Zero skew clock routing with minimum wirelength

Abstract

The deferred-merge embedding (DME) algorithm, which embeds any given connection topology to create a clock tree with zero skew while minimizing total wirelength, is presented. The algorithm always yields exact zero skew trees with respect to the appropriate delay model. Experimental results show an 8% to 15% wire length reduction over some previous constructions. The DME algorithm may be applied to either the Elmore or linear delay model, and yields optimal total wirelength for linear delay. DME is a very fast algorithm, running in time linear in the number of synchronizing elements. A unified BB+DME algorithm, which constructs a clock tree topology using a top-down balanced bipartition (BB) approach and then applies DME to that topology, is also presented. The experimental results indicate that both the topology generation and embedding components of the methodology are necessary for effective clock tree construction. >