Intermetallics formation and evolution in pure indium joint for cryogenic application

Intermetallic compounds (IMCs) properties play a significant role in determining the reliability of solder joints in service. IMCs and their evolution become more important for devices with micro- or nano-scale joints used in cryogenic applications. In this study, the interfacial reactions of In/Cu and In/Ni/Cu due to low-temperature cycling are investigated. The results illustrate that the character of IMCs is linked to thickness of indium joints exposed to low-temperature cycling. The formation of Cu-In IMCs and Ni-In IMCs are diffusion-controlled, and low-temperature cycling results in brittle IMCs.