JPS61144099A - Manufacture of substrate for metal based circuit - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application] The present invention relates to a novel manufacturing method with simple steps for a metal-based circuit board having an insulating layer also on the side surface of a metal plate.

[Conventional technology and problems]

With the miniaturization of electronic devices, hybrid ICs, which implement a single function by installing capacitors, resistors, etc. on a substrate, are now reaching the stage of practical use, replacing the monolithic ICs that existed up until then. It is.

Conventionally, the circuit board for hybrid IC is
Ceramic substrates containing alumina as a main component have been known. However, this has problems such as being easy to break, being difficult to form in large sizes, and having poor heat dissipation properties.

Therefore, as a solution to the above problem, a circuit board using a metal plate such as aluminum as a heat dissipation base has been proposed.

In this metal-based substrate, the metal plate is electrically conductive, unlike ceramics, and therefore requires insulation treatment for the metal plate. If the target circuit board is to be used with a lead frame such as a clip lead (Figure 8, number 4), the lead frame and metal plate may come into direct contact, such as on the side of the metal plate. Insulation treatment is also required for areas where there is a risk of damage.

In view of this point, the group to which the present inventors belong has previously proposed a metal-based substrate having an insulating layer even at such ends (for example, Japanese Patent Application No. 12961/1983).
No. 4, Patent Application No. 161077, 1983, etc.).

[Solution]

The present invention provides a method for manufacturing a metal-based circuit board having an insulating layer also on the side surface of a metal plate even more easily.

That is, in the manufacturing method of the present invention, a circuit conductor having an insulating layer is pasted on the circumferential surface of a metal plate through the insulating layer, and then the circuit conductor is bonded to the circumferential surface of a metal plate, leaving a portion necessary as a circuit forming surface. The purpose of this method is to remove the etchant by etching to obtain the desired metal-based circuit board.

The metal plate used in the present invention mainly plays a heat dissipation function in the circuit board, but can also serve as a conductor for electromagnetic shielding. In the present invention, for example, the thickness is 0.2 to 1011111, and <0.5 to 5
11K copper plates, aluminum plates, iron plates, silicon steel plates, or saliva-lead-plated or copper-plated products thereof are used. Of course, it is not limited to these.

The purpose of the method of the present invention is to provide a circuit conductor on the metal plate via an insulating layer to obtain a metal-based circuit board.

The manufacturing process begins by attaching a circuit conductor having an insulating layer to a predetermined position on a metal plate via the insulating layer. The predetermined positions include, for example, the entire circumference of the metal plate (Fig. 1), a part of either the front or back side of the metal plate, especially the circumferential surface excluding the central part (Fig. 2), or one side of the metal plate. (Fig. 3), a peripheral surface excluding one side of the metal plate, and a part of the front or back surface (Fig. 4), etc., determined as appropriate depending on the form of the intended circuit board. . However, it is attached to at least one side and either the front or back surface of the metal plate. In the figure, 1 is a metal plate, 2 is an insulating layer, and 3 is a circuit conductor.

Typical examples of the circuit conductor having an insulating layer used in the above steps include flexible copper-clad circuit boards based on polyimide, polyester, glass epoxy, and the like.

Further, as a manufacturing method of the circuit conductor, for example, the thickness is I0-1000 pm, and <20-500 μm.
A method of bonding a conductor in the form of a tape or sheet with an insulating tape or sheet, a method of forming an insulating layer on one side of the conductor by electrodeposition or powder coating, and a method of applying an insulating layer to the conductor. Examples include a method of forming an insulating layer using Of course, it is not limited to these.

The circuit board precursor obtained in the above process is then subjected to an etching process to remove predetermined portions of its circuit conductors. That is, for example, corresponding to those shown in FIGS. 1 to 4 above, there is one in which the circuit conductor is removed from both side surfaces (FIG. 5.6), and one in which the circuit conductor is removed from one side surface (FIG. 7.8). As shown in the figure), circuit conductors other than the circuit forming portions required for the intended circuit board are removed.

