JPS6318693A - Manufacture of printed circuit board - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a printed circuit board, and more specifically, after forming a circuit consisting of a copper plating layer on the surface of a metal foil and integrating it with an insulating base material. This invention relates to a method for manufacturing printed circuit boards that is simple and inexpensive, with excellent productivity, and in which metal foil is removed.

[Prior Art 1] Conventionally, there are a number of methods for manufacturing printed circuit boards, but the predominant practical method is a subtractive method using wet etching.

This method involves multiple steps, including the production of copper foil, the process of laminating the copper foil and the insulating substrate, the process of covering the non-etched areas on the surface of the copper foil with an etching resist agent, and the process of removing unnecessary areas of copper using wet etching. It requires many steps,
There is a problem in that it requires a large amount of cost.

In addition, in order to shorten or simplify the process, a method has been announced in which a copper circuit is directly formed on a metal plate or metal foil, and the copper circuit is transferred and bonded to an insulating substrate (for example,
5-32239, etc.). However, this method has the problem that the transfer adhesion is not necessarily sufficient, and to avoid this, high-density circuits cannot be formed.

UObject of the Invention] The present invention was made to solve the problems of these conventional techniques, and provides a method for shortening and simplifying the process and manufacturing a high-quality printed circuit board at low cost. The purpose is to

Structure and operation of the invention] The method for manufacturing an I+1 circuit board of the present invention involves forming a negative pattern on the surface of a metal foil using an insulating resist agent, then performing copper plating, and then forming a negative pattern on the surface of the metal foil. After forming a circuit consisting of a copper plating layer, and then integrating the metal cylinder with the insulating base material with the copper plating layer inside by kneading and heating and pressurizing,
This method is characterized by removing the metal foil.

In the present invention, first, a desired negative pattern is formed on a metal foil (metal plate) using an insulating resist agent. As a method for forming this negative pattern, a known method such as a screen method or a photoresist printing method is used.

The gold I11 foil used here is not particularly limited as long as it can be copper plated and etched. For example, zinc, aluminum, iron, nickel, or alloys containing these as main components are used, but in particular, gold I11 foil with a thickness of 10 to 200 μm is used. ,
Preferably, aluminum having a thickness of about 20 to ioo μm is used, and is suitable from the viewpoint of cost. Further, examples of the insulating resist agent used here include a thermosetting resist agent, an ultraviolet curing resist agent, and the like.

Next, copper plating is performed on the surface of the metal tube where the negative pattern is not formed, to form a circuit made of a copper plating layer having excellent circuit suitability in terms of adhesiveness, heat resistance, moisture resistance, etc. Copper plating may be electrolytic copper plating or electroless copper plating, but in the present invention, electrolytic copper plating using a metal foil as a cathode and a copper sulfate solution or the like as an electrolyte is preferable.

If desired, the copper-metsuki koshi tqed in this way can be
Perform surface roughening treatment and/or rust prevention treatment. The surface roughening treatment is performed by depositing fine copper on the copper plating layer by plating. Further, the rust prevention treatment is performed by an inorganic treatment such as chromate treatment or an organic treatment using benzotriazole or the like.

Next, the metal foil is integrated with the insulating base material with the copper plating layer on the inside by hand kneading and heating and pressing. Before integrating with this insulating base material, the insulating resist agent (negative pattern) on the metal foil may be peeled off. The adhesive used here is preferably a phenolic or epoxy adhesive.

Further, examples of the insulating group +4 used include paper-phenol base material, glass-phenol base material, glass-epoxy base material, and the like.

Here, the conditions for integration are a temperature of 100°C or higher,
Pressure: 1 to 120 k (1/ci), crimping time: 5 minutes or more. Compared to the J5 integration conditions used in conventional printed circuit board manufacturing, integration is possible at low temperatures, low pressure, and in a short time, shortening the process. and simplification can be achieved.

In the present invention, the metal tube is then removed. In removing this metal foil, it is necessary not to damage the copper plating layer, and etching using an etching solution is generally used. The etching solution used at this time differs depending on the gold R foil. If the metal foil is aluminum or zinc, an alkaline solution such as sodium hydroxide or potassium hydroxide is used, and if the metal foil is iron or nickel, an acidic solution such as hydrochloric acid or sulfuric acid is used. . Note that the metal foil may be removed not only by etching using an etching solution but also by etching using an etching gas or mechanical peeling.

Hereinafter, the present invention will be explained in detail based on the drawings.

FIGS. 1 to 5 show an embodiment of the manufacturing method of the present invention, and show schematic diagrams of each process preferably employed.

