JPS60175494A - Method of producing metal base 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 Field of the Invention The present invention relates to a method of manufacturing a metal-based circuit board used in electronic equipment.

Conventional configurations and their problems In recent years, in the field of electronic equipment, the question of how to package a wide variety of electronic components, including heat-generating components such as ICs, LSIs, and power transistors, in a compact and compact manner at low cost has become a major issue. Along with this, the technological direction is progressing toward multilayering and high integration. Here, the main types of conventional multilayer substrates will be described. By structure, there are ceramic multilayer substrates on substrates such as alumina, and metal-based multilayer substrates on which resins made of organic polymer materials are multilayered as insulating layers on metal bases such as aluminum and iron. epoxy.

There is a resin multilayer board made of a resin board made of phenol or the like and multilayered with resin insulation layers. Figure 1 is a cross-sectional view of a conventional multilayer metal base board with an insulating layer made of resin, in which 1 is a metal base, 2a and 2b are insulating layers, 3a and 3b are conductor layers, and 4 is a through-hole layer. .

The conventional method is to print a printable material or conductive material using a silk screen or a stainless steel screen, and repeat the steps of drying and curing to form a multilayer material. An insulating paste made of an organic polymer material is printed on a metal base 1 made of aluminum or the like, and after drying, it is cured to form a cured insulation)@2a. Next, as shown in FIG. 2, a low temperature curing type copper or silver paste is printed, dried and cured to form a cured conductor layer 3a. Furthermore, as shown in FIG. 3, a through-hole layer is formed by printing an insulating pattern with holes for through-holes, drying and hardening the insulating layer 2b, and then forming a hardened insulating layer 2b. 4. After complete printing, drying, and curing, the η-conductor layer 3b, which is electrically connected to the lower conductor layer 38 through through holes, is formed by the same method as in the conductor forming step described above. This is a method of forming multiple layers by repeating the insulating layer forming process, through hole forming process, and conductor forming process as described above. However, in the above manufacturing method, all pattern formation is done by printing, and as the number of layers increases, the surface becomes more uneven and the flatness deteriorates, making multilayering difficult. It also becomes difficult to form a through-hole pattern. In addition, in connection with these points, when it is desired to form a pattern over a dried pattern, if the pattern is not sufficiently dried, the underlying pattern may collapse and a fine line may not be formed. As for this drying process, it takes a long time, and since it is a necessary step for each printing, the overall time is very long, and the overall manufacturing cost is greatly increased.

OBJECTS OF THE INVENTION The present invention addresses the above-mentioned drawbacks and provides a method for manufacturing a metal-based circuit board that can be easily manufactured with high yield. Apply the entire surface to the base, expose to light to form the first hardened insulating layer,
A conductive material is coated on the first cured insulating layer and then cured to form a first circuit conductive layer, and then the high thermal conductive insulating layer) W
t, a second cured insulating layer is formed with a through-hole through which a part of the first circuit conductor layer is exposed by exposure, and the conductor is placed on the second cured insulating layer. forming a second circuit conductor layer using the material, filling the hole with the harmful material to form a through hole, and curing the second circuit conductor layer and the through hole simultaneously, as necessary. A cured insulating layer 1 circuit conductor layer and through holes are formed on the second circuit l body layer by the same forming method as for the second cured insulating layer, the second circuit conductor layer, and the through holes. It is something.

The above method greatly simplifies the production of culms compared to conventional methods. The first step is to form an insulating layer.

Metal oxide f: A method in which a completely conductive insulating layer dispersed in a photosensitive organic polymer with weather shielding properties is coated on the entire surface and exposed to light to form a hardened insulating layer, and through holes are also formed on the entire surface coated pattern. This method involves exposing and curing the area other than the through-hole area, allowing the edges of the through-hole to be formed into fine shapes. Furthermore, since it is photosensitive, it cures quickly and eliminates the drying step of conventional methods, significantly reducing the overall manufacturing cost. Next, since the tatami body portion is formed on the entire IFII coating pattern, the flatness of the surface is maintained and multi-layering is facilitated. Furthermore, compared to conventional thermosetting tights, the photosensitive tie 1 of this method has good adhesion to a base substrate such as a ceramic or metal base, and can contribute to improving the substrate properties.

