JP2839676B2 - Circuit pattern formation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for forming a circuit pattern developed on a circuit board used for, for example, electric equipment and electronic equipment.

(Prior Art) In general, a large number of circuit boards having circuit patterns are incorporated in electric devices and electronic devices. For mass-produced products, a method of forming a circuit pattern on such a circuit board by wet etching with good mass productivity is often adopted. For example, as shown in FIG. 4 (a), a circuit board 41 is composed of a circuit board insulating portion 51 and a metal layer 52 for forming a circuit pattern adhered to one main surface thereof. The layer 40 is applied.

Next, a desired circuit pattern 52 is formed on the positive resist layer 40.
Are brought into close contact with each other and irradiated with ultraviolet rays 43 (FIG. 4 (b)).

Then, when development is performed, the above-described photosensitive portion of the positive resist layer 40 is formed.
50b is removed. Reference numeral 50a denotes an unexposed portion of the positive resist layer 40 by the mask 42 (FIG. 4 (c)).

Next, the remaining unexposed portion 50 of the positive resist layer 40
By performing etching using b as a mask, the metal layer 5
The area 2 to be peeled is removed to leave the metal layer 52a having the desired circuit pattern shape (FIG. 4 (d)).

Next, the unexposed portion 50a of the positive resist layer is removed to obtain a circuit pattern metal layer 52a having a desired shape on the circuit board insulating portion 51 (FIG. 4 (e)).

As described above, the wet etching method requires a mask, and the higher the precision and the area, the higher the cost. For this reason, it was necessary to mass-produce as many products as possible with one mask and reduce the burden. In recent small-volume products and development-type products, even if circuit patterns are standardized at the time of design, it is difficult to explain them all with standard circuit patterns, and in many cases, newly developed circuit patterns are required . Also, there are many products that require several masks per circuit board. In particular, in a development-type system product in which only one is produced, the cost for the mask alone becomes very expensive. was there. Furthermore, there is a process in the wet etching process that uses dangerous chemicals because it is processed by electrochemical means,
Technically, pollution-free countermeasures are required, so that the processing equipment and processing steps must be complicated, and the number of manufacturing lead dimes increases, which is also expensive. In other circuit pattern forming methods, a screen instead of a mask is necessary without using electrochemical means, and a printing method in which conductive paint is printed and baked on a circuit board insulating portion, and a mask is not required but electrochemical method is required. The laser exposure method using a conventional method and the pattern plating method using an electrochemical method also have any of the above-mentioned problems. Therefore, lower cost is required in the design, development, and manufacture of small-scale products and development-type products. There was a strong demand for alternative technologies that could be used.

(Problems to be Solved by the Invention) As described above, the conventional circuit pattern is often formed by wet etching, and therefore, in a product with a small number of production units, a large number of masks are used, and the product is suitable for its function. There was a disadvantage that the price could not be reduced.

The present invention has been made to eliminate the above disadvantages,
An object of the present invention is to form a circuit pattern on a circuit board without going through a complicated wet etching process using a mask.

[Configuration of the invention]

(Means for Solving the Problems) In a method for forming a circuit pattern according to the present invention, a predetermined circuit is formed by partially removing a conductive layer of a circuit board composed of an insulating substrate and a conductive layer of a metal foil laminated thereon. In forming the pattern, the conductive layer is removed by irradiating a high-density laser beam on the boundary between the planned circuit pattern area and the planned peeling area, and then irradiated with a low-density laser beam on the planned peeling area of the conductive layer. A method for forming a circuit pattern, comprising means for removing and removing the adhesive force of the circuit pattern.

(Operation) In the present invention, since a circuit pattern is formed on a circuit board without using an etching process, various defects generated in the etching process are eliminated. Furthermore, by adopting CAD from the point of circuit pattern design and connecting directly to numerical control machines, etc., complete automation can be achieved,
Even in the formation of a circuit pattern on a circuit board in small-scale production, it can be achieved at low cost and in a short time.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

A YAG laser processing device section 30 in the laser processing device of FIG. 3 used in one embodiment is configured such that factors related to processing such as laser opening and closing and an output level are controlled by a control device 31. A high-precision moving table 35 having a dedicated high-precision optical lens 32 and a jig that can fix the metal layer surface of the circuit board 33 vertically to the laser beam 34 is provided immediately below. This high-precision moving table 5 can be moved and corrected in vertical, horizontal, and oblique rotations, and is controlled by a control device 31 common to the YAG laser processing device 30. Also, a control device for controlling the YAG laser processing unit 30 and the high-precision moving table 35
Numeral 31 is connected to a CAD device 36 so that numerical data of a circuit pattern created by the CAD device 36 can be exchanged.

In the circuit pattern forming method of the present invention, the CAD device 36
The control device 31 receives the numerical data of the circuit pattern drawn in the above, performs control of factors related to processing such as laser opening and closing and output level, and controls the high-precision moving table 35,
FIG. 1A is an enlarged view of a portion surrounded by a broken-line circle in FIG. 1A, and as shown in FIG.
Is squeezed using the dedicated optical lens 11 and is irradiated along the boundary between the planned area 23a of the desired circuit pattern formed on the metal layer 23 on the circuit board 12 and the planned peeling area 23b. By this laser beam irradiation, only the metal layer at the boundary portion is removed by sublimation and cut to form a boundary groove 13 where the circuit board insulating portion 22 is exposed at the bottom between the predetermined regions, and the predetermined regions are separated from each other.

Next, as shown in FIG. 1 (b), the low-density YAG laser beam 20 is irradiated only on the area 23b where the metal layer is to be separated, and heated. By this heat treatment, the metal layer 23 on the circuit board is
The adhesive force between the expected peeling region 23b and the circuit board insulating portion 22 is reduced.

Next, as shown in FIG. 1 (c), only the metal layer in the scheduled area 23b is peeled off using the peeling device 14, so that the metal layer in the area 23a where the circuit pattern is to be formed remains and a desired layer is left. The circuit pattern 15 is formed.

〔The invention's effect〕

As described above, according to the present invention, a circuit pattern can be formed on a circuit board without using an etching process. As a result, various drawbacks caused by the etching process can be easily released, and the CA
If D is used and is directly connected to a numerical control machine or the like, complete automation can be achieved, and even in the case of forming a circuit pattern on a circuit board that produces only one sheet, it can be provided at a low cost and in a short time.

[Brief description of the drawings]

1 (a) to 1 (c) are perspective views for explaining a circuit forming method according to an embodiment of the present invention in the order of steps, and FIG. 2 is an enlarged view of a part of FIG. 1 (a). Perspective view, third
The drawings are perspective views of a laser processing apparatus used for circuit formation, and FIGS. 4 (a) to 4 (e) are perspective views for explaining a conventional circuit formation method in the order of steps. 10 high-density laser beam, 12 circuit board 20 low-density laser beam 22, circuit board insulating part 23 metal layer of circuit board 23a circuit pattern formation area 23b peeling Area

Claims (1)

(57) [Claims] 1. A circuit board comprising an insulating substrate and a conductive layer of a metal foil laminated thereon, wherein said conductive layer is partially removed to form a predetermined circuit pattern. A circuit including a means for irradiating a boundary portion of an area to be peeled with a high-density laser beam to remove the area, and then irradiating an area to be peeled of the conductive layer with a low-density laser beam to reduce adhesion to an insulating substrate and to remove the area. The method of forming the pattern.