As shown in FIG. 1, after forming a negative pattern (mask) with an insulating resist agent 2 on the surface of a metal foil 1, a circuit 3 consisting of a copper plating layer is formed by copper plating. The formation of this copper-plated circuit 3 is carried out in a first electrolytic cell 5 equipped with an anode 4 and a metal foil 1 masked with an insulating resist agent 2 as a cathode, as shown in FIG. . As the electrolyte for this first electrolytic cell 5, a copper sulfate solution or the like is used. A circuit 3 made of a copper plating layer on a metal foil 1 is subjected to surface roughening treatment in a second electrolytic bath 7 equipped with an anode 6. The electrolyte at this time also uses a sulfuric acid steel solution or the like. Circuit 3 consisting of a copper plating layer subjected to surface roughening treatment
enters a third electrolytic cell 9 equipped with an anode 8 and is subjected to rust prevention treatment. The rust preventive agent used is zinc, chromium, nickel, etc., which have rust preventive properties and do not impair compatibility with the insulating base material. A metal foil 1 having an insulating resist agent 2 and a circuit 3 made of a copper plating layer subjected to surface roughening treatment and rust prevention treatment is dried in a dryer 10 and wound up.

At this time, it may be cut and made into a sheet.

Next, as shown in FIG. 3, the metal foil 1 is coated with an adhesive by an adhesive coater 11, dried by a dryer 12, and then wound or cut into sheets. Note that the insulating resist agent 2 forming the negative pattern may be peeled off at this stage.

Next, the metal foil 1 is laminated and pressed together with the insulating base material 13 in a laminated press 16 having a hot plate 14, a stainless steel plate 15, etc. as shown in FIG. Spray nozzle 17, roll conveyor 18 shown
The circuit 3 made of a high-quality copper plating layer is formed on the insulating base material 13 by etching away the entire surface of the metal foil using a metal etching device 19 having a metal etching device 19.

“Examples” The present invention will be specifically described below based on Examples and Comparative Examples.

Example 1 and Comparative Example 1 A negative pattern was formed on the aluminum foil using a commercially available aluminum foil as the metal foil and a commercially available thermosetting resist agent as the insulating resist agent. Note that the minimum width of the circuit was 0.2 mm, and the maximum width was 20 vun.

Next, 'AM copper solution (Cu30q/), 1i2S○45
Copper plating was performed using 0(1/j) as an electrolytic solution to create a circuit consisting of a copper plating layer, and then chromate treatment was performed by immersing it in a solution of 10 g/J of chromic anhydride as antirust treatment.

This aluminum foil was integrated with a glass-epoxy base material by lamination pressing, and then a sodium hydroxide solution (3
0g/J) to dissolve and remove the aluminum foil.

The thus obtained copper circuit board (Example 1) was tested for adhesive strength and 260°C soldering according to the test method for steel clad laminates for stamp circuits specified in JISC6481.
The test was conducted for 120 seconds and the results are shown in Table 1.

Further, for comparison, a similar test was conducted on a copper circuit board (Comparative Example 1) prepared from a commercially available copper-clad V4 leg plate by the sub-1 to lactive methods, and the results are also shown in Table 1.

Table 1 m;■ As shown in Table 1, according to the present invention, 1! ′? The printed circuit board (Example 1) produced by the present invention has characteristics equivalent to those of the printed circuit board (Comparative Example 1) produced by the conventionally used sub-1 to lactive methods.

[Effects of the Invention] As described above, the method for manufacturing a printed circuit board of the present invention has the advantage that the process can be shortened and simplified, and a high-quality printed circuit board can be manufactured at low cost.

[Brief explanation of the drawing]

Figures 1 to 5 show an example of the manufacturing method of the present invention, and show schematic diagrams of each process preferably adopted.1゜1: Metal foil,
2: Insulating resist agent, 3: Circuit made of steel coating layer, 13: Insulating hanging material. Patent applicant Mitsui Kinzoku Mining Co., Ltd. Agent Patent attorney Tatsuo Ito Agent Patent attorney Satoshi Ito No. 1 Figure 2 Figure 3 Figure 5

Claims (1)

[Claims] 1. After forming a negative pattern with an insulating resist agent on the surface of the metal foil, copper plating is performed, and a circuit consisting of a copper plating layer is formed on the surface of the metal foil, and then A method for manufacturing a printed circuit board, which comprises stacking the metal foil on an insulating base material with the copper plating layer on the inside and integrating the metal foil by heating and pressing, and then removing the metal foil. 2. The method for manufacturing a printed circuit board according to claim 1, wherein the copper plating layer is subjected to surface roughening treatment and/or antirust treatment. 3. The method for manufacturing a printed circuit board according to claim 1 or 2, wherein the copper plating is electrolytic copper plating using the metal foil as a cathode. 4. The method for manufacturing a printed circuit board according to claim 1, 2, or 3, wherein the metal foil is removed by etching using an etching solution.