Increasing EM Robustness of Placement and Routing Solutions based on Layout-Driven Discretization

Abstract

Nowadays, electromigration (EM) is mainly addressed in the verification step. This is no longer possible due to the ever increasing number of EM failures in the future. An EM-aware physical synthesis could reduce the number of critical locations but the layout complexities prevent this from already being used. To solve this problem, we propose a novel method to discretize placement and routing solutions to enable a fast EM analysis. In addition, we suggest adjustments in the placement and routing step to enhance the EM robustness based on early analysis results. In contrast to the standard approach of running a numerical simulation outside the physical design step and after the synthesis, we perform most of the analysis steps within our placement and routing tools to consider the results; thus enabling early and specialized EM-robust solutions. Particularly, our methodology exploits layout structures to enable an efficient discretization inside the geometrical representations of synthesis tools. We demonstrate how to reduce the discretization effort significantly while achieving sufficient accuracy to improve EM robustness.