JPH09309944A - Photopolymer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photopolymer composition which can be developed with a water-based developing solution by using a photosensitive oligomer (A) having a phenolic hydroxyl group and an acrylic group in the molecule, an epoxy compound (B), a radical photopolymerization initiator (C) and a cationic photopolymerization initiator (D) as the essential components. SOLUTION: Component A is not particularly limited so far as it is soluble in an aqueous alkali solution. It is exemplified by a novolac resin or a polyvinylphenol resin. Component B used may be a known epoxy resin and is exemplified by a bisphenol A epoxy resin. Component C is exemplified benzoin, benzil or a mixture of at least two compounds. Its amount of use is 0.05-25wt.% based on the composition. Component D is exemplified by diphenyliodonium hexafluoroantimonate and is used in an amount of 0.05-25wt.% based on the composition. When this composition is used as a solder resist, it is mixed with a diluent to form an ink, and this ink is applied to the entire surface of a printed wiring board on which a circuit has been formed.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a photosensitive resin composition capable of forming a pattern by exposure and development, and a resist ink using the same.

[0002]

2. Description of the Related Art As electronic devices become smaller and more sophisticated,
The printed wiring boards used for this have also been densified. Therefore, materials used for printed wiring boards are required to have finer workability, and materials that have been conventionally subjected to screen printing or the like are being replaced with materials that can be patterned by exposure and development. In recent years, so-called photo-developable type solder resists have been widely used, and alkali-developable type ones are mainly used from the viewpoint of preserving the working environment and preventing pollution. The technology relating to this is already known in many documents such as Japanese Patent Laid-Open No. 61-243869. However, conventional solder resists could be used if they simply had solder heat resistance during component mounting and insulation after mounting. Recently, however, the progress in the manufacturing method of printed wiring boards and the expansion of their application fields It has become necessary to meet more demanding performances. More specifically, first, gold plating is performed for the purpose of preventing circuit oxidation and bonding when directly mounting an IC, and resistance to a plating solution is required.
In particular, it is difficult to obtain durability against a strong alkaline gold plating solution that can obtain a good quality plating film. Further, a printed wiring board has been developed to reduce the cost of the IC package, but the solder resist used here is required to have resistance under a severe environment such as a pressure cooker test. In addition, a method of manufacturing a printed wiring board by a build-up process using a solder resist as an interlayer insulating material of a multilayer board (for example, Japanese Patent Laid-Open No. 4-148590) has been proposed, but in this case, it has higher insulation and heat resistance than conventional ones. is required.
However, conventional solder resists are not satisfactory in these characteristics, and in practical application of these new techniques, there is a strong demand for solder resists excellent in the above characteristics. Based on these circumstances, the inventors
-56336 discloses a photosensitive resin composition containing a compound having a phenolic hydroxyl group, a photosensitive oligomer derived from an acrylic compound having an epoxy group or an isocyanate group, and an epoxy compound as essential components. This is a useful invention which can be developed with an alkaline aqueous solution, and which gives a cured product having excellent heat resistance and plating resistance. However, the composition of the present invention has room for improvement in that it is inferior in productivity due to low sensitivity and long exposure time. As a photosensitive resin composition using a phenolic resin, Japanese Patent Laid-Open No. 63-71840 discloses a composition containing a phenolic resin, an epoxy resin, and a cationic photopolymerization initiator. However, this is a phenol resin soluble in alkali that contributes to developability.
Since it does not have photosensitivity, the coating film is easily eroded by the developing solution, and there is a problem that it is difficult to leave a fine pattern, and it is difficult to apply it to the formation of a fine pattern. In addition, in Japanese Examined Patent Publication No. 63-312375, an epoxy resin having a softening point of 50 ° C. or higher, a reaction product of a novolac epoxy resin, acrylic acid, and a polybasic acid anhydride, a photopolymerization initiator, and each component of a photocationic polymerization initiator are included. However, since the composition is a carboxylic acid-containing resin composition, it lacks resistance to a strongly alkaline plating solution, and in a high temperature and high humidity environment such as a pressure cooker test. However, it is not satisfactory in that the resin is severely deteriorated.

