To do so, ams created a statistical approach to the estimation of the undetected lot fraction defective passed by the adaptive testing method.
"Lot fraction defective" is a statistical term--it means the fraction of faulty ICs in a given population of good ICs.
The lower test time reduction in the case of Product E is consistent with its higher lot fraction defective, which means that the algorithm dynamically reduces the number of omitted tests.
Interestingly, the table shows that the calculated value of the lot fraction defective closely matches the real value derived from the conventional test program and that it is a meaningful indicator of the risk of potential test escapes when implementing adaptive real-time testing.
The MAPD is the value of fraction defective (p=[p.sup.*]) at which [d.sup.2][P.sub.a](p)/ d[p.sup.2] = 0 and [d.sup.3][P.sub.a](p)/d[p.sup.3] [not equal to], 0
It is also the inflection point of the operating characteristic (OC) curve and [P.sub.a](p) is the probability of acceptance at the quality level p fraction defective