JPH0744337B2 - Method for manufacturing printed wiring board - Google Patents

Description

The present invention relates to a method for manufacturing a printed wiring board, and more particularly to a method for manufacturing a printed wiring board in which a circuit pattern is formed by electroless copper plating.

[Conventional technology]

Conventionally, the manufacturing method of this kind of printed wiring board is shown in FIG.
It was manufactured by the process shown in- (f). That is, as shown in FIG. 3 (a), holes 10 to be through holes, via holes, etc. are made in the insulating substrate 1, and the catalyst 4 for electroless copper plating is treated as shown in FIG. 3 (b). Then the third
As shown in FIG. 3C, a dry film type photo-curable resin pattern 3a is formed, and then an electroless copper plating pattern 5 is formed as shown in FIG. 3D. As described above, a method for manufacturing a printed wiring board is described, in which the photocurable resin pattern 3a in the form of a dry film is peeled and removed, and then the second insulating resin pattern 6 is formed on a portion not to be soldered as shown in FIG. 3 (f). Was becoming.

[Problems to be Solved by the Invention]

The above-mentioned conventional method of manufacturing a printed wiring board has the following drawbacks.

(1) Since the catalyst residue easily remains on the surface of the insulating substrate other than the electroless copper plating pattern, the insulation resistance characteristic between the circuit patterns is poor. (Generally, a metal palladium or copper is used as a catalyst.) (2) When electroless copper plating is performed, a reversible plating resist pattern is formed by using a photocurable resin that can be peeled off. Organic substances are eluted from the photo-curable resin into the electrolytic copper plating solution and contaminate the electroless copper plating solution.

(3) Since the through hole for the through hole or the via hole is opened in the first step, the resin pattern must be aligned with the through hole when the resin pattern for electroless plating is formed. Therefore, since a clearance for alignment is absolutely necessary and cannot be made landless,
It is difficult to increase the wiring density.

The object of the present invention is to eliminate the drawbacks of the prior art, have excellent insulation resistance characteristics between line patterns, and enable high-density wiring without elution of organic substances from the photo-curing resin in the electroless copper plating solution. Another object of the present invention is to provide a method for manufacturing a printed wiring board.

[Means for Solving the Problems]

A method of manufacturing a printed wiring board according to the present invention comprises a step of forming an insulating first resin layer having photo-curing property and thermosetting property on both surfaces of an insulating substrate, and the first resin layer. Forming a second resin layer having photocurability on the layer, and forming a through hole in the insulating substrate on which the second resin layer is formed to form a through hole or a via hole. Forming holes so that the through holes of the second resin layer, the first resin layer, and the insulating substrate overlap each other in a self-aligned online manner; and the second resin layer and the second resin layer. After simultaneously exposing the first resin layer through the mask film,
A step of developing and removing an unexposed portion of each resin layer with the same developer to form a two-layer resin pattern, and a step of thermally curing the pattern of the first resin layer among the resin patterns A step of performing a catalytic treatment for electroless plating on the insulating substrate, and attaching an electroless plating catalyst on the through hole inner wall, the exposed portion of the insulating substrate and the resin pattern; A step of peeling off the pattern of the second resin layer to selectively remove the second resin layer pattern and the electroless plating catalyst thereon at the same time; and the catalytically treated portion of the insulating substrate. Electroless copper plating to form a conductor layer on the inner wall of the through hole and to form a predetermined conductor pattern on the insulating substrate, and to avoid unnecessary soldering of the conductor pattern. Characterized in that it comprises a step of forming a sexual resin layer.

In the method for manufacturing a printed wiring board of the present invention, since the first insulating resin layer and the photo-curing resin layer are formed in an overlapping manner, a pattern is formed at the same time, and a catalyst treatment is performed, the photo-curing resin pattern is formed. When peeled and removed, the catalyst remains only in a desired portion where the electroless copper plating pattern is desired to be formed, and the catalyst residue does not remain between the circuit patterns, so that the insulation resistance between the circuit patterns does not decrease.

Further, the photo-curable resin is liable to elute organic substances in the electroless copper plating solution and contaminates the electroless copper plating solution, but in the present invention, the photo-curable resin is peeled and removed before performing the electroless copper plating. Therefore, the electroless copper plating solution is not contaminated.

Further, in the present invention, a catalyst-resistant resin layer is formed on the entire surface of the insulating substrate in the first step, and then through holes for through holes or via holes are formed in the next step. Therefore, since the through holes of the resin layer and the insulating substrate overlap each other in a self-aligning manner on-line, a clearance for alignment is not required, and the wiring density can be increased by the landless method.

〔Example〕

Next, the present invention will be described with reference to the drawings. 1A to 1G are cross-sectional views of a printed wiring board shown in the order of steps for explaining the first embodiment of the present invention.

First, as shown in FIG. 1 (a), a photocurable and thermosetting liquid first insulating resin layer 2 is formed on the surface of an insulating substrate 1 by a curtain coater, a roll coater, a screen printing method, or the like. Dry at -100 ° C for 5-30 minutes. next,
A dry film-shaped photo-curable resin layer 3 is laminated on the upper surface of the first insulating resin layer 2 to be formed.

Next, as shown in FIG. 1 (b), holes 10 to be through holes, via holes, etc. are formed, and then, as shown in FIG. 1 (c), exposed through a mask film to form the first insulating resin layer 2 and The unexposed portion of the dry film type photo-curable resin layer 3 is developed and removed with 1,1,1 trichloroethane to obtain a desired first layer.
The insulating resin pattern 2a and the photo-curable resin pattern 3a in the form of a dry film are formed, and heat treatment is performed at 130 to 150 ° C. for 30 to 60 minutes to cure the thermosetting component of the first insulating resin pattern 2a. .

