JPS6286892A - Manufacture of printed wiring 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 for manufacturing a printed wiring board.

(Prior Art) Conventionally, there are various methods for manufacturing printed wiring boards, and they can be broadly classified into subtractive methods and adity methods. The subtractive method is an extremely highly developed method and is currently a widely used method for manufacturing printed wiring boards.

The steps of this subtractive method will be explained with reference to FIG. 2, ax to g. First, holes 2 are made as shown in FIG. 2 at desired positions in the laminated substrate 1 shown in FIG. Next, as shown in FIG. 2C, through-hole Cu plating is applied to the substrate 1 having the holes 2 formed therein, thereby forming a Cu plating layer 3 on the Cu foil 1a on both sides of the substrate 1 and on the inner surface of the hole 2. Next, a photoresist 4 for forming a required wiring pattern as shown in FIG. 1 and Figure 2 e
Apply Au plating as shown in . Next, the photoresist 4 on the substrate 1 is peeled off as shown in FIG. 2f. Thereafter, as shown in FIG. 2g, etching is performed to remove the Cu plating 3 and CuFgla in areas other than the Au plating 5, thereby forming the required wiring 6.

(Problems to be Solved by the Invention) By the way, in the conventional method for manufacturing a printed wiring board using the subtractive method described above, for example, holes 2 in the wiring pattern are
Since unnecessary Au plating 5 is applied to the inner surface and the periphery, expensive Au is wasted.

SUMMARY OF THE INVENTION Therefore, the present invention provides a method for manufacturing a printed wiring board in which unnecessary Au plating is not applied to the wiring pattern, such as the inner surface or periphery of a hole.

(Means for Solving the Problems) In order to solve the above problems, the method for manufacturing a printed wiring board according to the present invention involves drilling holes at required positions in a Cu foil-clad laminate board, then applying through-hole Cu plating, and then A first resist is provided on both sides of this substrate to close the hole and form the required Au plating wiring pattern, then Au plating is applied to the substrate, the first resist is peeled off, and then the hole is closed on both sides of the substrate. The method is characterized in that a second resist for forming a desired wiring pattern is provided, then etching is performed, and then the second resist is peeled off to form wiring.

(Function) As described above, in the method for manufacturing a printed wiring board of the present invention, after performing through-hole Cu plating, Cu plating on both sides of the board is performed.
Since the first resist that closes the holes and forms the Au plating wiring pattern is provided in the plating layer, when the substrate is plated with Au, unnecessary Au plating is not applied to, for example, the inner surface or the periphery of the through hole. Furthermore, during etching, since a second resist is provided on both sides of the substrate to close the hole, the Cu plating layer and Cu foil on the inner surface and periphery of the hole are not removed by etching.

(Example) An example of the method for manufacturing a printed wiring board according to the present invention will be described with reference to FIGS. 1a to 1i. First, a first plate is placed at a predetermined position on a multilayer substrate 1 with Cu foil 1a stretched on both sides as shown in FIG. 1a.
Drill a hole 2 as shown in the figure. Next, as shown in FIG.
A plating layer 3 is formed. Next, a photosensitive dry film is applied to both sides of the substrate 1, and this is exposed and developed to form a first resist 4' that closes the hole 2 and forms the required Au plating wiring pattern as shown in FIG. 1d. .

Next, Au plating 5 is applied to both sides of the substrate 1 as shown in FIG. 1e. Next, the first resist 4' on the substrate 1 is peeled off as shown in FIG. A photosensitive dry film is pasted, exposed and developed to form a second film that closes the hole 2 and forms the required wiring pattern, as shown in Figure 1g.
A resist 4" is provided. Next, as shown in the first figure, etching is performed to remove the Cu plating layer 3 and the Cu foil 1a other than the Au plating layer 5 and the second resist 4". As shown in FIG. 2, the second resist 4'' is peeled off to form the required wiring 6.

As in the above embodiment, in the method for manufacturing a printed wiring board of the present invention, after through-hole Cu plating is applied to the laminated board 1 made of Cu foil 1a with holes 2, the Cu plating layer 3 on both sides of the board 1 is coated. Since the first resist 4' is provided to close the hole 2 and form the required Au plating wiring pattern, unnecessary A is removed from the inner surface and periphery of the hole 2 when the Au plating 5 is applied.
U plating 5 is not applied. Furthermore, when etching, since a second resist 4'' is provided on both sides of the substrate l to close the hole 2, the etching removes the Cu on the inner surface and the periphery of the hole 2.
The plating layer 3 and the Cu foil 1a are not removed.

(Effects of the Invention) As described in detail above, the method for manufacturing a printed wiring board of the present invention is such that when performing Au plating, the hole is closed with the first resist, and the wiring portion other than the wiring portion that requires Au plating, the inner surface and the periphery of the hole. No unnecessary Au plating is applied to the surface. Therefore, since expensive Au is not wasted, the manufacturing cost of the printed wiring board can be reduced. Also, when etching, even if the inner surface and periphery of the hole are not plated with Au,
Since the hole in the board is closed with the second resist, the Cu plating layer and Cu foil on the inner surface and periphery of the hole are not removed, so there is no problem in mounting the terminal, and a high-quality printed wiring board can be manufactured. .

[Brief explanation of drawings]

1A to 1I are cross-sectional views showing the steps of the printed wiring board manufacturing method according to the present invention, and FIGS. 2A to 2G are main part sectional views showing the steps of the conventional subtractive method of manufacturing the printed wiring board. It is. Applicant Tanaka Kikinzoku Kogyo Co., Ltd. Figure 1 2... Generation 5... ALL Meuki Figure 1 6... Shiraki Jo

Claims (1)

[Claims] After drilling holes in the required positions of the Cu foil-clad laminate board, through-hole Cu plating is applied, then a first resist is provided on both sides of this board to close the holes and form the required Au plating wiring pattern, and then Au plating is applied to the board. Then, the first resist is peeled off, a second resist is provided on both sides of the substrate to close the holes and form the required wiring pattern, and then etching is performed, and then the second resist is peeled off to form the wiring pattern. A method for manufacturing a printed wiring board.