Embodiments disclosed herein generally relate to systems and methods to prevent free radical damage to sensitive components in a process chamber and optimizing flow profiles. The processing chamber utilizes a cover substrate on lift pins and an inert bottom purge flow to shield the substrate support from halogen reactants. During a clean process, the cover substrate and the purge flow restricts halogen reactants from contacting the substrate support. The method of cleaning includes placing a cover substrate on a plurality of lift pins that extend through a substrate support in a processing chamber, raising the cover substrate via the lift pins to expose a space between the cover substrate and the substrate support, supplying a halogen containing gas into the processing chamber, supplying a second gas through an opening in the processing chamber, and flowing the second gas through the space between the cover substrate and the substrate support.