Combined Modeling of Electromigration, Thermal and Stress Migration in AC Interconnect Lines

The migration of atoms in metal interconnects in integrated circuits (ICs) increasingly endangers chip reliability. The susceptibility of DC interconnects to electromigration has been extensively studied. A few works on thermal migration and AC electromigration are also available. Yet, the combined effect of both on chip reliability has been neglected thus far. This paper provides both FEM and analytical models for atomic migration and steady-state stress profiles in AC interconnects considering electromigration, thermal and stress migration combined. For this we expand existing models by the impact of self-healing, temperature-dependent resistivity, and short wire length. We conclude by analyzing the impact of thermal migration on interconnect robustness and show that it cannot be neglected any longer in migration robustness verification.