JP3841672B2 - Manufacturing method of double-sided flexible circuit board - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a double-sided flexible circuit board, and in particular, a conductive hole for processing an insulating base material and forming a through hole by laser processing, plasma etching, or wet etching techniques. It is related with the manufacturing method of the double-sided flexible circuit board which can form suitably.
[0002]
[Prior art and its problems]
Conventionally, in a manufacturing process of a double-sided flexible circuit board, a technique using a punch or a mold has been widely adopted. After forming the conduction hole by these techniques, etching of the conductor layer such as half etching for the purpose of suppressing the conductor thickness is performed. Thereafter, a conductive treatment is performed, plating is performed to form a through hole, and further, both-side wiring processing is performed to manufacture a double-sided flexible circuit board.
[0003]
However, when etching the conductor layer such as half etching after drilling to perform fine wiring processing, the warped end of the insulating base material, i.e., the flash, is exposed, and plating is performed from above. If adhered, the reliability of the through hole and the yield of the circuit board are reduced. If etching of the conductor layer such as half etching is performed before the formation of the conduction hole, a crack is generated in the conductor layer when drilling, so the half etching process is performed only after the formation of the conduction hole. I can't.
[0004]
Here, a conventional method for manufacturing a double-sided flexible circuit board using the double-sided copper-clad plate shown in FIG. 3 will be described. First, when a double-sided flexible circuit board is manufactured from a double-sided copper-clad board composed of a first conductor layer 20, an insulating base material 21, and a second conductor layer 22 as shown in FIG. As shown in FIG. 2 (2), the first conductor layer 20, the insulating base material 21, and the second conductor layer 22 are punched with a punch, a mold or the like to form a conduction hole 23.
[0005]
Next, as shown in FIG. 3 (3), the first conductor layer 20 and the second conductor layer 22 which are perforated are thinly processed by a half etching process and half etched. The conductor layer 24 and the second conductor layer 25 are obtained. Further, as shown in FIG. 4 (4), a conductive treatment and a plating layer 27 are applied, and a through hole 28 is formed by plating after the conductive treatment. Thereafter, wiring processing is performed on the two conductor layers 24 and 25 including the plating layer 27 to obtain a double-sided flexible circuit board.
[0006]
However, in this method, since the plating layer 27 is formed with the flash 26 left at the end of the conduction hole 23, the reliability of the through hole and the yield of the circuit board are lowered.
[0007]
[Means for Solving the Problems]
The present invention provides a method for manufacturing a double-sided flexible circuit board to suitably solve the problems of the above-described conventional example, and uses a double-sided copper-clad board in the manufacture of a double-sided flexible circuit board. Then, the insulating base material exposed at the end of the hole generated when etching the conductor layer such as half etching after the hole for conduction with a punch or die is laser processed, plasma A method of manufacturing a double-sided flexible circuit board, which is characterized by removing by an etching or wet etching technique, is employed.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be further described with reference to the illustrated embodiments. FIG. 1 is a manufacturing process diagram of a double-sided flexible circuit board according to an embodiment of the present invention. First, a double-sided copper-clad board having a first conductor layer 1, an insulating base material 2, and a second conductor layer 3 is prepared as shown in FIG. When the substrate is manufactured, as shown in FIG. 2B, the first conductor layer 1, the insulating base material 2, and the second conductor layer 3 are punched with a punch, a die, etc. Form.
[0009]
Next, as shown in FIG. 3 (3), the first conductor layer 1 and the second conductor layer 3 which are perforated are thinly processed by a half etching process and half etched. One conductor layer 5 and a second conductor layer 6 are formed.
[0010]
After that, as shown in FIG. 4 (4), the end portion of the insulating base material 2 drilled by laser processing, plasma etching method, wet etching method is removed, and there is no continuity. Hole 7 is formed. At this time, it is more effective to perform laser processing, plasma etching, and wet etching by spraying from the second surface where the flash is generated.
[0011]
Further, a through hole 9 is formed by applying a conductive treatment and a plating layer 8 as shown in FIG. Thereafter, wiring processing is performed on the two conductor layers 5 and 6 having the plating layer 8 to obtain a double-sided flexible circuit board.
[0012]
