JPH0770830B2 - 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 including a step of forming a circuit pattern and a through hole.

[Conventional technology]

Conventionally, a method of manufacturing a printed wiring board of this kind has been such that a through hole is formed by using a drill in an insulating substrate containing a plating catalyst in which a palladium catalyst is dispersed, and a plating resist is formed by screen printing on both front and back surfaces of the insulating substrate containing the plating catalyst. A circuit pattern and a through hole were formed by forming a pattern and depositing electroless copper plating on an exposed portion of an insulating substrate containing a plating catalyst mixed with a palladium catalyst.

[Problems to be Solved by the Invention]

The conventional printed wiring board manufacturing method described above has the following drawbacks.

(1) Since it is necessary to create a screen plate in order to form a circuit pattern, the cost is high and the manufacturing delivery time is long when manufacturing a small number of products.

(2) Since the circuit pattern is formed by screen printing, a highly accurate circuit pattern cannot be formed.

(3) There are many manufacturing steps because a step of forming a through hole and a step of forming a plating resist are required.

An object of the present invention is to provide a method for manufacturing a printed wiring board, which has a small number of manufacturing steps, a short delivery time, a low cost, and a high accuracy.

[Means for Solving the Problems]

The method for producing a printed wiring board of the present invention comprises a step of forming an insulating resin layer on both front and back surfaces of an insulating substrate containing a plating catalyst, and a predetermined insulating resin layer formed on both front and back surfaces of the insulating substrate by laser light. A circuit pattern and a through hole by simultaneously removing the pattern and forming a through hole in the insulating substrate containing the plating catalyst by the laser beam, and depositing electroless copper plating on the exposed portion of the insulating substrate containing the plating catalyst. And a step of forming a solder resist on a predetermined portion of the insulating substrate containing the plating catalyst.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

1 (a) to 1 (d) are sectional views showing the manufacturing method of the first embodiment of the present invention in the order of steps.

In the first embodiment, first, as shown in FIG. 1A, prepregs 2 are superposed on both front and back surfaces of an insulating substrate 1 containing a plating catalyst, and pressure lamination is performed to form an insulating resin layer by the prepreg 2.

Next, as shown in FIG. 1 (b), the prepreg 2 is removed in a predetermined pattern by a YAG or carbon dioxide laser to expose the plating catalyst-containing insulating substrate 1 and at the same time.
Through holes to be through holes are formed at predetermined locations by YAG or carbon dioxide laser. Further, as a post-treatment of the insulating substrate 1, for example, honing treatment or chromic acid treatment is performed.

Next, as shown in FIG. 1 (c), electroless copper plating 3 is deposited on the exposed portion of the insulating substrate 1 containing a plating catalyst in an amount of 20 to 30 μm to form a through hole 5 and a circuit pattern 6.

Next, as shown in FIG. 1 (d), a solder resist 4 was formed by screen printing to obtain a printed wiring board of the first embodiment.

2 (a) to 2 (d) are sectional views showing the manufacturing method of the second embodiment of the present invention in the order of steps.

In the second embodiment, as shown in FIG. 2 (a), first, a liquid insulating resin such as an epoxy resin or a polyimide resin is screen-printed or curtain-coated on both front and back surfaces of the insulating substrate 1 containing a plating catalyst. Alternatively, apply it to a thickness of 10 to 30 μm by the roller coating method and apply 20 to 130 to 160 ° C.
The insulating resin layer 7 is formed by heat curing for 60 minutes.

Next, in the steps of FIGS. 2B to 2D, the printed wiring board of the second embodiment was obtained by the same forming method as that of the first embodiment.

〔The invention's effect〕

As described above, the present invention forms an insulating resin layer on both front and back surfaces of an insulating substrate containing a plating catalyst, YAG, or
The insulating resin layer is removed in a predetermined pattern with a carbon dioxide laser, and through holes that will be through holes are simultaneously formed. Electroless copper plating is deposited on the exposed portion of the insulating substrate containing the plating catalyst to form circuit patterns and through holes. Has the following effects.

(1) Since the step of forming a through hole by a drill is not necessary and the step of forming a plating resist pattern by screen printing is not necessary, the manufacturing process can be shortened,
Printed wiring boards can be manufactured in a short time.

(2) Since a pattern is directly formed by YAG or carbon dioxide laser, a printed wiring board can be manufactured with high accuracy.

(3) Since it is not necessary to create a screen plate to form a circuit pattern, a product with a small manufacturing quantity can be manufactured at low cost.

[Brief description of drawings]

1 (a) to (d) are sectional views showing the manufacturing method of the first embodiment of the present invention in the order of steps, and FIGS. 2 (a) to (d).
7D is a sectional view showing the manufacturing method according to the second embodiment of the present invention in the order of steps. 1 ... Insulating substrate containing plating catalyst 2 ... Prepreg, 3
…… Electroless copper plating, 4 …… Solder resist, 5 ……
Through hole, 6 ... Circuit pattern, 7 ... Insulating resin layer.

Claims (1)

[Claims] 1. A step of forming insulating resin layers on both front and back surfaces of an insulating substrate containing a plating catalyst, and removing the insulating resin layers formed on both front and back surfaces of the insulating substrate into a predetermined pattern by laser light and at the same time. A step of forming a through hole in the plating catalyst-containing insulating substrate by the laser beam, and a step of forming a circuit pattern and a through hole by depositing electroless copper plating on the exposed portion of the plating catalyst-containing insulating substrate, And a step of forming a solder resist on a predetermined portion of the insulating substrate containing the plating catalyst.