Stuck-at fault diagnosis in scan chains

Scan chain diagnosis turns out to be an important yield enhancement factor in modern nanometer technologies. An easy to implement and cost effective design-for-diagnosis technique is presented. The proposed technique is compatible with the standard scan chain architecture and provides fast stuck-at fault diagnosis capabilities, at the maximum resolution, through simple operations, using only four predefined diagnosis vectors and independently of any test response compaction circuitry at the outputs of the scan chains.