JPS5999793A - 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 This invention relates to printed wiring board structures and, more particularly, to improved metal resists for copper etching.

FIGS. 1(a) to 1(g) show an example of a method for manufacturing a printed wiring board using a conventional copper etching method.

That is, holes are formed in the copper-clad laminate 1 (FIG. 1(a)), panel copper plating 2 is applied (FIG. 1(b)), and a resist 3 for metal resist plating is applied on the panel copper plating 2. , and solder plating 4 as a metal resist is applied directly between the resists 3 and 3 for metal resist plating.
Figure (C)), then remove the resist 3 for metal resist plating with a solvent etc. (Figure 1 (d)), solder plating 4.
As a metal resist, the Gunnel copper plating 2 and the copper foil 1a of the copper-clad laminate 1 are etched (Fig. 1(e)), and then the solder plating 4 is removed by peeling or the like (first
(Fig. 1 (f)), print the resist 5 for solder coating, and apply the solder coat 6 (Fig. 1 (g)).
Note that in the figure, reference numeral 7 indicates a through hole, and a mother plate copper plating 2 and a solder coat 6 are applied here as well.

However, solder plating 4 is porous and has a coarse structure.
Since there are pinholes, it is necessary to make the film thicker (approximately 7 to 14 μm) to compensate for this, and it is also necessary to remove this with a stripping solution and apply solder coat 6, so plating The working time is long (usually 15-17 minutes),
Removal time is long (approximately 3 to 5 minutes), and power consumption is high, leading to a rise in costs. Furthermore, since the solder plating 4 is not flat, it is relatively difficult to visually inspect the printed wiring, and the rate of finding defective parts of the printed wiring is low.

Therefore, an object of the present invention is to provide a printed wiring board that has good manufacturing efficiency and can reduce manufacturing costs.

The gist is that tin-nickel plating is used as a metal resist for copper etching, and a solder coat is applied on the remaining metal resist.

FIGS. 2(a) to 2(f) show an embodiment of the present invention. In this example, the copper-clad laminate 1 shown in FIG. 1 is used, and the manufacturing process is basically the same as that shown in FIG. 1, but the solder plating 4 in FIG. as a metal resist (resist for metal renost plating) 13.
Apply a thin layer (approximately 0.3 to 0.6 μm) between solder coats 13 and print the entire solder coat resist 15 while leaving it without removing it. It is applied on top of plating 8 (second
Figure (f)).

This tin-nickel plating 8 is mainly made of stannous chloride,
It is made of nickel sulfate, potassium pyrophosphate, eutectoid, brightening agent, etc., and has a high melting point and a dense structure. For you,
The plating film thickness can be made thinner (correspondingly, the film thickness of the resist 13 for metal resist plating can also be made thinner), and the solder coat 16 can be applied while the tin/nickel plating 8 remains. be. Therefore, the plating time for this tin-nickel plating 8 is extremely short (
(about 2 to 4 minutes), and the step of removing the plating resist is also completely omitted, so the overall manufacturing efficiency is greatly improved compared to the case of using conventional solder plating. In addition, by reducing the plating film thickness and the film thickness of the resist 13 for metal resist plating, power consumption and materials are significantly reduced, and chemical costs are also saved, resulting in an overall modest reduction in manufacturing costs. .

Furthermore, since the tin/nickel plating 8 is relatively flat, visual inspection of the printed wiring is relatively easy, and defects in the printed wiring can be easily discovered, among other effects. .

In addition to the double-sided printed wiring board with the structure shown in FIG. 2, the present invention can also be applied to double-sided printed wiring boards, single-sided printed wiring boards, and multilayer printed wiring boards with a moderate structure using known techniques. Examples of its application are shown in FIGS. 3 to 7.

That is, in FIGS. 3(a) to (f), as in the case of FIG. 2,
This shows the case where the copper-clad laminate 1 is used, and the characteristics of this case are that the resist for metal resist plating) 23.2
First, pattern copper plating 1° is applied to Figure 3 (C).
)), on which tin-nickel plating 8 is decorated (
It is located at point (d) in Figure 3.

The feature of the embodiments shown in FIGS. 4(a) to (f) as compared with the embodiment of FIG. 12, and on top of that, a resist 33 for metal resist plating and
It is tin-nickel plated 18.

The embodiments shown in FIGS. 5(a) to 5(f) are applied to a laminate 11 coated with flannel copper plating 12, similar to the embodiment shown in FIG. The characteristic of this is that pattern glaze plating 2o is first applied between the thicker metal resist plating resists 43 and 43 (Fig. 5(b)), and then tin/nickel plating 28 is applied on top of that. It is in.

The features of FIGS. 6(a) to 6(f) compared with FIG. 2 are that panel copper plating 12 is applied to the multilayer copper-clad laminate 21 on which the intermediate copper foil 21a has already been etched; A metal resist plating resist 53 and tin/nickel plating 38 are applied.

Figures 7(a) to (f) are applied to a panel copper plating 12 applied to the same multilayer copper-clad laminate 21 as in Figure 6, but the characteristic of this case is that it is slightly thicker. First, pattern copper plating 30 is applied between the metal resist plating resist 63.
It is located at the point where nickel plating 48 is applied (FIG. 7(d)).

[Brief explanation of the drawing]

Figures 1 (a) to (g) are explanatory diagrams showing an example of a conventional printed wiring board manufacturing method that uses solder plating as a metal resist for copper etching, and Figures 2 (,) to (f)
) is an explanatory diagram showing one embodiment of the present invention in which tin-nickel plating is used as a metal resist for copper etching, and FIGS. 3 to 7 are explanatory diagrams showing other embodiments of the present invention. 1... Copper-clad laminate 1.11... Laminate, 21...
Multilayer copper-clad laminate, 31...Multilayer laminate, 2.12.2
2...Panel copper plating, 3,13.23,33,43
゜53.63.73...Resist for metal resist plating, 4...Solder plating, 5.15...Resist for solder coat, 6.16...Solder coat, 7...
・Through hole, 8, 18, 28, 38, 48, 58°6
8...Tin/nickel plating, 10.20. ．． 30゜40... pattern copper plating. Patent applicant Yamashita Kako Co., Ltd. Patent attorney Masu 1) 9 Figure 1 (Q) (b) (C) (d) (9) Paper 2-mouth (Q) No. 30 1st tsubo (Q) (b ) (C) (d) (e) (f) Bian 50 (C1) (d) (e) (f) 60th (C1)

Claims (1)

[Claims] A printed wiring board using tin-nickel plating as a metal resist for copper etching, and applying a solder coat on the remaining metal resist.