Engineering Change Order  (ECO) routing is frequently requested in the later design stage for the purpose of delay and noise optimization. ECO routing is complicated by huge existing obstacles and the requests for various design rules. Tile-based routers have work with fewer nodes of the routing graph than grid and connection-based routers; however, the number of nodes of the tile-based routing graph has grown to over a thousand millions for SOC designs. This work depicts a new ECO routing design flow with routing graph reduction and enhanced global routing flow. Routing graph reduction reduces the complexity of nodes by removing redundant tiles and aligning neighboring tiles to merge adjacent block tiles. Routing graph reduction reduces tile fragmentation such that the ECO router can run twice as fast without sacrificing routing quality. Enhanced global routing flow incorporates ECO global routing with extended routing and GCell restructuring to prevent routing failure in a routable routing. The ECO router with new design flow can perform up to 20 times faster than the original tile-based router, at the cost of only a very small decline in routing quality.
['Jin-Yih Li', 'Yih-Lang Li']
An efficient tile-based ECO router with routing graph reduction and enhanced global routing flow