Diagnosis of Multiple Scan Chain Timing Faults

A diagnosis technique is presented to locate multiple timing faults in scan chains. Jump simulation is a novel parallel simulation technique which quickly searches for the upper and the lower bounds of every individual fault. The proposed technique takes into account the interaction of multiple faults so the diagnosis results are deterministic, not probabilistic. This technique is very useful in the production test environment because it requires only regular automated test pattern generator patterns, not specialized diagnosis patterns. Experiments on ISCAS´89 benchmark circuits show that this technique can successfully pinpoint almost every single one of 16 hold-time faults in a scan chain of more than 800 scan cells. The proposed technique is still effective when failure data are limited or faults are clustered.