A Global Minimum Clock Distribution Network Augmentation Algorithm for Guaranteed Clock Skew Yield

Nanometer VLSI systems demand robust clock distribution network design for increased process and operating condition variabilities. In this paper, we propose minimum clock distribution network augmentation for guaranteed skew yield. We present theoretical analysis results on an inserted link in a clock network, which scales down local skew and skew variation, but may not guarantee global skew and skew variation reduction in general. We propose a global minimum clock network augmentation algorithm, which inserts links simultaneously between all nearest sink pairs, apply rule-based link removal, and perform link consolidation by Steiner minimum tree construction for wire-length reduction with guaranteed clock skew yield. Our experimental results show that our proposed algorithm achieves dominant clock network augmentation solutions, e.g., an average of 16% clock skew yield improvement, 9% maximum skew reduction, and 25% reduction of clock skew variation standard deviation with identical wirelength compared with previous best clock network link insertion methods (Venkataraman et al., 2005).