JPS63102394A - Manufacture of flexible printed circuit - Google Patents

Abstract

(57) [Abstract] 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 of manufacturing a flexible printed wiring board.

BACKGROUND OF THE INVENTION Recently, with the miniaturization of electronic devices, consideration has been given to using flexible printed wiring boards that are much thinner than conventional rigid printed wiring boards.

A conventional method for manufacturing a flexible printed wiring board will be described below with reference to FIG. In Fig. 1, reference numeral 1 denotes an element body, and the element body is a strip-shaped material made of a flexible synthetic resin such as polyester or polyimide, and has a thickness of about 0.012 to 0.3,211 mm and is formed into a strip on one side of a flexible base material 2. Thickness approx. 0
．． 0351 ml of conductive foil 3 and conductive foil 4 of the same type and thickness are bonded together on a surface centered on the base film using a pressure roller 6 or the like under appropriate conditions such as pressure, temperature, adhesive, etc. .

Problems to be Solved by the Invention However, in conventional flexible printed wiring boards, tensicon is always added to prevent the flexible base material 2 from sagging when the conductive foil 3.4 is laminated to the flexible base material 2. The flexible base material 2 of the manufactured element body 1 had a problem in that it was somewhat stretched in its longitudinal direction.

The present invention has been made in view of the above problems, and includes a flexible printed wiring board that does not shrink or expand and has a certain degree of rigidity, and conductive foils having different thicknesses on the front and back sides. The purpose is to provide an efficient manufacturing method.

Means for Solving the Problems In order to achieve the above object, the method for manufacturing a flexible printed wiring board of the present invention includes providing a conductive foil for circuit formation on one side, and
A conductive foil for circuit formation, which also serves as a reinforcing plate made of the same or different materials and having different thicknesses, is provided on the surface of the base film at the center. Guide holes for transporting the base material are provided on both sides of the base material. The present invention is characterized in that a conductive foil containing the above is formed into a frame shape by etching, and a circuit conductive foil is efficiently formed in a predetermined circuit by etching inside the frame.

Function: Since the flexible printed wiring board of the present invention uses a material laminated with conductive foil that also serves as a reinforcing plate, it has a certain degree of rigidity and does not shrink or stretch.

Furthermore, since conductive foils having different thicknesses on the front and back sides are etched at the same time, there is an advantage of good manufacturing efficiency.

EXAMPLE Hereinafter, an example of the present invention will be described using FIGS. 1 to 6.

First, FIG. 2 sequentially shows the process of manufacturing a flexible printed wiring board from the element body 1. Figure 1 shows a part of it, with a conductive foil 3 on the entire surface of one side, and a conductive foil 3 that also serves as a reinforcing plate with different thicknesses on the side facing the base film (in this example, o, 1s). . In this first step 7, as shown in FIG. .

Then, guide holes 7 and 8 of a certain length 12 and other necessary holes are formed by pressing, and in the second step 11,
A lead insertion hole 9 of the lead-equipped electronic component is formed using a press or a drill machine, and in a third step 12, through-hole plating is performed.

Next, in a fourth step 13, a predetermined circuit set in advance is printed onto the element body 1 via a photosensitive film, and then developed in a fifth step 14. Then, in the sixth step 16, a conductive foil for a circuit is formed by simultaneously etching both sides of the element body 1 according to the present invention, in which the conductive foils 3 and 4 on both sides have different thicknesses.

In this embodiment, the thinner conductive foil 3 (
Place the board with the thicker side (thickness 0.1mm) facing up.
5111) 4 is placed in the etching device 15 with the side facing down. The solution used at this time is approximately 4 ml of ferric chloride solution.
The mixture is kept at 0°C and sprayed onto the upper and lower surfaces simultaneously from a nozzle 16 having a predetermined shape. However, since the thickness of the conductive foil on the upper and lower surfaces is different, as shown in FIG. 3, in the first and second tanks 17a and 17b, only the lower nozzle 16b injects, but the upper nozzle does not. The nozzle pressure at this time is 2.4 kg/i. Then, in the third bath, the upper and lower nozzles are set to a pressure of 2.4 kg/c11 and are simultaneously injected to form a circuit conductive foil, and then the etching solution is washed away. In this case, the conductive foil circuit 2
The size of the printed wiring board on which the guide holes 7 and 8 are formed is smaller than the distance 13 between the guide holes 7 and 8. The conductive foil 26 for the circuit is formed therein by etching the conductive foil 26 successively at equal intervals and having a width and a length having a constant relationship with the guide hole 8.9.

In the seventh step 20, a solder resist liquid is applied to the frame 26 of the element body 1 formed in this way, except for the circuit forming conductive foil 26 & that requires soldering.

Another method is to apply a sheet-like insulating film.

Next, in the eighth step 21, the lead-equipped electronic component 23 is inserted into the circuit conductive foil 25 into the lead insertion hole 9, and the lead is inserted into the lead insertion hole 9.
Further, the leadless electronic component 22 is temporarily held with an adhesive or the like, and after being soldered in a ninth step 29, the leadless electronic component 22 is held in a tenth step 29.
In step 3o, the flexible printed wiring board 31 is manufactured by cutting along the frame 26 and connecting the electronic components 22, 23 as shown in FIG.

Effects of the Invention As described above, according to the flexible printed wiring board of the present invention, the conductive foil still exists on both sides of the flexible board, and the conductive foil circuit that also serves as a reinforcing plate is formed. , moving the flexible body, and
Because the positioning is done, the flexible element will not contract or expand due to the remaining conductive foil, and especially around the guide hole, the presence of the conductive foil will prevent the flexible element from contracting or expanding. will no longer deform. In addition, when a high-density circuit is required, the circuit can be formed using a thin conductive foil, and the conductive foil for the circuit, which also serves as a reinforcing plate, is formed on the side facing the base film at the center, making it flexible. It is possible to obtain a part with a rigidity and a part with rigidity. Furthermore, according to the method for manufacturing a flexible printed wiring board, conductive foils of different materials and thicknesses can be simultaneously etched on the front and back sides to form a predetermined circuit, thereby producing an efficient and inexpensive flexible printed wiring board. It is possible to manufacture

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a method for manufacturing an element body of a flexible printed wiring board according to the present invention, FIG. 2 is a process diagram of a method for manufacturing a flexible printed wiring board according to an embodiment of the present invention, and FIG. 3 is a diagram showing the same process. 4 is a perspective view of the main part of the electronic component mounting process, and FIG. 6 is a top view of the board obtained by the same method. 1... Flexible element, 2... Flexible base material, 3... Conductive foil, 4...
Conductive foils with different plate thicknesses and materials, 7, 8... Guide holes, 25... Conductive foils for circuits.

Claims (1)

[Claims] Conductive foil for circuit formation is provided on one side of the flexible base material,
A flexible printed wiring board body with conductive foil for circuit formation of different thicknesses that also serves as a reinforcing plate on the opposite side is masked with a predetermined circuit, and etched to form conductive foil for circuit formation on one side. A method for manufacturing a flexible printed wiring board, characterized in that a predetermined circuit is simultaneously formed on conductive foils for circuits having different thicknesses (with the base film at the center).