Electromigration mechanisms in Cu nano-wires

In this article, we propose a new drift velocity technique to measure electromigration at temperatures of 125°C to directly assess electromigration transport at use conditions. We present measurements of the temperature of the drift velocity of Cu conductors with small and large polycrystalline grain size. A significant grain size dependence of drift velocity was found, indicating a large flux of atoms through grain boundaries when the fraction of polycrystalline segments is a significant fraction of the conductor length. A physical model is proposed to explain the drift velocity behavior in Cu nano-wires and we determine the diffusion parameters from grain boundary diffusion and interface diffusion.