JPH0758440A - Manufacture of circuit board - Google Patents

Abstract

PURPOSE:To provide a manufacturing method of a circuit board capable of easily forming a circuit pattern with high precision and at low cost eliminating any complicated steps. CONSTITUTION:Within the manufacturing method of a circuit board comprising an insulating substrate whereon a specific circuit pattern is formed, a specific position of the insulating substrate 1 immersed in an electroless plating solution 3 is irradiated with laser beams 5 so that a specific pattern comprising the metal-plate film formed of the electroless plating solution 3 may be beam- exposed and formed on the insulating substrate 1.

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 having a circuit pattern formed on an insulating board.

[0002]

2. Description of the Related Art Conventionally, as a method of obtaining a circuit board having a predetermined circuit pattern formed thereon, a method of forming a circuit pattern by etching from a substrate having a conductive film formed on an insulating substrate is generally used. Specifically, as shown in FIG. 3A, a substrate having the conductive film 12 formed on the entire surface of the insulating substrate 11 is prepared. The conductive film 12 is formed by a method of laminating a copper plate and a substrate material by hot pressing, an electroless plating method, or the like. First, as shown in FIG. 3B, a resist film 13 having a predetermined pattern is formed on the conductive film 12 by, for example, photolithography. Next, FIG.
As shown in (c), the unnecessary conductive film 12 is dissolved and removed except for the region where the resist film 13 is formed by etching. After that, as shown in FIG. 3D, the resist film 13 is removed with a solution to obtain a circuit board on which a predetermined circuit pattern is formed.

[0003]

However, in the above-described conventional method for manufacturing a circuit board, many steps such as forming a conductive film, forming a pattern with a resist, and etching are required, and the material cost and the manufacturing cost are low. It was expensive.
Further, there is a limit to the accuracy of the pattern by the resist and the etching accuracy, and there are problems that the accuracy of the circuit pattern is uniform, and it is difficult to form a fine line. Therefore, an object of the present invention is to solve the above problems of the conventional method for manufacturing a circuit board, to form a highly accurate circuit pattern inexpensively and easily without requiring complicated steps. It is to provide a method of manufacturing a circuit board that can be manufactured.

[0004]

In order to achieve the above object, the present invention is a method for manufacturing a circuit board in which a predetermined circuit pattern is formed on an insulating board, wherein the insulating board is immersed in an electroless plating solution. By irradiating a predetermined portion with a laser beam, a predetermined circuit pattern made of a metal plating film of the electroless plating solution is drawn and formed on the insulating substrate.

[0005]

According to the above method, the redox reaction of the metal ions in the electroless plating solution occurs due to the heat and light of the laser beam only on the part of the insulating substrate irradiated with the laser beam, and this part A metal plating film is deposited.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for manufacturing a circuit board according to the present invention will be described below with reference to the drawings. As shown in FIG. 1, an insulating substrate 1 such as an alumina substrate is immersed in a room temperature electroless copper plating solution 3 having a composition shown in Table 1 and placed in a quartz glass container 2. Then, the insulating substrate 1 is irradiated with a laser beam 5 emitted from the laser body 4 from the outside of the quartz glass container 2 with an output of several watts.

At this time, the insulating substrate 1 is installed so that one surface thereof is parallel to the side surface of the quartz glass container 2 and substantially perpendicular to the laser beam 5. In order to reduce the absorption of the laser beam 5 of the electroless copper plating solution 3 as much as possible, the insulating substrate 1 is separated from the side surface of the quartz glass container 2 by
Install closely so that the distance is 2 mm.

The laser body 4 can scan the laser beam 5 in any direction. Then, by scanning the laser beam 5, the insulating substrate 1 is sequentially irradiated with the laser beam 5 according to a predetermined circuit pattern.

As described above, in the portion of the insulating substrate 1 irradiated with the laser beam 5, the heat and light of the laser beam 5 cause a redox reaction of the metal ions in the electroless copper plating solution 3, and this A copper plating film is formed on the portion. In this way, a circuit board having a predetermined circuit pattern 6 made of a copper plating film on the insulating substrate 1 as shown in FIG. 2 is obtained. In this case, the width of the copper plating film, that is, the line width of the circuit pattern 6 can be drawn with an arbitrary width by changing the aperture of the laser beam.

[0010]

[Table 1]

In the above embodiment, the electroless copper plating solution having the composition shown in Table 1 was used. However, the composition is not limited to this, and an electroless plating solution other than copper, for example, It may be nickel, nickel-cobalt, gold, etc.,
Any electroless plating solution that can be plated only at a temperature higher than room temperature may be used.

As the laser, an excimer laser was used, but the laser is not limited to this, and an argon laser,
A YAG laser or the like may be used. The container for containing the electroless plating solution is not limited to the quartz glass container and may be any container that can transmit a laser beam.

[0013]

As described above, according to the method of manufacturing a circuit board according to the present invention, unlike the conventional example, it is not necessary to previously form a conductive film on an insulating substrate, and a pattern of a resist is formed. It does not require many complicated steps such as formation and etching.

That is, in a simple process of immersing an insulating substrate in an electroless plating solution and irradiating it with a laser beam,
A circuit pattern made of a metal plating film can be drawn and formed on the insulating substrate, and material cost and manufacturing cost can be significantly reduced. Then, by controlling the aperture of the laser beam, a circuit pattern having an arbitrary line width and a fine line width can be formed with high accuracy.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a method for manufacturing a circuit board of the present invention.

FIG. 2 is a cross-sectional view of a circuit board obtained by the manufacturing method of the present invention.

FIG. 3 is a cross-sectional view of a circuit board in each step of a conventional method for manufacturing a circuit board.

[Explanation of symbols]

 1 Insulating substrate 2 Quartz glass container 3 Electroless copper plating solution 4 Laser body 5 Laser beam 6 Circuit pattern

Claims (1)

[Claims] 1. A method for manufacturing a circuit board in which a predetermined circuit pattern is formed on an insulating substrate, by immersing the insulating substrate in an electroless plating solution and irradiating a predetermined portion with a laser beam. A method of manufacturing a circuit board, wherein a predetermined circuit pattern made of a metal-plated film of the electroless plating solution is drawn and formed on.