Electromigration-induced failure in passivated aluminum-based metallizations−The dependence on temperature and current density

Abstract

A new dynamic picture of electromigration-induced failure in passivated narrow lines allows the prediction of the variation of lifetimes with temperature and current density. According to the model, damage is usually nucleated by thermal stress-induced voiding. Small voids are trapped and grow at grain and phase boundaries. After reaching a critical size, voids then begin to migrate and coalesce, eventually leading to line severance. In most cases this leads to lifetimes varying approximately as the square of the current density j for low and moderate j, and faster for large j. The temperature dependence is determined by a combination of bulk, surface, and grain boundary diffusivities.