JPS609196A - Method of producing printed circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to a method V for manufacturing a printed wiring board by an additive method.
Regarding C.

[Technical background of the invention and its problems]

In general, a printed wiring board uses a copper-clad laminate as a material, and etches unnecessary portions of the copper foil layer on the surface of the board to form a desired wiring pattern. However, in the above method, the necessary copper foil part (pattern part 51))
Normally, it occupies only about 10 to 40'% of the area of the initial copper-clad laminate, and the remainder is removed by etching, which is extremely uneconomical. In addition, there are pollution problems such as waste liquid associated with the etching process, and side etching is unavoidable due to the characteristics, which has reached the limit in meeting the demands for high precision and high density.

For this reason, additive methods have been developed to improve these drawbacks. The additive method selectively forms conductive patterns on an insulating substrate by chemical plating, and there is no problem of waste of copper or pollution caused by etching, and through-holes and circuit patterns can be formed in a simple process. It has many advantages such as being able to form both at the same time. Many methods have been proposed for the additive method.

In other words, (1) Cover other parts except the necessary circuit parts with water-repellent ink or pre-catalyst-containing ink, then roughen the surface to make it hydrophilic and catalyze it to adhere plating catalyst nuclei, and then cover it with a chemical plating solution. There is a method in which the copper is immersed and then folded into the necessary circuit parts.

However, although this method is theoretically a method in which chemical plating is deposited only on the necessary circuit portions, it is extremely difficult to deposit chemical plating only on the necessary circuit portions in practice. Foreign matter in the ink, printing bugs, dirt, scratches, etc. may cause plating nuclei to adhere to the ink surface, and chemical plating may also precipitate.

This has the disadvantage that the surface of the ink must be polished and the copper on the ink must be dissolved and removed, resulting in a very complicated process.

(2) Cover other parts except the necessary circuit parts with alkali-soluble acid-resistant resist ink, then roughen the surface to make it hydrophilic and catalyze it to adhere plating catalyst nuclei, then apply the above resist ink. This method involves removing the resist ink, immersing it in a chemical plating solution, depositing copper on the necessary circuit areas, and then removing the resist ink.

However, this method has the disadvantage that chemical plating is also deposited on non-circuit areas 51) because plating nuclei migrate to areas other than circuits and remain in the resist ink removal process.

(3) After roughening the entire surface within the hole and making it catalytic to adhere plating catalyst nuclei, cover the outside except for the necessary circuit parts with plating-resistant resist ink and apply chemical plating solution. 'There is a method of soaking in noodles and depositing copper on the necessary circuit parts.

However, this method requires a drying process when applying resist ink, and in this process, the activation ability of the plating nuclei that adhere to the surface is lost due to the catalytic treatment, and the wettability of the plating nuclei decreases, resulting in a reduction in glitter. It has drawbacks such as uneven adhesion, blistering, and reduced adhesion.

As described above, the conventional additive method has the drawbacks that plating is deposited on non-circuit areas and adhesion is reduced, and improvements have been sought.

[Purpose of the invention]

An object of the present invention is to provide a highly reliable method for manufacturing a printed wiring board by an additive method that does not cause plating precipitation on non-circuit parts and has excellent adhesion of isobody circuits.

[Summary of the invention]

The present invention relates to improvement of the method (3) above,
As a result of various studies conducted by the present inventors, we found that by incorporating a wetting agent into the catalyst liquid in the catalytic treatment process,
The inventors have found that the above object can be achieved and have completed the present invention.

That is, the present invention comprises (a) a process of drilling holes for forming through holes in an adhesive-attached laminate; (a) a process of roughening and making the surface of the adhesive hydrophilic; (c) a roughened adhesive (d) applying a plating-resistant resist ink to the adhesive surface other than the area on which the conductive circuit is to be formed; (e) chemical copper plating; A method for manufacturing a printed wiring board, comprising the steps of: immersing it in a plating bath to form a copper plating film on the conductor circuit portion and the inner wall of the hole for forming the through hole, the method comprising: step (c)
This is characterized by the addition of a wetting agent to the catalytic sensitizing solution used in the catalytic sensitizing solution.

