JPS61144098A - Manufacture of substrate for one-side insulation type 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 method for manufacturing a metal-based circuit board in which one of the opposing sides is insulated.

[Conventional technology and problems]

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

Conventionally, the circuit board for hybrid IC is
Ceramic substrates containing alumina as a main component have been known. However, this had problems such as being easy to break, making it difficult to form large-sized pieces, and having poor heat dissipation properties. Therefore, to solve the above problems, metal plates such as aluminum were used to dissipate heat. A circuit board used as a base has been proposed.

In this metal-based substrate, unlike ceramic, the metal plate is electrically conductive, 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 4, 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.

The insulation treatment method was previously proposed by a group to which the present inventors belong. In other words, the vertical insulation tape method (Japanese Patent Application No. 161077/1983), the electrodeposition insulation method,
These include powder coating insulation methods (Japanese Patent Application No. 129614/1980, Utility Application No. 118194/1982, Utility Application No. 118195/1983, etc.).

When a lead frame is provided only on one side of a circuit board, it is not necessary to insulate the opposite side. Therefore, a circuit board having insulating layers on both opposing sides not only has excessive quality but also becomes a heavy object, which in turn hinders the reduction in weight of electronic devices.

Considering that the practical use of hybrid ICs is to reduce the weight of electronic equipment, the above-mentioned weight problem is an important practical problem that cannot be ignored.

[Means for solving problems]

The present invention overcomes the above problems and provides an efficient method for manufacturing a metal-based circuit board having an insulating layer on only one of the opposing side surfaces.

That is, the method for manufacturing a single-sided insulated circuit board of the present invention has an insulating layer on the entire periphery of the metal plate or on the surface of the metal plate except for a part of either the front side or the back side, and Alternatively, form a circuit board having a circuit conductor on one side or both sides having the insulating layer on the entire back surface, and place the obtained circuit board on the side having the insulating layer in that direction. The purpose is to cut the target object into a single-sided insulated 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, a copper plate, an aluminum plate, an iron plate, a silicon steel plate, or a galvanized or copper-plated product thereof with a thickness of 0.2 to 10 mm, especially 0.5 to 5 H, is used. Of course, it is not limited to these.

In the present invention, the metal plate is first made into a circuit board having insulating layers on both opposing sides. In other words, one side or The circuit board has a circuit conductor on both sides with an insulating layer interposed therebetween.

To manufacture this circuit board, for example, first, insulating tape is applied to a predetermined part of a metal plate, that is, the entire circumference of the metal plate or a part of either the front or back side of the metal plate, mainly excluding the central part. After forming an insulating layer by performing insulation treatment by an appropriate insulation method such as electrodeposition insulation method, powder coating insulation method, or other insulation face coating method, the entire surface or back surface of the obtained metal plate. one side or both sides having the insulating layer (if the insulating layer is on only one of the front and back sides, that side; if the insulating layer is on both the front and back sides, either one side or both sides) This can be done by pasting a circuit conductor on both sides of the metal plate through the insulating layer, or by using a circuit conductor with a pre-formed insulating layer and attaching it to a predetermined part of the metal plate through the insulating layer. It is also possible to do this by pasting the image on the screen.

Incidentally, a typical example of the circuit conductor to be used is copper foil, but of course the present invention is not limited to this.

Therefore, the circuit board at the above stage has the form shown in FIGS. 1 to 3, for example. In the figure, 1 is a metal plate, 2 is an insulating layer, and 3 is a circuit conductor.

In the present invention, the circuit board obtained in the above-mentioned forming step is then subjected to a cutting step, and, for example, as shown in FIG. 4, the circuit board in the form shown in FIG. It is cut in the direction and divided.

In this way, a circuit board having no insulating layer on the side surface opposite to the side surface having the insulating layer is obtained. In other words, a metal plate that had an insulating layer on four sides has two insulating layers on only three sides.
What used to have an insulating layer on its side surfaces now has an insulating layer on only one side.

