JPS6381895A - Manufacture of printed wiring board - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of manufacturing a printed wiring board.

[Technical background 7I of the invention] Purin KPi due to the miniaturization or weight reduction of electric FR equipment
? , 'In conjunction with the increased density of circuit wiring on La boards, the same wiring board now has low-current circuit wiring to operate microprocessors and other devices with small currents, and large-current circuit wiring to operate external devices with large currents. It is often provided indirectly with circuit wiring or power supply circuit wiring. A: Usually, the small current circuit wiring and the high current circuit wiring are made of a conductor layer (copper layer) of the same thickness, so the allowable current that flows through the large current circuit wiring is different from that of the small current circuit wiring. To increase this, the wiring width is expanded. However, expanding the wiring width in this way makes it possible to increase the density of circuit wiring on a printed wiring board.

[L of the invention] However, the present invention does not increase the allowable current flowing through the large current circuit wiring by expanding the wiring width, but by increasing the number of wiring parts by 17, This is intended to increase the density of circuit wiring with different allowable currents. Specifically, this was achieved by improving the partial additive method./:)6 [Example] Hereinafter, an example of the present invention will be described together with the N-side. Explanation 42--.gamma. In this embodiment, a double-sided printed wiring board will be explained, and since the same applies to a single-sided printed wiring board, the explanation thereof will be omitted.

First, as shown in Figure 1 (A), a double-sided steel clad laminate (1)
Prepare. (2) is a copper foil whose thickness is, for example, 18 μm or 35 μm (7). Then, in order to form a through hole, a through hole (3) is drilled as shown in FIG.
) and on the surface of the laminate (1), copper plating nuclei (4), usually palladium nuclei, are deposited as shown in Figure (C). Subsequently, as shown in 1fi (D), a laminate (
Chemical steel plating or electrolytic tin plating, that is, panel plating, is applied to the entire surface of 1) to form a first copper plating layer (5).

After this seam/cutting process is performed, as shown in FIG. , (6
) to protect the hole wall and dry it tightly.
Etching resists are formed using the same photosensitive film (6) for forming circuit wiring at required locations on the front and back sides of the tension laminate k (1). Instead of using this photosensitive film (6), the walls of the through holes (3) can also be protected by an ink filling printing method or the like.

After etching the first copper plating layer (5) and the lagoon foil (2), the kneeling resist (6) is separated by 711 points in the second layer (F) to protect the circuit wiring. The permanent resist (7), which is a semi-H resist, is shown in the same figure (G).
As shown in )).

When forming this permanent resistor l-('l, large current capacity t
This wooden arrow resist (7) should not be formed on the portion of the high current circuit wiring (8) that requires a high voltage. And again f
When applied with Higaku copper plating or electrolytic copper plating, 7 pJ
As shown in Figure z (H), a second copper plating layer (10) is formed on the large current circuit wiring (8) and through holes 9) where the permanent resist (7) is not formed. The thickness of the second copper plating layer (10) is approximately 25 to 35 μm.

Finally, by using the character printing process to display numbers, characters, marks, etc. on the printed wiring board, the high current circuit wiring part exposed at the first step was printed as shown in E21 (1). is coated with a character printing ink layer (11).

Through such a series of steps, a printed wiring board (12) according to the invention is obtained.

[Effects] According to the present invention described in -1- below, only the circuit wiring that requires a large current of 8 stars has its wiring part reduced to 7th, so it is very economical and small. +4L flow circuit wiring and large current circuit wiring can be formed at high density on the same printed wiring board.

4. Brief explanation of [1] Figures 1 and 2 are process diagrams showing the cutting method according to the present invention.

In the figure, (1)...Steel clad laminate, (2)...Copper τ
^, (3)...Through hole, (4)...Medical core, (5), (10)...T4 plating layer, (6)...
...Etching resist, (7)...Permanent resist,
(8)...High current circuit wiring, (9)...Through hole, (11)...Ink layer for character printing,
(12)...Printed wiring board.

ri, ν revision applicant: ELNA Co., Ltd. Figure 1 Figure 2 Ku

Claims (1)

[Scope of Claims] [1] A step of drilling a through hole in a copper clad laminate, plating the entire surface of the copper clad laminate with copper after activation treatment, and protecting the hole wall of the through hole and plating the copper clad laminate with copper. forming and etching an etching resist for forming circuit wiring at a required location on at least one side of the laminate; after peeling off the etching resist, forming a permanent resist;
A method for manufacturing a printed wiring board, comprising the steps of: further plating the circuit wiring portions on which no permanent resist is formed with copper; and covering the copper-plated circuit wiring portions with a layer of character printing ink.