JPH0771832B2 - Method for manufacturing ceramic coat laminate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a laminated board for a printed circuit board.

(Prior Art) Conventionally, as a printed circuit board, a paper-based phenol resin laminated board and a glass cloth-based epoxy resin laminated board have been widely used. However, with the recent increase in output and miniaturization of electronic devices, high-density mounting is desired, and heat resistance of printed circuit boards
Characteristics such as improved thermal conductivity and tracking resistance, and reduced thermal expansion due to dimensional stability, which are not available in conventional laminated plates, have been demanded.

Conventional plastic-based laminates have poor thermal conductivity and thus lack heat dissipation, and have a large coefficient of thermal expansion and poor heat resistance, making it difficult to achieve high-density packaging. On the other hand, a ceramic substrate such as alumina, or a metal core substrate in which a metal plate is used as a core material and the surface thereof is covered with an insulating layer has attracted attention and is actually used. Also, from the viewpoint of heat resistance, the development of substrates using high heat resistant polyimide resin or heat resistant thermoplastic resin such as polyether ether ketone, polysulfone, polyphenylene sulfide instead of conventional phenol resin and epoxy resin is active. Has been done in.

(Problems to be Solved by the Invention) However, there are various problems with these substrates.

Ceramic substrates such as alumina, silicon carbide, and aluminum nitride have excellent thermal conductivity and heat resistance, but the manufacturing process is complicated, the dimensional accuracy is poor, and the workability is poor. Further, it is mechanically fragile and the size of the substrate is limited, so that a large substrate cannot be obtained. Also, the cost is high.

The metal core substrate using a metal plate as the core material cannot fully utilize the high thermal conductivity of the metal core because it is the insulating layer made of resin with low thermal conductivity that is in contact with the conductor part that becomes the circuit, The radiation is not sufficient. Also, since the core material is a conductive metal plate, it is not easy to form through holes,
It requires a complicated manufacturing process to form.

Further, although the substrate using the heat resistant resin has improved heat resistance, improvement in heat dissipation cannot be expected due to the low thermal conductivity of the resin.

The present invention improves these drawbacks and enables the same manufacturing and processing methods as those of conventional plastic-based laminated boards, and also has excellent thermal conductivity, heat resistance and tracking resistance, and a manufacturing method for obtaining a substrate having a low coefficient of thermal expansion. Is provided.

(Means for Solving Problems) That is, according to the present invention, a ceramic coating is applied to one surface of a copper foil, dried and solidified to form a ceramic layer, and a prepreg is provided so as to be in contact with the ceramic layer side of the copper foil. It is characterized in that a laminated plate having a ceramic layer between a copper foil and a plastic laminated plate is obtained by laminating and thermocompressing and integrating them.

The reason why the ceramic coating is applied to the copper foil in order to obtain the ceramic-coated laminate having the constitution of the present invention is that it is advantageous in terms of adhesion and productivity. Since ceramic paints are mainly composed of inorganic materials, they show good adhesion to inorganic materials such as metals and ceramics, but on the other hand, they are different materials to organic materials such as plastics, so they have poor affinity. , The adhesion is not good. Therefore, in obtaining a ceramic-coated laminated sheet, if the ceramic coating is directly applied, dried, and solidified on the plastic substrate after the laminated thermocompression molding, it is not possible to obtain practical adhesion.
Furthermore, even if a ceramic layer can be formed, to attach a copper foil for forming a conductor circuit on it,
Since an adhesive has to be interposed, an adhesive layer is provided directly under the copper foil, and the characteristics of the ceramic layer cannot be fully utilized. In addition, it is disadvantageous because the number of processes is increased by one.

These problems can be solved by applying a ceramic paint to the copper foil as in the present invention. That is, the ceramic paint shows good adhesion to the copper foil which is a metal. Further, when the prepreg is laminated so as to be in contact with the dried and solidified ceramic layer and thermocompression-molded, the resin of the prepreg flows and acts as an adhesive. Therefore, sufficient adhesion can be obtained. Further, in this case, since the ceramic layer is formed immediately below the copper foil which becomes the conductor circuit, the surface characteristics of the ceramic can be fully utilized.

The ceramic coating used in the present invention has insulating properties, chemical resistance,
It is excellent in thermal conductivity, etc., and it is preferable to use alumina or aluminum nitride that is commonly used as a ceramic substrate as a main component, but silica, zirconia, mullite, spinel, silicon nitride, silicon carbide,
A material containing glass or the like as a main component, or a mixture thereof can be used. The form is generally an aqueous paste, which is sprayed, brushed, applied on a copper foil with a bar coater, a doctor blade, etc., at room temperature or 100-2.
Those that dry and solidify at a low temperature of 00 ° C can be used. Also,
It does not matter if a small amount of organic binder is added as long as the characteristics of the ceramic are not significantly deteriorated.

