Electromigration characterization of lead-free flip-chip bumps for 45nm technology node

We have conducted electromigration experiments on lead-free SnAg flip-chip bump interconnection for 45nm technology node. We report lifetime distributions, kinetic parameters and intermetallic compound formation. Further, we discuss the impact of Ag-concentration as well as current direction on the electromigration reliability of these flip-chip bumps. Based on these analyses, we conclude that lead-free bumps lead to significantly more robust electromigration reliability than their SnPb counterparts, which render lead-free bumps a suitable replacement for the present and future technology nodes in terms of their current-carrying capability.