Targeting Leakage Constraints during ATPG

In previous technology generations IDDQ testing used to be a powerful technique to detect physical faults that are not covered by standard fault models or functional tests. Due to shrinking feature sizes and consequently increasing leakage currents IDDQ testing becomes difficult in the deep-sub-micron area. One of the problems is the vector dependency of leakage current. Even in good devices the leakage current may vary significantly from one test vector to the next. In this work we present an ATPG framework that allows to generate test vectors within tight constraints on leakage currents. The target range for the leakage current is automatically determined. Experiments on the ITC99 benchmark suite yield test sets that achieve 100% fault coverage for the larger circuits, even when the range is narrowed down to 50% of the standard deviation of random vectors.