IC quality and test transparency

It is shown that extremely high single-stuck fault coverage is necessary for high-quality products. Even 100% single-stuck fault coverage may not guarantee adequate quality. Results are presented that extend previous work and show that for high required IC quality, process yield has a negligible effect on required test thoroughness. The extensions consist of: removing the assumption of a one-to-one correspondence between chip defects and single-stuck faults; demonstrating that for high quality levels the dependence of quality on test coverage is linear rather than exponential and that for high yields, the dependence of quality on yield is also linear; and showing that the yield used in the calculations should be functional rather than die yield. The theoretical results are compared with data obtained from measurements at a production IC facility.<
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