Automatic problem detection and documentation in a plasma etch reactor

IC manufacturing involves a large number of complex process steps. There is a probability of a misprocessing error, which may entail severe consequences, in each of these steps. The author describes two software tools, in a single-wafer plasma etcher, that have been developed to minimize the occurrence and maximize the efficiency of diagnosing misprocessing. The first examines the endpoint trace of every wafer and determines if that wafer has seen anomalous processing. If so, the software can terminate the processing of subsequent wafers. The second records the analog values of all the process control parameters during the entire etch process. When these two routines are linked appropriately, it is possible to record these analog values for only those wafers that have seen anomalous processing. This feature provides data for the analysis of the process problem. The procedures minimize the number of wafers that are misprocessed and provide pertinent diagnostic information for those wafers