JPS6156340A - Resist composition for forming printed wiring board circuit - Google Patents

Abstract

PURPOSE:To prevent the deterioration of the plating brightness on a substrate near a resist film and to increase current density by using a compsn. contg. an org. plating brightener at 0.001-10wt% by the weight of the compsn. CONSTITUTION:A resist compsn. which forms a prescribed circuit by, for example, a screen printing method and is thermally set, for example, a combination of an epoxy novolak resin and amine or the like is used as the resist compsn. Ordinarily used components (film formable polymer, etc.) are used for the compsn. at the ratio at which said components are ordinarily used. The resist compsn. contg. an ethylenic unsated. monomer having >=100 deg.C b. p. under atm. pressure and photopolymn. initiator or heat polymerization initiator and other additives is preferable. On the other hand, the org. plating brightener is added to the compsn. in a 0.001-10wt% range according to the kind thereof and the solubility in the compsn.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present BA relates to a resist composition for forming printed wiring board circuits.

(Prior Art) Electroplating is currently the mainstream method for forming circuits on printed wiring boards. This method involves first protecting the parts of the copper-clad laminate other than the circuit with a resist film, then electroplating the exposed copper parts, then peeling off the resist and etching. This is a method of forming a circuit.

Recently, studies have been underway to reduce the manufacturing cost of printed wiring boards, but in order to reduce the manufacturing costs of printed wiring boards, it is necessary to shorten the plating time, which takes a long time during the manufacturing process. be.

Generally, in order to shorten the plating time, a method is adopted in which the current density, temperature, etc. are increased to accelerate the deposition of the plating. However, although the plating time can be shortened by increasing the current density and temperature in this manner, there is a drawback that the plating on the substrate near the plating resist film loses its luster. As a method to prevent these phenomena, (l) a method of adding a large amount of plating brightener to the electroplating bath;

(2) At the design stage of a printed wiring board, methods such as designing a uniform plating area ratio over the entire circuit board are taken. However, although the above method (1) improves the plating precipitation and the plating gloss, other working conditions are narrow and process control becomes strict. In addition, if method (2) is used, the process becomes complicated, such as attaching conductive tape to the board before it is attached, and it also imposes restrictions on the artwork of the printed circuit board, so it is difficult to say that it is industrially useful. .

(Object of the Invention) An object of the present invention is to provide a resist composition for forming printed wiring board circuits that improves these problems.

(Structure of the Invention) The present invention uses an organic plating brightener in an amount of 0.00% based on the weight of the composition.
The present invention relates to a resist composition for forming one path on a printed wiring board, containing 1% to 10% by weight.

The resist composition of the present invention is not particularly limited; for example, a resist composition in which a predetermined circuit is formed by a screen printing method and then thermally cured; for example, a combination of an epoxy novolac resin and amines, an ethylenically unsaturated compound; and a thermal polymerization initiator, photocurable resist compositions such as ethylenically unsaturated compounds and photoinitiators, self-sensitization of ethylenically unsaturated compounds such as polystyrene derivatives, and the entire circuit. A negative-working photosensitive resin composition used by applying a resist composition, curing it with light through a negative, and removing the unexposed areas with a developer; it becomes soluble in dialkali type developers when exposed to light. A positive photosensitive resin composition or the like is used.

Nine commonly used components are added to the resist composition as necessary. For example, pigments, dyes, thermal polymerization inhibitors, hardeners, solvents, film-forming polymers such as methyl acrylate polymers, and the like are used in normally used amounts.

A resist composition containing an ethylenically unsaturated monomer having a boiling point of 100° C. or higher at normal pressure, a photopolymerization initiator or a thermal polymerization initiator, and other additives is preferred.

The organic plating brightener used in the present invention includes:

Depending on the type of plating bath, for example, in copper sulfate plating, gelatin 9. Organic polymer colloids such as glue and molasses, thiourea, saccharin, dextrin, etc.
For nickel plating, benzenesulfonate, naphthalenesulfonate, benzenesulfonamide, saccharin,
Nitrogen cyclic compound.

Polyamine etc. are used. These may be used alone or in combination of two or more. In addition, for zinc plating, aldehydes, ketones, glue, etc. may be used, but there is no particular restriction, and these may be used in one form or in combination of two or more types.

The amount of the organic plating brightener should be determined depending on the type of the plating brightener and its solubility in the resist composition, but it is added in an amount of 0.001% to 10% by weight based on the resist composition. If the amount is less than this, it is not possible to improve the phenomenon in which the plating gloss in the vicinity of the resist film is lost. Also.

