Electromigration-aware redundant via insertion

As the feature size shrinks, electromigration (EM) becomes a more critical reliability issue in IC design. EM around the via structures accounts for much of the reliability problems in ICs, and the insertion of redundant vias can mitigate the adverse effect of EM by reducing current density. In this paper, we model EM reliability of redundant via structures, considering current distribution with different via layouts. Based on our EM model, we choose redundant via layouts that can increase the EM-related lifetime by using integer linear programming (ILP). To overcome the runtime issue of ILP, we also propose speed-up techniques for our EM-aware redundant via insertion. Experimental results show that our scheme brings much more EM-robustness to circuits with the similar number of redundant vias, compared to the conventional redundant via insertion techniques.