JP2003298208A - Manufacturing method of circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a circuit board, by which a high-density narrow-pitch wiring pattern can be formed. <P>SOLUTION: In the conductor layer 1 on one face of an insulation base material 2, grooves 3 are formed so as to have shapes to be wiring patterns. While using the conductor layer having the grooves 3 as a mask layer, grooves 4 are formed in the insulation base material 2 by laser beam machining, plasma etching, or wet etching. By filling in the grooves 4 with a conductive member 5 composed of a conductive paste or a conductive ink, wiring patterns 6 are formed. Then other wiring patterns 7 are formed in the conductor layer 1 by etching, etc. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a circuit board, and more particularly to a method of manufacturing a circuit board capable of forming a high-density wiring pattern.

[0002]

2. Description of the Related Art In recent years, miniaturization and higher functionality of electronic devices have been increasingly promoted. Therefore, in order to support high-density mounting on circuit boards, it is necessary to reduce the pitch of wiring patterns. The demand is increasing.

On the other hand, in the conventional circuit board, the wiring pattern is formed by etching the conductor layer. The wiring pitch of the circuit board manufactured by using this method is limited to a conductor thickness of 10 μm and a pitch of about 50 μm. In order to manufacture a circuit board with a narrower pitch, a semi-additive method of patterning a plating resist on the seed layer and forming wiring by plating must be used, which requires a large capital investment. .

[0004]

SUMMARY OF THE INVENTION The present invention provides a method for suitably solving the above-mentioned problems of the conventional example, in which a wiring pattern is formed on a conductor layer on one surface of an insulating base material. Forming a groove having the following shape, and using the conductor layer in which the groove is formed as a mask layer, the insulating base material is subjected to thin film processing by laser processing, a plasma etching method or a wet etching method to form a groove, and A method of manufacturing a circuit board, which is characterized by filling a conductive paste or a conductive ink to form a wiring pattern is adopted.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be further described below with reference to the illustrated embodiments. FIG. 1 is a manufacturing process diagram of a flexible circuit board according to an embodiment of the present invention. First, as shown in FIG. 1A, a material having a conductor layer 1 on one surface of an insulating base material 2, such as a single-sided copper clad plate, is prepared.

Therefore, as shown in FIG.
Are processed by etching to form the groove 3 having the shape of the wiring pattern. Next, the insulating base material 2 is subjected to thin film processing by laser processing, plasma etching method, or wet etching method using the conductor layer 1 having the grooves 3 as a mask layer as shown in FIG. Forming a groove 4 for filling

Thereafter, as shown in FIG. 4 (4), the formed groove 4 is filled with a conductive member 5 made of a conductive paste or conductive ink. Then, as shown in FIG. 5 (5), the conductive member 5 made of conductive paste or conductive ink is selectively etched to form the wiring pattern 6.

For example, when the conductor layer 1 is a copper foil and a copper paste is used for the filled conductive member 5, the etching rate of the copper paste is significantly higher than that of the copper foil, so that the copper is selectively removed. The paste can be etched. However, it is preferable that the copper paste used at this time has a high packing rate of copper particles and a small amount of resin serving as a binder. Preferably, a copper paste having a filling rate of copper particles of 90% or more can be selectively etched with a conventionally used copper etching solution such as copper chloride or iron chloride.

In the case of a combination having a poor etching selectivity, a conductive layer or a conductive ink alone can be selectively etched by forming a resist layer on the conductive layer serving as a mask layer after the groove processing. If an electrodeposition resist is used as the resist layer in this case, not only the alignment step at the time of forming the resist layer can be omitted, but also the accuracy is high, which is preferable.

Further, by wiring the conductor layer 1 to form other required wiring patterns 7, it is possible to obtain a flexible circuit board having a wiring pattern of high density and narrow pitch.

FIG. 2 shows an insulating base material 2 by applying a method similar to the above using a material such as a double-sided copper clad plate.
An example of forming a double-sided flexible circuit board by forming wiring patterns 8 and 9 similar to the above on the other surface is also shown.

[0012]

The circuit board according to the present invention has a structure in which a conductive layer and a grooved insulating base material are filled with a conductive paste or the like, and the space between the conductors is further used as the conductive layer. It is possible to preferably achieve the narrowing of the pitch of the wiring pattern on the circuit board, which was difficult with the conventional circuit board manufacturing method.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram of a flexible circuit board according to an embodiment of the present invention.

FIG. 2 is a conceptual cross-sectional view of a double-sided flexible circuit board according to another embodiment of the present invention.

[Explanation of symbols]

1 conductor layer 2 Insulating base material 3 grooves 4 grooves 5 Conductive member 6 wiring patterns 7 wiring pattern

Claims (2)

[Claims] 1. A groove having a shape to be a wiring pattern is formed on a conductor layer on one surface of an insulating base material, and the conductor layer having the groove is used as a mask layer to perform laser processing on the insulating base material and plasma. A method for manufacturing a circuit board, characterized in that a groove is formed by thin film processing using an etching method or a wet etching method, and a conductive pattern made of a conductive paste or conductive ink is filled in the groove to form a wiring pattern. . 2. The method for manufacturing a circuit board according to claim 1, wherein the wiring pattern is formed on the other surface of the insulating base material.