JPH04154195A - Manufacture of multiwire wiring board - Google Patents

Abstract

PURPOSE:To enhance a roughened surface into more favorable shape and equalize adhesion strength by allowing a mask film to come into close contact with an electroless plating bonding agent and boring a hole and then etching back a coated layer of exposed insulation coated wire. CONSTITUTION:After the lamination of a wiring lay out resin layer on both sides of an insulation board 1, a wire 5 is laid out while a prepreg 6 is laminated and then the surface of the prepreg 6 is coated with an electroless copper plating bonding agent 10. Then, first and second hole cleaning mask films 11 and 12, which are contact-adhered in such a manner that they may be separated from each other, are contact-laminated on the top of the bonding agent 10. After a hole 8 is bored on the board 1, the coated layer of the wire 8 exposed in the hole 8 is etch back-processed by peeling off only the film 112 and carrying out hole cleaning. This construction makes it possible to obtain a favorable shape of roughened surface, equalize adhesion strength, enhance the quality of the bored hole, improve an in-hole permeability of a processing solution and carry out favorable etch back processing as well.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a method for manufacturing a multi-wire wiring board.

<Prior art> Conventionally, in this type of multi-wire wiring board, in order to etch back the coating layer of the insulator-coated wire (hereinafter referred to as wire) exposed in the hole, the inside of the hole is specially etched. As disclosed in Japanese Patent Publication No. 62-104197, hole cleaning is performed for a long time with a treatment solution of alkaline permanganic acid solution.

By the way, the multi-wire wiring board as described above is
The diameter is manufactured through the steps shown in Figures (a) to (e), and the etch-back treatment described above is carried out in the step shown in Figure 2 (d). Since the surface layer of the substrate was covered with the plating mask film 7, there was no need to consider corrosion by the processing liquid.

In the figure, 1 is an insulating substrate, and a power layer 2 and a ground layer 3 are formed on the surface of this insulating substrate 1. Each of these layers 2.3 is laminated with a resin layer 4, and the resin layer 2.3 is laminated with a resin layer 4. On the surface of the layer 4, a wire 5 and a prepreg 6 for laminating the wire 5 are laminated in this order.

Further, 8 is a hole, and a plated copper layer 9 is formed on the inner wall of the hole 8 .

<Problems to be Solved by the Invention> However, in the multi-wire wiring board as described above, after forming a surface pattern with a permanent resist, surface pads, lines, and hole conductors are formed only by electroless plating. When manufacturing multi-wire wiring boards with surface circuit boards using the fully additive method, which is advantageous for smooth and fine circuit formation, the conventional etch-back method is required because the adhesive for electroless plating is applied to the surface of the board. The adhesive applied as described above is eroded by the treatment liquid in the treatment.

Therefore, it was not possible to obtain a good roughened surface shape by roughening using the full additive method, and there were problems such as variations in plating adhesion.

The present invention is intended to solve the above-mentioned problems, and its purpose is to reduce the amount of electroless plating adhesive applied to the surface of a board when manufacturing a multi-wire wiring board using a fully additive method. The present invention provides a manufacturing method for etching back the coating layer of the wire exposed in the hole without damaging the wire.

Means for Solving the Problems> To achieve the above object, the invention of claim 1 provides a method for manufacturing a multi-wire wiring board in which hole conductors, surface pads, and line conductors are formed only by electroless plating. After applying an electroless plating adhesive to the surface of the board containing the circuit and insulator-covered wire, and placing a mask tightly on the applied adhesive and drilling a hole, the insulation exposed inside the hole is The invention according to claim 2 is characterized in that the coating layer of the body-coated wire is subjected to an etch-back treatment, and then the mask is peeled off, and after a surface pattern is formed with a permanent resist, electroless plating is performed. The invention according to claim 3 is characterized in that a double layer of mask film that is tightly adhered to each other in a peelable manner is used as a double mask film.
According to the present invention, the film on the upper surface side is peeled off after the holes are formed, and then an etch-back treatment is performed, and then the film on the lower surface side is peeled off. After the hole is drilled after the mask is placed in close contact with the hole, the coating layer of the insulator-coated wire exposed inside the hole is etched back.
The adhesive is protected from being eroded by the treatment liquid by a mask.

Further, since the holes are formed after the mask is placed in close contact with the mask, the roughness of the openings of the holes is small and the occurrence of cracks can be suppressed.

In particular, according to the second aspect of the invention, since a double layer of film is used as the mask, the roughness of the openings of the holes is further reduced, and the occurrence of flakes is also suppressed.

Furthermore, according to the third aspect of the invention, the upper film of the double film is peeled off after the holes are formed, and then the etch-back process is performed, so that during the etch-back process,
Since there is only a film on the upper surface side, the permeability of the processing liquid into the pores is good.

<Example> The present invention will be described below based on the drawings. Note that the same reference numerals are given to the same members as in the conventional case.

