Influence of Cu joining partner in transient liquid phase bonding

In power electronic assembly reliable interconnects are a major requirement and several efforts are made in order to assess suitable bonding technologies as a replacement for soft soldering. Transient liquid phase bonding with the Cu-Sn system could provide such a bonding solution. As in power electronic packaging several types of Cu with different grain morphology are in use, this study evaluates the growth of the intermetallic compounds Cu3Sn and Cu5Sn6 depending on the type of Cu as a joining partner. Further, two types of joining processes are applied, one in a vacuum solder equipment and one in an induction heating furnace. The influence of the heating rate on the joint quality as well as on the phase formation is reported.