JPS63160829A - Manufacture of ceramic-coated laminated 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 for manufacturing a laminate for printed wiring boards.

(Prior Art) Conventionally, phenolic resin laminates and epoxy resin laminates have been widely used as printed circuit boards. However, recently, as the performance of electronic devices has increased, high-density packaging is desired, and board materials also have high thermal conductivity, high heat resistance,
Properties such as low thermal tensile modulus and high dimensional stability are increasingly required.

On the other hand, conventional organic groups such as phenolic resins and epoxy resins lack heat dissipation properties due to poor thermal conductivity, have a large coefficient of thermal expansion, have poor single-method stability, and have poor resistance to stress. Therefore, it is not used for this purpose. For this reason, ceramic substrates such as alumina, or metal paste and metal core substrates that have a core material of a gold maple board and an insulating layer on the surface are attracting attention. In addition, from the viewpoint of heat resistance, substrates using heat-resistant thermoplastic resins such as polyimide super resin, polyether ether ketone, and polyfA-phone have been developed in place of conventional phenol resin and epoxy resin substrates.

(Problems that the invention attempts to solve) However, when looking at these substrates, there are some problems, both moral and virtuous. In other words, ceramic substrates such as alumina are superior in terms of thermal conductivity, heat resistance, and coefficient of thermal expansion when compared to organic substrates, but the manufacturing process is complicated and shrinkage during sintering is large. It has drawbacks such as difficulty in achieving precision, poor workability such as the impossibility of drilling, brittleness, limitations on the size of the substrate and the inability to obtain large substrates, and high cost. In addition, metal base substrates and metal core bases with a metal plate as the core material cannot take full advantage of the high thermal conductivity of the metal core because the insulating layer made of resin is in contact with the conductor part that serves as one path. Moreover, the heat resistance of the surface is not sufficient. Furthermore, since the core material is made of a conductive metal, it is difficult to form through holes, and forming through holes requires a very complicated manufacturing process. Furthermore, although the heat resistance of the heat-resistant resin substrate has been improved compared to conventional products, the heat transfer rate remains the same, so no heat dissipation effect can be expected.

The present invention improves these drawbacks, incorporates the advantages of conventional ceramic substrates and organic substrates, and makes it possible to manufacture and process conventional #** type substrates with several of these disadvantages. Furthermore, the present invention provides a method for safely obtaining a substrate having excellent thermal conductivity, heat resistance, and a low coefficient of thermal expansion.

(Determined Means for Solving the Problems) The present invention involves applying a thermosetting resin to one side of the copper foil, forming a ceramic layer on the thermosetting resin-coated side of the copper foil to make it into a B stage, and forming a ceramic layer on the ceramic layer side of the copper foil. The special purpose is to heat and press the prepregs so that they are in contact with each other, and to obtain a substrate with a ceramic sprayed layer sealed with resin between the copper foil and the organic substrate.

@Formation of ceramic layer on foil 11: Besides thermal spraying, there are other ceramic coating methods such as CVD and PVD.
Among these methods, the Numazari method has the highest film formation rate and high productivity, and it does not have the limitations of the fg projecting surface (because it is possible to apply ceramic coating to a large area). Yes, the gas 1fj9I4 method, plasma spraying method, reduced pressure plasma spraying method, water plasma spraying method, etc. can be used for ceramic thermal spraying.

In addition, prior to ceramic spraying on copper foil, one side of the copper foil,
That is, the reason why thermosetting shelf fat is applied to the surface to be thermally sprayed with ceramic to form a cloth or B stage is to seal in the pores present in the ceramic thermally sprayed layer. Unlike a sintered body, a ceramic sprayed layer generally has pores of 5 to 15 vol.

Therefore, without sealing these pores! When hot-pressing molded together with the casing prepreg, it is difficult to seal all the pores in the ceramic sprayed layer using only the flow of resin in the prepreg during prepreg molding. Therefore, the water absorption rate is large when the pores are present, and the insulation resistance when moisture is absorbed, ′t
Characteristics such as s'Rt% and Jll soldering heat resistance are greatly deteriorated. Therefore, it is necessary to completely seal the pores in the ceramic sprayed layer. As shown in the present invention, this sealing treatment can be easily achieved by applying a thermosetting resin to the ceramic sprayed surface side of the @ foil in advance to make it into a B stage. In other words, when thermosetting resin is coated on copper foil with ceramic sprayed on the cloth side and thermo-press molded together with prepreg, the resin will be applied to the copper foil and made into a B stage.
It easily melts in the bath due to the heat during hot pressure forming, flows under pressure, and impregnates into the pores of the ceramic sprayed layer. Furthermore, since this thermosetting resin has high fluidity under pressure, the excess resin protrudes out of the system as particles, eliminating the excess resin between the copper foil and the ceramic coating layer, resulting in a close bond between the copper foil and the ceramic coating layer. The state is obtained. The thermosetting resin impregnated into the pores of the ceramic bath layer is then cured together with the prepreg resin to obtain a laminate. In addition, by sealing the pores of the ceramic sprayed layer with the resin in this way, the adhesion between the copper foil and the ceramic sprayed layer is also greatly improved compared to the case where the pores are not sealed. The adhesion of ceramic thermal spraying to metals is affected by pretreatment such as blasting, but it varies depending on the type of metal, and it is said that the adhesion strength to steel or steel shears is the lowest.

Therefore, if the ceramic layer is not sealed using the pore sealing method 1c, a sufficient value of adhesion with the ceramic layer cannot be obtained. However, when the pores are sealed with a resin, the resin is present on the surface of the copper foil, and the adhesion is greatly improved.

