Multi-Physics Simulation of Electromigration in Cu Interconnect

Electromigration (EM) has become a serious reliability concern for Cu interconnects as the feature size of ultra-large-scale interconnects (ULSI) technology is reducing. It is governed by the interaction of various atomic fluxes (AF) due to electron-wind force, temperature and stress gradients, respectively. In this work, the non-uniform distribution of the current density, temperature and stress in Cu interconnects line/via structure was simulated using the finite element method. By coupling the current density, temperature and stress fields in the analysis, and using the site with maximum atomic flux divergence as the void location site, a good correlation between the model predictions and experimental observations is obtained.