The present invention will be explained in detail below. In the catalytic treatment of the present invention, the substrate is usually treated with a sensitizing solution containing stannous ions to adhere the stannous ions to its surface, washed with water, and then treated with an activating solution containing noble metal ions. This is a treatment in which plating catalyst nuclei such as palladium are deposited on the entire surface by treatment with a solution containing stannous ions and noble metal ions. If the next chemical plating process is started immediately, defects such as uneven adhesion of the plating and poor adhesion of the plating film are unlikely to occur, but if heated or left for a long time, palladium will lose its active ability and ,
The wettability with the plating solution etc. is reduced, resulting in uneven plating adhesion, poor layer density, blistering, etc. 9, which causes a significant deterioration in the quality of the printed wiring board. Therefore, as a result of intensive research to solve the above problems,
It has been found that the quality can be significantly improved by adding a wetting agent to the sensitizing solution.

As the infiltrating agent used in the present invention, Maronri! , Carboxylic acids such as succinic acid and adipic acid, hydroxycarboxylic acids such as malic acid, citric acid, tartaric acid, and gluconic acid,
Examples include alcohols such as butanediol and glycerin, and surfactants such as fatty acid salts, sulfate ester salts, phosphorus ester salts, sorbitan alkyl esters, and polyoxyethylene alkyl ethers.

[Embodiments of the invention]

The adhesive is paper epoxy laminate EPL-AD 1.6t
(manufactured by Toshiba Chemical) After drilling holes for through holes in the required locations, sulfuric acid 300ml
7 at 50°C using an i/l chromic acid-sulfuric acid mixture.
The adhesive layer was treated with water to make it rough and hydrophilic. Next, the object was treated with a sensitizing solution having the following composition to deposit plating catalyst nuclei on the entire surface of the object to be plated.

Composition Basic composition of sensitizing solution Palladium chloride 2g Stannous chloride 50g Hydrochloric acid (37%) 50% water Total amount 10100O The following substances were added to the above basic composition to prepare a sensitizing solution.

(1) Adipic acid 517/1 (2) Tartaric acid 5 g/13 (3) Glycerin 5 g/1 (4) Sodium dodecylbenzenesulfonate 5 g/1
3 Next, after drying at 80°C for 20 minutes, apply plating-resistant resist ink 0 to the adhesive surface other than the area where the conductor circuit is to be formed.
An ink layer was formed by screen printing using BZ-4000 (manufactured by Tokyo Ohka), and dried at 150°030°C to provide a mask layer on the non-plated area. Next, accelerator-1
9 (manufactured by Silapray Co., Ltd.), and immersed in a chemical solution to coat the inner wall of the hole and the required circuit area with a thickness of 30 to 35 mm.
A chemical copper plating layer of μη B was deposited.

The composition of the chemical copper plating solution used here is as follows.

%1bajji 0.04molhiD'l'AO, 10monoV Formalin 0.10mol Dipyridyl 10~ Surfactant 100m9 P H12,0 Warm 7000 In this way, 'J left behind printed wiring boards. The characteristics were as follows.

(Leaving space below) Table 1 (Evaluation method JIS 0-6481 [Effects of the invention]) As described above, according to the present invention, in the drying process of the resist, the active ability of the plating nuclei was lost and the wettability decreased. As a result, it has become possible to manufacture printed wiring boards using a highly reliable additive method without causing uneven plating, blistering, or deterioration of adhesion or heat resistance.

Claims (1)

[Claims] (1) (a) Process of drilling holes for forming through holes in the laminate for adhesive, (b) Process of making the adhesive surface rough and hydrophilic, (c) Process of making the adhesive surface rough and hydrophilic. The process of depositing a substance that has a catalytic effect on chemical copper plating, the process of applying plating-resistant resist ink on the adhesive surface other than the area where the FD1 etc. body circuit is to be formed, (immersion in an EL chemical copper plating bath) and forming a copper plating film on the isobody circuit portion and the inner wall of the hole for forming the through hole, in the method for manufacturing a printed wiring board, step (C)
1. A method for producing a printed wiring board, characterized in that a wetting agent is added to a catalytic sensitizing solution used in . (2. Production of a printed wiring board in the method described in claim 1, characterized in that the wetting agent is at least one selected from carboxylic acids, hydroxycarboxylic acids, alcohols, and surfactants. Method.