Congestion prediction in floorplanning

Routability optimization has become the major concern in floorplanning. In traditional floor planners, area minimization is an important issue. Due to the recent advances in VLSI technology, interconnect has become a dominant factor to the overall performance of a circuit. Routability prediction is thus very important in the floorplanning stage. In this paper, we propose a new congestion model to predict the congestion after detailed routing which is not confined to the assumption of shortest Manhattan distance routes. We have compared our new models and some existing models with the actual congestion measures obtained by global routing some placement results (using the Capo placer as stated in A. E. Caldwell et al. (2000)) with a publicly available maze router. Results show that our models can make significant improvement in estimation accuracy over the other models.