부산대학교 도서관

In the early stages of yield improvement, a faulty unit may produce a large volume of fail data because of the presence of multiple defects in the functional logic. Earlier solutions that address the fail data collection process on the tester make a decision to store fail data for every test separately. This article suggests a more fine-grained approach where fail data is collected for a subset of the tests and outputs. This is represented by storing a partially specified fault-free output response on the tester, and storing a fail data entry for a faulty unit only when it conflicts with a fully specified fault-free output value. Although the fault-free output response is larger, the fail data volume collected for faulty units is reduced. This is important since fail data is collected over many faulty units. This article considers the selection of the partially specified fault-free output response a priori and presents experimental results to demonstrate that the fail data volume is reduced significantly, and accurate logic diagnosis is possible with the reduced fail data.