We outline a microstructure‐based statistical model for passivated near‐bamboo interconnect structures to obtain quantitative predictions of stress migration and electromigration failures, and their stress, temperature and current dependence. In particular, we find the failure distributions to be multimodal, and the mode responsible for failure at the early failure level is often not significant in the experimentally accessible regime of the cumulative failure, about 5–95%. We show that the early and longer term failure modes, both at vias and the straight line portions, depend differently on the stress, temperature and current density, which necessitates devising improved extrapolation procedures for the prediction of the time to early failure in service conditions. As far as electromigration lifetimes are concerned, the effect of refractory metal barrier layers is simply to allow larger void sizes at failure.