JPS62250689A - Manufacture of insulating substrate - 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] (Industrial Application Field) The present invention provides a metal core I with excellent thermal conductivity and heat resistance.
The present invention relates to a method of manufacturing a P3 edge substrate.

(Prior Art) Conventionally, phenol/L-resin laminates and epoxy resin laminates have been widely used as printed wiring boards. However, in recent years, as electronic devices have become more sophisticated and more compact, there has been a desire for higher density packaging of components, and the problem has become how to deal with the resulting heat sieve density.

On the other hand, conventional organic substrates have poor thermal conductivity, lack heat dissipation properties, and lack heat resistance, making it difficult to implement high-density packaging. Therefore, as substrates with excellent thermal conductivity, ceramic substrates such as alumina, aluminum nitride, and silicon carbide, and metal core substrates with a metal plate as the core and an insulating layer on the surface are attracting attention.
ing. In particular, metal core substrates are attracting attention because they are cheaper than ceramic substrates, have excellent workability, and have a high heat dissipation property due to their core being made of metal such as aluminum, which has high thermal conductivity. It has come to be used for. Research and development to improve performance for this purpose is actively being conducted.

(Problems to be Solved by the Invention) A typical metal core board has an insulating layer of glass/epoxy resin with a thickness of 50μ to 100μ on the surface of a metal elliptical plate made of aluminum or the like, and a circuit is further formed on top of that. It is made of steel foil pasted onto it. That is, what is in direct contact with the circuit is a resin layer with poor thermal conductivity. Therefore, the heat generated in the circuit is transferred to the core metal plate through the resin layer, which has poor thermal conductivity. Therefore, the thermal conductivity of the metal core cannot be fully utilized, and sufficient heat dissipation cannot be obtained.

For this reason, there is an idea to improve this by spraying ceramic such as alumina on the surface of the core metal plate to provide a ceramic insulating layer, without using a resin layer. In this way, heat is conducted to the metal core through the ceramic layer, which has a sufficiently higher thermal conductivity than resin, so that a large heat dissipation effect can be obtained. However, such a substrate has the following drawbacks.

The first problem is that the ceramic layer obtained by thermal spraying has pores, and the dielectric strength of the insulating layer is insufficient. That is, this is because the ceramic insulating layer has poor withstand voltage, and the layer underneath is a conductive metal. The second problem is the adhesion between the ceramic layer and the metal core. When ceramic is thermally sprayed on metal9, the dense layer and bond are due to the so-called anchor effect, in which the molten ceramic hits the rough metal surface at high speed. Therefore, chemical condensation cannot be obtained, and gold and ceramic have different coefficients of thermal expansion, so
It is difficult to develop adhesion that can withstand thermal shock.

To address these shortcomings, methods such as sealing the pores by infiltrating the ceramic layer with resin after ceramic spraying have been considered, but these methods have not been sufficiently effective and have complicated royal authority. Put it away.

The present invention improves these drawbacks and provides excellent heat dissipation.
Furthermore, the present invention provides a method for manufacturing a metal core substrate with excellent characteristics and S productivity.

(Means for Solving the Problems) That is, the present invention injects ceramic onto a metal plate A to form an insulating layer, and after integrating the ceramic layer and metal plate B via an adhesive layer, This method is characterized by peeling the metal plate A from the ceramic layer.

In the present invention, a metal plate made of iron, copper, aluminum, nickel, stainless steel, or the like can be used as the metal plate A on which ceramic is sprayed.

Further, as the ceramic, alumina is most suitable due to its electrical insulation properties, thermal conductivity, ease of thermal spraying, etc., but other electrically insulating materials such as spinel, mullite, beryllia, and silconi 1 can also be used. The thickness of this ceramic layer is preferably in the range of 30 μm or more and 500 μm or less. If it is less than 30μ, the sprayed layer tends to be non-uniform and the heat dissipation effect is insufficient.If it is more than 500μ, the cost increases and defects such as cracks are more likely to occur in the sprayed layer.

Examples of thermal spraying methods that can be used include glass bath spraying, plasma spraying, water plasma spraying, and reduced pressure plasma bathing.

As the adhesive layer for integrating the ceramic magnetic layer and the core metal plate 2, glass fiber or Keplerian fiber is used from the viewpoint of ensuring uniform thickness of the adhesive layer and adhesion of IM sliding strength. It is desirable to use a prepreg impregnated with an epoxy resin or a polyimide resin, and to attach the layers by hot-pressing molding. By doing this, the ceramic layer and the core metal plate can be completely integrated through an adhesive layer with excellent electrical insulation properties and a uniform thickness, which makes it possible to completely integrate the ceramic layer and the core metal plate. It is possible to obtain unreliable things such as withstand voltage, which was previously unknown to Kouma.