FIG. 2 is a manufacturing process diagram of a double-sided flexible circuit board according to another embodiment of the present invention. First, double-sided copper comprising a first conductor layer 10, an insulating base material 11 with high etching resistance, an adhesive material or adhesive polyimide 12 with low etching resistance, and a second conductor layer 13 as shown in FIG. Prepare a tension plate.
[0013]
When a double-sided flexible circuit board is manufactured from this double-sided copper-clad board, as shown in FIG. 2 (2), the first conductor layer 10, the insulating base material 11 with high etching resistance, and the adhesive with low etching resistance. The material or adhesive polyimide 12 and the second conductor layer 13 are drilled with an NC drill, a die, or the like in the direction shown in the figure, thereby forming a conduction hole 14.
[0014]
Next, as shown in FIG. 3 (3), the first conductor layer 10 and the second conductor layer 13 which are perforated are processed thinly by a half etching process and half etched. A conductor layer 15 and a second conductor layer 16 are formed.
[0015]
Thereafter, as shown in FIG. 4 (4), the edge 17 of the adhesive material 12 or the adhesive polyimide 12 having a low etching resistance, which has been drilled using a plasma etching method or a wet etching method, is removed. At this time, it is effective to perform the treatment from the second surface as described above, but it is also important to consider the selectivity of etching. For example, a double-sided copper-clad board manufactured by applying an insulating base material to the first conductor layer by the cast method and then thermocompression bonding the second conductor layer via adhesive polyimide is processed with fine wiring. It is often used for circuit board materials that require If an alkaline etchant is used for this material, the wet etching selectivity is high and effective. It is also effective to change the wet etching selectivity by changing the type of adhesive, heat treatment conditions, and the like.
[0016]
Further, as shown in FIG. 5 (5), a through hole 18 is formed by applying a conductive treatment and a plating layer 19. Thereafter, wiring processing is performed on the conductor layers 15 and 16 on both sides having the plating layer 19 to obtain a double-sided flexible circuit board.
[0017]
【The invention's effect】
The double-sided flexible circuit board according to the present invention uses a double-sided copper-clad board in the production of a double-sided flexible circuit board to form a conduction hole with a punch or a mold, and after the processing, half etching or the like Since the insulating base material exposed at the end of the hole generated when the conductor layer is etched is removed by laser processing, plasma etching, or wet etching, the formed through hole is formed. Reliability is improved.
[0018]
Further, according to another method of the present invention, when a conduction hole is formed with a punch and a mold using a double-sided copper-clad plate, the conduction hole is formed with a punch and a mold from the side having high etching resistance. Since the insulating base material to be removed is exposed on the side having low etching resistance, the flash can be removed more efficiently by the plasma etching method and the wet etching method.
[0019]
Furthermore, there is an effect of improving the wettability of the hole for conduction by performing the plasma etching method and the wet etching method. From the above, the production of a double-sided flexible circuit board, which was difficult with the conventional method for producing a double-sided flexible circuit board, can be stably achieved at a low cost.
[Brief description of the drawings]
FIG. 1 is a manufacturing process diagram of a double-sided flexible circuit board according to an embodiment of the present invention.
FIG. 2 is a manufacturing process diagram of a double-sided flexible circuit board according to another embodiment of the present invention.
FIG. 3 is a manufacturing process diagram of a double-sided flexible circuit board according to a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st conductor layer 2 Insulation base material 3 2nd conductor layer 4 Conductive hole 5 First conductor layer 6 half-etched Second conductor layer 7 half-etched Conductive hole 8 Plating layer 9 Through hole

Claims (2)

When manufacturing a double-sided flexible circuit board, a double-sided copper-clad plate was used to form a hole for conduction with a punch and a mold, and the conductor layer was etched by half etching after processing of the hole for conduction. A method of manufacturing a double-sided flexible circuit board, comprising: removing an insulating base material exposed at an end of the conduction hole generated by laser processing, plasma etching, or wet etching. As the double-sided copper-clad plate, a double-sided copper-clad plate comprising a first conductor layer, an insulating base material having high etching resistance, an adhesive or adhesive polyimide having low etching resistance, and a second conductive layer is prepared. 2. The method of manufacturing a double-sided flexible circuit board according to claim 1, wherein when the conduction hole is formed with a punch and mold using a copper-clad plate, the conduction hole is formed with the punch and mold from the side having high etching resistance. .

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