[0003]

In view of the above situation, the present invention provides a photosensitive resin composition which can be developed with a water-based developer, and is excellent in various properties such as high sensitivity, plating resistance and moisture resistance. An object of the present invention is to provide a resist ink capable of obtaining a cured product.

[0004]

As a result of intensive studies, the inventors have found that this problem can be solved by the following photosensitive resin composition, and have completed the present invention. That is, a photosensitive resin composition containing (A) a photosensitive oligomer having a phenolic hydroxyl group and an acrylic group in the molecule, (B) an epoxy compound, (C) a photoradical polymerization initiator, and (D) a photocationic polymerization initiator. Is.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Next, each component constituting the composition of the present invention will be described in detail. First, the photosensitive oligomer as the component (A) is not particularly limited as long as it has a phenolic hydroxyl group and an acrylic group in the molecule and is soluble in an alkaline aqueous solution. Alkali-soluble means that when a substrate coated with the composition containing the present photosensitive oligomer is exposed to an alkaline aqueous solution, it is completely removed together with other compounding components. Specifically, JP-A-7-56
The photosensitive oligomer disclosed in 336 can be used. That is, a photosensitivity obtained by adding an acrylic compound having an epoxy group or an isocyanate group in the molecule to a part of the phenolic hydroxyl group of a compound represented by novolac resin or polyvinylphenol resin and having two or more phenolic hydroxyl groups. It is an oligomer.

Next, as the epoxy compound as the component (B), known and commonly used epoxy resins can be used. For example, bisphenol-A type epoxy resin, bisphenol-F type epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin, bisphenol-A
-Novolak type epoxy resin, glycidyl ether of phenol and hydroxybenzaldehyde condensate, bisphenol S type epoxy resin, biphenol type epoxy resin, alicyclic epoxy resin, triglycidyl isocyanurate, etc. can be used. Further, a homopolymer of glycidyl (meth) acrylate or a copolymer with another monomer can be used. The epoxy resin is not particularly limited as long as it does not inhibit cationic polymerization, and may be used alone or in combination of two or more. If necessary, a polyfunctional epoxy resin partially modified with a fatty acid such as acrylic acid can be used.

Next, as the photoradical polymerization initiator of the component (C), benzoins such as benzoin, benzyl, benzoin methyl ether, benzoin isopropyl ether, benzoin alkyl ethers, acetophenone,
2,2-dimethoxy-2-phenylacetophenone,
2,2-diethoxy-2-phenylacetophenone,
Acetophenones such as 1,1-dichloroacetophenone and 1-hydroxycyclohexyl phenyl ketone, 2-
Methylanthraquinone, 2-ethylanthraquinone, 2
Anthraquinones such as -tert-butylanthraquinone, 1-chloroanthraquinone, 2-amylanthraquinone and 2-aminoanthraquinone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2-
Chlorothioxanthone, 2,4-diisopropylthioxanthone and other thioxanthones, acetophenone dimethyl ketal, benzyl dimethyl ketal and other ketals, benzophenone, methylbenzophenone, 4,4 ′
There are benzophenones such as dichlorobenzophenone and xanthones, which can be used alone or in combination of two or more kinds. A suitable range of the amount of the photo radical polymerization initiator used is 0.05 to 25% by weight of the composition,
It is preferably 2 to 10% by weight. If it is less than this range, the sensitivity tends to be poor.

As the photocationic polymerization initiator of the component (D), known iodonium salts, sulfonium salts, phosphonium salts, ferrocenes and the like can be used. Specific examples include diphenyliodonium hexafluoroantimonate, diphenyliodonium hexafluorophosphate, diphenyliodonium tetrafluoroborate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium hexafluorophosphate, triphenylsulfonium tetrafluoroborate, (1-6 −η− cumene) (η−
Cyclopentadienyl) iron hexafluorophosphate (IRGACURE2 manufactured by Ciba-Geigy Co., Ltd.)
61) and the like. These can be used as one kind or as a mixture of two or more kinds. For example, Union Carbide Co., Ltd. CYRACURE-UVI-6990, UVI
Some of them are commercially available as a mixture, such as -6974, and can be used in the same manner as the above compounds. A suitable range of the amount of the cationic photopolymerization initiator used is 0.05 to
It is 25% by weight, preferably 1 to 10% by weight. If it is less than this range, the sensitivity tends to be poor. On the other hand, if more than this range is added, the sensitivity cannot be expected to be improved, which is not preferable.

