Legalization Framework with Design Rule Constraints Enhanced by Monte-Carlo-Based Cell Priority Optimization

Legalization holds significant importance in VLSI physical design, as it significantly influences the manufacturability and reliability of circuits. Recently, advanced foundry nodes introduced complex constraints in standard-cell legalization, which makes legalization even harder. In this paper, we develop a legalization framework with design rule constraints enhanced by Monte-Carlo-Based cell priority optimization. We first handle abnormal density distribution to reduce the subsequent legalization’s hardness. Then, we propose an interval-assisted sequential legalization algorithm considering multiple design rule constraints with a Monte-Carlo-Based cell priority decision technique. Besides, based on the characteristics and complexity of different design rule constraints, we present a refinement phase to handle the remaining design rule constraints with corresponding detectors. Compared with a leading commercial tool, experiments on industrial benchmarks show that our legalization framework achieves 11% smaller average displacement, 15% smaller maximum displacement, 1.63× speedup, and 13% fewer remaining design rule violations on average.