Stress and alloying effects in electromigration

Abstract

Narrow conductor lines used in microelectronic circuits at the chip level, are vulnerable to failure by stress migration (SM) and electromigration (EM). We outline a unified approach to model SM and EM damage in interconnects, where the gradients in the stress, electric potential, and concentration are considered as the driving forces for diffusion. We apply this framework analyze the Blech length effect and then proceed to show how EM, SM, and chemical diffusion act together in Cu depletion during accelerated testing. Finally we analyze several cases where SM and EM interaction enhances void nucleation and growth.