JPS60250685A - Electric circuit board - 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 [Technical Field] The present invention relates to an electrical circuit board on which electronic components can be mounted with high density.

[Background technology]

When electronic components are mounted in a high density, the temperature of the circuit board increases, causing problems such as degrading or changing the characteristics of the electronic components. A conductive metal plate like an aluminum plate is attached to it. The circuit board uses a glass epoxy resin copper-clad laminate with excellent heat resistance. This laminate has a standard thickness of 1.6M and has poor heat dissipation. Therefore, a thinner plate (0.5 IIiW ~ 1.01 m) is used, but although it does not improve #1, the price increases significantly.

Furthermore, the thermal expansion coefficients of the glass epoxy resin laminate and the aluminum plate are different, and there is a risk that the laminate may warp or twist and come off from the aluminum plate.

[Purpose of the invention]

The present invention aims to improve the above-mentioned drawbacks,
To provide an electrical circuit board that has good heat dissipation even when electronic components are mounted at high density and does not cause deterioration of the electronic components.

[Disclosure of the invention]

The present invention will be described in detail below based on examples.

In the figure, 6 is an aluminum plate with an insulating layer 7 on its surface.
is formed. This isolation layer 7 can be formed by a positive temporary oxidation method. In the anodic oxidation method, the aluminum plate 6 is used as an anode in an electrolyte such as an aqueous solution of oxalic acid, chromic acid, or sulfuric acid, and a current is passed through it as an anode.The oxygen generated by the electrolysis combines with aluminum to form an oxide film, resulting in a beautiful μ It is also possible to do more than that. 8 is an adhesive layer. A suitable adhesive for this adhesive is an epoxy adhesive that is resistant to heat. For example, silicone-modified epoxy resin and NBR are used as main ingredients,
An adhesive prepared by blending a curing agent and a curing accelerator used as necessary is used.

The silicon-modified epoxy resin has polysiloxane added as a side chain to the main chain of the following structural formula, and preferably has an epoxy equivalent of 700 to 1,700 and a silicate modification rate of 5% by weight or more. -8i -0-R <Hisatsu R Here, in the above configuration, n = 2 to + (especially 4 to 7), m = l
-8 (particularly 2-4) are preferred, R is aromatic or aliphatic hydrogen, and R is preferably aliphatic, particularly preferably an ethyl group.

Note that since the insulating layer 7 is a porous insulating layer, as shown in FIG. 3, the adhesive flows into the holes 9, increasing the adhesion.

This adhesive is applied to a thickness of approximately 1 to 1 ω.

After coating, it is dried in hot air or placed in an infrared oven to harden to B-stage. The conditions are 150°Q, 30~
Approximately 120 minutes is appropriate.

Next, the surface of the adhesive layer is roughened by a physical method. For example, Sandbator.

Next, electroless plating and electroplating are applied to the roughened surface, but first, the rough surface of the adhesive is subjected to activation treatment.

Planting can be activated by, for example, applying wrinkle play catalyst lip 404, caterpillar, foot lever, and accelerator 19 in this order. After performing this activation treatment, it is immersed in an electroless copper plating bath to form a very thin conductive layer, and then immersed in an electrolytic copper plating bath to form a conductive layer 10 from the conductive plating layer.

Thereafter, the adhesive is completely cured from the B stage.

The conductive plating 810 is etched, etched, etc. to form a necessary front circuit pattern. Between the conductors M and Fm 10 and the aluminum plate 6, an oxide insulating layer 7 (approximately 10 μm) of the aluminum plate 6 and an adhesive layer 8 (approximately 30 to 100 μm thick) are interposed to form an extremely thin insulation layer. layers are formed.

Since this insulating layer is thin, its dielectric strength is not significantly compromised, but sufficient insulation can be obtained for electrical circuits commonly used at low voltages such as DC 12V or DC 6V.

Therefore, even if a circuit is formed on the conductive layer 10 and electronic components are mounted on this circuit at an extremely high density, the temperature of the adhesive layer 8 and the insulating layer 7 will remain constant even if the temperature of the conductive layer 10 increases significantly. It is considerably thinner than the conventional example, so it has good thermal conductivity, and since the aluminum plate 6 is a good conductor of heat, if the aluminum plate 6 is attached to another metal plate with good heat dissipation, it will dissipate heat rapidly. do.

〔Effect of the invention〕

As described above, according to the present invention, the conductive metal plate 6 has an insulating layer 7 formed on its surface by oxidation treatment, the adhesive layer 8 coated on the surface of the insulating layer 7 of this metal plate 6, and Since the circuit board is provided with the circuit board 10 formed on the surface of the adhesive layer 8, it is possible to mount electronic components at high density even when the temperature rise is high.

Since the insulating layer and adhesive layer are thin, heat radiation is good in the direction of the aluminum plate 6. Therefore, there is no deterioration of electronic components or change in characteristics.

Furthermore, the cost is extremely low compared to conventional glass epoxy laminates.

[Brief explanation of the drawing]

In the drawings, FIG. 1 is a partial sectional view showing a conventional example, and FIGS. 2 and 3 are partial sectional views showing a dormitory embodiment of the present invention. 6: Aluminum plate, 7: Oxidized insulating layer, 8: Adhesive layer, IO;
conductive plate.

Claims (1)

[Claims] (1) A conductive metal plate with an insulating layer formed on the surface by oxidation treatment, an adhesive layer applied to the surface of the insulating layer of this metal plate, and an electric path formed on the surface of this adhesive layer. Electrical circuit board with.