Abstract: At least one method, apparatus and system disclosed herein involves performing a wafer to wafer feedback control of process performed on a semiconductor substrate. A first process on a first semiconductor wafer of a run of semiconductor wafers is performed using a processing tool. A first gas analysis of a gas in the processing tool is performed upon performing the first process. Determining a process feedback adjustment based upon a result of the first gas analysis. Data relating to the process feedback adjustment is provided. Performing a second process on a second semiconductor wafer based on the data relating to the process feedback adjustment.