Abstract
Ni-7wt.%V(8at.%V) is an important under bump metallization material, and Sn is the primary element in most solders. This study examines the Sn/Ni-8at.%V interfacial reactions at 160°C, 200°C, 250°C, 300°C, 325°C, 350°C, and 400°C. Unlike the interfacial reactions in the Sn/Ni couples, a ternary T phase and the binary Ni 3 Sn 4 phase are formed at 160°C. The vanadium solubility in the Ni 3 Sn 4 phase is only 0.2 at.%, while the T phase contains 13.9at.%V. Similar results are found in the couples at 200°C, and the reaction paths are Sn/Ni 3 Sn 4 /T/Ni-V. The reaction paths are liquid/T/Ni 3 Sn 4 /Ni-V at 250°C and 300°C and are liquid/Ni 3 Sn 4 /Ni-V at 350°C and 400°C. Because the reaction products and the reaction rates in the Sn/Ni-8at.%V and Sn/Ni couples are different, reliabilities of the electronic products with the Ni-8at.%V barrier layer should not be assessed based only on the results of the Sn/Ni couples.