FIGS. 1(a) to 1(e) show the manufacturing process of a multi-wire wiring board according to the present invention, and this manufacturing process uses a full additive construction method.

In Figure 1(a), a copper foil laminate board (manufactured by Hitachi Chemical Co., Ltd.) is shown.
(trade name MCL-E168) is etched to form inner layer circuit parts such as a power supply layer 2 and a ground layer 3 on the insulating substrate 1 of the copper foil laminated board.

In FIG. 1(b), resin layers 4 for wire wiring are laminated on both sides of the insulating substrate 1 on which the layers 2 and 3 as described above are formed.

In FIG. 1(C), a wire 5 is placed on the surface of the resin layer 4.
After wiring, the prepreg 6 is laminated, and then an adhesive 10 for electroless copper plating (HA-21, manufactured by Hitachi Chemical Co., Ltd.) is applied to the surface of the prepreg 6.

Thereafter, a first mask film 11 (manufactured by Hitachi Chemical Co., Ltd., H-5310) for hole cleaning that is in close contact with each other in a peelable manner as a mask, and a second mask film (12) (manufactured by Hitachi Chemical Co., Ltd., L3380) is closely laminated on the upper surface of the adhesive 10.

In FIG. 1(d), as described above, both mask films 11
．． 12 is laminated with the insulating substrate 1, and then only the second mask film 12 of both mask films 11 and 12 is peeled off, and hole cleaning is performed to fill the holes 8. Etch back the exposed wire coating layer.

In FIG. 1(e), after the above etchback process,
After peeling off the second mask film 12, apply a permanent resist 14 (Hitachi Chemical Co., Ltd.) to the surface of the first mask film 11.
After forming a surface pattern with 5R-3200 (manufactured by Co., Ltd.), the holes 8, surface pads, terminals, lines, etc. are plated with a commonly used thick electroless copper plating solution to form hole conductors. A second surface pad conductor 13a1 and a surface line conductor 13b are formed, thereby obtaining a multi-wire wiring board using the full additive construction method.

Therefore, in the above embodiment, since the etch-back treatment is performed after peeling only the second mask film out of the first and second mask films, the adhesive for electroless copper plating is It is protected by the first mask film, is not attacked by the processing liquid, and has good permeability into the pores of the processing liquid.

Further, in the above embodiment, since the holes are formed in the substrate on which the first and second mask films are laminated, the openings of the holes have small roughness and burrs are suppressed.

<Effects of the Invention> As described above, the method for manufacturing a multi-wire wiring board according to the present invention is such that a mask is placed on top of the adhesive for electroless plating, holes are formed, and then insulation exposed in the holes is formed. To etch back the coating layer of the body covering wire, the adhesive is protected by a mask and is not attacked by the processing liquid.

As a result, a multi-wire wiring board can be provided in which a good roughened surface shape can be obtained through roughening in the full additive process, and which has uniform plating adhesion.

In particular, in the invention of claim 2, since a double layer of film that is tightly adhered in a peelable manner is used as a mask, when a hole is made, the opening part of the hole is The roughness is small and burrs are suppressed, resulting in even better hole quality.

Further, in the invention of claim 3, the upper film of the double film is peeled off after the holes are formed, and then the etch-back treatment is performed. The material quality is good, and since only the film on the lower surface side is exposed during etchback processing, the permeability of the processing liquid into the pores is good, and good etchback processing can be performed.

[Brief explanation of the drawing]

FIGS. 1(a) to (e) are cross-sectional views showing a method for manufacturing a multi-wire wiring board according to the present invention, and FIGS. 2(a) to (e) are cross-sectional views showing a conventional method for manufacturing a multi-wire wiring board. figure. 2... Power supply layer 3... Ground layer 5... Insulator coated wire 8... Hole 11... First mask film 12... Second mask film 14... Permanent resist ( a) (b) (c) (d) (e) Fig. (a) (k+) (d) (e) Fig.

Claims (3)

[Claims] 1. In a method for manufacturing a multi-wire wiring board in which hole conductors, surface pads, and line conductors are formed only by electroless plating, an adhesive for electroless plating is applied to the surface of the board containing the inner layer circuit and insulator-covered wire, and the After a mask is placed on top of the applied adhesive and a hole is drilled, the coating layer of the insulator-coated wire exposed in the hole is etched back, and then the mask is peeled off and permanently etched. A method for manufacturing a multi-wire wiring board, characterized by forming a surface pattern with a resist and then performing electroless plating. 2. 2. The method of manufacturing a multi-wire wiring board according to claim 1, wherein a double layer of film that is peelably adhered to each other is used as the mask. 3. 3. The multi-wire according to claim 2, wherein the upper film of the double mask film is peeled off after the holes are formed, and then an etch-back process is performed, and then the lower film is peeled off. Method of manufacturing wiring boards.