Virtual sensor for chamber cleaning endpoint

Implementations of the present disclosure generally relate to methods for cleaning processing chambers. More specifically, implementations described herein relate to methods for determining processing chamber cleaning endpoints. In some implementations, a "virtual sensor" for detecting a cleaning endpoint is provided. The "virtual sensor" is based on monitoring trends of chamber foreline pressure during cleaning of the chamber, which involves converting solid deposited films on the chamber parts into gaseous byproducts by reaction with etchants like fluorine plasma for example. Validity of the "virtual sensor" has been confirmed by comparing the "virtual sensor" response with infrared-based optical measurements. In another implementation, methods of accounting for foreline pressure differences due to facility design and foreline clogging over time.