Patent Document ID: 9519026
Application ID: 14502284
Patent Status: 1

Claim One:
1. A method, comprising: receiving failure information from a first test of a device under test (DUT) performed using automatic test equipment (ATE), wherein the DUT includes a plurality of scan chains that each include a plurality of scan cells and wherein the first test is based on a first compressed test pattern; determining that the failure information is usable to identify a group of scan cells as scan cells that have potentially failed the first test, but the failure information does not permit a definitive determination as to whether a scan cell in the group is a failing scan cell; in response to the determining, generating, based on the first compressed test pattern, a plurality of compressed test patterns, wherein ones of the plurality of compressed test patterns specify respective modes in which ones of the plurality of scan chains directly control a scan output independent of other ones of the scan chains, wherein the ones of the plurality of scan chains correspond to ones of the group of scan cells; performing one or more second tests of the DUT using the ATE and the plurality of compressed test patterns; and definitively determining one or more scan cells in the group as failing scan cells based on failure information from the one or more second tests.