JPH0137877B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has a conductor network of a predetermined shape on both sides,
The present invention relates to a method for manufacturing a printed wiring board in which these conductor networks are electrically connected by through-hole conductors, and its purpose is to efficiently form plated layers for different uses on the conductor network. An object of the present invention is to provide a method for manufacturing a printed wiring board that allows for the production of printed wiring boards.

Generally, when a keyboard switch circuit and its peripheral circuits are integrated on a single printed wiring board, the printed wiring board has conductor networks of a predetermined shape on both sides, and these conductor networks are connected to through-hole conductor circuits. A double-sided printed wiring board with electrical connections is used. In double-sided printed wiring boards, the conductor circuit network for the switch circuit of the keyboard is often plated with gold as a contact plating, and also with copper plating as a through-hole conductor path. However, the above-mentioned different plating process for double-sided printed wiring boards involves providing a release paper, etc. in the area where the gold plating is to be formed, and then applying a plating resist film to all other areas, then removing the release paper, and then applying the gold plate. The area where plating is to be formed is exposed and subjected to gold plating, and then, after removing the plating resist film, the surface on which the gold plating is to be formed is covered with a plating resist film and copper plating is performed, and finally Since the plating resist film on the surface on which the gold plating is formed must be removed, a copper plating layer is also provided on the conductor network that has already been formed, There was a problem that a glazed layer was formed. Therefore, if you try to form a copper plating layer only on the necessary parts of the already formed conductor network, you will have to selectively apply a plating resist film, especially on the parts where through-hole conductor paths will be formed. There was a problem that the plating process became extremely troublesome when there were both non-formed parts.

The present invention solves these conventional drawbacks and efficiently forms plating layers for different uses by selectively printing plating resist on the surface of the substrate body and the through holes at the same time. It was made so that it could be done.

Examples of the present invention will be described below.

Example First, as shown in FIG. 1, conductor layers (copper foil) 1 and 2 as a conductor network of a predetermined shape are provided on both sides, and through holes 3 are provided at predetermined locations.A glass cloth base epoxy resin is prepared. A printed circuit board 4 made of a laminated board was prepared. Next, as shown in FIG. 2, a metal mask 7 having a mask hole 5 and a stepped mask hole 6 is placed on the surface of the printed circuit board 4 on which the conductor layer 1 as one conductor circuit network is provided. Plating resist 8 was printed using a screen printing method. At this time,
As the plating resist 8, vinyl resin paint 205B manufactured by Nazda Corp. was used after adjusting the viscosity to 20,000 CPS with a butyl carbitol solvent. Through this screen printing, three-dimensional printing of the plating resist 8 is selected on the hole wall of the through hole 2 and the conductor layer 1 around the hole, which corresponds to the area where the through-hole conductor path is not formed, as shown in FIG. At the same time, a plating resist 8 was selectively printed on a plane on the conductor layer 1 corresponding to the location where the gold plating was to be formed. Next, the printed circuit board 4 is reversed,
As shown in FIG. 3, a metal mask 11 having mask holes 9 and stepped mask holes 10 is arranged on the surface on which the conductor layer 2 as the other conductor circuit network is provided, and a plating resist 8 is screen printed. Printed using the method. By this screen printing, the plating resist 8 is selectively printed three-dimensionally on the hole wall of the through hole 2 and the conductor layer 2 around the hole, which corresponds to the area where the through-hole conductor path is not formed, as shown in FIG. At the same time, plating resist 8 was selectively printed on a plane on the conductor layer 2 corresponding to the areas where copper plating was not formed. Next, the printed circuit board 4
After hardening the printed layer of the plating resist 8 in an electric furnace at 120°C for 10 minutes, a plating activation process is performed, and then the fourth layer is immersed in a known copper plating solution. As shown in the figure, a copper plating layer 12 is formed in a grommet shape on the hole wall of the through hole 2 corresponding to the area where the printed layer of the plating resist 8 is not formed and on the conductor layers 1 and 2 around the hole. At the same time, a copper plating layer 12 was provided on the conductor layer 2 corresponding to the portions of the plating resist 8 where the printed layer was not formed. After this plating treatment, the printed circuit board 4 was immersed in a 2% alkaline solution to peel off the printed layer of the plating resist 8. In this way, the first plating process for forming the copper plating layer 12 is completed. Next, as shown in FIG. 5, a metal mask 15 having a mask hole 13 and a stepped mask hole 14 is placed on the surface of the printed circuit board 4 on which the conductor layer 1 as one conductor circuit network is provided. Plating resist 8 was printed using a screen printing method. By this screen printing, as shown in FIG. 5, the hole wall of the through hole 2 corresponding to the area where the through hole conductor path is not formed, the conductor layer 1 around the hole, and the copper plating layer 12 as the through hole conductor path. The plating resist 8 is three-dimensionally printed on the hole wall of the through hole 2 provided with the through hole 2 and the copper plating layer 12 around the hole, and at the same time, the conductor layer 1 corresponding to the area where the gold plating is planned to be formed is printed. Planar printing of plating resist 8 was selectively performed on all conductor layers 1 except for . Next, the printed circuit board 4 is turned over, and a metal mask 18 having mask holes 16 and stepped mask holes 17 is placed on the other surface on which the conductor layer 2 as the conductor circuit network is provided, as shown in FIG. Then, a plating resist 8 was printed using a screen printing method. By this screen printing, as shown in FIG. 6, the hole wall of the through hole 2 corresponding to the area where the through hole conductor path is not formed, the conductor layer 2 around the hole, and the copper plating layer 1 as the through hole conductor path.
The plating resist 8 is three-dimensionally printed on the hole wall of the through hole 2 in which the conductor layer 2 is provided and the copper plating layer 12 around the hole. A flat resist 8 was printed. Next, the printed circuit board 4 is placed in an electric furnace and the printed layer of the plating resist 8 is cured at 120° C. for 10 minutes, followed by a plating activation treatment, followed by a known gold plating solution. As shown in FIG. 7, a gold plating layer 19 was provided on the conductor layer 1 corresponding to the portion where the printed layer of the plating resist 8 was not formed. After this plating treatment, the printed circuit board 4 was immersed in a 2% alkaline solution to peel off the printed layer of the plating resist 8. In this way, the second plating process for forming the gold plating layer 19 is completed.

