Estimating path delay distribution considering coupling noise

Accurately estimating critical path delays is extremely important for yield optimization and for path selection in delay testing. It is well known that dynamic effects such ascoupling noise can significantly affect critical path delays. In traditional static timing analysis, the coupling effect isincorporated by estimating the switching window overlaps between aggressor and victim and then assuming a constant (worst case) coupling factor if any overlap is present. However in path based statistical timing analysis, using a constant coupling factor can overestimate the mean delay while under estimating the delay variance. In this paper, we propose a technique to estimate the dynamic variation in pathdelay caused by coupling noise. We treat the effective coupling capacitance as a random variable that varies as a function of the relative signal arrival times between victim andaggressor nodes. A modeling technique to estimate the capacitance variation is shown and a framework that gives therelative signal arrival time distribution at the victim nodesis developed.