EST: the new frontier in automatic test-pattern generation

An algorithm, called EST, is presented which is a new combinatorial automatic test-pattern generation (ATPG) branch-and-bound search algorithm, based on the generation of equivalent logic decompositions (search states) at each search decision point. The E-frontier is an efficient representation of a search state and is used with a hashing algorithm to detect equivalent search states. When EST matches an equivalent search state from a prior fault, and both prior and current faults are sensitized, EST completes the current fault test-pattern with values from the prior fault test-pattern and terminates search immediately. A new method of redundant fault analysis is also introduced that uniquely determines signal values for subsequent test-pattern search. Results show that this algorithm accelerates the base ATPG algorithm by a factor of 1.03 to 328 when considering all faults, a factor of 1347:1 for hard-to-test faults and a factor of 200000 for certain redundancy proofs for the test cases shown