In the above example, the entire printed layer of the plating resist 8 was removed at the end of the first plating process; Only the printed layer of the resist is removed, and in a second plating process, the printed layer of the resist 8 is plated, leaving only the conductor layer 1, which corresponds to the area where the gold plating layer is to be formed, and plating all remaining parts. You may also cover it with water.

Further, the order of the first and second plating processes may be reversed so that the copper plating process is performed after the gold plating process.

As described above, according to the present invention, the plating resist is printed on the surface of the double-sided printed wiring board and the through holes at the same time, so the printed layer of the plating resist can be selectively provided. Gold plating and copper plating can be selectively and appropriately formed only at necessary locations, and the plating process can be performed economically. In addition, even when there are areas where through-hole conductor paths are formed and areas where they are not formed, it is possible to selectively and easily form a printed layer of plating resist, so the plating process does not become complicated, and the printed layer can be printed at the required locations. This has the advantage that different plating layers can be provided only on the two sides.

[Brief explanation of drawings]

The drawings show an embodiment of the method for manufacturing a printed wiring board of the present invention, in which FIG. 1 is a sectional view of a double-sided printed circuit board as a starting material, and FIGS. 2 and 3 are cross-sectional views of a plating resist for copper plating. Explanatory diagram of the printing process, 4th
The figure is an explanatory diagram of the copper plating and resist removal process,
FIGS. 5 and 6 are explanatory diagrams of the printing process of plating resist for gold plating, and FIG. 7 is an explanatory diagram of the gold plating and resist removal process. 1, 2... Conductor layer, 3... Through hole, 4... Printed circuit board, 5, 9, 13, 16... Mask hole, 6,
10, 14, 17...Stepped mask hole, 7, 1
1, 15, 18...Metal mask, 8...Plating resist, 12...Copper plating, 19...Gold plating.

Claims (1)

[Claims] 1. A printed circuit board having a conductive circuit network of a predetermined shape on both sides and a plurality of through holes at predetermined locations thereof, and a predetermined portion including a predetermined location of one of the conductor circuit networks of the printed circuit board and the hole wall of the through hole. At the same time, a plating resist is selectively printed on the other conductive circuit network of the printed circuit board and at a predetermined location including the hole wall of the through hole. After curing the plating resist, a first plating resist is applied in a first plating solution.
a first plating treatment step in which a metal plating layer is deposited; a plating resist is simultaneously selectively printed on predetermined locations of one conductor network of the printed circuit board and all of the through holes; A plating resist is simultaneously selectively printed on predetermined locations of the other conductor circuit of the printed circuit board and all of the above-mentioned through holes, and after the above-mentioned plating resist is cured, a plating resist different from the first plating solution is applied. a second step of depositing a second metal plating layer in a second plating solution;
A method for manufacturing a printed wiring board, comprising a plating process, and depositing different metal plating layers on different parts of the printed circuit board by the first and second plating processes.