Abstract:
We present a new method to generate compact stuck-at
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 bridging-fault
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 multi-detect
testing to get high-quality, compact test sets.