It is also superior to the conventional multilayer substrate described in iiJ in terms of other characteristics. The insulating material of the present invention uses a metal oxide dispersed in a pollutant organic polymer, and has a -lower heat transfer ηf compared to conventional organic polymer materials alone. Often, this means that an insulating layer with vague heat dissipation characteristics can be obtained while forming a thick insulating layer film to improve insulation properties and pressure characteristics.

Description of a real plum example A real plum example of the present invention will be described below with reference to Figure rfiJ. Figures 6 to 11 show the actual tifxWI of the present invention.
3 is a cross-sectional view of J in the order of steps. In the figure, 1 is a metal base sa, csb is an insulating layer, ea, 6b
is a circuit conductor layer, and 7 is a through hole.

A method of manufacturing the conductive metal base circuit board of this example formed as described above will be described below. First, as shown in FIG. 6, a coating pattern of a highly thermally conductive material in which a metal oxide is dispersed in an adhesive photosensitive organic polymer is formed on the entire surface of a metal base 1 such as aluminum, and then exposed to light to form a hardened insulating layer. 6a (!-Shadow Formation 0) Next, as shown in FIG. 7, a low @ hardening type copper or silver paste is applied and hardened to form a hardened circuit conductor layer 6a.Next, as shown in FIG.

As shown in FIG. 9, after coating the entire surface of the photosensitive highly thermally conductive material, it is exposed to light to form a cured insulating layer 6b with holes 8 for through holes. Furthermore, the through holes 7 and the circuit conductor layer 6b are simultaneously cured and formed using the conductive material.

As described above, according to this embodiment, by using a highly thermally conductive insulating material in which a metal oxide is dispersed in an adhesive photosensitive organic polymer, the drying process in the conventional screen printing method is eliminated. The rapid hardening of the photosensitive material shortens the manufacturing time, leading to a significant reduction in manufacturing costs. Furthermore, since the through holes are formed by exposing and curing the entire surface coating pattern of the insulating layer, the edges of the through holes can also be formed finely. In terms of other characteristics, the insulating material of the present invention has better thermal conductivity than conventional organic polymer materials only, and this means that it is necessary to form a thick insulating layer to improve insulation and voltage resistance characteristics. Moreover, an insulating layer with excellent heat dissipation properties can be obtained.

Effects of the Invention As is clear from the above explanation, the present invention eliminates the drying step in the conventional screen printing method by using a highly thermally conductive insulating material, and shortens the manufacturing time due to the quick curing of the photosensitive material. This will result in a significant reduction in manufacturing costs.

In addition, through holes are formed by exposing and curing the entire surface coating pattern of the insulating layer, so the edges of the through holes can also be formed finely. It has a particularly good specific thermal conductivity, which means that it is possible to form an insulating layer thickly in order to improve insulation properties and dielectric strength I characteristics, and to obtain an insulating layer with excellent heat dissipation properties.

[Brief explanation of drawings]

FIG. 3 is a process diagram showing a method of disposing a metal-based circuit board in an embodiment of the invention. 1...metal substrate, sa, esb...cured insulating layer, ea, eb...circuit conductor layer, 7...
...Through hole 8...hole. Name of agent: Patent attorney Toshio Nakao and one other person
A color (No. 5)) j, l'+

Claims (2)

[Claims] (1) At least 1 piece of a metal-based commercial thermally conductive phase family in which a metal oxide is dispersed in a photosensitive organic polymer with layering properties.
After coating the entire surface of the insulating layer, a first hardened insulating layer is formed by exposing to light, and a conductive material is applied on the first hardened insulating layer and then hardened.
A second cured insulating layer is formed by forming a circuit conductor layer, and then applying the high heat conductive insulating layer, and providing a through hole through which a part of the first circuit conductor layer is exposed by exposure. A second cured insulating layer is formed on the second cured insulating layer using the conductive phase material.
The step of forming a circuit conductor layer and filling the hole with the conductor to form a through pole, and curing the second circuit conductor layer and the MiJ through hole simultaneously, if necessary. A metal base circuit in which a cured insulating layer 1, a circuit groove body layer, and a through hole are formed on the second circuit conductor layer by the same formation method as the second cured insulating layer, the second circuit conductor layer, and the through hole. Substrate manufacturing method. (2) Claim 1 using aluminum or alumite-treated aluminum as the metal base
A method for manufacturing a metal-based circuit board as described in Section 1.