Pulse Propagation for the Detection of Small Delay Defects

This paper addresses the problems related to resistive opens and bridging faults which cannot be detected using delay fault testing because they lie out of the most critical paths. Even if the induced defect is not large enough to result in timing violations, these faults may give rise to reliability problems. To detect them, we propose a testing method that is based on the propagation of pulses within the faulty circuit and that exploits the degraded capabity of faulty paths to propagate pulses. The effectiveness of the proposed method is analyzed at the electrical level and compared with the use of reduced clock period which can detect the same class of faults. Results show similar performance in the case of resistive opens and better performance in the case of bridgings. Moreover, the proposed approach is not affected by problems on the clock distribution network.