JPS6155990A - 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] (Industrial application field) The present invention relates to a method of manufacturing a wiring board.

(Prior art) With the increasing density of printed wiring boards, planar circuits are constructed by etching copper-clad laminates. Therefore, the following method has been developed, assuming that the planar circuits have a uniform thickness and are suitable for forming fine line patterns. There is.

In other words, an etching resist is formed on the steel foil of the catalyst-containing copper-clad laminate, a plating resist is printed on the etching line, and electroless plating is applied only to the inner walls of the holes and on the pads to ensure continuity on both sides. This is a method for creating a single-sided through-hole wiring board.

In this case, when printing the plating resist, printing misalignment occurs for some reason, and due to the printing misalignment, the surface portion of the catalyst-containing substrate where the plating resist is not printed is exposed depending on the degree of the printing misalignment. If it is immersed in an electroless plating solution in that state, plating will be deposited on the exposed part of the catalyst-containing substrate surface where the plating resist is not printed, which is caused by misalignment of the plating resist printing.As a result, the shape of the bat will change due to the plating resist printing. is expanded in the direction of deviation of V
The distance between the four-contact pattern became narrower, and this became an obstacle to increasing the density of printed wiring boards.

(Object of the Invention) An object of the present invention is to provide a method for manufacturing a printed wiring board that enables the formation of a high-density wiring pattern.

(Structure of the Invention) The present invention is a method for manufacturing a printed wiring board including the following steps A to F.

A. A copper-clad laminate is prepared by laminating a copper foil on the surface of a probe plate, which has a catalyst-containing resin layer provided on the surface of the catalyst-containing laminate.

B. Drill a hole.

C, seeding row 51 D. Perform etching to remove unnecessary copper other than the circuit.

E. Form a plating resist.

F. Immerse in electroless steel plating solution.

The present invention will be explained below based on the drawings.

@1 Figure is a copper-clad laminate containing a catalyst; 1 is a laminate;
2 is a copper foil, and 5 is a resin layer that does not contain a catalyst. Preferably, the catalyst-free resin layer is the same type of prepreg as that constituting the laminate. An adhesive layer on the back side of the steel foil is also used. There are no particular restrictions on the thickness of this layer.

As a catalyst, group Ⅰ and group 18 VC of the periodic table of elements are used.
metals such as nickel, gold, silver, platinum,
Examples include palladium, rhodium, copper, iridium, etc., or their oxides, fluorides, bromides, fluorides, ethyl acetates, fluoroborates, nitrates, sulfates, acetates, and the like. Particularly useful are palladium, gold, platinum, copper, palladium chloride, gold chloride, platinum chloride, copper oxide or their combinations with stannous chloride. Aj these catalysts! It was adsorbed onto a 0B-5i02 carrier, and mixed with epoxy resin and dispersed in a face to make a ``''C laminate, which was then used as a catalyst-containing copper-clad laminate.

Next, as shown in FIG. 2, holes 4 are drilled at predetermined locations. The hole is made by drilling, punching, etc.

Next, seeding is performed as shown in FIG.

Seeding is performed using a catalyst treatment liquid (e.g. HS-201B
1. It is carried out by immersing it in Hitachi Chemical Co., Ltd. (product name). 5 is cedar.

Next, as shown in FIG. 4, an etching resist 6 is formed. The etching resist 6 can be formed using a silk screen method (or it can also be formed by using a photosensitive resin film and performing exposure and development. Form the holes and the areas that should become pads around the large periphery.

The etching resist 6 may be formed before seeding (or may be formed before the holes 8A are formed).

Next, as shown in FIG. 5, after etching is performed, the etching resist is removed. For etching, common etching solutions such as ferric chloride solution, cupric chloride solution, ammonium persulfate solution, and alkaline etching solution are used. After etching, the etching resist is removed.

The etching resist can be removed by conventional methods such as solvent removal and mechanical removal.

Next, a plating resist 7 is formed as shown in FIG.

The plating resist 7 is formed except for the large area and the areas around the large area that should become pads.

The plating resist can be formed by a silk screen method or by using a photosensitive resin film, exposing it to light, and developing it.

Next, as shown in Figure 7, it is immersed in an electroless 88 copper plating solution.
Electroless plating 8 is formed on areas where the plating resist is not formed, that is, on the inner wall and pad portions.

For example, the electroless steel plating solution contains copper ions α004 to α2
Mol/! , a copper ion complexing agent αo.

4-1 mole/l, reducing agent 0.01-0.25 moh/l
and an amount of adjusting agent necessary to bring the grain size to 11.8 to 155. Electroless plating will be formed to a thickness of about 10 to 100 μm (effect of the invention) FIG. 7 is a cross-sectional view of a printed wiring board obtained according to the present invention.
In the present invention, even if the plated resist printing is shifted and the base material surface is exposed, the plating will not precipitate on that part, so even if the plated resist printing is shifted, the shape of the pad part will change or the shape of the adjacent pad will not change. It is possible to create a printed wiring board with high precision without getting close to the conductor part.

Therefore, the alignment work for the plating resist printed pattern is simplified.

[Brief explanation of drawings]

1 to 7 are cross-sectional views showing the method of the present invention. Explanation of symbols 1. Laminate plate with catalyst 2. Steel foil 5. Resin layer that does not contain catalyst 4. Hole 5. Seagu & etching resist Otsu plating resist & Electroless plating

Claims (1)

[Claims] 1. A method for manufacturing a printed wiring board including the following steps. A. A copper-clad laminate is prepared by laminating copper foil on the surface of a laminate containing a catalyst and a resin layer not containing a catalyst provided on the surface of the laminate. B. Drill a hole. C. Perform seeding. D. Perform etching to remove unnecessary copper other than the circuit. E. Form a plating resist. F. Immerse in electroless copper plating solution.