Removing metal contamination from surfaces of a processing chamber

A substrate processing system for treating a substrate, comprising:

• a processing chamber comprising chamber walls and a substrate support;
• a gas delivery system configured to selectively deliver gases to the processing chamber, the gas delivery system comprising a first gas source comprising a first gas and a second gas source comprising a second gas, wherein the first gas is selected from a group consisting of silicon tetrachloride (SiCl4), carbon tetrachloride (CCl4), a hydrocarbon (CxHy where x and y are integers) and molecular chlorine (Cl2), boron trichloride (BCl3), and thionyl chloride (SOCl2), wherein the first gas is configured to selectively etch tin (Sn) relative to silicon (Si), and wherein the second gas includes a fluorine species and is configured to selectively etch Si relative to Sn;
• a plasma generator configured to selectively generate plasma in the processing chamber;
• and
• a controller configured to control the gas delivery system and the plasma generator, wherein the gas delivery system and the plasma generator are configured to, responsive to the controller:
• a) supply the first gas;
• b) strike plasma in the processing chamber to selectively etch Sn relative to Si from surfaces of the processing chamber;
• c) extinguish the plasma struck in b) and evacuate the processing chamber;
• d) supply the second gas;
• e) subsequent to d), strike plasma in the processing chamber to selectively etch Si relative to Sn from the surfaces of the processing chamber;
• and
• f) extinguish the plasma struck in e) and evacuate the processing chamber.