Post-placement power distribution network optimization for higher routability

Abstract

Power distribution network (PDN) design aims to satisfy IR drop constraint while using less routing resources. Post-placement PDN design can insert only demanded PDN straps by considering detailed current distribution. In this dissertation, post-placement PDN optimization considering static IR drop constraint is addressed. The goal of optimization is minimizing the number of placed PDN straps to improve routability. This problem has been formulated as sequential mixed integer quadratically constrained programming (MIQCP). Each MIQCP determines the location of PDN straps in each layer at once. For practical application, heuristic method that iteratively determines the PDN straps in each layer is also proposed. Experiment results demonstrated that heuristic method can be applied for various IR drop constraints. Also, heuristic method achieves 8% improvements in congestion overflow by minimizing the number of inserted PDN straps.