Studies on the interfacial reactions between electroless Ni UBM and 95.5Sn-4.0Ag-0.5Cu alloy

Abstract

Even though electroless Ni and Sn-Ag-Cu solder are widely used materials in electronic packaging applications, interfacial reactions of the ternary Ni-Cu-Sn system have not been known well because of their complexity. Because the growth of intermetallics at the interface affects reliability of solder joint, the intermetallics in Ni-Cu-Sn system should be identified, and their growth should be investigated. Therefore, in present study, interfacial reactions between electroless Ni UBM and 95.5Sn-4.0Ag-0.5Cu alloy were investigated focusing on morphology of the IMCs, thermodynamics, and growth kinetics.