A photopolymerizable vinyl monomer may be added to the photosensitive resin composition of the present invention as a diluent or a crosslinking agent, if necessary. A typical example of the photopolymerizable vinyl-based monomer is 2-hydroxyethyl acrylate.
, Hydroxyalkyl acrylates such as 2-hydroxybutyl acrylate, ethylene glycol, methoxytetraethylene glycol, polyethylene glycol
Glycol, mono- or diacrylates of glycol such as propylene glycol, polyhydric alcohols such as trimethylolpropane, pentaerythritol and dipentaerythritol, or ethylene oxide, propylene oxide or ε thereof. -Caprolactone adduct polyvalent acrylates, phenoxy acrylate, phenoxyethyl acrylate and the like phenols, or ethylene oxide or propylene oxide adducts thereof acrylates, trimethylol There are epoxy acrylates derived from glycidyl ethers such as propane triglycidyl ether, and / or methacrylates corresponding to the above acrylates. Further, the above-mentioned diluents can be used by mixing two or more kinds, and a suitable range of the amount used is 1 to 50% by weight of the composition.

Further, the solder resist of the present invention may be used by adding a curing accelerator or a curing agent of an epoxy compound which exerts an effect by heating. Epoxy curing accelerators include dicyandiamide or modified products thereof, amine compounds, imidazole compounds, polybasic hydrazides, carboxylic acid compounds, phenols, quaternary ammonium salts, quaternary phosphonium salts, phosphines or These epoxy adducts, microcapsule-type curing catalysts, and the like are known. These are used in a range that does not inhibit the effect of the cationic photopolymerization initiator.

In the present invention, in addition to the above components, known and commonly used additives can be added and used. For example, as an inorganic filler, barium sulfate, barium titanate, silicon oxide powder, finely divided silicon oxide, amorphous silica, zirconium silicate, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide,
Known and commonly used materials such as mica powder can be used. Further, if necessary, phthalocyanine blue, phthalocyanine green, iodin green, disazo yellow, crystal violet, titanium oxide, carbon black,
Known and commonly used coloring agents such as naphthalene black, known and commonly used thermal polymerization inhibitors such as hydroquinone, hydroquinone monomethyl ether and phenothiazine, known and commonly used thickeners such as Aerosil and Orben, silicone-based, fluorine-based, Known and commonly used additives such as a defoaming agent of a molecular system or the like and / or an adhesion imparting agent such as a leveling agent and a silane coupling agent can be used.

The photosensitive resin composition composed of these components can be used by adding it to an ink by adding a suitable diluent and coating it on a substrate. Further, the photosensitive resin composition of the present invention can be used by being processed into a so-called dry film in advance and being attached to a printed wiring board. A fine pattern can be formed by selectively exposing the resist film thus formed on the wiring board with an active energy ray and further removing the unexposed portion with an alkaline aqueous solution.

The method of using the solder resist of the present invention will be described below. A diluent is added to the present solder resist to form an ink, and the printed circuit board on which a circuit is formed in advance is coated on the entire surface by screen printing, a coater coater, a spin coater, a spray coater or the like.
Examples of the diluent include glycol ethers such as ketone ethers such as methyl ethyl ketone, esters such as ethyl acetate and acetic acid esterified products of the above glycol ethers, petroleum-based oils such as petroleum naphtha and solvent naphtha. There is a solvent. Diluents such as the above may be used alone or
Used as a mixture of more than one species. This is heated to remove the diluent and dry the surface. Alternatively, the solder resist of the present invention may be applied to an appropriate base material such as a PET film and then dried to form a so-called dry film, which is then pressed onto a circuit and used. Then laser
The pattern is formed by direct irradiation of light or through a photomask on which a pattern is formed, and then selectively exposing it with an actinic ray such as a high pressure mercury lamp or a metal halide lamp, and developing the unexposed portion with a developing solution. Further, if necessary, after the light irradiation, an appropriate heating is performed before the development, whereby the crosslinking reaction of only the light-irradiated portion can be promoted and the contrast can be increased. This heating is desirably performed in the range of 40 to 130 ° C. Sodium hydroxide as a developing solution for pattern formation,
An alkaline aqueous solution such as potassium hydroxide or tetramethylammonium hydroxide can be used. Although an organic solvent such as methyl ethyl ketone, methyl cellosolve, and cyclohexanone can be used, it is preferable to use an alkaline aqueous solution in view of the working environment. 100 after pattern formation
By performing the heat treatment at ˜200 ° C., a permanent protective film satisfying various properties as a solder resist can be obtained. Further, after the heat treatment, an active energy ray such as an ultraviolet ray may be exposed if necessary.

