Electromigration-induced failures at Cu/Sn/Cu flip-chip joint interfaces
We observed various EM-induced failures in current-stressed Cu/Sn/Cu flip-chip solder joints. EM-induced Cu-pad consumption occurred at the current-entry point (maximum current-density) on the cathode interface, and voiding occurred at the other joint corner away from the current-entry point (minimum current-density). We believe that the above various EM-induced failure modes were the result of different current-stressing densities and joule heating at the cathode joint interfaces.