Provided is a method for determining and utilizing process completion of post heat treatment (PHT) of a dry etch process, the method comprising: providing a substrate in a process chamber, the substrate having a film layer and an underlying layer, the film layer having one or more regions; performing a dry etch process to remove the film layer or region of the film layer, the dry etch process generating a byproduct layer; measuring one or more properties of the byproduct layer; adjusting the PHT process based on the measured one or more properties of the byproduct layer; and performing the PHT process to remove the byproduct layer on the substrate; wherein the PHT process utilizes a real time in-situ process to concurrently determine when removal of the byproduct layer is complete.