Directed-binary search in logic BIST diagnostics

Logic BIST is about to become a more main stream test method for IC testing. In some flows when a failure is encountered the IC is diagnosed to determine the cause of the failure. Diagnosing fails in Logic BIST is significantly different from that in a stored pattern test methodology. The first step is to determine the failing pattern or interval among the many patterns that were applied. Today this involves a binary search of the tests that were applied with Logic BIST. In this paper we improve on this binary search strategy to reduce the time taken to isolate the failing patterns by orders of magnitude.