer binders, thermal polymerization inhibitors, dyes, pigments, coatability improvers, antifoaming agents, flame retardants, adhesion improvers, and latent curing agents for epoxy resins.

The photosensitive resin composition of the present invention is prepared using a dip coating method.

Coat directly onto the substrate to be processed and protected using conventional methods such as flow coating and screen printing to a thickness of 10 to 150 μm.
m photosensitive layers can be easily formed. In coating, if necessary, the composition can be dissolved in a solvent. Examples of the solvent include methyl ethyl ketone, methyl cellosolve acetate, ethyl cellosolve acetate, cyclohexanone, methyl cellosolve, methine chloride, and 1,1.1-1-lichloroethane.

In addition, this solution is coated onto a film such as a polyethylene terephthalate film or a polyimide film by a knife coating method or a roll coating method, and the photosensitive element obtained by drying is heated and pressed onto a substrate using a hot roll. A photosensitive layer can also be formed by laminating them. At this time, the substrate is a printed wiring board or the like on which conductor wiring lines are formed.
When the layers have irregularities of μm or more, it is preferable to laminate them under a vacuum of 200 mmHg or less in order to prevent air from being entrained. As an apparatus for this purpose, for example, a laminating apparatus described in Japanese Patent Publication No. 55-13341 is used. In addition, when using a support film that is opaque to actinic light, it is necessary to peel off the support film at the time of exposure.

Exposure and development of the photosensitive layer thus formed are 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 transparent film such as a polyethylene terephthalate film through a negative mask. If a transparent film remains after exposure, it is peeled off and then developed.

The type of developer used in the development process is not particularly limited as long as it does not damage the exposed areas and selectively elutes the unexposed areas. As a developer, 2, for example, 1
．． 1.1- Halogenated hydrocarbons such as trichloroethane are used. It is also possible to use a cleaning agent 9 containing 1,1,1-trichloroethane as a main component, for example, Three-One EX (manufactured by Toagosei Chemical Co., Ltd.).

The image-like protective film obtained by the above method has properties as a corrosion-resistant film for ordinary etching, plating, etc., but after development, exposure to active light and heat treatment at 80 to 200°C are necessary. By doing so, properties such as adhesion, heat resistance, and solvent resistance can be improved.

A permanent protective film that satisfies the properties of a solder mask is obtained. The order of exposure to active light and heat treatment may be in any order.

(Effects of the Invention) The protective film obtained using the photosensitive resin composition of the present invention has sufficient resistance to organic solvents such as tricrene, methyl ethyl ketone, Ia7'lopyl alcohol, toluene, etc., and also resistance to acidic or alkaline aqueous solutions. . Furthermore, since it has excellent heat resistance and mechanical properties, it can be used as a corrosion-resistant film for etching, plating, etc., and as a permanent protective film for solder masks, etc. Furthermore, the film formed using the photosensitive resin composition of the present invention has excellent chemical and physical properties, and therefore can be used as an interlayer insulating layer of a multilayer printed wiring board.

It can also be used in photosensitive adhesives, paints, plastic reliefs, printing plate materials, metal precision processing materials, etc.

Furthermore, by using the photosensitive resin composition of the present invention,
1,1.1-) It can be developed with a flame-retardant developing solution such as dichloroethane, and a solder mask with excellent resolution and heat resistance can be formed. Moreover, it is also possible to form a thick film solder mask using a photographic method.

(Example) Parts in the examples mean parts by weight.

Example 1 (a) Synthesis of photoreactive unsaturated compound Orthocresol novolak type epoxy resin, EOCN102 (epoxy equivalent weight 230) 1095 parts Methyl ethyl ketone 800 parts Part B. Lilic acid 69 parts Benzyltrimethylammonium chloride 7 parts p-methoxyphenol 3 parts Methyl ethyl ketone 100 parts C, incyanato Ethyl methacrylate 163 parts Dibutyl tin dilaurate 0.5 parts Methyl ethyl ketone 100 parts Methanol
10-part heating and cooling 5t with thermometer, stirrer, cooling tube and dropper! The above A was added to the reactor, and the temperature was raised to 60°C while stirring to uniformly dissolve it. B was added dropwise thereto over about 1 hour while maintaining the reaction temperature at 60°C. After dropping B, the temperature was raised to 80°C over 2 hours, and the mixture was stirred at 80°C for about 15 hours until the number of caricatures in the reaction system was reduced to 1 or less.

