JPS60211994A - Method of producing printed circuit substrate - 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 The present invention relates to a method of manufacturing a printed wiring board.

The printed wiring board is made by drilling holes in a Cuiu board (for example, a board made of glass fiber-containing epoxy with Cu foil pasted on it), pasting an etching resist photosensitive film on it, exposing it to light, developing it, and drawing a wiring pattern using an etching resist. Then, the Cu foil is further etched to form a Cu wiring circuit. Conventionally, in this development process and etching unevenness, the Cu foil sheet is held horizontally and fed from both sides between rollers from above and below. The developer and etching solution were sprayed onto the surface. However, with this method, it is difficult to form a uniform wiring circuit on both the upper and lower surfaces. On the top surface of the Cu foil plate, small warps or drilled holes on the board can easily cause pools of sprayed liquid to form, preventing new liquid from being supplied (which can lead to uneven development and etching. On the other hand, the bottom surface of the opposite side has the disadvantage that the substrate vibrates on the feed roller due to the pressure difference between the upper and lower spray liquids, and the resist film for etching is struck, rubbed, and easily damaged. The disadvantage is that the higher the density of wiring, the more it becomes a cause of disconnections and short circuits, especially in wirings with a density of 0.1 or less.

The present invention has been made in view of the above-mentioned drawbacks, and provides a method for manufacturing a printed wiring board without disconnection or short-circuiting.

The present invention relates to a method for manufacturing a printed wiring board, in which a developing or etching solution is applied to both surfaces of a Cu foil sheet plate on which an etching resist film on which a wiring pattern is drawn by exposure to light is vertically conveyed. This is a method for manufacturing a printed wiring board characterized by uniform spraying. In the present invention, the CU7G board having an etching resist film on which a wiring pattern is drawn by photo-sensing is conveyed vertically in a puddle. This is to prevent this from occurring.

In this case, when the nozzle moves from top to bottom or shakes its head while passing through the Cu foil plate spray nozzle and sprays the developing or etching solution, the solution flows from top to bottom and hits the liquid. This eliminates uneven development and etching. The spray nozzle is adjusted so that the liquid is sprayed uniformly over the entire Cu foil substrate. In addition, since the water pressure surface from the spray nozzle is horizontal and vertically placed on the Cu foil sheet feed roller, the Cu foil sheet wiring pattern is not rubbed by the feed roller and the pattern is Can be transported without causing damage. In the present invention, spraying the developing or etching solution evenly from the left and right is
This is to reduce horizontal deflection due to hydraulic pressure of the foil plate. Therefore, even if the pattern is printed on only one side of the substrate, it is necessary to spray from both the left and right sides. If the horizontal vibration is reduced, the feeding structure can be made easier.

In addition, as a feeding mechanism, it is also possible to use a mechanism that presses the upper end surface of the Cu foil plate with a roll, a mechanism that has a U-shaped groove in cross section, or a mechanism that has a groove with a U-shaped cross section, or in the case of a flexible printed circuit board, a feeding roll and a winding roll can be set up on both sides. .

Examples and conventional examples will be described below.

〔Example〕

External dimensions 60cm x 50cm as shown in Figure 1,
The wiring width is 100μ and the pitch is 200μ as shown in Figure 2 on the Cu foil substrate 1 with a Cu foil thickness of 0.035I
A set of five 500 μm wires were meandered onto the Cu foil substrate 1, and a 5 m long wiring pattern 2 was drawn on both sides by exposure.

Such a substrate 1 is vertically erected using a feed roll 4 and a presser roll 5 as shown in FIG. 3, and is fed at a rate of 0.5 to 2 m per minute. During this feeding, the developing solution, washing solution, and etching solution are sprayed in this order from the spray nozzle 6. This spray nozzle 6 swings vertically, has 50 holes of 9.3 m', and is designed to spray approximately 240 β of liquid per minute. Five substrates thus obtained were used as the actual amount.

[Conventional example]

As shown in FIG. 4, the same substrate l used in the example was placed horizontally on the feed roll 4, the spray nozzles 6 were arranged vertically, and development and etching were carried out under the same conditions as in the example.
Five sheets were used as conventional products.

Next, the amount obtained in the above example and the conventional product obtained by the conventional method were compared to the pin J width of the printed wiring board 1.
Short-circuits were investigated in the circuit portion with a pinch width of 500 μ, and disconnections were investigated in the circuit portion with a pinch width of 500 μ. The results are shown in the table below.

As is clear from the above table, the amount produced by the manufacturing method of the present invention has significantly fewer disconnections and short circuits than the conventional products obtained by the conventional method.

As described above, the manufacturing method of the present invention is known to be effective in producing high-density wiring patterns of 0.1 mm or less, as there is no liquid pooling or rubbing caused by feed rollers, so disconnections and short circuits are significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is a front view of the printed wiring board, FIG. 2 is a partially enlarged view of FIG. 1, FIG. 3 is a perspective view for explaining the present invention in detail, and FIG. 4 is for explaining a conventional example. FIG. 1---One board, 2---One circuit pattern, 4------
1 feeding roll, 5-111~-pressing roll, 6---spray nozzle. Applicant Tanaka Kikinzoku Kogyo Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] A method for manufacturing a printed wiring board, characterized by spraying a developing or etching solution evenly on both surfaces of a Cu foil sheet plate having an etching resist film on which a wiring pattern has been exposed by exposure to light while being conveyed vertically. A method for manufacturing a printed wiring board.