The present invention is generally directed to plasma state monitoring to control etching processes and across-wafer uniformity, and a system for performing same. In one illustrative embodiment, the method comprises generating a plasma within an etching tool, monitoring at least one characteristic of the generated plasma, and controlling at least one parameter of a plasma etching process performed in the tool based upon the monitored at least one characteristic of the plasma. In another illustrative embodiment, the method comprises generating a plasma within an etch tool, performing a plasma etching process within the etch tool, determining at least one characteristic of the plasma, and controlling at least one parameter of the etching process based upon a comparison of the determined at least one characteristic of the plasma and a target value for the determined at least one characteristic of the plasma.