A reliability performance is the major concern for flip chip solder joint. The electromigration behaviors of lead free (Sn4.0Ag0.5Cu) flip chip solder joint made with Cu, Al trace and with Cu and Ni underbump metallurgy on the chip under current stres...
A reliability performance is the major concern for flip chip solder joint. The electromigration behaviors of lead free (Sn4.0Ag0.5Cu) flip chip solder joint made with Cu, Al trace and with Cu and Ni underbump metallurgy on the chip under current stressing were carefully studied. The simulation results show that Cu trace provides lifetime of 24% longer than Al trace. Moreover, by adding UBM into the flip-chip structure even increases the lifetime to failure upto 25% in case of Ni UBM and 32% in case of Cu UBM. In another word, the simulations clearly validate that the time to failure of flip chip solder joint with Cu trace structure and with Cu UBM is approximately 32% longer than that of none UBM structure. In conclusion, Cu is the suitable material for trace and UBM of flip chip solder joint structure in a lifetime to failure aspect.