PURPOSE: To make it possible to seal cracks existing in the peripheries of vias and small holes in a ceramic circuit board with a silicone resin by a method wherein a ceramic green sheet is formed into a multilayer structure and after the sheet is sufficiently impregnated with a silicon high-molecular compound, this compound is crosslinked and polymerized.
CONSTITUTION: A ceramic green sheet is formed of a raw material made by kneading a binder, a plasticizer and a solvent into borosilicate glass, silica glass and alumina powder, the sheet is punched into a 100-mm square, 100-μm diameter vias are formed, the vias are filled with a Cu paste and a pattern is formed. Then, after 50 layers of these patterns are laminated, they are made to closely adhere by pressing, are calcined, are crosslinked and hardened, are formed into resin and a glass ceramic multilayer board is formed. Then, after the surface of the board is polished and is flattened, the board is impregnated with polymethyl silsesquioxane in a vacuum state and moreover, pressing and impregnation are performed. Then, the board is heated to harden the polymethyl silsesquioxane being impregnated and a silicone resin adhered on the periphery of the board is removed by buffing.
YAMAGISHI YASUO
IMANAKA YOSHIHIKO
