A new multi-layer global routing flow for congestion elimination

With the progress of very large scale integration, using traditional global routing algorithms to solve multi-layer routing problem causes the routing resource waste of lower layers or the lack of higher layers because the pitch size is different in different layer pairs and traditional algorithms use uniform pitch size for all layer pairs. The paper presents a global routing algorithm that performs layer assignment before routing. This algorithm is based on a new flow for multi-layer routing, and uses bounding box of the nets to estimate the congestion, and distributes them to different layer pairs based on the aim of even congestion. The algorithm has been implemented and tested. The experimental results show that the algorithm is more effective.