Interfacial reaction and melting/solidification characteristics between Sn and different metallizations of Cu, Ag, Ni and Co

The interfacial reaction between pure Sn and different metallizations of Cu, Ag, Ni and Co, as well as the melting/solidification characteristics of each reaction system were investigated using a differential scanning calorimeter (DSC). Results show that there exists the early interfacial eutectic reaction in Sn/Cu and Sn/Ag systems, which leads to the occurrence of the Sn melting at the interface at a temperature 4.9°C (for Sn/Cu system) and 10.6°C (for Sn/Ag system) lower than the actual melting point of pure Sn (231.9°C), and consequently both of Sn/Cu and Sn/Ag soldering systems exhibit scallop-like morphology of intermetallic compound (IMC). Although there was the diffusion of Ni and Co atoms into pure Sn, no obvious change in the melting temperature of Sn/Ni and Sn/Co soldering systems, compared to the melting point of pure Sn, was observed, and the interfacial morphologies of Sn/Ni and Sn/Co systems showed platelet-like IMC. In addition, it has been shown that the undercooling values of Sn/Ni and Sn/Co systems are much smaller than that of Sn/Cu and Sn/Ag ones.