Incremental computation of delay fault detection probability for variation-aware test generation

Large process variations in recent technology nodes present a major challenge for the timing analysis of digital integrated circuits. The optimization decisions of a statistical delay test generation method must therefore rely on the probability of detecting a target delay fault with the currently chosen test vector pairs. However, the huge number of probability evaluations in practical applications creates a large computational overhead. To address this issue, this paper presents the first incremental delay fault detection probability computation algorithm in the literature, which is suitable for the inner loop of automatic test pattern generation methods. Compared to Monte Carlo simulations of NXP benchmark circuits, the new method consistently shows a very large speedup and only a small approximation error.