Abstract: Methods and apparatus for processing a substrate are provided herein. For example, a method for processing a substrate comprises supplying pulsed DC power to a target disposed in a processing volume of a processing chamber for depositing sputter material onto a substrate, during a pulse off time, determining if a reverse current is equal to or greater than at least one of a first threshold or a second threshold different from the first threshold, and if the reverse current is equal to or greater than the at least one of the first threshold or second threshold, generate a pulsed DC power shutdown response, and if the reverse current is not equal to or greater than the at least one of the first threshold or second threshold, continue supplying pulsed DC power to the target.