Defect Coverage-Driven Window-Based Test Compression

Although LFSR reseeding based on test cubes for modeled faults is an efficient test compression approach, it suffers from the drawback of limited, and often unpredictable, coverage of unmodeled defects. We present a new defect coverage-driven window-based LFSR reseeding technique, which offers both high test quality and high compression. The efficiency of the proposed encoding technique in detecting defects is boosted by an efficient “output deviations” metric for grading the calculated LFSR seeds. We show that, compared to standard compression-driven LFSR reseeding, higher defect coverage is obtained without any loss of compression.