Fault Dictionary Based Scan Chain Failure Diagnosis

In this paper, we present a fault dictionary based scan chain failure diagnosis technique. We first describe a technique to create small dictionaries for scan chain faults by storing differential signatures. Based on the differential signatures stored in a fault dictionary, we can quickly identify single stuck-at fault or timing fault in a faulty chain. We further develop a novel technique to diagnose some multiple stuck-at faults in a single scan chain. Comparing with fault simulation based diagnosis technique, the proposed fault dictionary based diagnosis technique is up to 130 times faster with same level of diagnosis accuracy and resolution.