JPH05304345

PURPOSE:To improve mechanical strength, insulation breakdown strength, etc., without failing a heat radiation of a metallic wiring board. CONSTITUTION:A metallic wiring board is provided with an aluminum substrate 1, an insulation covering layer 2 consisting of a plurality of insulation films piling on the substrate 1, and a copper wiring 6 prepared on the layer 2, and the wiring 6 is fixed on the substrate 1 with the layer 2 in between. Since the wiring 6 is fixed on the substrate 1 with a plurality of insulation films in between, the excellent heat radiation of the substrate 1 can be obtained and simultaneously the thin layer 2, that has mechanical strength, insulation breakdown strength, etc., suitable for practical use, can also be obtained thanks to a plurality of insulation films. Further the layer 2 can be produced as to be superior in thermal conductivity, insulation breakdown strength, distribution capacity, etc., by mixing silicon dioxide in the insulation films.