JPH0655477B2 - Method for manufacturing ceramic coat laminate - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a laminated board for printed wiring boards, which is excellent in heat resistance and thermal conductivity.

(Prior Art) Conventionally, as a printed wiring board, a phenol resin laminated board,
Epoxy resin laminates have been widely used. However, recently, as electronic devices have become higher in performance and smaller in size, higher density mounting of components has been desired, and how to handle the high density generation of heat generated thereby has become a problem.

On the other hand, the conventional organic substrate has poor heat conductivity and thus lacks heat dissipation, and has poor heat resistance. Therefore, high-density mounting is difficult. Therefore, attention is focused on a ceramic substrate such as alumina as a substrate having excellent thermal conductivity, or a metal core substrate whose surface is covered with an insulating layer using a metal plate as a core material. Substrates using heat-resistant resins such as polyimide resin, polyether ether ketone, and polysulfone are being developed in place of phenol resin and epoxy resin substrates.

(Problems to be Solved by the Invention) However, there are various problems with these substrates. In other words, ceramic substrates such as alumina, silicon carbide and beryllia have excellent thermal conductivity and heat resistance,
It has drawbacks such as complicated manufacturing process, poor workability, low mechanical strength, limited size of substrate, and large substrate cannot be obtained. In addition, since the metal core substrate using the metal plate as the core material is in contact with the conductor portion that becomes the circuit because of the insulating layer made of resin having low thermal conductivity, the high thermal conductivity of the metal core can be fully utilized. No heat dissipation is sufficient. Further, since the core material is a metal plate, it is not easy to form the through holes, and a very complicated manufacturing process is required.

Furthermore, although the heat resistant resin substrate has improved heat resistance,
The heat dissipation effect cannot be expected due to the low thermal conductivity of the resin.

The present invention solves these drawbacks, and provides a manufacturing method capable of manufacturing and processing methods similar to those of conventional organic substrates, and obtaining a substrate excellent in thermal conductivity and heat resistance.

(Means for Solving Problems) That is, according to the present invention, an electrically insulating ceramic is sprayed on one surface of a metal plate to form a ceramic layer, and a prepreg is laminated on the ceramic layer side and thermocompression molded to be integrated. After the molding, the metal plate is peeled off to obtain a laminated plate having a ceramic layer on the surface of the organic substrate.

In the present invention, the reason why the ceramic is thermally sprayed on the metal plate and the prepreg is placed on the metal plate and thermocompression-molded to integrate them is to improve the adhesion between the ceramic and the resin and to smooth the surface ceramic layer. . In general, inorganic ceramics and organic resins are different from each other and have different thermal expansion coefficients, so that the adhesion is poor. Therefore, it is difficult to obtain sufficient adhesion by spraying the ceramic on the surface of the organic substrate after molding. Further, the surface of the sprayed layer is a rough surface as it is, and it has to be polished to be smooth in order to form a circuit on the surface. Therefore, ceramic is sprayed on a metal plate, a prepreg is laminated on it, thermocompression molding is performed to integrate it, and after molding, the metal plate is removed to remove the metal plate from the resin of the prepreg on the ceramic sprayed layer with rough surface and pores. Melts, has a low viscosity, penetrates into the gaps, and hardens, so that the adhesive area increases and good adhesion is obtained. Also, after molding, the surface of the metal plate is transferred as it is to the ceramic sprayed layer that appears on the surface by removing the metal plate, so that a smooth surface is obtained and no polishing treatment is required.
It is possible to form the circuit as it is.

As the metal plate used in the present invention, an iron plate, a copper plate, an alumina plate, a stainless plate, or the like is used, and the metal plate and the ceramic layer after molding can be peeled off with a small mechanical force, but for easy peeling, It is desirable not to blast the metal plate before spraying or to lightly perform it. Further, in order to facilitate the peeling, it is effective to apply a mold release treatment for applying a mold release agent such as a silicone type or a fluorine type, which is performed in general plastic molding.

Alumina, which is most often used as a ceramic substrate, is suitable as the electrically insulating ceramic used here, but it is also possible to use a highly thermally conductive and electrically insulating ceramic such as spinel, mullite, beryllia, or aluminum nitride. it can. As a ceramic spraying method, a plasma spraying method, a gas spraying method, a water plasma spraying method, or the like can be applied.

