Methods for providing asymmetric run to run control of process parameters

摘要

Methods for providing asymmetric control of process parameters are described. One such method includes receiving a data point for the process parameter relative to the wafer, selecting a first value for a process weighting factor when the data point is consistent with a first criteria, selecting a second value for the process weighting factor when the data point is consistent with a second criteria, where the second value is not equal to the first value, calculating an exponential weighted moving average of the process parameter based on the data point and the process weighting factor, updating the process parameter with the exponential weighted moving average, and using the updated process parameter to control the process and thereby treat the wafer. The methods can use one or more weighting factor switch limits to define different areas of risk associated with a target for the process parameter.