Patent ID: 7127317

Claim:
A method of improving wafer yield of wafers processed within a wafer fabrication facility comprising the steps of: performing a fabrication operation on a plurality of wafers disposed within at least one wafer lot; determining if an abnormal event occurred while performing the fabrication operation on the plurality of wafers disposed within the at least one wafer lot; using a nonconforming wafer tracing system to determine a statistical correlation between an occurrence of an abnormal event and a wafer yield of the plurality of wafers being processed during the occurrence of the abnormal event if the abnormal event occurred during processing of the plurality of wafers disposed within the at least one wafer lot by using a statistical test method to test non-conforming event and calculate a hit rate (HR), wherein the HR ranges between 0 and 1 such that 0≦HR≦1 to indicate a probability that the abnormal event impacted wafer yield of the plurality of wafers disposed within the at least one wafer lot, wherein if the HR equals zero, then the probability that the abnormal event impacted wafer yield is low, and wherein if the HR equals 1, then the probability that the abnormal event impacted wafer yield is high; and using the determined statistical correlation to analyze the fabrication process and thereby improve wafer yield.