Impact of current crowding on electromigration-induced mass transport

Abstract

To assess the relevance of current crowding to electromigration-induced mass transport, a test structure was designed to structurally induce and accelerate current crowding in Cu damascene lines. Electromigration experiments and quantitative finite element analysis demonstrate how current crowding can substantially enhance local atomic flux along critical diffusion paths. The resulting flux divergence leads to rapid void nucleation and growth. The observed increase in atomic flux and flux divergence is also moderately affected by the presence of Joule-heating-induced temperature gradients.