Furthermore, regarding the prepreg, epoxy resin and polyimide resin are preferable as the resin from the viewpoint of electrical characteristics and moldability, but in addition, thermosetting properties such as phenol resin, unsaturated polyester resin, melamine resin, vinyl ester resin, etc. A resin or a thermoplastic resin such as polysulfone, polyetheretherketone, polyethersulfone, or polyetherimide can be used. Further, as the fiber, in addition to commonly used glass fiber, Kepler fiber, paper, SiC fiber, silica fiber or the like can be used.

The ceramic layer may be provided on both sides or one side of the organic substrate, and the thickness thereof is 20 μ to 50 μm.
It is preferably in the range of 0 μ. This is because if it is less than 20 μm, the effect on heat resistance and thermal conductivity is not sufficient, and if it exceeds 500 μm, workability such as drill workability is deteriorated and it becomes expensive.

By the method of the present invention, a laminated plate having a ceramic layer on the surface of an organic substrate can be easily obtained. In the method of the present invention, unlike the conventional idea of spraying the ceramic on the organic substrate, the ceramic is formed on the metal plate. Since a thermal sprayed layer is formed and a prepreg is laminated on it and thermocompression molded and integrated, the adhesion between the ceramic and the organic substrate is very good. Further, the ceramic layer on the surface of the obtained ceramic-coated laminated plate is smooth because the surface of the metal plate is transferred as it is, and a circuit can be formed as it is.

Hereinafter, the present invention will be described in more detail with reference to examples.

(Example) FIG. 1 is a schematic diagram of a laminated structure of an example of the present invention, and FIG. 2 is a schematic sectional view of a ceramic-coated laminated plate obtained in the example.

After coating the surface of a stainless steel plate 1 (thickness: 2 mm) having a smooth surface with a silicone-based mold release agent, alumina was sprayed to a thickness of about 100 μm using a plasma spraying device to form an alumina layer 2.

The stainless steel plate and the glass cloth / epoxy resin impregnated prepreg 3 were stacked in the laminated structure shown in FIG. After cooling this molded product, the stainless steel plate on the surface was peeled off and removed to obtain a laminated plate having an aluminum layer on the surface as shown in FIG.

The obtained laminated plate has a smooth alumina layer on the surface, the adhesion between the alumina layer and the epoxy resin is good, and since the alumina layer with good thermal conductivity is on the surface, it has excellent heat dissipation, It also had heat resistance and good arc resistance and tracking resistance. Further, since the core of this laminated plate is the same glass / epoxy substrate as the conventional one, formation of through holes, drilling and the like can be performed by the conventional method.

(Effects of the Invention) According to the present invention, a laminate having excellent thermal conductivity and heat resistance can be easily manufactured. The resulting laminate has both excellent moldability and processability of organic substrates and excellent heat resistance and thermal conductivity of ceramic substrates, and is capable of solving these conventional drawbacks. Is.

[Brief description of drawings]

FIG. 1 is a stacking diagram of an embodiment of the present invention, and FIG. 2 is a schematic sectional view of a ceramic-coated laminate obtained in the embodiment. Explanation of symbols 1 ... Metal plate, 2 ... Ceramic sprayed layer 3 ... Prepreg, 4 ... Fiber / resin layer

Claims (5)

[Claims] 1. A method of spraying an electrically insulating ceramic on one surface of a metal plate to form a ceramic layer, laminating a predetermined number of prepregs on the ceramic layer side of the metal plate, and peeling the thermocompression-molded metal plate. A method of manufacturing a ceramic-coated laminate characterized by the above. 2. The method for producing a ceramic-coated laminate according to claim 1, wherein the surface of the metal plate on which the ceramic is sprayed has been subjected to a release treatment in advance. 3. The method for producing a ceramic-coated laminate according to claim 1, wherein the ceramic contains alumina as a main component. 4. The method for producing a ceramic-coated laminate according to claim 1, wherein the prepreg resin is an epoxy resin or a polyimide resin. 5. The method for producing a ceramic-coated laminate according to claim 1, wherein the prepreg fibers are glass fibers.