Methods and apparatus for processing a substrate are provided herein. For example, a processing chamber for processing a substrate comprises a sputtering target, a chamber wall at least partially defining an inner volume within the processing chamber and connected to ground, a power source comprising an RF power source, a process kit surrounding the sputtering target and a substrate support, an auto capacitor tuner (ACT) connected to ground and the sputtering target, and a controller configured to energize the cleaning gas disposed in the inner volume of the processing chamber to create the plasma and tune the sputtering target using the ACT to maintain a predetermined potential difference between the plasma in the inner volume and the process kit during the etch process to remove sputtering material from the process kit, wherein the predetermined potential difference is based on a resonant point of the ACT.