Investigation of New Assembly Process of Substrates System with High Performance : Design and Assembly Process of Substrates System for Power Semiconductor (Report 3)

New assembly process of the substrates system with high performance has been establised by adopting the same bonding condition of both Cu sheet-Mo sheet by vaccum diffusion bonding process and Cu sheet-alumina by the adjusting Ti content in active brazing metal. The substrates system has been consisted by the conductors with three layered structure of Cu and Mo sheets, and 96% alumina as insulator, as already reported.The bond with high reliability of Cu and Mo sheets has made by vacuum diffusion bonding process under the condition of 1, 300K for 2, 400s under the pressure of 10-2 Pa. Furthermore, in order to assemble the substrates system with high performance by one processing stage, the bonding condition of Cu sheet and alumina requires to coincide with that of Cu and Mo sheets. It was shown experimen-tally that the bond of Cu sheet-alumina with high reliabilty was obtained by selecting nearly 30 wt% Ti powder mixed with Cu powder as active brazing metal. As the results, the assemly process of the both the conductor and the insulator-Mo sheet, Cu sheet and alumina-has been able to be achieved with bonding of one processing stage by adopting the bonding condition of 1, 300 K for 2, 400 s. In addition, it was also confirmed that voids or other defects are not observed in the bond interface by the inspection of SEM etc.