High temperature resistant joint technology for SiC power devices using transient liquid phase sintering process

Abstract

A high temperature resistant joint technology for bonding SiC power devices is developed using a transient liquid phase sintering (TLPS) process with a paste containing Cu and Sn powders with the size less than 15μm. The SiC devices are bonded to the Si3N4/Cu/Ni(P) substrate with the TLPS process at 260°C in a N2 atmosphere for 20 minutes. The microstructure of the bond is mainly composed of Cu6Sn5 and Cu phases, which is not molten up to 415°C. The joint strength at 300°C after sintering is 38MPa. During high temperature aging, the Cu6Sn5 phase transforms to Cu3Sn, which is not molten up to 676°C. The joint strength increases with aging time due to the phase transition from Cu6Sn5 to Cu3Sn and further sintering of Sn and Cu during high temperature aging. The joint strength at 300°C after aging at 300°C for 500h reaches approximate 50MPa. After thermal cycling test at -40~250 °C for 500 cycles, the joint strength is approximate 20MPa, which is 3 times higher than the joint strength standard.