Selecting Nets to Rip Up and Reroute via SAT

Global routing has been a critical step in the design of integrated circuits. Most existing global routers will first use techniques like pattern routing to quickly generate a routing solution that optimizes total wirelength and via usage. Then rip-up and reroute (RRR) will be applied to reduce the number of overflows in the whole design iteratively. Current RRR methods generally rip up all the nets that pass through the overflowed area and reroute them sequentially, which ignores the congestion information obtained by initial routing. This paper introduces a simple yet effective SAT-based method to extract the root causes of congestion from the initial routing results and selectively rips up and reroutes only those nets contributing to congestion. Experiments show that our RRR technique can achieve a significant reduction in design rule violations without increasing wirelength and via counts.