Next, the temperature was lowered to 60°C, and C was uniformly added dropwise to the reactor over about 3 hours while maintaining the temperature at 60°C. After dropping C, the reaction temperature was gradually raised to 80"C over about 5 hours, and then the temperature was lowered to 60"C, D was added, and stirring was continued for about 1 hour.In this way, the nonvolatile content was 57] Ut%. Orthocresol novolak type epoxy resin / acrylic acid / isocyanato ethyl methacrylate (acid equivalent / epoxy equivalent ratio = 0.2. incyanato equivalent / hydroxyl group equivalent ratio = 1)
．． 1) A solution (1) of a photopolymerizable unsaturated compound was obtained.

(b) Preparation of photosensitive resin composition Solution of photopolymerizable unsaturated compound obtained in (a) (118
8 parts (non-volatile content 50 parts), 1.5 parts of λ4 diethylthioxanthone, 2 parts of isobutyl benzoate, Micro Ace P-
4 (manufactured by Nippon Talc, ultrafine talc average particle size 1.5 μm
), 0.1 part of phthalocyanine green, and 0.1 part of Modaflow were mixed and dispersed using a roll mill to prepare a solution of the photosensitive resin composition of the present invention.

(c) Formation of a cured film The solution of the photosensitive resin composition obtained in (b) was applied onto a copper-clad laminate and dried at room temperature for 20 minutes and at 80°C for 20 minutes to form a film with a thickness of 40 μm. A photosensitive layer was formed. Then, through the negative mask, the orc manufacturing company ■cracked.

200mJ/c using Phoenix 3000 exposure machine
After exposure, the film was heated at 80°C for 5 minutes.

After being left at room temperature for 30 minutes, spray development was performed at 20° C. for 90 seconds using Lift h dichloroethane.

Next was the Toshiba ultraviolet irradiation equipment (rated voltage 2) manufactured by Toshiba Denzai ■.
00V, rated power consumption cuff, 2KW, compatible lamp H560
0L/2. (1 lamp) is used.

After irradiation at 1 J/cIn2, a heat treatment was performed at 150° C. for 30 minutes to obtain a solder mask with excellent dimensional accuracy corresponding to a negative mask. This solder mask has excellent cold and thermal shock resistance, and was soldered at 260°C for 10 seconds using rosin-based flux A-226 (Tamura Kakenhira), and then soldered at 25°C with Triclean.

After cleaning for 10 minutes, MIL-8TD-202E
107D Condition B (-659C for 30 minutes, room temperature for 5 minutes or less, 125°C for 30 minutes), no cracking or peeling of the coating was observed in 50 cycles of thermal shock testing, and the long-term reliability is extremely excellent. I understand.

Example 2 (a) Synthesis of photopolymerizable unsaturated compound A, orthocresol novolac type epoxy resin, EOCN104 (epoxy equivalent weight 230) 920 parts Halogenated phenol novolac type epoxy resin, BR
EN (epoxy equivalent weight 285) 285 parts Methyl cellosolve acetate 600 parts B, acrylic acid 288 parts Benzyltrimethylammonium chloride 7 parts p-methoxyphenol 3 parts Methyl cellosolve acetate 100 parts C, incyanato ethyl methacrylate 620 parts Dibutyl tin dilaurate 0. 5 parts methyl cellosolve acetate 100 parts methanol
10 parts A-D were used, and the rest was Example 1.
In the same manner as in (a), photopolymerization of a novolac type epoxy resin with a nonvolatile content of 54% by weight/acrylic acid/incyanatoethyl methacrylate (acid equivalent/epoxy equivalent ratio = 0.8 incyanato equivalent/hydroxyl group equivalent ratio = 1) A solution of sexually unsaturated compounds +II) was obtained.

(bl Solution of photopolymerizable unsaturated compound obtained in preparation (a) of photosensitive resin composition (111
148 parts (non-volatile content 80 parts), 3 parts of antimony trioxide (average particle size 0.15 μm), 2 parts of benzophenone, . 7th part,
Michler's ketone 0.3 parts, Hosmer M (oil product ■,
Equimolar salt of phosphoric acid ester) and benzotriazole 0
．． A bath liquid of the photosensitive resin composition of the present invention was prepared by blending 1 part and 2 parts of Victoria Pure Blue 060 and mixing with a triple roll.

Thereafter, a cured film with excellent heat resistance was obtained in the same manner as in Example 1(c).

Further, the photosensitive resin composition had a thickness of 0.8 mm and a UL94
V-0 glass epoxy flame retardant base material (manufactured by Hitachi Chemical Co., Ltd.,
Applied to both sides of MCL-E-67).

