| 摘要 |
PURPOSE:To protect an Al2O3 plate against cracks caused by a stress applied to it from a Cu foil when a Cu plated Al2O3 board is formed thick so as to enhance a mounted semiconductor element in heat dissipating properties. CONSTITUTION:Provided that an Al2O3 plate is 0.26-0.29mm in thickness, a dimensional difference between the edge of a Cu foil and the end face of the Al2O3 plate provided to surely insulate the Cu foils formed on both the sides from each other is limited to 0.5mm or below, whereby the sides of the plate are set equivalent to each other in stress so as to protect the plate against cracks. Furthermore, patterns are so formed on the Cu foils provided to both the sides of the plate as to overlap each other, whereby the sides of the plate are set equivalent to each other in stress. |
