JPH10335762A - Flexible printed wiring board and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible printed wiring board capable of increasing the yield in the mounting time of various component, while eliminating the metallic mold by leaving copper foils on the connecting part. SOLUTION: In a flexible printed wiring board, non-continuous slit parts 6 are formed by laser between a part 1 to be a product and another part 2 to be removed from the product, while the slit connecting parts 5 between the slits are to be the flexible printed wiring board including copper foils.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible method in which a discontinuous slit is formed between a part to be a product and a part to be removed from the product by a laser, and a copper foil is provided in a slit connecting part between the slits. The present invention relates to a printed wiring board and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, flexible printed wiring boards have
Because it is lightweight and freely bendable, it is used in all electronic devices. Flexible printed wiring boards are usually made by laminating copper foil on one or both sides of an insulating film such as polyimide resin or polyester resin, forming the required circuit by photo etching, etc., and further covering the circuit with an insulating coating layer such as an insulating film. Then, the outer periphery of a part to be a product is punched out with a mold or the like to obtain a flexible printed wiring board.
Various components such as C are mounted.

Further, as one mode of a flexible printed wiring board, as shown in FIG. 3, a discontinuous slit portion 6 is formed between a portion 1 to be a product and a portion 2 to be removed from the product, and a component connection portion is formed. After mounting various components such as ICs, there is a nicked flexible method (hereinafter referred to as N-FT) in which the slit connecting portion 5 is cut to take out the product. The flexible printed wiring board is thin and has no rigidity, so it is difficult to transport it when mounting various components on its circuit, or it is difficult to position at the time of automatic mounting, so it will not be finally removed from the product part By adopting the N-FT with holes for transporting and positioning in parts, continuous automation of component mounting, electrical check, and product take-out processes is realized.

However, this method has the following disadvantages. Generally, the outer periphery of a flexible printed wiring board has a complicated shape, and when forming a discontinuous slit along this complicated shape, it is punched out with a die, but it takes time and cost to design and manufacture the die. It takes. Further, the shape of the male mold of the mold is complicated, thin and flat, and the mechanical strength is reduced, and the life of the mold is extremely shortened. On the other hand, if the minimum width of the female mold of the slit connecting portion is 2 mm or less, the mechanical strength is reduced and the life of the mold is shortened. The slit connection part is cut off at the end, and the product is taken out, leaving it as it is until component mounting. It is preferable that it breaks easily with a weak force and that the break position is as designed and the fracture surface is smooth. There is a possibility that the shape becomes irregular and deviates from the design shape and becomes defective. It is also possible to reduce the minimum width of the slit connecting part to 2 mm or less by a special punching method (punching in two parts), but the die manufacturing cost is high, and furthermore, it is connected when transporting and mounting various parts. There is a possibility that the probability of the part breaking increases.

[0005]

DISCLOSURE OF THE INVENTION The present invention is based on the results of various studies to solve the problems of the mold life, the breaking position of the slit connecting portion, the broken surface, etc. when forming the discontinuous slit as described above. It is an object of the present invention to provide a flexible printed wiring board which does not require a mold by leaving a copper foil at a slit connecting portion and can improve the yield at the time of mounting various components, and a method of manufacturing the same.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a flexible printed wiring board in which a circuit is formed on one or both surfaces of an insulating base material and the circuit is further covered with an insulating coating layer. A flexible printed wiring board and a method for manufacturing the same, characterized in that a discontinuous slit portion is formed by a laser between a portion to be removed from the substrate and a copper foil is included in a slit connecting portion between the slits.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The flexible printed wiring board used in the present invention is a polyester resin film, a copper clad board in which a copper foil is adhered to one or both sides of an insulating substrate made of a thermoplastic resin film such as a polyimide resin film, by a photo-etching method or the like. A circuit is formed, and a slit connecting portion, a positioning hole for laser processing, a positioning hole for component mounting, and the like are formed, and the surface thereof is covered with an insulating resin film. Materials such as a polyester resin film used in the present invention are not particularly limited,
It may be the same as that used for N-FT or the like. Although the number of slit connection parts is required to be two or more per one circumference of the slit in terms of function, an optimum number may be determined according to the area of the wiring circuit. Is preferred. The shape of the copper foil remaining at the connecting portion connecting the slits includes a butterfly shape, a triangle, a convex shape, a rectangular shape, and the like, and the butterfly shape is more preferable. The copper foil remaining in the slit connecting portion can be arranged on both sides, but is more preferably arranged on only one side. The laser used for forming the slit portion is not particularly limited, but may be an excimer laser, YA
G lasers and carbon dioxide lasers are preferred.

Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 (a) shows a circuit 7 by a photo-etching method, a copper foil 8 remaining at a slit connection portion, a positioning hole 4 for laser processing, a component mounting hole, and a copper-clad plate obtained by laminating a copper foil on one surface of an insulating base material. Coverlay (polyimide resin film) to be used as insulating coating layer after removing unnecessary copper foil while leaving positioning holes
FIG. 3 is a plan view of a flexible printed wiring board obtained by subjecting a flexible printed wiring board obtained by integrally heating, pressurizing and pressing to form a slit portion 6 by laser processing. The inside is the part 1 where the product is formed, and the outside is the part 2 which is removed from the product with the slit part 6 as a boundary. Laser processing is
A flexible printed wiring board is placed on a movable table that can be moved in the X, Y, and θ directions, and a slit is formed while moving the movable table numerically while irradiating a laser beam with reference to the laser processing positioning holes. I do. The energy intensity of the laser beam depends on the portion of the flexible printed circuit
That is, the condition may be set so that the slit connecting portion does not penetrate, but penetrates only a portion having no remaining copper foil. FIG.
FIG. 1A is a plan view of a flexible printed wiring board in which the size of the slit portion and the shape of the copper foil remaining in the slit connection portion are different from those in FIG.

The shortest length of the slit connecting portion after being processed by the laser is preferably from 0,05 to 1,0 mm, and more preferably from 0,2 to 0,7 mm. If the thickness is less than 0,05 mm, there is a problem that the slit connecting portion is cut off during the mounting of the component, or a part to be a product is dropped, and the like, so that 1,0 mm.
If it exceeds mm, there is a possibility that a part to be a product and a part to be removed from the product are not easily separated. The width of the slit portion is not particularly limited, but is preferably as narrow as possible. The same applies to both sides. After forming the slit, to remove the carbide generated during laser processing,
It is necessary to perform ultrasonic cleaning and solvent cleaning. In the step of mounting components on the flexible printed wiring board of the present invention,
By leaving the copper foil in the slit connection part, the strength is increased and the slit connection part does not break when loading and transporting parts, and the shortest length of the slit connection part can be shortened, so it is removed from the product part and product The part can be easily broken, the precision of the breaking position at the time of removal is excellent, and the broken surface is smooth.

[0010]

According to the present invention, a copper foil is left on the slit connecting portion, thereby eliminating the need for a mold, improving the yield when mounting various components, and obtaining a flexible printed wiring board in which the slit connecting portion can be easily broken. be able to.

[Brief description of the drawings]

FIG. 1 is a plan view showing a flexible printed wiring board of the present invention. FIG. 1B is an enlarged plan view of a portion A.

FIG. 2 is a plan view showing a flexible printed wiring board according to the present invention. FIG. 2B is an enlarged plan view of a portion B.

FIG. 3 is a plan view showing a flexible printed wiring board according to a conventional nicked flexible method. FIG. 3B is an enlarged plan view of a portion C.

Claims (4)

[Claims] 1. A flexible printed wiring board in which a circuit is formed on one or both surfaces of an insulating base material, and the circuit is further covered with an insulating coating layer, between a part to be a product and a part to be removed from the product. A flexible printed wiring board, wherein discontinuous slit portions are formed by a laser, and a copper foil is included in a slit connecting portion between the slits. 2. The flexible printed wiring board according to claim 1, wherein the shape of the copper foil of the slit connecting portion is a butterfly shape. 3. The shortest length of the slit connecting portion is 0.05.
The flexible printed wiring board according to claim 1 or 2, which has a thickness of 1.0 to 1.0 mm. 4. A flexible printed wiring board in which a circuit is formed on one or both surfaces of an insulating base material and the circuit is further covered with an insulating coating layer, between a part to be a product and a part to be removed from the product. Forming a discontinuous slit portion by a laser and leaving a copper foil at a slit connecting portion between the slits.