JPS622694A - Manufacture of printed wiring board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is applicable to a printed wiring board having an uneven surface due to a multilayer structure such as a multilayer conductive circuit or an overprinted circuit. The present invention relates to a method for manufacturing a printed wiring board that can effectively prevent the occurrence of defects such as cracks in such locations due to local concentration of working force during processing.

[Conventional technology]

In recent years, printed wiring boards have been produced in which two or more layers of conductive circuits are laminated with an intervening insulating layer, particularly by using conductive paste.

However, in the manufacturing process of conventional printed wiring boards having a multilayer structure, multilayer conductive circuits are formed by means such as screen printing, and then external processing such as punching is performed. For this reason, the surface becomes uneven with the formation of a multilayer conductive circuit, and as a result, when the external shape is processed using a punching machine A as shown in FIG. A large pressure is concentrated on the protruding portion B of the multilayer conductive circuit, and defects such as cracks may occur in the portion B. Similar problems occur with other processing machines such as routers and drills. In addition, when stacking two or more layers with an insulating layer interposed as described above,
Even when service characters, symbols, and other inks are printed in multiple layers on top of the resist ink using screen printing or other means, and as a result, some areas stick out more than others. A similar problem was occurring.

Moreover, in recent years, the quality of the base material of printed wiring boards has been improved, and the peripheral technology after processing has also been improved, making it possible to perform punching at room temperature.

In other words, in the conventional method, the printed wiring board is heated to change its properties to be more easily processed, such as to make it more flexible, and then punched out, thereby preventing damage such as loss of the punched edges and the so-called moth-eaten phenomenon. Ta.

This method has the disadvantage that the dimensions rtw: are likely to be distorted due to shrinkage of the base material due to heating, etc. As a result, improvements in the material of the base material that is less likely to cause the worm-eaten phenomenon and improvements in peripheral technology have been made. Punching has come to be performed at room temperature. However, even with this method, cracks and defects may occur in the base material, particularly in the laminated portion of the resist layer/layer formed on the base material. One of the reasons for this kind of damage to racks, etc. is that the surface of the printed wiring board is uneven due to the multilayer structure, such as multilayer conductive circuits formed on the base material and overprinting of ink such as service letters. Since punching is performed in such a surface condition, a large force is applied locally, resulting in defects such as cracks.

Therefore, by improving the yield ratio of the number of good products to the total number of products manufactured, it is possible to always produce printed wiring boards of a constant and high quality regardless of the type or type of punching process. was desired.

[Problem to be solved by the invention]

In view of the above-mentioned circumstances, the present invention has been devised to produce a printed wiring board with a multilayer structure in which multilayer conductive circuits, service characters, etc. are overprinted and the surface becomes uneven.
It is an object of the present invention to provide a method for manufacturing a printed wiring board that can prevent defects such as scratches and produce a printed wiring board of good quality.

[Means to be solved by the invention]

In order to achieve the above object, the present invention relates to a printed wiring board whose surface is formed into an uneven shape by a multilayer structure such as a multilayer conductive circuit or an overprinted sheet. The present invention is characterized by a method of manufacturing a printed wiring board formed into a multilayer structure after processing.

〔Example〕

EMBODIMENT OF THE INVENTION Hereinafter, one Example of the manufacturing method of the printed wiring board based on this invention is demonstrated based on drawing. In FIG. 1, 1 is a copper-clad laminate in which a copper foil 3 is laminated on a base material 2. Of course, any method may be used to laminate the copper foil 3 on the base material 2. The base material 2 is preferably made of a material that can be punched out at room temperature, which has been particularly developed and used in recent years, but the material is not limited thereto, and various materials can be used. As shown in FIG. 2, the steel-clad laminate 1 has
Perform external processing such as drilling holes 4 for mounting electronic components. Next, the copper foil 3 is etched to form a preset wiring pattern. Although the wiring pattern can be easily formed by etching, it is very suitable, but it does not necessarily have to be formed by etching, and other methods may of course be used. Further, the external shape processing shown in FIG. 2 can also be performed after forming the wiring pattern.

Thereafter, as shown in FIG. 4, a 9$1 undercoat 5 as an insulating layer was applied by screen printing, and then a fifth layer was applied.
As shown in the figure, a conductive paste is applied on the first undercoat 5 by screen printing to form a first conductive bridging circuit layer 6 in order to bridge the circuits formed by the predetermined copper foils 3. Furthermore, a second undercoat 7 as an insulating layer is formed on the nuclear conductive bridging circuit layer 6 by screen printing. On the second undercoat 7, as shown in figure w46, a predetermined copper foil 3 is applied in the same manner as the first conductive bridging circuit layer 6.
′, a second conductive bridging circuit layer 8
After forming, an overcoat 9 is applied. The first undercoat 5, second undercoat 7, first conductive bridging circuit layer 6, second conductive bridging circuit layer 8 and over;
- G-9 was coated by screen printing, and then
Of course, it can be cured. Also, as shown in Figure 7,
Furthermore, after forming the third electrically conductive bridging circuit layer 10, an overcoat 11 may be applied, and the electrically conductive bridging circuit layer becomes '! p
The number of laminated layers is not limited to those shown in the JG diagram and FIG. 7. After forming the multilayer structure in this way, it is manufactured into a product as it is without any external processing.

In addition, before laminating only the areas where defects such as cracks are expected to occur due to the formation of the multi-layer conductive bridging circuit layer and the subsequent contour processing, It is also possible to perform processing such as holes and the like in advance, and to perform processing on other parts after lamination.

In addition to forming a multilayer conductive bridging circuit layer, the above method prevents electronic components such as resistors from being damaged by press pressure during processing when forming electronic components such as resistors by screen printing or the like. It can also be applied in the same way when the surface becomes uneven due to overprinting of ink with service letters for displaying electronic parts.

〔Effect of the invention〕

As described above, according to the method for manufacturing a printed wiring board according to the present invention, the external shape is processed in advance before forming a multilayer conductive circuit or a multilayer structure of overprinting. After forming a multilayer structure, when the external shape is processed, the press pressure during processing applies a large force to the protruding parts of the surface of the board, which causes defects such as cracks at the parts. Also, due to the unevenness of the surface of the substrate, the press pressure acts not only in the pressing direction but also in other directions, effectively preventing defects such as cracks on the substrate. Furthermore, the processing machine is convenient because there is no need to form a recess in the mold to allow the protrusion of the printed wiring board to escape.

[Brief explanation of drawings]

1 to 6 are explanatory diagrams showing an example of the method for manufacturing a printed wiring board according to the present invention, and FIG. 7 is an illustration showing an embodiment of the method for manufacturing a printed wiring board according to the present invention, and FIG. Explanatory diagram,
FIG. 8 is an explanatory diagram showing the state of conventional external shape processing. 1... Copper-clad laminate, 2... Base material, 3, 3'.
...Copper foil, 4. Mounting hole, 5. First undercoat, 6. First conductive bridging circuit layer, 7.
...Second undercoat, 8...Second conductive bridging circuit layer, 9...Overcoat, 10...Third conductive bridging circuit layer, 11...Overcoat patent applicant Tokyo Print Kogyo Co., Ltd. Figure 1 Figure 2 Ward 3 Figure 5 Figure 16 Figure O 8

Claims (1)

[Claims] In printed wiring boards whose surfaces are formed into an uneven shape due to multilayer structures such as multilayer conductive circuits and overprinting, the copper-clad laminate is formed into a multilayer structure after external processing such as drilling is performed. A method of manufacturing a printed wiring board characterized by: