Defect level calculation: the importance of accurate models for defect distribution and multiple fault coverage in low yield situations

The authors studied multiple-fault coverage versus single-fault coverage and compared these to the traditional models. They found that, for low-to-moderate single-fault coverage, fault exposure and fault masking may be considerable. For single-fault coverages above 90%, however, it was observed that traditional models are surprisingly good. Defect-level calculations reveal that, for the benchmark circuits C432 and C499, satisfactory accuracy is achieved at high single-fault coverages when ignoring fault exposure and fault masking. However, circuit function and circuit topology must be considered in each case