End point determination of process residues in wafer-less auto clean process using optical emission spectroscopy

摘要

A method for determining an endpoint of an in-situ cleaning process of a semiconductor processing chamber is provided. The method initiates with providing an optical emission spectrometer (OES) configured to monitor selected wavelength signals. Then, baseline OES threshold signal intensities are determined for each of the selected wavelength signals. Next, an endpoint time of each step of the in-situ cleaning process is determined. Determining an endpoint time includes executing a process recipe to process a semiconductor substrate within the processing chamber. Executing the in-situ cleaning process and recording the endpoint time for each step of the in-situ cleaning process are also included in determining the endpoint time. Then, nominal operating times are established for each step of the in-situ cleaning process. A plasma processing system for executing a two step in-situ cleaning process is also provided.