Structural test of power-only defects: ATPG or ad-hoc?

Power-only defects do not cause logical failures in a chip but induce more power consumption. For battery-driven semiconductor chips and others with military-level quality requirements, power-only defects have to be screened out during manufacturing test. To reduce the associated test cost, structural test of those defects is a must. With a dedicated example, this paper demonstrates two methods to structurally detect such defects, i.e., testing them along with regular ATPG vectors and creating a special test mode for detection. This paper also compares the two proposals based on different tradeoff requirements. Finally, it summarizes general criteria for selecting structural test methods for detecting those power-only defects.