FABRICATION OF POWER SEMICONDUCTOR MODULE BOARD

PURPOSE:To obtain a power semiconductor module board having simplified structure and excellent in dielectric strength, heat dissipation properties, and heat shock resistance wherein a Cu member is jointed firmly to an AlN member by producing a molten alloy of Cu and an active metal between the AlN member and the Cu member and then thermally diffusing the molten alloy into the Cu member. CONSTITUTION:An active metal layer or an alloy layer of an active metal and copper is interposed between an AlN member 11 and a Cu member 12. The AlN member 11 and the Cu member 12 sandwiching the active metal layer or the alloy layer are then heated in vacuum or inert atmosphere thus producing a molten alloy of Cu and active metal between the AlN member 11 and the Cu member 12. It is further heated to diffuse the molten alloy into the Cu member 12. The active metal is titanium or zirconium, for example. The active metal layer or the alloy layer has thickness of 100mum or less.