When a cured film with a thickness of 75 μm is formed.

It was found that the flame retardant tube maintained UL94V-1.

Example 3 (al Synthesis of photopolymerizable unsaturated compound A, orthocresol novolac deaf epoxy resin, BOCN104 (epoxy equivalent weight 230) 1095 parts Methyl cellosolve acetate 600 parts B, methacrylic acid 368 parts Benzyltrimethylammonium chloride 7 parts p-methoxy Phenol 3 parts Methyl cellosolve acetate 100 parts C, incyanato ethyl methacrylate 287 parts dibutyl tin dilaure) 0.5 parts Methyl cellosolve acetate 100 parts, methanol
Using 10 parts A-D, and in the same manner as in Example 1(a), a novolak with a non-volatile content of 69% by weight was mixed with epoxy resin/methacrylic acid/ethyl isocyanate methacrylate (acid equivalent/epoxy equivalent ratio = O,
S, Incyanate equivalent/hydroxyl group equivalent ratio = 0.8
8) A solution (m) of a photopolymerizable unsaturated compound was obtained.

(bl Solution of photopolymerizable unsaturated compound obtained in Preparation Example 2 (a) of photosensitive resin composition ([In place of 1, solution (III) of photopolymerizable unsaturated compound obtained in (a)) A cured film with excellent heat resistance was obtained using 116 parts (non-volatile content: 80 parts) and in the same manner as in Example 1(b) and (c) except for the following.

Example 4 (a) Synthesis of photopolymerizable unsaturated compound A, rough enol novolac epoxy resin.

YDPN-638 (x-boxy equivalent: 18o) 857 parts Ethyl cellosolve acetate 600 parts B Cinnamic acid 176 parts Acrylic acid
86 parts Benzyltrimethylammonium chloride 7 parts p-methoxyphenol 3 parts Ethyl cellosolve acetate 100 parts CO incyanato Ethyl methacrylate 369 parts Dibutyltin dilaurate 0.1 part Ethyl cellosolve acetate 100 parts Methanol
10 parts A-D were used, and the rest was Example 1.
In the same manner as in (a), phenol novolak type epoxy resin with nonvolatile content of 65% by weight/cinnamic acid/acrylic acid/isocyana-toethyl methacrylate (acid equivalent/epoxy equivalent ratio = 0.5, incyanate equivalent/hydroxyl group equivalent) Ratio=1) A solution (IVI) of a luminous flux-combining unsaturated compound was obtained.

(b) Solution GV19 of photopolymerizable unsaturated compound obtained in preparation of photosensitive resin composition ta)
2 parts (non-volatile content 60 parts), fine alumina A-5ON (
Manufactured by Showa Light Metal ■, average particle size 1μm) 15N, 2.4-
2 parts of diethylthioxanthone, 3 parts of ethyl dimethylaminobenzoate, 0.02 parts of Victoria Buaf K, 1 part of Curazole CttZ AZINE, and 5 parts of methyl cellosolve were blended and mixed and dispersed using a triple roll to produce the photosensitive resin of the present invention. A dispersion of the composition was prepared.

(c) Formation of a cured film Three-one EX (a cleaning solution containing 1,1,1-1-trichloroethane as a main component, manufactured by Toagosei ■) was used instead of 1,1,1-trichloroethane as the developer.

A cured film with excellent heat resistance was obtained in the same manner as in Example 1(c) in other respects.

As is clear from the examples, by using the photosensitive resin composition of the present invention, it is possible to form a thick film image by photography, and it is possible to form a thick film using the photosensitive resin composition of the present invention. A highly reliable solder mask with excellent resolution and heat resistance can be formed using a developer.

Claims (1)

[Scope of Claims] 1. (a) at least one novolac-type epoxy resin selected from the group consisting of orthocresol novolac-type epoxy resin, phenol novolak-type epoxy resin, and halogenated phenol novolak-type epoxy resin; and unsaturated carboxylic acid and the acid equivalent/epoxy equivalent ratio is 0.
．． Isocyanate ethyl methacrylate is added to the secondary hydroxyl group of an unsaturated compound obtained by addition reaction in the range of 1 to 0.98, and the isocyanate equivalent/hydroxyl group equivalent ratio is 0.1.
A photopolymerizable unsaturated compound obtained by reacting in the range of ~1.2, (b) a sensitizer and/or a sensitizer system that generates free radicals by actinic light, and (c) a fine particulate filler. , A photosensitive resin composition comprising: