JPH04195043A - Photosensitive composition and production of printed circuit board with solder resist using the same - Google Patents

Abstract

PURPOSE:To prevent incomplete development due to back fogging and to improve resolving characteristics by using a compsn. contg. a compd. having ethylenic unsatd. groups, a sensitizer forming free radicals and a specified anti- back-fogging agent. CONSTITUTION:A solvent and a catalyst are added to trimethylhexamethylene diisocyanate, they are brought into a reaction at about 60 deg.C and hexane diol is added. Hydroxyethyl acrylate, a solvent and a thermal polymn. inhibitor are then added, a terminator is further added and they are stirred and dried under reduced pressure to synthesize a urethane diacrylate compd. This compd. is mixed with trimethylolpropane triacrylate or tetrahydrofurfuryl methacrylate and diethoxyanthracene as an anti-back-fogging agent represented by general formula I (where each of R1 and R2 is alkoxy and R3 is H, alkyl or alkyl sulfonate).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photosensitive composition and a method for producing a printed wiring board on which a solder resist is formed using the photosensitive composition.

[Conventional technology]

Printed wiring boards have insulating layers and conductor pattern layers alternately laminated, and the outermost conductor pattern layer is usually used to prevent solder bridging between conductors during soldering or to permanently protect the conductor patterns. A fuldale cyst is formed on top.

In recent years, for the purpose of improving precision and workability, the formation of solder resist has been replaced by the screen printing method with a photoprinting method using photosensitive resin. There is.

In order to produce a printed wiring board having a solder resist using a photosensitive composition, a conductive pattern is created on a copper-clad laminate by etching or plating to produce a multilayer printed wiring board or a double-sided printed wiring board. A method is used in which a photosensitive composition layer is provided on one or both sides, exposed to light under predetermined conditions, and developed. For example, double-sided printed circuit boards are
This is a printed wiring board that has conductor patterns on both sides of the insulating layer, which is the central layer, and when forming solder masks on both sides, a photosensitive composition is applied to the entire surface of both sides of the printed wiring board, and then a negative is passed through the printed wiring board. By selectively exposing the photosensitive composition to vertically incident light and developing the unexposed areas of the photosensitive composition, a pattern corresponding to the exposure, that is, a solder resist, is formed on both sides of the printed wiring board.

The edge shape of the solder resist to be formed needs to be sharp. If the edge shape is not sharp, the solder may not adhere to the conductor sufficiently during soldering, or the solder may adhere to edge portions that do not require soldering.

In order to make the edge shape of the solder resist sharp and good, a photosensitive composition with good resolution is used, the negative and the photosensitive resin are brought into close contact with each other during exposure, and the exposure light is irradiated at right angles. However, since the printed wiring board allows the exposure light to pass through, exposing it from both sides will also expose the photosensitive compositions on opposite sides, causing a photoreaction in areas that are not desired to be exposed. As a result, development remains due to back fogging or the edge shape is insufficiently sharp. In order to avoid this phenomenon, a method can be considered in which the photosensitive composition is applied, exposed, and developed on one side at a time, but compared to simultaneous exposure on both sides, the work is doubled, the manufacturing cost increases, and the initial The problem is that the solder resist on the side that has been developed is once again exposed to unnecessary processes during coating, exposure, and development on one side, resulting in various quality deteriorations such as peeling of the solder resist. be.

[Problem to be solved by the invention]

An object of the present invention is to solve the problems of the prior art, and to provide a photosensitive composition capable of forming a solder resist with excellent resolution, no development residue due to back-fogging, and sharp edges, and a photosensitive composition using the same. An object of the present invention is to provide a method for manufacturing a printed wiring board that can be formed on both sides of the printed wiring board at the same time.

[Means to solve the problem]

As a result of various studies, the present inventors found that 405 nm and 43
A layer of a photosensitive composition containing a compound that absorbs an emission spectrum of 5 nm and causes a photocrosslinking reaction is formed on both sides of a printed wiring board, and then exposed and developed, so that there is no development residue due to back fogging. They have also discovered that a sharp edge-shaped solder resist can be formed, and have completed the present invention.

That is, the present invention provides (A) a compound having at least one ethylenically unsaturated group, (B) a sensitizer and/or a sensitizer system that generates free radicals by actinic light, and (C
) As a back-fogging prevention agent, -Fanzo (I) [In the formula, R1 and R2 represent an alkoxy group, and R3 represents a hydrogen atom, an alkyl group, or an alkyl sulfonate group]
A photosensitive composition containing a compound represented by the above and a layer of the photosensitive composition are formed on a printed wiring board on which a conductive pattern is formed, and then imagewise exposed to actinic rays and developed. The present invention relates to a method of manufacturing a printed wiring board on which a characteristic solder resist is formed.

First, the photosensitive composition of the present invention will be explained.

The photosensitive composition of the present invention contains a compound having at least one ethylenically unsaturated group as an essential component (A). The compound includes, for example, a polyhydric alcohol containing α,
Compounds obtained by adding β-unsaturated carboxylic acids, such as trimethylolpropane di(meth)acrylate [
(Meth)acrylate means methacrylate or acrylate. (same below), trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, tetramethylolmethanetetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, etc. Compounds obtained by adding α,β-unsaturated carboxylic acid to chrycidyl group-containing compounds, such as trimethylolpropane triglycidyl ether triacrylate, bisphenol A diglycidyl ether di(meth)acrylate, polyhydric carboxylic acids,
For example, an esterified product of phthalic anhydride, etc., and a substance having a hydroxyl group and an ethylenically unsaturated group, such as β-hydroxyethyl (meth)acrylate, an alkyl ester of acrylic acid or methacrylic acid, such as (meth)acrylic acid. Methyl ester, (meth)acrylic acid ethyl ester, (meth)acrylic acid butyl ester, (meth)acrylic acid 2-ethylhexyl ester, etc., trimethylhexamethylene diisocyanate, dihydric alcohol, and
A urethane di(meth)acrylate compound obtained by reacting a monoester of (meth)acrylic acid with a dihydric alcohol, a urethane di(meth)acrylate compound obtained by reacting trimethylhexamethylene diisocyanate, a dihydric alcohol, and 2-hydroxyethyl (meth)acrylate. Urethane di(meth)acrylate compounds and the like can also be used. Two or more of these compounds may be used in combination.

The photosensitive 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 such as 2-ethylanthraquinone, 2-butylanthraquinone, octamethylanthraquinone, 1,2-benzanthraquinone, and 2,3-biphenylanthraquinone, and diacetyl. , ketoaldonyl compounds such as benzyl, α-ketaldonyl alcohols and ethers such as benzoin and pivalone, α-phenyl-
α such as benzoin, α, α-jethoxyacetophenyl, etc.
- Hydrocarbon-substituted aromatic acyloins, benzophenone,
4. Aromatic ketones such as 4'-bisdialkylaminobenzophenone, 2-methylthioxanthone, 2,4
- Thioxanthone such as diethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, and 2-ethylthioxanthone are used. These compounds may be used alone or in combination of two or more.

In addition, as a sensitizer system, 2,4.5-)lyarylimidazole dimer and 2-methylcaptobenzoquinazole, leuco crystal violet, tris(4-diethylamino-2-methylphenyl)methane, etc. A combination is used. Also, additives which do not have photoinitiating properties by themselves but which, when used in combination with the above compounds, result in a sensitizer system with better overall photoinitiation performance, such as triethanolamine for benzophenone, etc. Tertiary amines and the like can also be used.

The sensitizer and/or sensitizer system is preferably 2-methyl-
It is a combination of 1-(4-(methylthio)phenyl-2-morpholinopropanone-1 and 4.4'-bis(diethylamino)benzophenone.

The photosensitive composition of the present invention further contains, as an essential component (C), a compound represented by the general formula (I), which is a backfogging inhibitor. As the alkoxy groups R1 and R2 in general formula (I), methoxy group, ethoxy group, propyloxy group, isopropyloxy group, butyloxy group,
Examples include 5ec-butyloxy group and tert-butyloxy group.

Examples of the alkyl group R1 in general formula (1) include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a 5ec-butyl group, a tert-butyl group, and the like. - Examples of the alkyl group of the alkyl sulfonate group in Funazou (I) include the alkyl groups listed above. Examples of the compound represented by the general formula (I) include 9
, 10-jethoxyanthracene, 2-ethyl-9,1
Examples include ethyl 0-dimethoxyanthracene, 9,10-dimethoxyanthracene-2-sulfonate, and the like.

These compounds absorb the emission spectrum of 405 nm and 435 nm of the emission spectrum of high-pressure mercury lamp,
It is also a compound that causes a photocrosslinking reaction, and these can be used alone or in combination of two or more.

In the present invention, essential component (A) from the viewpoint of the effect obtained
It is preferable to use the essential component (B) in a range of 0.1 to 80 parts by weight and the essential component (C) in a range of 0.01 to 30 parts by weight based on 100 parts by weight. If (B) is too small, the sensitivity tends to decrease, and if it is too large, the heat resistance tends to decrease.

Furthermore, if the amount of (C) is too small, the effect of preventing back fogging will decrease, and if it is too large, the sensitivity and heat resistance will tend to decrease.

The photosensitive composition of the present invention includes the above (A), (B) and (C).
) In addition to the component, one or more of a linear polymer compound, a thermosetting compound, and a compound having a thermally crosslinkable functional group and a polymerizable vinyl group can be contained.

As a linear polymer compound, for example, Japanese Patent Publication No. 41-15
Thermoplastic polymers described in Japanese Patent No. 932 can be used. Preferred linear polymer compounds include, for example, vinyl monomers such as methyl methacrylate, ethyl acrylate, acrylic acid, styrene, 2-hydroxyethyl methacrylate, t-butylaminoethyl methacrylate, acrylamide, acrylonitrile, and vinyl acetate. These include vinyl-based polymer compounds obtained by polymerizing or copolymerizing, synthetic rubbers such as butadiene/acrylonitrile copolymers, butadiene/acrylonitrile/styrene copolymers, linear polyurethane compounds, alcohol-soluble nylons, and the like.

Two or more of these linear polymer compounds may be used in combination.

In addition, examples of the thermosetting compound that can be contained in the photosensitive composition of the present invention include epoxy resins, melamine resins, etc., and these may be used in combination of two or more kinds. It may be used in combination with other compounds.

Further, examples of the compound having both a thermally crosslinkable functional group and a polymerizable vinyl group that can be contained in the photosensitive composition of the present invention include oligomers having an epoxy group and a polymerizable vinyl group in the side chain.

The oligomer is disclosed in JP-A-61-132947, JP-A-60-107785, and JP-A-60-107786.
Preferably, a small amount (total 2
Isocyanate ethyl methacrylate is added to the hydroxyl group of the unsaturated compound obtained by addition-reacting a compound having 5 epoxy groups with an unsaturated carboxylic acid in an acid equivalent/epoxy equivalent ratio of 0.1 to 0.98. , is an oligomer obtained by reacting in a range where the isocyanate equivalent/hydroxyl group equivalent ratio is 0.1 to 1.2.

As the compound having two epoxy groups, for example, bisphenol A type epoxy resin obtained by reacting bisphenol A and epichlorohydrin (for example, manufactured by Shell Chemical Co., Ltd., trade name Epicote 812,
Epicort 828, Epicor) 1001, etc.), brominated bisphenol A type epoxy resins (e.g. manufactured by Tobu Kasei Co., Ltd., trade name Ebitoto YDB-340, YDB-400 etc.), bisphenol F type epoxy resins (e.g. manufactured by Tobu Kasei Co., Ltd., Product name Epotote YDF-170, YDF-1
90 etc.), epoxy compounds obtained by adding alkylene oxide to bisphenol 8 and then reacting with epichlorohydrin (for example, Kyoeisha Yushi Co., Ltd., trade name Meiko Polite 3002 etc.), hydrogenated bisphenol A type epoxy resin (for example, Tobu Kasei Co., Ltd.) Manufactured by Santoto 5T-1
000, 5T-3000, etc.), glyoxal type epoxy resin (for example, Tobu Kasei Co., Ltd., trade name Meiko Bototo YD)
G-414, etc.), glycidylamine type epoxy resin (for example, manufactured by Tobu Kasei Co., Ltd., trade name Epotote YDM-120)
, YH-434, etc.), orthocresol novolac type epoxy resin (for example, manufactured by Nippon Kapaku Co., Ltd., trade name EOCN1
02, etc.), phenol novolak type epoxy resin (for example, Tobu Kasei Co., Ltd., trade name YDPN-638, etc.), brominated phenol novolac type epoxy resin (for example, Nippon Kapaku Co., Ltd., trade name B R, E N, etc.), Alicyclic epoxy compound (for example, Chisso Corporation, trade name Chissonox 2)
21, Chissonox 201, etc.), glycidyl ether type epoxy resins obtained by the reaction of dicarboxylic acids such as phthalic acid with epichlorohydrin (for example, manufactured by Showa Denko K.K., trade names Shodine 508, Shodine 540,
Shodyne 550, etc.), glycidylamine type epoxy resin (manufactured by Shell Chemical Co., Ltd., trade name Epicote 604, etc.),
Examples include trimethylolpropane polyglycidyl ether.

As the unsaturated carboxylic acid, acrylic acid, methacrylic acid, β-furylacrylic acid, β-styrylacrylic acid, etc. are used.

Two or more kinds of compounds having both a thermally crosslinkable functional group and a polymerizable vinyl group may be used in combination. Further, it may be used in combination with the linear polymer compound and/or thermosetting compound.

Furthermore, the photosensitive composition of the present invention may contain other subsidiary components. The secondary components include thermal polymerization inhibitors, dyes, pigments, fillers, coatability improvers, antifoaming agents,
Examples include flame retardants, flame retardant aids, adhesion improvers, and latent curing agents for epoxy resins.

Next, a method for manufacturing a printed wiring board on which a solder resist according to the present invention is formed will be explained.

When forming a photosensitive layer using the above-mentioned photosensitive composition, for example, the photosensitive composition is dissolved in an organic solvent such as methyl ethyl ketone, methyl cellosolve acetate, ethyl cellosolve acetate, cyclohexanone, etc., and this solution is applied by dip coating or flow coating. By applying the coating directly onto the substrate to be processed and protected using conventional methods such as coating, roll coating, and screen printing, and drying, the substrate is then turned over and the same process is performed to coat both sides of the substrate. A photosensitive layer with a thickness of 10 to 150 μm can be easily formed.

Alternatively, the photosensitive element obtained by coating a solution of the photosensitive composition on a support film such as a polyethylene terephthalate film or a polyimide film by a knife coating method, a roll coating method, etc. and drying the solution is heated. It is also possible to form a photosensitive layer by laminating the photosensitive layer on both sides of the substrate simultaneously under heat and pressure. At this time, if the board has irregularities of 10 μm or more, such as a printed wiring board on which conductor wiring lines are formed, a
It is preferable to laminate under a vacuum of mmHg or less. As a device for this purpose, for example, the Japanese Patent Publication No. 55-13341
The laminating apparatus described in the publication 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 formed photosensitive layer are performed by conventional methods. That is, an ultra-high-pressure mercury lamp, a high-pressure mercury lamp, or the like is used as a light source, and the layer of the photosensitive resin composition is imagewise exposed directly or through a negative mask through a support film. After exposure,
If the support film remains, the support film 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.

The image-like protective film obtained by the above method is a corrosion-resistant film for ordinary etching, plating, etc., but after development, it can be further exposed to active light and heat treated at 80 to 200°C. A protective film with even better properties can be obtained. The order of exposure to active light and heat treatment may be either first.

The printed wiring board on which the conductive pattern is formed in the present invention may be a multilayer printed wiring board.

〔Example〕

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples.

In addition, parts in Examples and Comparative Examples indicate parts by weight.

Example 1 (a) Synthesis of urethane diacrylate compound A Trimethylhexamethylene diisocyanate 16
80 parts (16 equivalents) toluene (solvent)
1200 parts di-n-butyltin dilaurate (catalyst) 1 part Bl, 6-hexanediol 472 parts (8 equivalents) C2-hydroxyethyl acrylate 928 parts (8 equivalents) Toluene (solvent) 88 parts Hydroquinone (thermal polymerization inhibitor) 0 .4 parts D methanol (terminator)
The above contents were added to a reactor with a capacity of about 51 which can be heated and cooled, equipped with a 32-part thermometer, a stirrer, a cooling tube, a nitrogen gas inlet tube and a dropper, and the mixture was heated to 60°C with stirring.
The temperature rose to . While keeping the reaction temperature at 55-65℃, about 3
B was added dropwise evenly over time. After the completion of dropping B, the temperature was kept at 60°C for about 2 hours, and then C was uniformly dropped at a temperature of 60'C over about 3 hours. After the dropwise addition of C was completed, the reaction temperature was gradually raised to 8°C over about 5 hours. after that,
The temperature was lowered to 60°C, D was added, and stirring was continued for about 1 hour. In this way, a solution of the urethane diacrylate compound was obtained.

Thereafter, it was dried under reduced pressure to obtain a viscous urethane diacrylate compound.

(b) Preparation of photosensitive composition Urethane diacrylate compound 40 parts Trimethylolpropane triacrylate 10 parts Methyl methacrylate/methacrylic acid/tetrahydrofurfuryl methacrylate (88/2/2
0 weight ratio) copolymer (molecular weight approximately 150,000, glass transition temperature 95°C) 47 parts Benzophenone 4 parts 4.4'-Bis(diethylamino) Benzophenone 0.2 parts 9.1
0-Jethoxyacetracene 1 part p-methoxyphenol 0.1 part Crystal violet 0.1 part Methyl ethyl ketone
80 parts talc
A solution of the photosensitive composition was prepared using 10 parts of the above formulation.

(c) Formation of a cured film On both sides of the printed wiring board on which the conductor pattern is formed, (b)
The photosensitive composition prepared above was applied by dip coating and dried at 80° C. for 20 minutes. Thickness after drying is approximately 30mm
It was μm. A negative film was adhered to both sides of a printed wiring board with a thickness of 0.6 m on which a conductor pattern was formed and a layer of the photosensitive composition was formed, and a 200 mJ /cffl
exposed to light.

1.1.1-) using dichloroethane at 20°C.
Spray developed for 0 seconds.

When the cured film on the printed wiring board that had gone through the above steps was observed, there was no development residue. Furthermore, the printed wiring board was exposed to an ultraviolet irradiation device (manufactured by Toshiba Denzai Co., Ltd., rated voltage 200 V).
, rated power consumption cuff, 2kW, compatible lamp H5600L/
2. Using one lamp), ultraviolet rays were irradiated at an amount of 2 J/cnfO, and then heat treatment was performed at 160° C. for 20 minutes. After the printed wiring board thus obtained was subjected to flux treatment, it was immersed in a solder bath heated to 260° C. for 10 seconds to obtain a printed wiring board on which sharp edge-shaped resist resists were formed.

Example 2 In Example 1, 4 parts of benzophenone contained in the photosensitive composition was replaced with 2-methyl-1-(4-(methylthio)phenyl]-2-morpholinopropanone-1 (manufactured by Ciba Geigi, trade name Irgar Cure 907). ) A photosensitive composition was prepared by changing the amount to 4 parts, and the same treatment as in Example 1 was performed, and a printed wiring board was obtained in which a solder resist with sharp edges and excellent surface gloss was formed. .

Comparative Example 1 The photosensitive composition prepared in Example 1(b) was coated with 9°10-
When a photosensitive composition similar to that of Example 1 was prepared except that no jetoxyanthracene was added, and the same treatment as that of Example 1 (C) was performed, development residues were found on both sides of the printed wiring board. Further development was carried out, but the residual development did not disappear.

Example 3 (a) Synthesis of photopolymerizable unsaturated compound A Orthocresol novolak type epoxy resin, EOCNI O2 Epoxy equivalent: 280) 1095 parts Methyl ethyl ketone 800 parts B Acrylic acid
69 parts Benzyltrimethylammonium chloride 7 parts p-methoxyphenol 3 parts Methyl ethyl ketone 100 parts C isocyanate Ethyl methacrylate 163 parts Dibutyltin dilaurate 0.5 parts Methyl ethyl ketone 100 parts D Methanol 10 parts Thermometer, stirrer, cooling tube and dropper The above A was added to a reactor No. 51 that can be heated and cooled, and the temperature was raised to 60° C. while stirring to uniformly dissolve. 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 stirring was continued at 80°C for about 15 hours to bring the acid value of the reaction system to 1 or less. The temperature was then lowered to 60°C, and C was uniformly added dropwise over about 3 hours while maintaining the reaction 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 increased to 60°C.
D was added and stirring continued for about 1 hour. In this way, an ortho-cresol novolac type epoxy resin/acrylic acid/isocyanate ethyl methacrylate (acid equivalent/epoxy equivalent ratio = 0.2, isocyanate equivalent/hydroxyl group equivalent ratio = 1.1) type photopolymerizable non-volatile resin with a non-volatile content of 57% was obtained. A solution of saturated compound was obtained.

(b) Preparation of photosensitive composition Solution of photopolymerizable unsaturated compound (non-volatile content 50 parts) 88 parts Benzophenone 2.0 parts 4.4
'-Bis(diethylamino) benzophenone 0.2 parts 2-ethyl-9,10-dimethoxyanthracene 1 part Micro Ace P-4 (Nippon Talc Co., Ltd. ultrafine talc average particle size 1.5 μm) 30 parts Phthalocyanine Green 0.1 part moda flow
A solution of a photosensitive resin composition was prepared by mixing and dispersing 0.1 part of the above formulation using a roll mill.

(c) Formation of a cured film The solution of the photosensitive resin composition obtained in (b) was applied onto a copper-clad printed wiring board for 20 minutes at room temperature and then for 20 minutes at 80°C.
After drying for a minute, the printed wiring board was reversed and the same process was repeated to form photosensitive layers with a thickness of 40 μm on each side of the printed wiring board with a thickness of 0.68 mm on which a conductor pattern had been formed.

Next, both sides were simultaneously exposed at 200 mJ/cm through a negative mask using a Phoenix 3000 exposure machine.

After exposure, heat at 80°C for 5 minutes, leave at room temperature for 30 minutes, and then heat at 20°C using 1.1.1-trichloroethane at 90°C.
Spray developed for seconds.

When the printed wiring board was observed after development, there was no development residue. Furthermore, using Toshiba ultraviolet irradiation equipment,
After irradiating with IJ/cd, 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 was soldered using rosin-based flux A-226 (manufactured by Tamura Kaken Co., Ltd., trade name) at 260°C for 10 seconds, and then purified with Triclean for 10 minutes at 25°C. 202E 107 parts Condition B (-65℃ 30 minutes, room temperature within 5 minutes, 125℃ 3
A thermal shock test was conducted for 50 cycles (0 minutes), but □
No cracking or peeling of the film was observed.

These results showed that the solder resist formed using the photosensitive composition of the present invention has excellent cold and thermal shock resistance, and a printed wiring board with excellent long-term reliability can be obtained.

Example 4 In Example 3, the photosensitive composition was prepared by changing 2 parts of benzophenone contained in the photosensitive composition to 2 parts of 2-methyl-1(4-(methylthio)phenylcy2-morpholinopropanone-1). was prepared and subjected to the same treatment as in Example 3(c). As a result, a printed wiring board was obtained which exhibited properties equivalent to those in Example 3, had a sharp edge shape, and had a solder resist with excellent surface gloss formed thereon. were obtained, and these had excellent cold shock resistance.

Comparative Example 2 A photosensitive composition was prepared in the same manner as in Example 3(b), except that 2-ethyl-9,10-dimethoxyanthracene was not added, and the same treatment as in Example 3(C) was performed. However, there was development residue on both sides due to back fogging. Further development was carried out, but the residual development did not disappear.

Example 5 In Example 3, 1 part of 2-ethyl-9,10-dimethoxyanthracene contained in the photosensitive composition was replaced with 9.10-
A photosensitive composition was prepared by changing the composition to 1 part of ethyl jetoxyanthracene-2-sulfonate, and when it was processed in the same process as in Example 3(c), it showed the same characteristics as Example 3, and the edge shape Printed wiring boards were obtained on which a solder resist with a sharp surface and excellent surface gloss was formed, and these had excellent resistance to cold and thermal shock.

Example 6 In Example 5, the photosensitive composition was prepared by changing 2 parts of benzophenone contained in the photosensitive composition to 2 parts of 2-methyl-1-(4-(methylthio)phenylcy2-morpholinopropanone-1). When a product was prepared and processed in the same process as Example 3 (C), it showed the same characteristics as Example 3, and a printed wiring with sharp edges and a solder resist with excellent surface gloss. Plates were obtained which had excellent cold shock resistance.

〔Effect of the invention〕

The photosensitive composition of the present invention produces a solder resist with excellent resolution, no development residue due to back-fogging, and sharp edges.

Therefore, according to the present invention, in particular, photosensitive layers are provided on both sides of a double-sided printed wiring board, and both sides are exposed simultaneously to eliminate development residue due to back fog (double-sided printing having solder resist with sharp edges on both sides). Wiring boards can be easily manufactured.Furthermore, the resulting solder resist is
A printed wiring board with excellent surface gloss and resistance to thermal shock and long-term reliability can be obtained.

Claims (4)

[Claims] 1. (A) a compound having at least one ethylenically unsaturated group; (B) a sensitizer and/or sensitizer system that generates free radicals upon actinic light; and (C) an anti-backfogging agent. I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, R_1 and R_2 represent an alkoxy group, and R_
3 represents a hydrogen atom, an alkyl group, or an alkyl sulfonate group. 2. (B) The sensitizer and/or sensitizer system that generates free radicals by actinic light is 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone-1 and 4,4' The photosensitive composition according to claim 1, which is -bis(diethylamino)benzophenone. 3. A solder resist is formed by forming a layer of the photosensitive composition according to claim 1 on a printed wiring board on which a conductive pattern is formed, and then exposing the layer to actinic rays in an imagewise manner and developing it. A manufacturing method for printed wiring boards. 4. 4. A method for producing a printed wiring board on which a solder resist is formed according to claim 3, wherein a layer of the photosensitive composition according to claim 1 is formed on both sides of the printed wiring board, and exposure is performed on both sides simultaneously.