On Hazard-free Patterns for Fine-delay Fault Testing

This paper proposes an effective method for applying finedelay 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.