In addition, in the case of a metal plate 1 having a shape in which the front or back surface is exposed at L as shown in FIG. 1, the part obtained by dividing it (for example, FIG. (Fig. 4) As a result, as shown in Fig. 1, since there is an insulating layer 2 on both sides, the heat sink, etc. 5 can be directly attached to the heat sink, etc. In some cases, it has the advantage that it can be used as a circuit board or device that works well with a metal plate.

Considering that the preferred embodiment of the method of the present invention is a continuous IaI manufacturing method using long metal plates from the viewpoint of manufacturing efficiency, it is possible to manufacture a circuit board having an insulating layer on only one side. The shape is normal.

That is, as shown in FIG. 4, it is obtained by cutting a long metal plate having insulating layers on both opposing side surfaces in the longitudinal direction along the longitudinal direction.

〔Effect of the invention〕

According to the present invention, a circuit board having an insulating layer on both opposing sides is first formed, and then this is divided to form a circuit board having an insulating layer on one side. As a result of being able to efficiently insulate or attach circuit conductors to the
As a result of being able to manufacture individual pieces at once, it is possible to obtain a one-sided insulated circuit board with high manufacturing efficiency and a simple process.

〔Example〕

Example 1 A long aluminum plate having a thickness of 2 saw and a width of 5 Gm11 was coated with adhesive (OX-035: manufactured by Toshisha Co., Ltd.) on one side, leaving a 40 ff portion at the center of the back side.
A 5 μm Kapton film (polyimide film, manufactured by Depond) was heated at 190°C for 1 hour with a press pressure of 40 kf/
The aluminum plate was attached using the heat press method described in d to obtain an aluminum plate having an insulating layer on the front surface, both side surfaces, and a part of the back surface of the side surfaces.

Next, a copper foil with a thickness of 35 μm and a width of about 40 ff was placed on the surface of the aluminum plate via a Kapton film layer.
-035, and then cut at the center in the width direction to continuously obtain a metal-based circuit board having an insulating layer on only one side and having a width of 25fi and a thickness of about 2ff. Its manufacturing efficiency was 4.9 ml/min.

Example 2 A polyester chive with a width of 42 mm was attached to the center of the back of a long aluminum plate with a thickness of 21 ff and a width of 50 mm, which was copper-plated on the entire circumference, and then masked. It was introduced into an electrodeposition bath (V・551-20: manufactured by Ryoden Kasei Co., Ltd.) for electrodeposition treatment, and then baked to a thickness of 3.
The aluminum plate with an electrodeposited insulating layer of 0 μm was obtained.

Next, a copper foil with a thickness of 35 μm and a width of about 40 pieces was pasted on the surface of this aluminum plate via OX-035, and then
By cutting at the center in the width direction, a metal paste-based circuit board having a width of 25 fi and a thickness of about 21 a1 and having an insulating layer on only one side was continuously obtained. Its manufacturing efficiency is 10.1#! /minute.

Note that the polyester cheese for the mask was peeled off immediately before the baking process.

[Brief explanation of the drawing]

Figures 1, 2, and 3 are cross-sectional views showing examples of the form of a circuit board formed in the first step of the present invention, which has insulating layers on both opposing sides, and Figure @4 is the target object. FIG. 2 is a cross-sectional view showing an example of the form of a single-sided insulated circuit board. 1: metal plate, 2: insulating layer, 3: circuit conductor, 4: clip lead, 5: heat sink, etc.

Claims (1)

[Scope of Claims] 1. An insulating layer is provided on the entire circumference of the metal plate or on the circumferential surface excluding a part of either the front or back surface, and the insulating layer is provided on the entire front or back surface of the metal plate. forming a circuit board having a circuit conductor on one or both sides thereof with an insulating layer interposed therebetween, and cutting the obtained circuit board in the direction along the side having the insulating layer. A method for manufacturing a side-insulated circuit board. 2. The method according to claim 1, wherein the circuit board is a metal plate with an insulating layer provided on a predetermined portion and then a circuit conductor attached thereto. 3. The method according to claim 1, wherein the circuit board is a metal plate in which a circuit conductor having an insulating layer is attached to a predetermined portion of the metal plate via the insulating layer. 4. The method according to claim 1, wherein the circuit board has an insulating layer on both opposing sides in the longitudinal direction of the long metal plate.