A new algorithm for standard cell global routing

The algorithm considers all of the interconnection nets in parallel. This produces superior results, since information about all of the nets is available throughout the global routing process. The global routing is formulated as finding the optimal spanning forest (a generalization of optimal spanning trees) on a graph that contains all of the interconnection information. The results of several theorems allow many nonoptimal connections to be pruned before the process begins. This approach successfully solves the net-ordering and congestion-prediction problems from which other approaches suffer. The algorithm was implemented as part of the DATools systems. The benchmarks from the Physical Design Workshop are used as part of the comparison suite. The algorithm achieves up to 11% area reduction compared to the previous global routing package used in the DATools systems and up to 17% reduction in the total channel density compared to the Timberwolf 4.2 package. In no case does the algorithm do worse than its competitors.<
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