On test application time and defect detection capabilities of test sets for scan designs

Abstract

The test application time of test sets for scan designs can be reduced (without reducing the fault coverage) by removing some scan operations, and increasing the lengths of the primary input sequences applied between scan operations. In this paper, we study the effects of such a compaction procedure on the ability of a test set to detect defects. Defect detection is measured by the number of times the test set detects each stuck-at fault, which was shown to be related to the defect coverage of the test set. We also propose a compaction procedure that affects the numbers of detections of stuck-at faults in a controlled way.