Electromigration-Induced Void Formation at the Cu_(5)Zn_(8)/Solder Interface in a Cu/Sn-9Zn/Cu Sandwich

摘要

The electromigration that occurs in a Cu/Sn-9Zn/Cu sandwich was investigated for void formation at room temperature with 10~(3) A/cm~(2). A focused ion beam revealed that voids nucleated at the intermetallic compound (IMC)/solder interface regardless of the electron flow direction. The needle-like voids initiated at the cathode Cu_(5)Zn_(8)/solder interface due to the outward diffusion of Zn atoms in the Zn-rich phase and expanded as a result of the surface diffusion of Sn atoms upon current stressing.