If more than 10% by weight is added, the curability, plating resistance, electrical properties, etc. of the resist composition will decrease, and the properties as a resist will be adversely affected. Regarding the effects of these organic plating brighteners, there are various documents (for example, "Plating Technology J
Published in 1979 (Nikkan Kogyo Shimbun), Chemical Handbook (Maruzen 11)
According to this, adding a plating brightener to the plating bath improves the plating deposition properties, but also increases the current density (overcurrent) that worsens the plating deposition properties. It will be done. These organic plating brighteners are known, and the present invention uses these brighteners in a resist composition.

(Effects of the Invention) The use of the OAK regimen composition of the present invention eliminates the phenomenon of deterioration of the plating gloss on the substrate near the resist film, and has the advantage that the current density can be increased accordingly.

The phenomenon of loss of gloss in the vicinity of the resist film occurs when metal ions in the plating bath concentrate in this vicinity, resulting in a partial overcurrent state. The organic plating brightener is gradually eluted from the resist.

The plating brightness in the vicinity of the resist film is improved, and in addition, the organic plating brightener in the resist composition always maintains a constant concentration of brightener in the plating bath to compensate for the consumption of the plating brightener already present in the plating bath. can be present, and it is possible to obtain uniform gloss on the electrical circuit pattern.

Further, according to the resist composition according to the present invention.

The current density is high and the work time can be significantly shortened.

It also stabilizes the process.

The resist composition of the present invention is prepared by coating and drying the solution on, for example, a polyester film as a support, and pasting a protective film such as a polyethylene film thereon, a resist composition layer, and a resist composition layer. It may also be used as a laminate consisting of a protective film.

(Example) Comparative examples and examples are shown below.

Comparative example 1 A printed wiring board was obtained in the following manner.

First, a solution is prepared using secondary components.

Polymethyl methacrylate 60g Trimethylolpropane triacrylate 309 N,N-dimethylaminobenzophenone 0.2g Benzophenone 5g Victoria Pure Blue dye 0.59 Methyl ethyl keto 7
100 g of each monomer was dissolved in methyl ethyl ketone and applied to a thickness of 50 μm on a copper-clad plate.

Remove the solvent by drying with warm air at 80°C and use a negative.
Only the predetermined circuit portions were exposed to 50 mJ/cm" and developed.

The remaining unexposed areas were removed using 1.1.1-trichloroethane to create a substrate having a predetermined resist image.

Next, a neutral surfactant aqueous solution (trademark Nutra Tariff)
After degreasing the surface using a 30% by weight aqueous solution of amthonium persulfate, the copper surface was etched for 90 seconds, and the copper surface was thoroughly washed again with water. The substrate made in this way still has a resist image,
The area without the resist image formed a clean copper surface.

Example 1 Next, 3 g of saccharin was added to the composition of Comparative Example 1, and a substrate was prepared in the same manner.

Pt12'FIIJ 2
A first thermopolymerizable composition was prepared, and a circuit with a thickness of 25 μm was formed on a copper-clad laminate by screen printing.

Dibromoglycidyl ether 8g 2-ethyl-4-methylimidazole 2g talc (manufactured by Nippon Merck) 7g phthalocyanine green 0.2g butyl cellosolve
After heating and curing at 12,980° C. for 3 hours, degreasing and etching were performed in the same manner as in Comparative Example 1 to prepare a printed circuit board.

Example 2 A composition prepared by adding 3 g of saccharin to the composition of Comparative Example 2 was prepared, and a printed circuit board was prepared in the same manner.

Nickel plating was performed on these substrates using Leftronic 10-03 manufactured by Nippon Electro Engineering Co., Ltd., and the plating gloss was evaluated.

Table 1 Current density of nickel plating and plating gloss O...
Glossy (11 plated surface x...no gloss (2) Plating near the resist As shown in Table 1, Example 1 in which saccharin, an organic plating brightener, was included in the resist composition In No. 2, the plating gloss near the resist was good even at 3 A/d[I+2, and was improved compared to Comparative Example 1 and Comparative Example 2.

Example 3 A resist composition was prepared by adding o, osg of thiourea, and 1 g of saccharin to the composition of Comparative Example 1, and a printed circuit board was prepared in the same manner as in Comparative Example 1, and sulfuric acid steel plating was performed. As a result, the plating gloss near Resis S was not lost up to 5 A/dm2.

Claims (1)

[Claims] 1. A resist composition for forming a circuit on a printed wiring board, which contains an organic plating brightener in an amount of 0.001% to 10% by weight based on the weight of the composition. 2. A laminate comprising a support, a layer of the resist composition according to claim 1, and a protective film.