Next, as shown in FIG. 1 (d), a catalyst treatment is performed to form the catalyst 4 on the insulating substrate 1 and a dry film type photo-curing resin pattern.
It adheres to the surface of 3a and the walls of holes that will be through holes and via holes.

Next, as shown in FIG. 1 (e), the dry film type photo-curable resin pattern 3a is peeled off with methylene chloride, and the desired electroless copper plating is performed by electroless copper plating as shown in FIG. 1 (f). The pattern 5 is formed.

Finally, as shown in FIG.
A desired printed wiring board was obtained by forming the insulating resin pattern 6.

2A to 2G are cross-sectional views of the printed wiring board shown in the order of steps for explaining the second embodiment of the present invention.

First, as shown in FIG. 2 (a), a photocurable and thermosetting liquid first insulating resin layer 2 is formed on the surface of the insulating substrate 1 by a curtain coater, a roll coater, a screen printing method, or the like. Dry at 70-100 ° C for 5-30 minutes. Next, a liquid photocurable resin layer 7 is formed on the upper surface of the first insulating resin layer 2 by a curtain coater, a roll coater, a screen printing method or the like, and dried at 70 to 100 ° C. for 5 to 30 minutes.

Next, as shown in FIG. 2 (b), exposure is performed through a mask film, and the unexposed portions of the first insulating resin layer 2 and the liquid photocurable resin layer 7 are developed and removed with 1,1,1 trichloroethane. Then, a desired first insulating resin pattern 2a and a liquid photocurable resin pattern 7a are formed, and the first insulating resin pattern is formed.
30 ~ 60 at 130 ~ 150 ℃ to cure the heat-cured component of 2a.
Heat treatment is performed for a minute.

Next, as shown in FIG. 2 (d), a catalyst treatment is performed to deposit the catalyst 4 on the insulating substrate 1, the surface of the liquid photo-curable resin pattern 7a, and the walls of the holes to be through holes and via holes.

Next, as shown in FIG. 2 (e), the liquid photocurable resin pattern 7a is peeled off with methylene chloride, and as shown in FIG. 2 (f), a desired electroless copper plating pattern is formed by electroless copper plating. 5 is formed.

Finally, as shown in FIG. 2 (g), a desired printed wiring board was obtained by forming the second insulating resin pattern 6 on the soldering unnecessary portion.

〔The invention's effect〕

 As described above, the present invention has the following effects.

(1) Since the catalyst residue 4a does not remain between the electroless copper plating patterns, the insulation resistance characteristic between the circuit patterns is good.

(2) In the case of performing electroless copper plating, the electroless copper plating solution is eluted from the photocurable resin pattern in order to perform the electroless copper plating after peeling and removing the peeling type photocurable resin pattern. The life of the electroless copper plating solution can be extended without contamination.

(3) Since the resin pattern for catalyst resistance treatment is formed on the entire surface of the insulating substrate in the first step, the through hole for the through hole or the via hole is opened in the next step. Through-holes are self-aligned and overlap online. Therefore, it is not necessary to provide a clearance for alignment, and it is possible to increase the density of wiring by making the landless.

[Brief description of drawings]

1 (a) to 1 (g) are sectional views of a printed wiring board shown in order of steps for explaining the first embodiment of the present invention, and FIGS. 2 (a) to 2 (g) are drawings of the present invention. Sectional drawing of the printed wiring board shown in order of process for explaining 2nd Example, FIG.
(F) is sectional drawing of the printed wiring board shown in order of process in order to demonstrate an example of the manufacturing method of the conventional printed wiring board. 1 ... Insulating substrate, 2 ... First insulating resin layer, 2a ... First insulating resin pattern, 3 ... Dry film type photo-curing resin layer, 3a ... Dry film type photo-curing resin Pattern 4 ... Catalyst, 4a ... Catalyst residue, 5 ... Electroless copper plating pattern, 6 ... Second insulating resin pattern, 7 ... Liquid photocurable resin layer, 7a ... Liquid photocuring Mold resin pattern, 10 ... holes.

Claims (1)

[Claims] 1. A step of forming an insulative first resin layer having photo-curing property and thermosetting property on both surfaces of an insulating substrate, and photo-curing property on the first resin layer. Forming a second resin layer including: a through hole formed in the insulating substrate on which the two resin layers are formed to form a through hole that is to be a through hole or a via hole; Forming a through hole of each of the first resin layer, the first resin layer and the insulating substrate so as to overlap each other in a self-aligning manner online, and masking the second resin layer and the first resin layer After simultaneously exposing through the film, an unexposed portion of each resin layer is developed and removed by the same developer to form a two-layer resin pattern, and the first resin layer of the resin pattern is formed. The step of heat curing the pattern of A step of performing a catalyst treatment for deplating to attach an electroless plating catalyst on the inner wall of the through hole, the exposed portion of the insulating substrate and the resin pattern; and a pattern of the second resin layer of the resin pattern And removing the second resin layer pattern and the electroless plating catalyst thereon selectively at the same time, and applying electroless copper plating to the catalyst-treated portion of the insulating substrate. A step of forming a conductor layer on the inner wall of the through hole and forming a predetermined conductor pattern on the insulating substrate, and a step of forming an insulating resin layer on a portion of the conductor pattern not to be soldered. A method of manufacturing a printed wiring board, comprising: