Routability-driven placement for hierarchical mixed-size circuit designs

A wirelength-driven placer without considering routability could introduce irresolvable routing-congested placements. Therefore, it is desirable to develop an effective routability-driven placer for modern mixed-size designs employing hierarchical methodologies for faster turnaround time. This paper presents a novel two-stage technique to effectively identify design hierarchies and guide placement for better wirelength and routability. To optimize wirelength and routability simultaneously during placement, a new analytical net-congestion-optimization technique is also proposed. Compared with the participating teams for the 2012 ICCAD Design Hierarchy Aware Routability-driven Placement Contest, our placer can achieve the best quality (both the average overflow and wirelength) and the best overall score (by additionally considering running time).