A wafer is provided into an entrance load lock chamber. A vacuum is created in the entrance load lock chamber. The wafer is transported to a processing tool. The wafer is processed in a process chamber to provide a processed wafer, wherein the processing forms halogen residue. A degas step is provided in the process chamber after processing the wafer. The processed wafer is transferred into a degas chamber. The processed wafer is treated in the degas chamber with UV light and a flow of gas comprising at least one of ozone, oxygen, or H2O. The flow of gas is stopped. The UV light is stopped. The processed wafer is removed from the degas chamber.