JPS59108390A - Method of producing flexible printed circuit 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 Field of the Invention The present invention relates to a method for manufacturing flexible printed wiring boards.

Conventional Structures and Problems Conventionally, the method for manufacturing flexible printed wiring boards with through-holes is to laminate a dry film resist onto a through-hole plated substrate and photoprint the circuit to form the desired pattern. It was something that This method is often used to manufacture printed wiring boards with through holes.

The purpose is to protect the through holes from etching liquid. However, this method had the disadvantage of increasing costs because the dry film resist used to form the circuit tends to be limited to expensive ones.
-There is also a method of forming a resist pattern for N formation by screen printing on a base material using a screen with a predetermined pattern, but this method is different from the above-mentioned photographic method using dry film renost. Although it is simple, there is a disadvantage that unless the copper foil and the spacing between the copper foils are 0.2 nrm or more, a resist structure cannot be formed due to problems with the printing plate, resist ink, etc. Moreover, it is extremely difficult to manufacture a flexible printed wiring board that supports through holes using the screen printing method. This is because it is not easy to coat the inner wall of the through hole with photoresist ink.

As described above, the conventional photographic method using a dry film-like lens in the Lennost pattern formation method is suitable for flexible printed wiring boards with through holes, but the material cost is high, and the Although the printing method is simple, it is not suitable for flexible printed wiring boards having through holes.

Purpose of the Invention The present invention solves the above-mentioned conventional drawbacks, and is inexpensive and low-N.
The present invention provides a method for manufacturing a flexible printed wiring board with a flexible pattern.

Structure of the Invention The present invention is a method for manufacturing a flexible printed wiring board that covers the steps of coating the inner walls of holes in a flexible element with liquid photorenost and coating the surface of the flexible element with liquid photoresist, and is inexpensive and It is capable of forming fine patterns.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

1. First, in FIG. 1, strip-shaped conductive foils 3 and 4 are applied to both sides of a strip-shaped flexible base material 2 made of flexible synthetic resin such as polyester or polyimide using pressure rollers 5 and 6, etc., using appropriate pressure, temperature, and adhesive. The process of manufacturing the flexible cord body 1 by laminating the cables together by the following methods is shown.

Figure 2 shows the process of manufacturing a flexible printed wiring board from the flexible element body 1, and in the first step hA, the flexible element body 1 with conductive foils 3 and 4 provided on both sides is attached to the flexible element body 1 as shown in Figure 3a. As shown in the figure, a lead insertion hole 7 of an electronic component is drilled by a punching machine 8.

Next, in a second step B, the hole 7 is plated with through-hole plating 10 as shown in FIG. The conductive foils 3 and 4 are coated with liquid photoresists 12a and 12b'lil'' as shown in FIG. 3C.The third step C will now be described in detail with reference to FIG.

1. In the coating device 11a, the flexible element 1
is elastically held between a pair of supply rollers 13a and 13b, and by rotation of the supply rollers 13a and 13b in the direction of the arrow, the element body 1 is transported in the direction of the arrow a. This transferred element body 1 is a tank 15 filled with liquid photoresist) 12a.
The entire element body 1 is immersed in the liquid photoresist 12a.

16 is a guide line that prevents the body 1 from lifting up.

Multiple pieces are arranged at predetermined intervals in the width direction of the element body 1.
The element 1 immersed in liquid photorence 12a is elastically held between a pair of grading rollers 1a and 17b which have a plurality of grooves cut on the circumference and are rotated in the direction of the arrow. The liquid photoresist 12a attached to the surface of the hole 7 is squeezed to coat the inner wall of the hole 7 with the liquid photoresist 12a, and the liquid photoresist 12a is transferred to the coating device 11b. This coating device 11b includes a pair of transfer rollers 18a.

18b and a pair of doctor rollers 19a and 119b, the doctor rollers 19a and 19b can provide a clearance between the transfer rollers 1sa and 1sb, and the clearance can be adjusted depending on the coating thickness of the liquid photoresist. Can be adjusted. The transfer roller 18a.

A liquid photoresist 12b is placed on the doctor rollers 18b and 19b, and the liquid photoresist 12b is placed on the doctor rollers 19a and 19b.
b is uniformly supplied to the circumferential surfaces of the transfer rollers 18a and 18b. This uniformly supplied liquid photoresist 12b is transferred to the transfer roller 18a.

By rotating 18b in the direction of the arrow, the surface of the element body 1 and the liquid photoresist 12 previously coated are removed.
A uniform liquid photoresist 12b is again coated on the edge of a. Then, the element body 1 is further transferred and entered into the hot air oven 20, which is the next drying device 11C. The element body 1 entered into the hot air oven 20 is transferred by feed rollers 21 and 22 rotating in the direction of the arrow, and during this transfer, hot air generated from a hot air generator 23 coats the element body 1 with the liquid photoresists 12a and 12b. Liquid photoresists 12a and 12b are sprayed onto both sides of the element body 1.
Dry.

The flexible element body 1 coated with the liquid photoresists 12a and 12b as described above is supplied to the fourth step in FIG. 2. This fourth step is a step of baking the element body 1 coated with the liquid photoresists 12a, 12b into a desired pattern.As shown in FIG. 3d, the element body 1 coated with the liquid photoresists 12a, 12b A desired pattern mask 24 is brought into close contact thereon, and the exposure machine 25 performs printing. In the fifth step E, the pattern mask 24 is removed and unnecessary portions of the liquid photoresist 12a, 12b are developed by the developing device 26 as shown in FIG. 3e. Furthermore, in the sixth step F, etching is performed by the developing device 27, and the liquid photoresist 12a,
The through-hole plating 13 and the copper foils 3 and 4 in the area where the plating 12b has been removed are removed to form a circuit conductive foil as shown in FIG. 3f.

Effects of the Invention As described above, the present invention coats the entire surface of a flexible element including the inner walls of the holes with a liquid photoresist and applies a photographic method to manufacture a flexible printed wiring board. For example, it is possible to form a resist pattern at a lower cost than the conventional dry film photography method, and it is also easy to form a fine pattern, and its effects are outstanding.

[Brief explanation of drawings]

Figure 1 is a diagram showing an example of the manufacturing process of a flexible element body;
Fig. 2 is a diagram showing the process of one embodiment of the present invention, Fig. 3 is a sectional view of a flexible printed wiring board corresponding to the same process, and Fig.
The figure is a schematic diagram showing the main parts of the liquid photoresist coating apparatus. 1... Flexible element body, 3, 4... Conductive foil, 7... Hole +10... Through hole plating +12a. 12b...Liquid photoresist, 17a, 17
b...Aperture roller, 18a, 18b...Private school roller. 24...Pattern mask. Name of agent: Patent attorney Toshio Nakao (1st person)
Figure 2 Figure 3'' 2I=Lt-ge2)/ b 1≠N death to associate 〒Chishi 2

Claims (1)

[Claims] After immersing a flexible printed wiring board element with plating on at least the inner walls of the holes in a liquid photoresist for circuit configuration, a pair of rollers with a plurality of grooves formed on the surface are used to coat the liquid photoresist. into the inner wall of the hole, then coat the surface of the element body with liquid photoresist, re-coat the liquid photoresist with a pair of rollers, and photograph the circuit on the coated liquid photoresist. The resist film is developed by baking. A method for manufacturing a flexible printed wiring board, which comprises etching unnecessary copper foil portions to form an electric circuit.