Formation manner null of ceramic metal compound substrate and insulating Characteristic protecting film for the said substrate

摘要

PURPOSE:To enable an insulating film high in reliability to be formed on a double-sided wiring ceramic board by a method wherein a ceramic board provided with a circuit pattern on both its sides is bonded to a metal material, which serves as a ceramic metal bonded board. CONSTITUTION:Inorganic material composed of 10% by weight of alumina and 90% by weight of borosilicate lead glass, acryl binder, plasticizer, and MFK are mixed together by a ball mill into slurry. The slurry is formed into a sheet on a PET film. A 96% alumina wiring board provided with circuits which are formed on its sides and electrically connected together through a through-hole is formed. The sheet concerned is laid on the rear side of the 96% alumina wiring board and bonded together through thermocompression by a pressure of 50kg/cm2 at a temperature of 80 deg.C. Then, the bonded board is made to pass through a belt oven to be thermally treated at a temperature of 520 deg.C for 10 minutes and totally 90 minutes, whereby an insulating film is fixed to the rear side of the alumina wiring board. At this point, the insulating film concerned is formed as thick as 2O0mum or so. An aluminum material is bonded to the rear of an alumina wiring board with silicone adhesive agent through a thermal treatment carried out at a temperature of 150 deg.C for 30 minutes to form a ceramic metal composite board.