A Seed-Selection Method to Increase Defect Coverage for LFSR-Reseeding-Based Test Compression

LFSR reseeding forms the basis for many test compression solutions. A seed can be computed for each test cube by solving a system of linear equations based on the feedback polynomial of the LFSR. Despite the availability of numerous LFSR-reseeding-based compression methods in the literature, relatively little is known about the effectiveness of these seeds for unmodeled defects. We use the recently proposed output deviation measure of the resulting patterns as a metric to select appropriate LFSR seeds. Experimental results are reported using test patterns for stuck-at faults derived from selected seeds. These patterns achieve higher coverage for stuck-open and transition faults than patterns obtained using other methods.