Investigation on Aging-induced Softening of Eutectic Microstructurein SnBi/Cu Interconnect by Nanoindentation
Investigation on Aging-induced Softening of Eutectic Microstructure in SnBi/Cu Interconnect by Nanoindentation

Nanoindentation was used to probe softening of the eutectic microstructure in a SnBi/Cu interconnect following thermal aging. Tests were conducted at constant loading rates and under constant loads to characterize the flow stress and creep behavior of the eutectic microstructure. Aging was found to reduce the flow stress but to increase strain-rate sensitivity of the eutectic SnBi microstructure. While the reduction in the flow stress was related to the coarsening of the eutectic microstructure, the increased creep rate sensitivity was resulted from additional contribution of grain boundary movement to indentation creep.