The layer properties between the ceramic sprayed layer and the adhesive layer are extremely strong because the surface of the ceramic sprayed layer is rough and has pores, so the tikI product is large. Since the adhesion between the thermal spray nozzle and the metal plate A is low, it is possible to easily separate the metal planting plate A from the ceramic thermal spray layer without adhesion. In order to further facilitate the flaking, it is possible to either not perform surface roughening treatment such as sandblasting before thermal spraying of metal plate A, or to roughen it lightly, or to perform mold release treatment. be.

Since the surface of the ceramic layer on the side where metal plate A has been abraded in this way is a surface that has transferred the surface condition of metal plate A, conductor circuits can be formed by plating, printing, etc. to ensure smoothness. It is possible to do so.

Note that the metal plate B serving as the core can be made of aluminum, iron, copper, stainless steel, nickel, or the like.

(Function) In the present invention, instead of spraying ceramic directly onto the core metal plate as in conventional thermal sprayed substrates, the ceramic sprayed layer and the core metal plate are bonded together using an adhesive layer. , it is possible to obtain strong compactness. Furthermore, since the surface of the ceramic sprayed layer is rough and has pores, the adhesion area is large and the adhesive layer penetrates into the interior of the sprayed layer, further increasing the adhesion.

In addition, the surface of the metal core substrate obtained in this way is a transfer of the surface of the metal plate on which ceramic is sprayed in the first process, so it is extremely smooth compared to the thermal sprayed substrate obtained by conventional methods. It becomes blood. Therefore, it is possible to form a fine conductor circuit pattern as it is by plating or printing.

The metal core substrate thus obtained has excellent heat dissipation and heat resistance because it has a ceramic layer with excellent thermal conductivity under the conductor circuit.

(Example) Alumina was sprayed onto one side of a stainless steel plate 10 with a thickness of 2 mm using a plasma spraying device to form an alumina sprayed layer 2 with a thickness of about 100 μm. Next, as shown in Fig. 1 (alumina sprayed layer 2
An epoxy resin-impregnated glass cloth prepreg S<thickness of 50 μm in a shape) was placed between the aluminum plate 4 having a thickness of 1 fin, and was integrally formed by hot pressure molding.

After the resin was cured, it was cooled and the stainless steel plate 1 was peeled off from the alumina sprayed layer 2. Since the alumina sprayed layer 2 was firmly adhered to the aluminum plate 4 by epoxy resin, the stainless steel plate 1 could be easily peeled off by prying it open with a probe.

The substrate obtained in this way is smooth because the surface of the alumina sprayed layer 2 transfers the surface condition of the stainless steel plate 1 on which alumina was first sprayed, as shown in FIG. It was possible to form a circuit using electrolytic steel metski etching treatment. In addition, unlike conventional metal core substrates, the alumina sprayed layer 2 with excellent thermal conductivity was directly below the circuit, so its heat dissipation properties were very good. Furthermore, since the alumina sprayed layer 2 is firmly adhered to the core aluminum plate 4 by the glass epoxy resin adhesive layer 5, it has good heat resistance and thermal shock resistance. Due to the existence of layers,
The withstand voltage characteristics were also good.

(Effects of the Invention) According to the method of the present invention, a metal core substrate with excellent heat dissipation properties, heat resistance, and reliability can be produced at low cost through a simple process. This makes it possible to more densely package components onto the board, which has an extremely large effect on the miniaturization of electronic components.

[Brief explanation of drawings]

FIG. 1 is a lamination configuration diagram when forming an adhesive layer according to an embodiment of the present invention;
FIG. 2 is a schematic cross-sectional view of the obtained metal core insulating substrate. Explanation of symbols 1 Stainless steel plate 2 Alumina l

Claims (1)

[Claims] 1. In the production of an insulating substrate in which an insulating layer made of ceramic is provided on the surface of a metal plate, a. a first step of thermally spraying ceramic onto the metal plate A to form a ceramic layer; b. A second step of interposing an adhesive layer between the ceramic layer and the metal plate B serving as the core of the substrate to integrate them; c. Peeling the metal plate A on which the ceramic was sprayed in the first step from the ceramic layer. 3. A method for manufacturing an insulating substrate, comprising the steps of: 2. The method for manufacturing an insulating substrate according to claim 1, wherein the electrically insulating ceramic is mainly composed of alumina. 3. The method for manufacturing an insulating substrate according to claim 1, wherein the adhesive layer is made of glass fiber or Kepler fiber impregnated with epoxy resin. 4. The method for manufacturing an insulating substrate according to claim 1, wherein the adhesive layer is made of glass fiber or Kepler fiber impregnated with polyimide resin.