MARCH: MAze Routing Under a Concurrent and Hierarchical Scheme for Buses

The continuous development of modern VLSI technology has brought new challenges for on-chip interconnections. Different from classic net-by-net routing, bus routing requires all the nets (bits) in the same bus to share similar or even the same topology, besides considering wire length, via count, and other design rules. In this paper, we present MARCH, an efficient maze routing method under a concurrent and hierarchical scheme for buses. In MARCH, to achieve the same topology, all the bits in a bus are routed concurrently like marching in a path. For efficiency, our method is hierarchical, consisting of a coarse-grained topology-aware path planning and a fine-grained track assignment for bits. Additionally, an effective rip-up and reroute scheme is applied to further improve the solution quality. In experimental results, MARCH significantly outperforms the first place at 2018 IC/CAD Contest in both quality and runtime.