*Thermosetting resins applied to the foil for sealing include epoxy resins, phenolic resins, solidified resins, melamine resins,
Unsaturated polyester resins, vinyl ester resins, etc. are used, and in order to obtain the greatest adhesive strength with the prepreg used for lamination, it is preferable to use a resin of the same class aI as the prepreg resin. Coating methods to the copper foil include coating, spraying, doctor blade, and ale coater methods, and the applied resin is staged for ease of handling. Note that when applying an uncured thermosetting resin that is solid at room temperature using a hot melt method, it is not necessarily necessary for B-stage formation. Even more completely cured!
However, this must be avoided as it will not flow during hot press molding.

In the present invention, as the ceramic to be emitted to the copper foil, alumina, which is most widely used as a ceramic substrate, is suitable, but other electrically insulating materials such as spinel, mullite, beryllia, silicon carbide, zirconia, and aluminum nitride are also suitable. The semi-)mic is used.

Epoxy resins and polyimide resins are suitable for Gripreg resin in terms of electrical properties and moldability, but thermosetting resins such as phenol resins, unsaturated polyester resins, melamine resins, and vinyl ester resins, as well as polyester resins, are also suitable.
Thermosetting resins such as fh7t, polyether; -thiylketone, polyester sulfur, and polyetherimide can be used. Also, #J! In addition to commonly used glass fibers, fibers include Kepler shrapnel, paper, and SiC fibers.
Fibers, silica junctions, etc. can be used.

(Function) Since the laminate obtained by the method of the present invention has a ceramic layer on the surface of the organic substrate, it has excellent heat dissipation, heat resistance, surface hardness, etc. The number of threads is also /J%. Furthermore, since the pores of the ceramic layer are sealed with @ fat, the water absorption rate is lower than that of conventional organic substrates, and the electrical and mechanical properties when absorbing heat are also good, and the dense layer between the copper foil and the ceramic layer is also improved. It is enough.

In addition, circuits can be easily formed by forming a resist layer on copper foil and etching it in the same way as with conventional steel-clad laminates. It is also easy to form.

The present invention will be explained below with reference to Examples.

(Example) Fig. 1 is a diagram showing the configuration of the a-layer of prepreg and copper foil sprayed with ceramic, and Fig. 2 is a schematic cross-sectional view of the obtained Teishokubutsu.

Epoxy resin 2 was coated on one side of copper foil 1 with a thickness of 35 μm to a thickness of 50 μm using a roll coater, and heated and dried to form a B stage, and a non-stick state was obtained at room temperature. In this way, a plasma f! ! Depending on the shooting method, A/L-Mina total about 10
Alumina layer 3 was formed by pricking seedlings to a thickness of 0 μm.

This aluminum sprayed copper foil and glass cloth/epoxy resin-impregnated prepreg 4 were stacked in the laminated configuration shown in Figure 1, and then shaped under heat and pressure to obtain a laminated plate with the configuration shown in Figure 2.◎ This laminated plate is made of glass The fiber base epoxy resin 50 has an alumina layer on its surface, and a copper foil I@wm is further applied thereon.

The JISC6481 copper foil peeling strength of this laminate was 1.7 kg/am, and the water absorption rate was Q.04%. With this laminate, it was possible to form circuits by etching, drill holes, and form through holes in the same manner as general glass fiber-based epoxy resin copper-clad laminates.

In addition, since there is an alumina layer with good thermal conductivity in contact with the circuit, it has excellent heat dissipation, has high heat resistance and surface hardness, and because alumina has low thermal expansion, the coefficient of thermal expansion is also smaller than conventional ones. We were able to.

(Comparative Example) An AT laminate was produced in the same manner as in the example without sealing the alumina bath with resin, but under the same conditions. The JISC6481 copper foil peeling strength of the obtained laminate is extremely low at 01 kg/Cl11, and the water absorption rate is (L
At 35%, the insulation resistance decreased significantly when water was absorbed.

(Effects of the Invention) By the method of the present invention, it is possible to easily and inexpensively produce a conventional rock-based base having a ceramic layer on its surface. The laminate obtained by the present invention has excellent characteristics, and circuit formation and through-hole formation can be performed in the same manner as conventional organic substrates. This could solve the problems of Metalpace and Metalcore Funds.

[Brief explanation of the drawing]

FIG. 1 is a laminated lR orientation of the ceramic of the present invention, gamma foil and prepreg, and FIG. 2 is a schematic cross-sectional view of the obtained laminate. Explanation of symbols 1 Copper foil 2 Epoxy resin layer 6 Alumina bath layer 4 Prepreg 5 Glass llIm base epoxy resin - ＼

Claims (1)

[Claims] 1. A thermosetting resin is applied to one side of the copper foil to form a B stage, and a ceramic layer is formed by thermal spraying a ceramic layer on the thermosetting resin-coated side of the copper foil. A method for manufacturing a ceramic coated laminate, characterized by laminating prepregs so as to be in contact with the layer side and thermo-pressing forming the prepregs. 2. The method for manufacturing a laminate according to claim 1, wherein the ceramic is mainly composed of alumina. 5. The method for manufacturing a laminate according to claim 1, wherein the thermosetting resin applied to one side of the copper foil has the same type of resin as the resin used for lamination as a main component. 4. The method for manufacturing a laminate according to claim 1, wherein the resin of the prepreg is an epoxy resin. 5. The method for manufacturing a laminate according to claim 1, wherein the resin of the prepreg is a polyimide resin. 6. The method for manufacturing a laminate according to claim 1, wherein the fibers of the prepreg are glass fibers.