JPS6235593A - Metal substrate for circuit - 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] [Technical Field of the Invention] The present invention relates to a metal substrate for circuits, and more specifically, a novel electrical insulating layer that has excellent adhesion, electrical insulation, and soldering heat resistance, and also has improved heat dissipation. The present invention relates to a circuit board having a FI board.

[Technical background of the invention and its problems] In general, synthetic resin laminate molded products based on metal plates such as aluminum and iron have excellent heat dissipation properties, electrical properties, and mechanical strength. It is used as a circuit board and a board for hybrid integrated circuits. Of this molded body, copper foil coated with adhesive on the back side is laminated and bonded onto a metal plate.
Circuit boards with an electrically insulating layer of adhesive coated on copper foil (hereinafter referred to as "coated boards"), and lamination and bonding of metal foil onto metal plates via glass paper cloth impregnated with thermosetting resin. A circuit board (hereinafter referred to as a "prepreg" board) having an electrically insulating layer made of hardened impregnated glass paper cloth is known and used.

However, although coated substrates have a thin electrical insulating layer and are advantageous in terms of heat dissipation, it is difficult to adjust the thickness of the adhesive to a uniform and desired thickness with high precision when manufacturing circuit boards. However, if the thickness is not uniform, pinholes may occur, resulting in poor insulation properties.

On the other hand, in prepreg boards, the electrical insulating layer is made of glass cloth or glass vapor impregnated with thermosetting resin, so the surface is not smooth and the thickness is limited by the thickness of the cloth or paper. Therefore, it is thicker than the coated substrate described above.

Therefore, although the insulation properties are advantageous, the heat dissipation property is poor. Furthermore, glass cloth and glass paper,
The impregnating property of the thermosetting resin is poor, the adhesion with the thermosetting resin and the metal plate is poor, and the mechanical strength is also reduced.

[Object of the Invention] The object of the present invention has been made to eliminate the above-mentioned drawbacks, and has a thin and uniform electrical insulating layer, high heat dissipation properties, and
Electrical insulation, W! The present invention aims to provide a highly reliable metal substrate for circuits with excellent adhesion, soldering heat resistance, and mechanical properties.

[Summary of the Invention] As a result of intensive research aimed at achieving the above object, the present inventors found that the above object could be achieved by using an aromatic polyamide sheet or an aromatic polyamide-imide sheet, and the present invention This is what we have come to complete.

That is, in the first aspect of the present invention, on at least one side of the metal plate,
A circuit metal substrate formed by fixing and integrating an electrical insulating layer made of a synthetic resin and a sheet of an aromatic hX polymer having an aromatic group in its main chain, such as an aromatic polyamide system or an aromatic polyamideimide system; The present invention is a circuit metal board formed by laminating and bonding metal foils together via an electrically insulating layer according to the first invention. The aromatic polymer sheet of a preferred embodiment is a paper body composed of aromatic polymer pulp particles and aromatic polymer fibers.

The metal plate used in the present invention may be made of any metal, but generally, aluminum plates, various corrosion-resistant aluminum plates, copper plates, steel plates, stainless steel plates, brass plates, silicon steel plates, etc. are used. . The thickness of the metal plate is not particularly limited, but the general thickness is about 0.5 to 2.5 mm, and is selected depending on the purpose of use. It is desirable to roughen the surface of this metal plate in order to improve its adhesion with the electrical insulating layer, but if the type of metal plate has high adhesion, the surface may not be roughened. The surface roughening method may be a mechanical method, a chemical method, or any other method.

The aromatic polymer used in the present invention has an aromatic group in the main chain, such as (1) aromatic polyamide, (2) aromatic polyamideimide, etc., and can be spun into extremely thin fibers of, for example, 15μ. I can do it.

(1) Aromatic polyamide is composed of units represented by the following general formulas (A) and/or (B).

-NH-Ar , -NH-Co-Ar 2-CO-...
・(A>-Nl-1-At' z -CO-...(B) (However, Ar+, Ar2.Ar3 are divalent aromatic groups, and may be the same or different. ) Representative examples of such aromatic polyamides include poly(m-phenylene isophthalamide), poly(tophenylene terephthalamide), poly(p-phenylene isophthalamide), poly(p-phenylene terephthalamide), Poly(4,4'-oxydiphenylene isophthalamide), poly(4,4'-oxydiphenylene terephthalamide), poly(tobenzamide), poly(p-
benzamide), but copolymers of these may also be used, and a small amount of components other than aromatic groups,
For example, it may contain components such as piperazine and cyclohexanedicarboxylic acid.

(2) Aromatic polyamideimide is a polyamideimide having a unit represented by the following general formula (C).

