Electromigration reliability of Sn-37Pb and Sn-3Ag-1.5Cu/Sn-3Ag-0.5Cu composite flip-chip solder bumps with Ti/Ni(V)/Cu under bump metallurgy

We examine electromigration fatigue reliability and morphological patterns of Sn-37Pb and Sn-3Ag-1.5Cu/Sn-3Ag-0.5Cu composite solder bumps in a flip-chip package assembly. The test vehicle is subjected to test conditions of five combinations of applied electric currents and ambient temperatures, namely, 0.4 A/150 degC, 0.5 A/150 degC, 0.6 A/125 degC, 0.6 A/135 degC, and 0.6 A/150 degC. An electrothermal coupling analysis is employed to investigate the current crowding effect and maximum temperature in the solder bump in order to correlate with the experimental reliability using the Black's equation as a reliability model