Simulating early failure in integrated circuits

A layout-level Monte-Carlo simulator capable of predicting the probability of defect-related early failure in the metal-interconnect subsystem of integrated circuits is presented. The interconnect is decomposed into distinct layout-level objects, namely contiguous metal runs and vias, and user-defined cumulative distribution functions are used to determine the probability of failure. 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 sampling from the reliability network comprising all nets. Variance reduction techniques are used wherever possible to improve the statistical confidence in estimates made. A prototype that interfaces directly with commercially used CAD software has been implemented. Results provide a qualitative verification of the methodology and show that failures due to defects are significant during the first few years of system operation