[0014]

EXAMPLES The present invention will be specifically described below with reference to production examples, examples and comparative examples, but the present invention is not limited thereto. Note that "parts" and "%"
All parts are by weight unless otherwise noted.

[0015]

[Production Example] 190 parts of isophorone diisocyanate and 180 parts of carbitol acetate are placed in a reaction vessel equipped with a stirrer and a condenser and heated to 60 ° C. A solution obtained by mixing 360 parts of pentaerythritol triacrylate, 90 parts of solvent naphtha, 2 parts of dibutyltin dilaurate, and 0.5 parts of hydroquinone monomethyl ether,
The mixture was added dropwise to the reaction vessel over 1 hour, and stirring was continued for another 2 hours. Separately, 500 parts of phenol novolac resin was dissolved in 500 parts of carbitol acetate by heating at 65 ° C. and added to the above reaction solution and reacted at 60 ° C. for 20 hours. This is referred to as resin 1.

[0016]

[Comparative Production Example] 1070 parts of a cresol novolac type epoxy resin (epoxy equivalent 214) was added to 620 parts of carbitol acetate and heated and dissolved at 90 ° C. 400 parts of acrylic acid, polymerization inhibitor (p-methoxyphenol)
One part and benzyldimethylamine (6 parts) were added and reacted at 110 ° C. for 20 hours with stirring. Further, 370 parts of tetrahydrophthalic anhydride was added and reacted at 100 ° C. for 4 hours to obtain a photosensitive oligomer solution having an acid value of 50 mgKOH / g. This is referred to as resin 2.

[0017]

Example 1 Resin 1 75 parts Cresol novolac type epoxy resin (epoxy equivalent 214) 35 parts Dipentaerythritol hexahexaacrylate 5 parts 2,2-dimethoxy-2-phenylacetophenone Irgacure 651 (photo radical polymerization start manufactured by Ciba Geigy) Agent) 5 parts Irgacure 261 (photocationic polymerization initiator manufactured by Ciba Geigy) 4.8 parts Barium sulfate 30 parts Talc 20 parts Aerosil 2 parts Phthalocyanine lean 1 part Defoamer 2 parts

[0018]

[Comparative Example 1] Resin 1 75 parts Cresol novolac type epoxy resin (epoxy equivalent 214) 35 parts Dipentaerythritol hexaacrylate 5 parts Irgacure 907 (Ciba Geigy photopolymerization initiator) 5 parts Diethylthioxanthone 1 part Barium sulfate 30 Part talc 20 parts aerosil 2 parts phthalocyanine lean 1 part defoamer 2 parts

[0019]

Comparative Example 2 Polyvinylphenol (Maruzen Maruka Linker M, number average molecular weight 6000) 75 parts Bisphenol-A-diglycidyl ether 90 parts Irgacure 261 (Ciba-Geigy photocationic polymerization initiator) 4.8 parts Isopropylthioxanthone 2. 4 parts Phthalocyanine green 1 part Carbitol acetate 60 parts