(However, R is and X is -o-, -so+, -Co- or a lower alkylene group) The aromatic polymer sheet is a paper-like sheet of the above aromatic polymer, and is particularly suitable. This is a paper body composed of pulp-like particles of an aromatic polymer and fibers of an aromatic polymer.The paper body-like sheet 1 made of an aromatic polymer has a thin electrical insulating layer and a thick one. can maintain uniformity.

Pulp-like particles are male-shaped, with numerous protrusions that can be made into paper-like structures using a paper machine.
Refers to particles with an l-shaped or ribbon-like structure. The pulp-like particles are obtained by introducing a solution of the aromatic polymer into a precipitant and precipitating it as fine particles. For example, Japanese Patent Publication No. 37-5732 discloses an example of its production method, but the production method is not limited to this method, and any polymer particles may be used as long as they have the ability to form wet paper. The composition ratio of pulp particles and fibers is 70:30 to 10:90 in weight%.
It is preferably 20 + 80 to 50:
More preferably, it is 50. Pulp-like particles are 70
If it exceeds 1Q%, the structure of the sheet becomes dense and impregnation with the synthetic resin becomes uneven, which is not preferable. If the amount is less than 10% by weight, the impregnating property of the synthetic resin is good, but the mechanical strength of the sheet is low and it is not practical. In this way, it is possible to control the properties of an aromatic polymer sheet, such as mechanical properties, electrical insulation, and synthetic resin impregnation properties, by changing the composition ratio of aromatic polymer pulp particles and fibers. The ratio is appropriately selected depending on the purpose of use. Therefore, by selecting the above range, it is possible to obtain a circuit metal substrate having excellent electrical insulation, mechanical strength, soldering heat resistance, and adhesion. Furthermore, if necessary, inorganic materials such as glass fibers, rock wool, alumina fibers, and ceramic materials may be mixed within a range that does not impede the effects of the present invention.

Examples of the synthetic resin used in the present invention include thermosetting resins such as thermosetting polyesteramide resin, epoxy resin, phenol resin, and polyimide resin, and these may be used alone or in combination of two or more. These thermosetting resins can contain polyvinyl butyral resin, heat-resistant elastomer, phenoxy resin, etc. to further improve adhesiveness, and to improve heat dissipation,
Those containing inorganic fillers can be used.

In the case of the first invention in which a circuit metal board is obtained by simply fixing an electrically insulating layer on a metal plate, it is necessary to form a conductive circuit on the electrically insulating layer by plating, etc. Pretreatment such as surface roughening must be performed. Therefore, it is advisable to select a type of synthetic resin suitable for such pretreatment. In the case of the second invention in which a metal foil is layered and bonded onto a metal plate via this electrical insulating layer to form a circuit metal board, the synthetic resin may be any synthetic resin as long as it has good heat resistance and adhesive properties. The inorganic filler that is mixed in to improve the heat dissipation of the synthetic resin is inorganic powder such as alumina, silica, magnesia, zirconia, and boron nitride.
It is preferable to mix it by weight%.

Among these synthetic resins, epoxy resins and thermosetting polyesteramide resins have excellent adhesiveness and are particularly effective. Thermosetting polyesteramide resin is 2.2'
-(1,3-phenylene)bis(2-oxyzoline) and a dibasic organic acid are reacted by heating, and the following two reactions proceed and cure.

(1) Generation of linear polyester amide (polymerization reaction) +
HOOC-R-COOH (2) Ring-opening addition of oxazoline ring to amide bond (crosslinking reaction) *1 Nitriphenylphosphite The metal foil used in the second invention is not particularly limited, but generally Copper foil and aluminum foil are used because they are easy to etch during the circuit formation process, have good electrical conductivity, and can be plated.

For this metal foil, back-roughened copper foil, chemical conversion treated copper foil, etc. can be used as necessary to improve adhesion to the electrical insulating layer. The thickness of the metal foil is preferably 150 μm or less in consideration of etching accuracy during circuit formation, and generally 18 μm, 35 μm, or 70 μm is used.

[Examples of the Invention] Next, the present invention will be explained with reference to Examples, but the present invention is not limited to these Examples.

Example 1 One side of an aluminum plate with a thickness of 1.2 nua was coated with #20
Polished and roughened by liquid honing using 0 abrasive grains.

On the other hand, as an aromatic polymer sheet, 50% by weight of aromatic polyamide pulp particles and 4950 aromatic polyamide fibers were used.
Epicoat 1001 (manufactured by Yuka Shell Co., Ltd.) as an epoxy resin was applied to aramid paper (manufactured by Nippon Aroma Co., Ltd.) containing 1%
(Product name) 1001 parts by weight, 6 parts by weight of dicyandiamide, 0.4 parts by weight of benzyl dimethylamine, and methyl ethyl ketone (solvent). It was placed on the rough surface of the aluminum plate.
The gelation time of this prepreg is 150 seconds at 170°C. Furthermore, a 35 μm thick copper foil was layered on top of the prepreg, and a gold gA substrate was manufactured by heating and press molding using a conventional method. When this gold a substrate was tested for peel strength, soldering heat resistance, and dielectric breakdown voltage, all of them showed excellent properties as shown in Table 1, demonstrating the remarkable effects of the present invention.

Example 2 One side of a silicon steel plate with a thickness of 0.5 mm was coated with sand vapor #
Polished and roughened with No. 100. On the other hand, on the aramid paper (mentioned above) containing 25% by weight of aromatic polyamide pulp particles and 75% by weight of aromatic polyamide fibers, 2.2'-
CP resin (manufactured by Souen Yakuhin Kogyo Co., Ltd., trade name), which is a thermosetting polyesteramide resin made by reacting (1,3-phenylene)bis(2-oxapurine) with a dibasic acid, is coated and impregnated. A prepreg was obtained by heating and semi-curing at 160° C., and this prepreg was stacked on the rough surface of the silicon steel plate.

Further, a 35 μm thick copper foil was layered on top of the prepreg, and a metal substrate was manufactured by heating and press-forming using a conventional method. The obtained metal substrate was tested in the same manner as in Example 1, and as shown in Table 1, the remarkable effects of the present invention were demonstrated.

Example 3 One side of an aluminum plate with a thickness of 1.2111ffl was
Polished and polished by liquid honing using #200 abrasive grains.
It became rough. On the other hand, the aramid paper used in Example 2 was coated with Epikote 1001 (mentioned above) and phenolic resin TOC-1.
(manufactured by Sumitomo Durets Co., Ltd., trade name) 1, dicyandiamide,
A synthetic resin varnish consisting of acrylonitrile rubber, Hiker 1072 (manufactured by Gutdrich, trade name) and finely powdered silicon oxide is applied and impregnated, then dried and semi-cured to obtain a prepreg, and this prepreg is placed on the rough surface of the aluminum plate. Then, a polypropylene film for mold release was layered on top of that, and heat and pressure molding was carried out in a conventional manner to produce a temporary additive table H1. The obtained metal substrate was tested in the same manner as in Example 1, and as shown in Table 1, the remarkable effects of the present invention were demonstrated.

Comparative Example 1 One side of a 1.2 ml thick aluminum plate was polished and roughened with #100 sandpaper. On this rough surface, epoxy resin Epicoat 1001 (
(mentioned above) An epoxy resin varnish consisting of 100 parts by weight of FFI, 61 parts by weight of dicyandiamide, 0.4 parts by weight of benzyldimethylamine d3 and methyl ethyl ketone (solvent) was coated, impregnated, and semi-cured, and the obtained prepreg was layered, and then the prepreg was layered. A copper foil with a thickness of 35 μm was placed thereon, and a gold fiR substrate was manufactured by heating and pressure molding using a conventional method.
The same test as in Example 1 was conducted on this metal substrate.

The results are also shown in Table 1.

Comparative Example 2 A metal substrate was manufactured in the same manner as in Comparative Example 1 except that glass paper was used instead of the ceramic paper used in Comparative Example 1. Further, since the test was conducted in the same manner as in Example 1, the results are also shown in Table 1.

"Effects of the Invention" As is clear from the explanation below and Table 1, in the circuit metal substrate of the present invention, by using the aromatic polymer sheet, the electrical insulating layer has a thin and uniform thickness. In addition, heat dissipation properties were also improved.

In addition, the sheet is well impregnated with synthetic resin, so even though it is thin, there are no defects in electrical insulation, it has excellent mechanical strength, and it has excellent adhesion to metal plates or synthetic resin. We can produce reliable metal substrates for circuits,
It is extremely useful industrially.

Claims (1)

[Claims] 1 At least one side of the metal plate is made of aromatic polyamide,
A metal circuit board made by fixing and integrating an electrical insulating layer made of a sheet of an aromatic polymer having an aromatic group in its main chain, such as aromatic polyamide-imide, and a synthetic resin. 2 The aromatic polymer sheet has a ratio by weight of aromatic polymer pulp particles and aromatic polymer fibers of 70:30 to 10.
The circuit metal substrate according to claim 1, which is a paper body substantially composed of :90. 3 At least one side of the metal plate is made of aromatic polyamide,
A circuit metal board made by laminating and bonding metal foil together via an electrically insulating layer made of a synthetic resin and a sheet of an aromatic polymer having an aromatic group in its main chain, such as aromatic polyamide-imide. 4 The aromatic polymer sheet has a ratio by weight of aromatic polymer pulp particles and aromatic polymer fibers of 70:30 to 10.
The circuit metal substrate according to claim 3, which is a paper body substantially composed of :90.