Use of Multicasting-Scan Architectures for Compound Defect Diagnosis

In this paper, we explore the inherent benefit of the multicasting-scan architecture for enhancing the diagnostic resolution of compound defects - i.e., a situation when there are faults in both the scan chain and the core logic. The proposed scheme exploits the flexibility of independent controlling of each scan chain offered in a multicasting-scan architecture. The proposed method can provide a high diagnostic resolution even when a high output compaction ratio is in use. Experimental results indicate that for a design with 128X output compaction ratio, the proposed method can improve the diagnostic hit rate from 40% to 99% for logic faults and 64% to 100% for chain faults.