JPS616896A - Method of tripping multilayer 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 Industrial Application] The present invention relates to a method for trimming a multilayer circuit board in which a multilayer printed coil isostatically used.

[Technical background of the invention and its problems] Multilayer printed coils used in flat motors etc. are made by connecting a flexible circuit board with circuit parts of similar shape formed on one or both sides of a plastic film base material through an adhesive insulating material. It is made by laminating many sheets. Generally, a multilayer circuit board is formed by forming a large number of circuit patterns on a base material having a relatively large area, and then cutting the board into unit circuit blocks. After lamination, the board is trimmed into a predetermined shape using a router or punching process.

However, router machining is complicated and time-consuming, making it difficult to mass-produce. -1 punching process is advantageous in terms of %t++'lz property, but since a large impact force is applied to the punched part of the base material, the base material may dent in the punching direction, spoiling the appearance, or causing damage between the layers. There have been problems such as poor connection due to contact between the circuit parts and breakage and deformation of the circuit parts due to impact.

[Purpose of the invention]

The present invention has been made in view of the above situation, and it is an object of the present invention to provide a method for trimming a multilayer circuit board that does not have the above-mentioned drawbacks.

[Disclosure of the invention]

That is, the gist of the present invention is to provide a method for trimming a multilayer circuit board formed by laminating a plurality of flexible circuit boards each having a circuit formed on at least one side, in which a thin strip having the same pattern at the boundary between a circuit forming part and a non-circuit part is provided. non-41t
A method for trimming a multilayer circuit board is characterized in that flexible circuit boards on which fj bands are formed are laminated and bonded, and the non-conductive band portions are punched out.

In the present invention, the circuit portion refers to a portion surrounded by an outline of a circuit forming portion having a predetermined shape. Further, the non-circuit portion refers to a portion other than the circuit portion.

The method for forming the non-conducting band is as follows: 50 to 500 strips are formed along the boundary between the circuit part and the non-circuit part when forming the circuit on the flexible circuit board.
The non-conducting band is left as a resist image by a method of removing the metal in a narrow width of approximately μm (etching method) or by using a photomask pressure created in advance to form the non-conducting band, and the circuit area and the non-circuit area are removed. There is a method of forming a non-conductive zone by plating (plating method). The width of the non-conducting band is usually 50 to 500 μm, preferably 80 to 200 μm. Below this value, alignment during punching is difficult, and above this value, sagging during punching is likely to occur.

The embodiments of the present invention will be described below based on Examples, but the present invention is not limited to the following Examples.

Example: Copper foils having the same thickness were laminated on both sides of a polyester film with a thickness of 35 μm using an epoxy adhesive, and circuit areas, non-circuit areas, and non-conductive bands were formed on both sides of the copper foil surfaces by an etching method. A flexible circuit board was obtained. FIG. 1 shows a turning board, in which 1 is a circuit section, 2 is a non-circuit section, and 3 is a non-conducting band with a width of 100 .mu.m. Next, 10 layers of the double-sided flexible circuit board were laminated using insulating adhesive films and bonded by hot pressing, and the conductivity of each layer was connected by through-hole plating, etc., and this was formed into a non-conductive band 3 as shown in FIG. By punching along the center of the board, we obtained a multilayer circuit board with no sagging of the base material, no interlayer connections, and no circuit damage.

〔Effect of the invention〕

As described above, in the present invention, flexible circuit boards each having a narrow non-conducting strip at the boundary between a circuit section and a non-circuit section are laminated, and the center of the non-conducting strip of each layer is punched out. High shear force is concentrated on the base material due to the edges of the copper parts of the formed circuit part and non-circuit part, and punching is performed, resulting in a multi-I circuit board without sagging of the base material, poor interlayer connection, or circuit breakage. .

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a perspective view of a flexible circuit board, and FIG. 2 is a sectional view of a multilayer circuit board. 1. Circuit section 2. Non-circuit part 5 Non-conducting part 4. Base material 5, adhesive 61 positioning hole Fig. 1 Fig. 2

Claims (1)

[Claims] 1. In a method for trimming a multilayer circuit board formed by laminating a plurality of flexible circuit boards each having a circuit formed on at least one side, a narrow non-conductive band having the same pattern is provided at the boundary between the circuit forming part and the non-circuit part. A method for trimming a multilayer circuit board, which comprises laminating and bonding the formed flexible circuit boards and punching out the non-conductive band portions.