JPS61222296A - Manufacture of through hole substrate - 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 of the Invention] The present invention relates to a method for manufacturing a through-hole substrate that allows easy formation of fine patterns.

[Technical Background of the Invention and Problems Therewith] Full additive methods and subtractive methods are conventionally known as methods for manufacturing printed wiring boards.

Among these methods, in the full additive method, a circuit is formed by drilling a hole in an insulating substrate and then applying thick chemical copper plating only to the inside of the hole and the pattern area.

Further, in the subtractive method, a circuit is formed by drilling a hole in a copper-clad laminate, applying copper plating inside the hole and on the entire surface of the copper foil, and then performing image formation and etching.

However, the former fully additive method has the disadvantage that it is difficult to form fine patterns and cannot be used to manufacture solder through holes, gold through holes, or multilayer printed wiring boards, while the latter subtractive method has the disadvantage that it is difficult to form fine patterns. Therefore, the thickness of the copper foil to be etched becomes thicker, and there are also variations in the thickness, making it difficult to obtain a high-quality fine pattern.

Although it is possible to form relatively accurate patterns using the subtractive method using ultra-thin copper-clad laminates, the problem is that the overall cost is high because ultra-thin copper-clad laminates are expensive. . - [Object of the Invention] The present invention was made to solve these conventional difficulties, and provides six fJ manufacturing methods for through-hole boards that can easily form fine patterns using ordinary copper-clad laminates. The purpose is to

[Summary of the invention] That is, the method of the present invention involves drilling a hole in a copper-clad laminate and treating it immediately before chemical copper plating, and then attaching a resist film to the surface of the copper foil to fill the holes in the copper-clad m-layer board. By drilling holes in the resist film and then applying chemical copper plating only to the inner surface of the holes in the copper-clad laminate, fine patterns can be easily formed at low cost using ordinary copper-clad laminates. It is.

According to the method of the present invention, chemical copper plating is applied only to the inside of the hole in the copper-clad laminate, so the pattern forming portions on both sides are formed only from the original copper foil of the copper-clad laminate. Therefore, the thickness of the copper foil to be etched is uniform, and a fine pattern can be easily formed.

Note that it is desirable to use a photosensitive resist film as the resist film used in the present invention, but other plastic films may be used as long as the film in the holes can be easily and completely removed by, for example, high-pressure water washing. It is also possible.

Further, chemical copper plating inside the hole need not be performed alone; for example, electrolytic copper plating may be performed after thin material chemical copper plating.

Further, solder plating or gold plating may be applied thereon as necessary.

[Embodiments of the invention] Next, embodiments of the present invention will be described with reference to the drawings.

In this method, first, a copper clad laminate 2 having, for example, a 35 μm thick copper foil 1 adhered to both sides, is subjected to a drilling process and treated immediately before chemical copper plating.

(Fig. 1), a photosensitive resist film 3 is pasted on both sides (Fig. 2), and after exposing the entire surface to ultraviolet rays, the resist film covering the hole 4 is completely removed by, for example, high-pressure water washing (Fig. 2). figure).

Next, after activating the inside of the hole 4 and washing with water, chemical plating is performed to form a chemical copper plating 11 with a thickness of 25 to 28 μm.
5 (Figure 4).

The through-hole board thus formed has a uniform thickness of 35 μm, which is the same as the copper clad laminate 2 in which the thickness of the copper foil 1 on both sides on which the circuit pattern is formed is different.

Therefore, a fine pattern can be easily formed by peeling off the photosensitive resist film 3 on this through-hole substrate and performing image formation and etching using a conventional method.

In addition, in the above example, an example using a double-sided copper-clad laminate was explained, but the present invention is not limited to such an example, and can also be applied to the production of a multilayer printed wiring board. .

[Effects of the Invention] As explained above, according to the method of the present invention, through holes can be formed using a normal copper-clad 811wI board without changing the thickness of the copper foil portion on the surface, Therefore, high-quality fine-pattern printed wiring boards can be manufactured at low cost and with a high yield.

[Brief explanation of the drawing]

1 to 4 are cross-sectional views of a copper-clad laminate for explaining the method of the present invention. 1... Copper foil 2... Copper clad laminate 3...
・・・・・・Photosensitive resist 4・・・・・・・・・・・・
·hole

Claims (1)

[Claims] (1) After drilling a hole in a copper-clad laminate, attach a resist film to the surface of the copper foil, and drill a hole in the resist film in the hole in the copper-clad laminate. A method for manufacturing a through-hole board characterized by applying chemical copper plating only to the inner surface.