Athermal recrystallization behavior of (Sn) solid-solution at an intermetallic-free Cu/Sn interface induced by room temperature electromigration

The present study, for the first time, revealed the athermal recrystallization behavior at a heterogeneous metallic interface using room temperature electromigration. The athermal recrystallization occurred within the meta-stable amorphous Cu-Sn interphase, which was formed during the early stage electromigration, for stress relaxation after further electromigration. The nano-scale polycrystalline (Sn) interphase was favorably recrystallized at the intermetallic-free Cu/Sn interface where the current crowding effect occurred. Athermal electromigration force facilitated the nucleation of Sn nuclei through the kinetic energy provided by the electron momentum transfer. The formation of the recrystallized (Sn) interphase is believed to be an intermediate material interaction product prior to further intermetallic nucleation under room temperature electromigration.