JP2583365B2 - Manufacturing method of printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 having a high-density wiring circuit.

[0002]

2. Description of the Related Art Generally, a printed wiring board (hereinafter referred to as PWB) having a high-density wiring circuit is manufactured by using FIGS.
As shown in FIG. 4D and FIG. 5A to FIG. 5C, a hole filling method is used.
As shown in FIG. 4B, the inside of the through hole 1e of the insulating substrate 2 in which the conductor layer 1 including the copper plating layer and the through hole 1e are formed is filled and cured as shown in FIG.
4C, a photosensitive dry film 6 is attached to the surface of the insulating substrate 2, and a mask film 4 having a predetermined wiring pattern is brought into contact with the photosensitive dry film 6 as shown in FIG.
Bake. Next, the photosensitive dry film 6 in the unexposed portion is removed with a developer to obtain an etching resist 6a in a wiring circuit portion as shown in FIG.

Further, after the exposed conductor layer 1 is removed by etching as shown in FIG. 5 (b), finally, as shown in FIG. 5 (c), the etching resist 6a and the filling resin 7 are peeled off to obtain PWB. .

In this method, instead of the photosensitive dry film 6, an image formed by screen printing can be used as an etching resist.

[0005]

In the above-mentioned conventional method, when obtaining a PWB having a through hole without a land, it is difficult to fill the through hole larger than a predetermined diameter with a uniform filling resin. In addition, since it is difficult to form a through hole, as shown in FIG. 6, there is a problem that the variation in the hole diameter becomes large and the positioning accuracy at the time of component mounting is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a printed wiring board having a land-free through-hole with a small variation in hole diameter and high positioning accuracy when mounting components.

[0007]

According to the method of manufacturing a printed wiring board of the present invention, a positive photosensitive resin coating film is applied to the through holes and the surface of the conductor layer of an insulating substrate having the conductor layer and the through holes formed thereon. In the step of coating and coating, a portion larger than the diameter of the through hole for a through hole having a land and a portion smaller than the diameter of the through hole by 50 to 300 μm for a through hole having no land and a wiring portion are shielded from light. A step of abutting a mask film having a pattern and exposing by a printer, a step of selectively removing a positive photosensitive resin coating film exposed by development, and a step of etching and removing the conductor layer exposed by development. And a step of removing the remaining positive-type tourist resin coating film, and a land having a land with a small variation in through-holes and hole diameters. Characterized in that to obtain a free through-holes and the wiring circuit.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

1 (a) to 1 (c) and 2 (a) to 2 (a)
(C) is sectional drawing shown in order of the process explaining one Example of this invention.

First, as shown in FIG.
Is subjected to a copper plating process to form a conductor layer 1 and a through hole 1e. As a material of the insulating substrate 2, for example, a glass cloth base epoxy resin plate or a glass cloth base polyimide resin plate is used.

Next, as shown in FIG. 1B, a positive photosensitive resin coating 3a having a thickness of 3 to 15 μm is formed on the entire surface of the insulating substrate by electrodeposition coating and then dried.

Further, as shown in FIG. 1 (c), a mask film having a pattern in which through-holes having lands and through-holes without lands and wiring portions on the positive type photosensitive resin coating film 3a block light is provided. 4 and is irradiated with ultraviolet rays 5 of 200 to 1000 mJ / cm @ 2 by a printer. Thus, the inside of all through holes 1e is not exposed.

Next, the mask film 4 is removed, and FIG.
As shown in (a), the exposed positive photosensitive resin coating film 3b
Is removed with a developer such as an aqueous alkaline solution having a pH of 10 to 13. As the alkaline aqueous solution, Na2 Co3, N2
a2 SiO3 or the like can be used.

Thereafter, as shown in FIG. 2B, the exposed conductor layer 1 is removed with an acidic etchant.

Next, as shown in FIG. 2C, the positive photosensitive resin coating film 3a is peeled off with a hot aqueous solution of 1 to 4% of NaOH or KOH to remove the wiring circuit 1c and a land having a land. A PWB having a hole 1a and a through hole 1b without a land is obtained.

FIG. 3 is a sectional view for explaining the exposure step of FIG.

As shown in FIG. 3, the portion forming a through hole without a land has a diameter of 50 to 300 μm with respect to the hole diameter.
By contacting the mask film 4 which shields a small portion from light, the inside of the through hole can be sufficiently shielded from light.

In FIG. 1 (c), scattered ultraviolet light can be used.

[0019]

As is apparent from the above, according to the present invention, it is possible to obtain a PWB having a landless through-hole with a small variation in hole diameter as compared with the conventional hole filling method, and the positioning accuracy at the time of component mounting can be obtained. Is improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view shown in the order of steps for explaining an embodiment of the present invention.

FIG. 2 is a cross-sectional view shown in the order of steps for explaining an embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating an exposure step of FIG. 1 (c).

FIG. 4 is a cross-sectional view showing a PWB manufacturing method by a conventional hole filling method in the order of steps for explaining the method.

FIG. 5 is a cross-sectional view shown in the order of steps for explaining a PWB manufacturing method by a conventional hole filling method.

FIG. 6 is a cross-sectional view of a through-hole portion having no land by a conventional hole filling method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conductor layer 1a through hole with land 1b through hole without land 1c wiring circuit 1e through hole 2 insulating substrate 3a positive photosensitive resin coating 3b exposed positive photosensitive resin coating 4 mask film 5 ultraviolet ray 6 photosensitive Dry film 6a Etching resist for wiring circuit 7 Resin filling

Claims (1)

(57) [Claims] A step of electrodepositing a positive photosensitive resin coating on the through hole of the insulating substrate having the conductor layer and the through hole formed thereon and the surface of the conductor layer; A step of abutting a mask film having a pattern that shields light to a portion larger than the hole diameter and a through hole having no land by 50 to 300 μm with respect to the through hole diameter and a wiring portion, and exposing by a printer; A step of selectively removing the positive-type photosensitive resin coating film exposed by development, a step of removing the conductor layer exposed by development by etching, and further removing the remaining positive-type tourist resin coating film And a step of obtaining a through-hole having a land and a through-hole and a wiring circuit without a land having a small variation in hole diameter. Method of manufacturing a printed wiring board that.