<title>Reliability simulator for improving IC manufacturability</title>

Abstract

A Monte-Carlo reliability simulator for integrated circuits that incorporates the effects of process-flaws, material properties, the mask layout and use-conditions for interconnects is presented. The mask layout is decomposed into distinct objects, such as contiguous metal runs, vias and contacts, for which user-defined cumulative distribution functions (cdfs) are used for determining the probability of failure. These cdf's are represented using a mixture of defect-related and wearout-related distributions. The failure distributions for nets, which are sets of interconnected layout objects, are obtained by combining the distributions of their component objects. System reliability is obtained by applying control variate sampling to the reliability network which is comprised of all nets. The effects of series, parallel and k-out-of-n substructures within the reliability network are accounted for. A Bayesian approach to incorporating burn-in data with simulated estimates is also presented. A program that interfaces directly with commercially used CAD software has been implemented. Results provide a qualitative verification of the methodology and show that predictions which incorporate failures due to process flaws are significantly more pessimistic than those obtained by following current practice.