JPH118465A - Manufacture of printed wiring board through additive method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a part mounting land required for mounting a part of a copper foil area and to make the surface of a printed wiring board smooth by a method, wherein a second plating resist layer and a second conductive circuit are formed on a plating resist layer and a conductive circuit. SOLUTION: A through-hole 4 is bored in an adhesive-coated insulating board 1, a plating resist layer 2 is formed, and a conductor circuit 3 is formed through a first electroless copper plating process after the board has been subjected to a surface-roughening process. Then, a dry film which is used for the plating resist layer 2 is formed is laminated for the formation of a second plating resist layer 16. After the dry film has been laminated, a light exposure process and a development process are carried out using a negative film, a UV-curing process is carried out, and the board 1 except the through-hole 4 and the part mounting land 5 is covered with the second plating resist layer 16. Thereafter, a second conductor circuit 15 is formed through a second electroless copper- plating process. Even if the second plating resist layer 16 deviates in position, the component-mounting land 5 is formed through the second electroless copper plating process to ensure a copper foil area required for mounting a component.

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 an additive method printed wiring board.

[0002]

2. Description of the Related Art FIG. 2 is a cross-sectional view for explaining a conventional method of manufacturing a printed wiring board by the additive method, which will be described with reference to FIG. In the figure, a through hole 4 is drilled in an insulating substrate 1 with an adhesive, a plating catalyst treatment is performed to deposit electroless copper plating, a plating resist layer 2 is provided, and electroless copper plating is performed. Then, a conductor circuit 3 is formed in a portion other than the plating resist layer 2. next,
The copper foil surface which is not related to the component mounting, for example, other than the component mounting land 5 is covered with the solder resist layer 6. The solder resist layer 6 is formed by a printing method or a photographic method using a thermosetting type or ultraviolet (hereinafter referred to as UV) curing type ink. In general, the solder resist layer 6 is made of electroless nickel / gold. Some of them can withstand plating, but none can withstand electroless copper plating, which requires a long processing time.

[0003]

In the printing method, the solder resist layer 6 formed by the above-described method has a copper foil area of the component mounting land 5 necessary for component mounting due to printing misalignment or bleeding of the solder resist ink. In some cases, the same problem as in the printing method may occur in the photographic method, but a thin solder resist film is formed as a residue on the copper foil surface of the component mounting land 5 in the developing process, resulting in poor soldering. There is also danger.

Further, as shown in FIG. 2, the additive printed circuit board P is not removed after the plating resist layer 2 is formed, usually after the conductor circuit 3 is formed. The surface is smooth.
Thereafter, by providing the solder resist layer 6 on the surface of the copper foil other than the component mounting lands 5, the smoothness characteristic of the surface may be lost.

In the present invention, the plating solution resistant dry film used in the formation of the plating resist layer 2 is used as a second plating resist layer (solder resist layer) 16, and this is combined with electroless copper plating. Accordingly, a method of manufacturing an additive-type printed wiring board in which the copper foil area of the component mounting land 5 necessary for component mounting is secured and the surface of the printed wiring board P is smoothed.

[0006]

In order to solve the above-mentioned problems, as shown in FIG. 1, a through hole 4 is formed in an insulating substrate 1 with an adhesive, a plating resist layer 2 is formed, and the surface is roughened. After the treatment, the conductor circuit 3 is formed by the first electroless copper plating. Next, a dry film used for the plating resist layer 2 is laminated on the plating resist layer 2 and the conductor circuit 3 to form a second plating resist layer (solder resist layer) 16 on the conductive film 3. Exposure, development, and UV curing are performed to provide a second plating resist layer 16 covering portions other than the necessary component mounting lands 5. afterwards,
A second conductive circuit 15 is formed by performing a second electroless copper plating.

[0007]

FIG. 1 is a block diagram showing an embodiment of the present invention.
It will be described based on. FIG. 3 is a cross-sectional view illustrating a method for manufacturing an additive method printed wiring board according to the present invention. As shown in FIG. 1, a through-hole 4 is drilled in an insulating substrate 1 with an adhesive (trade name: ACL-E-168 of Hitachi Chemical Co., Ltd.), and a plating catalyst treatment is performed. Plating solution-resistant dry film on the insulating substrate 1 with a coating solution (trade name of Hitachi Chemical Co., Ltd .: SR-3000)
Is laminated. Next, using a negative film, the film is exposed and developed by a printing machine, and is subjected to UV curing or thermal curing to form a plating resist layer 2 on a portion other than the conductor circuit 3. The conductor circuit 3 is formed by electrolytic copper plating.

Next, in order to form a second plating resist layer (solder resist layer) 16, the dry film used for the plating resist layer 2 is laminated. After lamination, exposure using a negative film, development and U
V-cured, through-holes and component mounting lands 5
Are covered with a second plating resist layer 16. Then, a second electroless copper plating is performed to form the second conductor circuit 15.
To form The second formed by this second electroless copper plating
The conductor circuit 15 may include only the through-hole portion and the component mounting land 5, and the conductor circuit for wiring may be disposed on the conductor circuit 3 formed by the first electroless copper plating.

The second plating resist layer (solder resist layer) 16 formed by the above-described method for manufacturing an additive printed wiring board according to the present invention does not always coincide with the plating resist layer 2 on a plane. However, since the second conductive circuit 15 is also formed by the second electroless copper plating on the plating resist layer 2 at the position where the second plating resist layer 16 is displaced, the copper foil area required for component mounting is required. Can be formed stably. Further, since the heights of the second plating resist layer 16 and the second conductor circuit 15 (the component mounting land 5) are substantially the same, the surface of the printed wiring board P becomes smooth.

[0010]

As described above, according to the present invention,
It has the following effects: (1) Even if the displacement of the second plating resist layer 16 occurs, the component mounting land 5 is formed by the second electroless copper plating after this step, so that the copper foil area required for component mounting can be stably maintained. Can be secured. (2) If only the component mounting land 5 is formed on the second conductor circuit by the second electroless copper plating, the workability, the inspection efficiency, the quality, and the like of the component mounting can be greatly improved. (3) In the present invention, the conductor circuits 3, 15 are formed by electroless copper plating.
And the second plating resist layer 16 and the second conductive circuit 15 have substantially the same height, and a printed wiring board P having a smooth surface can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a method of manufacturing an additive printed wiring board according to the present invention.

FIG. 2 is a cross-sectional view illustrating a method for manufacturing a conventional additive printed circuit board.

[Explanation of symbols]

P ... Printed wiring board 1 ... Insulating substrate with adhesive 2 ... Plating resist layer 3 ... Conductor circuit 4 ... Through hole 5 ... Component mounting land 6 ...
Solder resist layer 15: second conductive circuit 16: second plating resist layer (solder resist layer)

Claims (2)

[Claims] 1. A through hole (4) is formed in an insulating substrate (1) with an adhesive, a plating resist layer (2) is formed, and a conductive circuit (3) is formed by electroless copper plating after a surface roughening treatment. Forming a second plating resist layer (16) and a second conductor circuit (15) on the plating resist layer (2) and the conductor circuit (3). A method for manufacturing an additive method printed wiring board, comprising: 2. The circuit according to claim 1, wherein
5) A method of manufacturing an additive-processed printed wiring board, wherein only a through-hole portion and a component mounting land (5) are formed.