Patent ID: 7212950

Claim:
A method of determining process matching of one or more process tools so that the one or more process tools running the same process produce substantially the same results for processing workpieces, the method uses a first data set and a second data set where the first data set includes an operating characteristic measured while running the process and the second data set includes the operating characteristic measured while running the process, the method comprising: i. fingerprinting the one or more process tools using the first data set and the second data set; ii. finding correspondences between transition points in the first data set and the second data set; and iii. comparing the first data set and second data set using the correspondences from step ii to determine whether there is process matching for the one or more process tools running the same process; wherein step i comprises: A. detecting transition points in the first data set and the second data set so as to define data intervals wherein each data interval comprises the data between successive transition points; B. computing a best fit of the data in each of the data intervals using basis functions; and C. computing fitting errors between the data in the data intervals and the best fit and determining if the errors are less than a predetermined threshold and recursively finding additional transition points as necessary to produce fitting errors less than the threshold.