Patent ID: 8112249

Claim:
A parametric test time reduction method for reducing time expended to conduct a test program flow on a population of semiconductor devices, the test program flow comprising at least one parametric test having a specification which defines a known pass value range wherein a result of the test is considered a passing result if the result falls within said known pass value range, the method comprising: for at least one parametric test, computing an estimated maximum test range, at a given confidence level, on a validation set comprising a subset of the population of semiconductor devices, the estimated maximum test range comprising the range of values into which all results from performing said test on said set will statistically fall at said given confidence level, said validation set defining a complementary set including all semiconductors included in said population and not included in said validation set; and at least partly disabling said at least one parametric test based at least partly on a comparison of said estimated maximum test range and said known pass value range, wherein said computing an estimated maximum test range comprises: performing said parametric test on semiconductor devices included in said validation set, thereby to generate results for said semiconductor devices respectively and selecting from among said semiconductor devices at least one extreme subset including at least one of a high-scoring subset including all devices whose results exceed a high cut-off point and a low-scoring subset including all devices whose results fall below a low cut-off point; plotting results of said at least one extreme subset as a normal quantile probability plot having a zero probability axis and fitting a plurality of curves to a plurality of subsets of said results respectively; extending each of said plurality of curves to said zero probability axis thereby to define a corresponding plurality of intersection points and thereby to define a zero probability range along said zero probability axis within which all said intersection points fall; and defining said estimated maximum test range to include said zero probability range.