Application of Electroless Fe-42Ni(P) Film for Under-bump Metallization on Solder Joint

摘要

Because Fe has a more negative standard reduction potential than Ni, the simultaneous electroless deposition of Fe and Ni is difficult. In this study, Fe-42Ni(P) electroless deposit was prepared by using disodium ethylene diamine tetraacetate (ETDA-2Na) as complexing agent to reduce the difference in the electrode potential between Ni2+ and Fe2+ . The solderability and the interfacial reaction between Fe-42Ni(P) alloy and Sn were investigated. It was found that the electroless Fe-42Ni(P) alloy has excellent wettability with Sn. Moreover, the interfacial reaction rate between Fe-42Ni(P) and Sn is very slow. These results suggest that Fe-42Ni(P) alloy may become an attractive under-bump metallization (UBM).