Unified adaptivity optimization of clock and logic signals

Abstract

VLSI design is increasingly sensitive to variations which often degrade the parametric yield. Post-silicon tuning techniques can compensate for specific variations on the die and thus significantly improve the yield. Previous works on adaptivity optimization for post-silicon tuning focus on either logic signal tuning or clock signal tuning. This paper proposes the first unified adaptivity optimization on logical and clock signal tuning, which enables us to significantly save resource. In addition, it does not need any assumption on variation distributions. Our unified optimization is based on a novel linear programming formulation which can be efficiently solved by an advanced robust linear programming technique. Due to the discrete nature of the problem, the continuous solution obtained from linear programming is then efficiently discretized. This procedure involves binary search accelerated dynamic programming, batch based optimization, and Latin Hypercube sampling based fast simulation. Our experimental results demonstrate that up to 50% area cost reduction can be obtained by the unified optimization compared to optimization on logic or clock alone. In addition, the proposed discretization approach significantly outperforms the alternatives in terms of solution quality and runtime. © 2007 IEEE.