PURPOSE: To join a metallic member to an AlN-based base body at high joining strength by forming an oxidative film on the AlN-based base body by a sol-gel method in the case of producing a thermally conductive base plate wherein an aluminum nitride-based sintered body is used.
CONSTITUTION: An AlN-based base body is coated with a soln. formed of metallic alkoxide and an organic solvent. The coated film is allowed to gelatinize by a proper method. An oxidative film is formed by heat-treating the film allowed to gelatinize. In order to enhance wettability of the liquid phase of eutectic alloy which is formed of the metallic member to be joined together with oxygen, this oxidative film is formed in a preceding state of a joining stage. Thickness thereof is preferably regulated to ≤5μm because the thermal expansion coefficient ordinarily differs from AlN. Then, this oxidative film is brought into contact with the metallic member and heated to join metal to the AlN-based base body via the oxidative film. Metal is joined to the AlN- based base body at high joining strength by this method. The thermally conductive base plate is obtained which is free from blistering, warpage, waviness and peeling.
UENO FUMIO
KASORI MITSUO
HORIGUCHI AKIHIRO
