Generation of Compact Stuck-At Test Sets Targeting Unmodeled Defects

Abstract

We present a new method to generate compact stuckat test sets that offer high defect coverage. The proposed method first selects the most effective patterns from a large N-detect pattern repository, by using a new output deviation-based metric. Then it embeds complete coverage of stuck-at faults within these patterns, and also uses the proposed metric to further improve their unmodeled defect coverage. Simulation results are presented for ISCAS and IWLS benchmark circuits by using two surrogate fault models, the transition-delay and the bridging fault model, respectively, to measure defect coverage. The results show that the proposed method provides considerably higher transition-fault coverage and coverage ramp-up compared to another recently published method with similar test length. Moreover, in all cases, the proposed method either outperforms or is as effective as the competing approach in terms of bridgingfault coverage. In many cases, higher transition-fault coverage is obtained even than much larger N-detect test sets for several values of N. Finally, our results provide the insight that, instead of using N-detect testing with as large N as possible, it is more efficient to combine the output deviations metric with multidetect testing to get high-quality, compact test sets.

Test-Quality Optimization for Variable <inline-formula> <tex-math notation="TeX">$n$ </tex-math></inline-formula>-Detections of Transition Faults

“…Various researchers worked on the multidetection of SFs to cover complex interconnect faults such as bridge faults or open faults [2]- [6], [9], [10], [17]- [20], [22], [23], [26], [27]. Multidetection of TFs is used to cover complex timing behavior faults such as crosstalk, power supply noise, and path delay fault [8], [11], [12], [21], [24], [25], [28], which shows the great potential of n-detection TF test for detecting unmodeled timing failures.…”

“…Test-compaction approaches focus on exploring don't care bits (x bits) in the patterns to cover more defects [22]- [24]. In [22], it presented the embedded multidetection ATPG to explore the unspecified bits in the patterns to improve the n-detection coverage for a given one-detection test set.…”

“…Simultaneously, it generated compact test sets for the K longest path set. In [24], it first selected the patterns from a large n-detection test set, with a proposed output deviation-based metric. Then, it exploited the unspecified bits to increase coverage of stuckat faults within the patterns and improved unmodeled defect coverage.…”

Reduced complexity test generation algorithms for transition fault diagnosis

“…But the number of test patterns also grows with increasing N , which leads to longer test time and/or higher cost. Methods have been proposed [8,9,14] for compaction of N -detect vector set. These require computational effort.…”