Rapid manufacturing of complete intermetallic joints using Cu/Sn foam composite by ultrasonic- assisted soldering

In this paper, Cu/Cu/Sn foam composite/Cu joints with excellent high-temperature resistance were rapidly manufactured by ultrasonic-assisted soldering. The diffusion behavior of Cu-Sn intermetallic compounds (IMCs) in such joints was investigated under various bonding times. Rapid growth of the Cu
₆
Sn
₅
IMCs was observed, and the structure-induced growth behavior was discussed. The non-uniform growth of Cu
₆
Sn
₅
in different regions was attributed to the fast dissolution of Cu atoms and ultrasonic-induced diffusion reaction. Moreover, the smaller radii of surface curvature of Cu foams, the larger the dissolution rate. In addition, after the Sn phase was completely replaced by the IMCs, the joints with excellent high-temperature resistance and good mechanical property were created. This study may be helpful to develop the novel high-temperature solder for high-power devices.