On hazard-free patterns for fine-delay fault testing

This work proposes an effective method for applying fine-delay fault testing in order to improve defect coverage of especially resistive opens. The method is based on grouping conventional delay-fault patterns into sets of almost equal-length paths. This narrows the overall path length distribution and allows running the pattern sets at a higher speed, thus enabling the detection of small delay faults. These small delay faults are otherwise undetectable because they are masked by longer paths. A requirement for this method is to have hazard-free paths. To obtain these (almost) hazard-free paths we use a fast and simple postprocessing step that filters out paths with hazards. The experimental data shows the effectiveness and the necessity of this filtering process.