JPH01185992A - 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 Field of the Invention The present invention relates to an improvement in the method of manufacturing double-sided printed circuit boards.

<Prior art> When forming a conductor circuit with through-holes in a printed circuit board, holes for through-holes are provided in a double-sided copper-clad substrate (or a single-sided copper-clad substrate with copper foil adhered to the other side).
Copper is electrolessly plated on the entire surface of the base material, the entire surface is coated with Menki resist, the through holes are exposed by exposure and phenomenon, copper is electrolytically plated on the ft through holes, and after this plating, the above resist is applied. After that, the entire surface is covered with a new etching resist, and the copper surface is exposed in a predetermined pattern (negative for the conductor circuit pattern) by exposure and phenomenon.Then, this exposed copper surface is etched to form the conductor circuit. is forming.

<Problems to be Solved> However, in this method, a step occurs in the land portion of the through-hole plating, and a step also occurs in the etching resist film, which deteriorates the adhesion between the resist film and the photomask. When exposing with the above-mentioned predetermined pattern (negative for the conductor circuit pattern), the generation of noticeable haley silane is unavoidable, and the dimensional accuracy of the conductor circuit is inevitably reduced.

However, this disadvantage can be avoided by plating the land portions after forming the conductor circuit pattern.With this method, the conductor circuit (discontinuous) cannot be used as a lead conductor for plating, so plated leads must be prepared separately. Therefore, the land plating work becomes complicated.

An object of the present invention is to provide a method for manufacturing a printed circuit board that can eliminate the above-mentioned halation and does not require a separate plating lead.

<Technical Means for Solving the Problems> The method for manufacturing a printed circuit board according to the present invention includes a single-sided conductor insulating plate having a conductor layer A on one side of an insulating support, and a conductor layer A on the other side of the insulating support. A thin conductor layer B is provided, a hole for a through hole is formed in the double-sided conductor insulator, and a conductor material is plated on the hole and the conductor layer B.
This method is characterized in that the conductor layers on both sides are made to have the same thickness by chemical etching, and then the conductor layers on both sides are formed into a predetermined pattern.

<Explanation of Examples> The present invention will be explained below with reference to the drawings.

FIG. 1 shows a double-sided conductor insulating plate P. In FIG. 1, reference numeral 1 denotes a single-sided conductive insulating plate, in which a rolled gA foil A is laminated on one side of a plastic film, sheet or plate 11 with an adhesive 12. B is a conductor layer provided on the other side of the insulating plate 11, for example, a copper foil (rolled W4 foil or electrolytic copper foil) laminated with an adhesive 22, and its thickness is smaller than the conductor NA on one side.

To carry out the present invention, as shown in FIG. 2, a through-hole hole 3 is processed, and only the through-hole hole 3 and the conductor NB on the other side are plated with conductor material C (Ii) and copper is chemically plated. Then, the thickness of the entire conductor layer (B to allow etching of the full thickness of each conductor layer). In this case, the thickness of each of the good conductor layers A and (B C) is strictly speaking rolled copper,
Although it differs depending on the corrosivity of chemically plated copper, electrolytically plated copper, etc., it is usually sufficient to have approximately the same thickness. For example, if the rolled GIA foil A on one side has a thickness of 35μ, the rolled or electrolyzed copper foil on the other side. B is 18 μm, and the copper plating layer C on top is 18 μm thick.
It may be 8 μm.

Above, attach conductive material to the through-hole hole and single-sided conductor layer.
・To do this, use a double-sided conductor insulating plate P as shown in Figure 3.
, (P) are superimposed on one side through the insulating plate 1,
Hole 3 for through hole is provided, and each double-sided conductor insulation plate P, C
P) through-hole insertion 3. +31 and the other side conductor layer B,
(B) The conductor material C may be plated all at once.

Afterwards, each surface conductor layer is coated with an etching resist, a photomask is closely attached to each resist film, and exposure is performed. The conductor is then etched to form a predetermined conductor circuit pattern.

The conductor layer B is flat even around the through holes 3, and the photomask can be brought into close contact with the entire surface of the conductor layer B, so that exposure can be performed without causing halation. Furthermore, since the thicknesses of the good conductor layers A and (BC) are made the same for chemical etching, both conductors can be etched under the same etching conditions.

Figure 4A to Figure 4 are examples of the method for manufacturing a flexible printed circuit (Figure 4E) in which printed conductors are provided on both sides at both ends and printed conductors are provided only on one side in the center. It shows.

゛For the single-sided conductor insulating board 1, rolled copper Fg is attached to one side of a plastic film (for example, a polyimide film with a thickness of 25 to 75 μm) 11 with an adhesive (for example, an epoxy adhesive with a thickness of 10 to 30 μm) 12. (thickness 35μR1) A
A laminated layer is used.

As shown in FIGS. 4A and 4B, a thin copper foil (18 μm thick rolled copper foil ) Adhere B using base lamination press or roll lamination (150''~170'C, 10kg/d~40
kg/c+J, 30-60 minutes).

Next, in the same manner as described above, as shown in FIG. (
The copper plating thickness is set to a predetermined thickness (18 μm) so that BC) is equivalent to chemical etching.

After that, both sides are coated with etching and resist, each predetermined photomask is closely attached to each conductor surface, and by exposure and phenomenon, the resist lia and resist are formed in the pattern of the conductor circuit pattern as shown in Figure 4. (b c) remains;
The exposed copper foil portions on each side are etched to obtain the product shown in FIG. 4E.

<Effects of the Invention> The method for manufacturing a printed circuit board according to the present invention is the method described above, in which the inner surface of the through-hole hole is plated and the entire surface of the conductor layer on the other surface is peeled at the same time, and the entire surface is flatly plated. Halation can be avoided because the conductor surface is coated with resist and this flat surface can be exposed using a photomask. Of course, since the conductor layer can be used as a plating lead, plating is also easy. Further, since the conductor layers on both sides are made to have the same thickness for chemical etching, both sides can be etched under the same conditions, and a double-sided conductor circuit can be formed in the same manner as in the conventional method.

[Brief explanation of the drawing]

Figures 1 to 3 are explanatory diagrams showing one embodiment of the present invention. Figure 1 shows a double-sided conductor insulating plate, Figure 2 shows the conductor material after plating, and Figure 3 shows the plating in the conductor. Each shows the time. Figure 4A, Figure 4B1, Figure 4C1, Figure 4C, and Figure 4E show the double-sided conductor insulating plate on the separate flow side in the present invention, the frame adhesive of the same insulating plate, the state after plating, and the etching. The previous state as well as the printed circuit board are respectively shown. In the figure, 11 is an insulating support, A is a conductor layer, B is a thin conductor layer, 1 is a double-sided conductor insulating plate, 3 is a hole for a through hole, C
is a plated conductor material.

Claims (1)

[Claims] A conductor layer A is provided on one side of the insulating support, and a conductor layer B thinner than the conductor layer A is provided on the other side of the insulating support, a through hole is formed in the double-sided conductor insulator, and the holes and A printed circuit characterized in that a conductor material is plated on the conductor layer B, the conductor layers on both sides are made to have the same thickness against chemical etching, and then the double-sided conductor layers are formed into a predetermined conductor pattern. Method of manufacturing the board.