An Automatic Test Pattern Generation Method for Multiple Stuck-At Faults by Incrementally Extending the Test Patterns

Abstract

As the number of transistors in the fabricated circuits becomes extremely larger, not only single stuck-at faults, but also multiple stuck-at faults (MSAFs) are likely to happen in the circuits, especially for the large-scale circuit. Multiple faults are difficult to be fully covered due to the exponentially enormous number of all possible faults. Although there are methods proposed to deal with the multiple faults, they fail to generate compact test patterns to detect all faults within an acceptable running time. In order to solve these problems, this article proposes an incremental automatic test pattern generation method to deal with MSAFs. Instead of traversing the entire ${n}$ multiple fault list, the proposed method only selects the faults undetected by the existing test patterns for ${n-1}$ faults, and then generates additional test patterns. Staring from a complete test set for single faults, the proposed ATPG method can be incrementally applied to handle all multiple faults. Moreover, since the number of undetected faults that are selected is extremely smaller comparing to the total number of the entire fault list, the proposed method can generate compact test patterns to cover all faults within an acceptable running time.