Codar: a congestion-directed general area router

A general area router that integrates the phases of global routing and detailed routing has been developed. The global phase coarsely places the nets based on the congestion of the routing region, and the detailed phase modifies the course wiring to find legal positions for all wire segments. Both phases use the same grid space of routing tracks with two or more levels of interconnect. With this integrated data structure, the router can alternate between global and detailed routing operations, both of which use rip-up and reroute techniques. This integration has resulted in a router that can solve difficult problems not solvable by other programs while exhibiting runtimes that grow only moderately with the size of the routing problem.<>