Fuzzy reasoning model for semiconductor process fault detection using wafer acceptance test data

摘要

System and method for detecting suspicious process faults. A preferred embodiment comprises determining a strength relationship between wafer acceptance test (WAT) parameters and process steps. The strength relationships indicate the affect of a failed process step on the value of a WAT parameter. Thus, if a WAT parameter is not within the parameters set in the WAT, then the suspicious process steps that caused the failure are the process steps that had a strength relationship with the failed WAT parameter. Furthermore, in a preferred embodiment, negative inferences are determined and utilized to determine a degree of suspiciousness. The degree of suspiciousness is used to determine a total degree of suspiciousness.