The material shown in Fig. 6 can also be obtained by cutting the material shown in Fig. 6 at the center portion in the width direction in the length direction.

Etching agents used in the above etching process include, for example, ferric chloride-hydrochloric acid aqueous etching agents, aqueous ammonia-ammonium chloride-sodium chlorite etching agents, sodium persulfate, potassium persulfate, and ammonium persulfate. Examples include persulfate-based etching agents, hydrogen peroxide-sulfuric acid-based etching agents, and the like.

Of course, it is not limited to these.

A preferred embodiment of the method of the present invention is a continuous manufacturing method using a metal plate, which is extremely efficient in terms of manufacturing efficiency.

That is, for example, a circuit conductor having an insulating layer is continuously attached to a long metal plate via the insulating layer, and
Mask tape is pasted on the necessary parts of the circuit conductor and then introduced into an etching bath, or an etching agent is sprayed on the parts of the circuit conductor that need to be removed. A preferred embodiment is a manufacturing method in which the processing steps are performed in series.

〔Effect of the invention〕

According to the present invention, it is possible to easily and efficiently manufacture a metal-based circuit board having only an insulating layer in the visible portion of the side surface through a simple process.

〔Example〕

Example 1 A polyimide-based flexible copper-clad circuit board (Nicaflex F-30T, Nirakan Kogyo Co., Ltd.) with a width of 27 mm, a length of 300 mm, and a thickness of 60 μm on an aluminum plate with a thickness of 2 m, a width of 20 WJml, and a length of 300*g. ) was attached to the circumferential surface of the aluminum plate in the direction from the upper end to the other end of the aluminum plate through its polyimide side. The adhesive was applied to the polyimide surface by applying an adhesive (KVD-10, manufactured by Konishi Corporation) and drying it at 60°C for 10 minutes.
The process was carried out using a kQ/(ylO) heat press method. The obtained product had the form shown in FIG.

After washing, the product obtained above was subjected to an etching treatment to obtain the product shown in FIG. At that time, the etching process was carried out using the following method and conditions.

゛ That is, after printing an etching resist for circuit formation on the circuit board and drying it, it is immersed in a sodium persulfate solution (NPE-300, manufactured by Mitsubishi Gas Chemical Co., Ltd.) to form a copper foil on the circuit board. Then, the etching resist was removed.

As described above, the circuit board (see Fig. 8) has an insulating layer on the upper surface, one side surface, and the lower surface portion of the aluminum plate, and has a copper-clad portion on the upper surface portion as a circuit forming surface. form) was obtained.

Example 2 A circuit board having the form shown in Fig. 7 was obtained according to Example 1, except that a polyimide-based flexible copper-clad circuit board having a width of 421 km was used, and the form shown in Fig. 3 was obtained. .

Example 3 Thickness 1. s mm, width 25 north, length 300 mm aluminum plate, thickness 6011 WJ, width 32 mm, length 3
A polyester-based flexible copper-clad circuit board (Nicaflex F-10T, manufactured by the same company) was attached with its adhesive (KVD-10) (dried for 150° Cl2O minutes) through the polyester side. Other than that, in the same manner as in Example 1, a circuit board having the form shown in FIG. 8 was obtained through the form shown in FIG. 4.

[Brief Description of the Drawings] Figures 1, 2, 3, and 4 show examples of the form of a precursor for a circuit board, and Figures 5, 6, 7, and 8 show examples of the form of a precursor for a circuit board. FIG. 2 is a cross-sectional view showing an example of the form of a circuit board. 1: Metal plate, 2: Insulating layer, 3: Circuit conductor, 4: Clip lead.

Claims (1)

[Claims] 1. A circuit conductor having an insulating layer is pasted on the circumferential surface of a metal plate via the insulating layer, and then the circuit conductor is etched leaving a portion necessary as a circuit forming surface. A method for manufacturing a metal-based circuit board, characterized in that it is removed by processing. 2. The method according to claim 1, wherein the circuit conductor having an insulating layer is a flexible copper-clad circuit board.