Congestion minimization during placement without estimation

Abstract

This paper presents a new congestion minimization technique for standard cell global placement. The most distinct feature of this approach is that it does not follow the traditional "estimate-then-eliminate" strategy. Instead, it avoids the excessive usage of routing resources by the "local" nets so that more routing resources are available for the uncertain "global" nets. The experimental results show that our new technique, SPARSE, achieves better routability than the traditional total wire length (Bounding Box) guided placers, which had been shown to deliver the best routability results among the placers optimizing different cost functions [2]. Another feature of SPARSE is the capability of allocating white space implicitly. SPARSE exploits the well known empirical Rent's rule and is able to improve the routability even more in the presence of white space. Compared to the most recent academic routability-driven placer Dragon[8], SPARSE is able to produce solutions with equal or better routability.