Combining process and statistical variability in the evaluation of the effectiveness of corners in digital circuit parametric yield analysis
P. Asenov, Noor Ain Kamsani, D. Reid, COLIN A. MILLAR, Sanghamitra Roy, A. Asenov · 2010
This paper focuses on two main types of MOSFET variability - systematic (process) and statistical (random) variability and discusses the use of process corners as a measure of yield and circuit performance. We provide a methodology for performing large-scale statistical SPICE simulations as a means of evaluating the accuracy of corners in a system dominated by statistical variability and then expand the methodology to include both systematic and statistical variability within the same large-scale SPICE simulations. This large-scale statistical/systematic approach is compared to the “global + local” statistical corner approach, which consists of statistical simulations around the process corners. Finally 2D kernel density estimates are used to extract yield data from the statistical simulations to allow energy/delay/yield optimization to be performed. This in turn highlights the deficiencies of the statistical corner approach.