After pre-kneading each of the above components, three rolls
The resist ink was prepared by kneading twice with a rumill. This resist ink was applied to the entire surface of the printed circuit board by a screen printing method. It was placed in a hot air circulating oven, dried at 80 ° C. for 30 minutes, and then cooled to room temperature to obtain a dried coating film. 50 to 2
A photomask having a line pattern of 00 micron was brought into contact with the surface of the coating film and exposed using a metal halide lamp manufactured by Oak Manufacturing. Exposure amount is 300 to 1000 mJ
/ Cm2 of 300 mJ / cm2 after exposure 8
Crosslinking was promoted by heating at 0 ° C. for 5 minutes. Next, using a 2% aqueous sodium hydroxide solution as a developing solution, development was carried out for 1 minute, washing with water and drying. After the development, each line pattern remained without being dropped was evaluated as ◯, and the dropped pattern was evaluated as x, and the resolutions of the resist inks were compared and shown in Table 1. The photosensitive resin of the present invention shown in Example 1 was shown to have high resolution at low exposure. On the other hand, in Comparative Example 1 containing no cationic initiator and Comparative Example 2 containing no cationic group in the phenol resin and containing only a cationic initiator, a fine pattern was formed when the exposure amount was small. Can not do it.

[0021]

[Table 1]

[0022]

Example 2 The ink prepared in Example 1 was applied to a printed board and dried, exposed, developed and heat-cured to form a solder resist pattern. The substrate on which the solder resist film is formed is treated with an electroless nickel plating solution ICP Nicoron manufactured by Okuno Seiyaku Kogyo at 85 ° C for 15 minutes, and 90 ° C with a substitution type electroless gold plating solution OPC Muden Gold AD manufactured by the same company at 20 ° C. Processed for a minute. Furthermore, using the reduction type electroless gold plating bath OPC Muden Gold 25 manufactured by the same company,
After plating at 30 ° C for 30 minutes, the state of peeling after the peeling test with cellophane tape was visually observed.
No resist peeling was observed. In addition, this board,
Pressure cooker tester (PC manufactured by Hirayama Seisakusho Co., Ltd.)
-422RIII), 121 ° C., 2 atm, 100
After standing for 168 hours under a saturated condition of 0.1%, it was taken out and the peeled state after the peeling test with cellophane tape was visually observed. No resist peeling was observed.

[0023]

Comparative Example 3 Resin 2 70 parts Cresol novolak type epoxy resin (epoxy equivalent 214) 30 parts Dipentaerythritol hexaacrylate 10 parts Irgacure 651 (photo radical polymerization initiator manufactured by Ciba Geigy) 5 parts Irgacure 261 (Ciba Geigy) Cationic polymerization initiator) 1 part Diethylthioxanthone 1 part Dicyandiamide 2 parts Barium sulfate 30 parts Talc 20 parts Aerosil 2 parts Phthalocyanine lean 1 part Defoamer 2 parts Kneading the above-mentioned compounding ingredients and applying in the same manner as in Example 2, Dry,
Development, exposure, and heat curing were performed to form a solder resist pattern. When this substrate was plated in the same manner as in Example 2 and subjected to a peeling test using cellophane tape, resist peeling was observed at the pattern boundary of the developed resist. On the other hand, when the substrate was subjected to a pressure cooker test under the same conditions as in Example 2, swelling of the resist film was observed and peeling was performed by a tape peeling test.

[0024]

INDUSTRIAL APPLICABILITY As described above, the solder resist using the photosensitive resin composition of the present invention can be developed with an aqueous developer containing no organic solvent, and is a conventional photosensitive resin based on phenol resin. Higher sensitivity than the composition.
In addition, it is excellent in various properties such as plating resistance and pressure cooker resistance. Therefore, it is possible to obtain an excellent solder resist which can be applied not only for general printed wiring boards, but also for advanced applications such as IC packages and build-up inner layer agents.

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Claims (3)

[Claims] 1. A photosensitive oligomer containing (A) a photosensitive oligomer having a phenolic hydroxyl group and an acrylic group in the molecule, (B) an epoxy compound, (C) a photoradical polymerization initiator, and (D) a photocationic polymerization initiator. Resin composition 2. A photosensitive oligomer having (A) a phenolic hydroxyl group and an acrylic group in the molecule, (B) an epoxy compound, (C) a photoradical polymerization initiator, (D) a photocationic polymerization initiator, and (E) a diluent. Resist ink as a component 3. A photosensitive oligomer containing (A) a photosensitive oligomer having a phenolic hydroxyl group and an acrylic group in the molecule, (B) an epoxy compound, (C) a photoradical polymerization initiator, and (D) a photocationic polymerization initiator. Printed wiring board having a cured product obtained by irradiating and heat-treating a resin composition as a constituent component