Next, the resin of the prepreg is preferably an epoxy resin or a polyimide resin from the viewpoint of electrical characteristics and molding processability, but in addition, a thermosetting resin such as a phenol resin, an unsaturated polyester resin, a melamine resin or a vinyl ester resin, or Thermoplastic resins such as polysulfone, polyetheretherketone, polyethersulfone, and polyetherimide can be used.

As the fibers, Kevlar fibers, paper, quartz fibers, etc. can be used in addition to the commonly used glass fibers.

(Function) The laminated plate obtained by the method of the present invention has a ceramic layer on the surface of a plastic substrate, and further has a metal foil for forming a conductor circuit thereon.

Since there is a ceramic layer directly under the circuit, the heat dissipation property in the plane direction is particularly excellent as compared with the conventional plastic substrate. In addition, heat resistance, tracking resistance, and surface hardness are greatly improved, and since it has a ceramic layer with a low coefficient of thermal expansion,
The coefficient of thermal expansion of the substrate can be kept low.

Note that the circuit can be easily formed by forming a resist layer on the copper foil on the surface and performing an etching treatment as in the case of the conventional metal-clad laminate. It can be performed by drilling or the like like the substrate.

The present invention will be described below with reference to examples.

(Example) FIG. 1 is a laminated constitution diagram of a copper foil coated with a ceramic coating and a prepreg, and FIG. 2 is a schematic sectional view of the obtained laminated plate.

Spray the alumina ceramic coating on one side of the 35μ thick copper foil 1 and dry it at room temperature.
It was put in for 0 minutes to be solidified to form an alumina-based ceramic layer 2 having a thickness of about 100 μm.

The copper foil having an alumina-based ceramic layer on one side thus obtained and the glass cloth base material epoxy resin prepreg 3 are stacked in the laminated structure shown in FIG. 1 and thermocompressed to obtain a laminated plate having the structure shown in FIG. Obtained.

The obtained laminated plate has an alumina-based ceramic layer on the surface of the glass cloth base epoxy resin 4, and further has a copper foil thereon. Adhesion between the copper foil and the alumina-based ceramic layer, and between the alumina-based ceramic layer and the epoxy resin layer is good, and even after 50 cycles of the thermal shock test of alternately immersing in 260 ° C. oil and room temperature water,
No defects such as peeling, blistering, and cracking were found.

Further, it was possible to form a circuit by etching, drilling, and forming a through hole by a through hole plating in the same manner as a general glass cloth base material epoxy resin copper clad laminate.

Further, it has excellent heat dissipation, heat resistance, surface hardness, and a low coefficient of thermal expansion, as compared with the conventional glass cloth-based epoxy resin laminate.

(Effect of the Invention) According to the method of the present invention, it is possible to easily and inexpensively manufacture a laminated plate having a ceramic layer on the surface of a conventional plastic substrate as a base. The laminated board thus obtained is excellent in characteristics and can be processed in the same manner as a conventional laminated board for forming circuits, through holes and the like. It is possible to solve such problems.

[Brief description of drawings]

FIG. 1 is a laminated constitution diagram of an alumina-based ceramic coated copper foil and a prepreg, and FIG. 2 is a schematic sectional view of a laminated plate obtained by the present invention. Explanation of symbols 1 ... Copper foil, 2 ... Alumina-based ceramic coating layer 3 ... Prepreg, 4 ... Glass cloth base epoxy resin

Claims (6)

[Claims] 1. A ceramic coating is applied to one surface of a copper foil, dried and solidified to form a ceramic layer, and a prepreg is laminated so as to be in contact with the ceramic layer side of the copper foil, followed by thermocompression molding. And a method for manufacturing a ceramic-coated laminate. 2. The method for producing a ceramic-coated laminated plate according to claim 1, wherein the ceramic paint contains alumina as a main component. 3. The method for producing a ceramic-coated laminated sheet according to claim 1, wherein the ceramic paint contains aluminum nitride 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. 5. The method for producing a ceramic-coated laminate according to claim 1, wherein the prepreg resin is a polyimide resin. 6. The method for producing a ceramic-coated laminate according to claim 1, wherein the prepreg fibers are glass fibers.