FLUTE-EM: Electromigration-Optimized Net Topology Considering Currents and Mechanical Stress

The future reliability of integrated circuits is endangered by ever shrinking feature sizes and the resulting rise in electromigration (EM) damage. In order to guarantee reliability in future circuits, new approaches are needed in physical synthesis. These approaches must prioritize reliability constraints, such as EM-induced stress reduction during net-topology generation. In line with these insights, our rectilinear Steiner tree is optimized for currents and mechanical stress. We thus aim for optimized EM robustness rather than minimal wire length in the generated net topology. Our results imply a mechanical stress reduction in most cases of more than 50%, thereby significantly abating EM vulnerability. In addition, we show that reservoirs can further reduce the absolute mechanical stress level, and we present an equation for directly calculating the optimal reservoir length.