Cleaning process end point determination using throttle valve position

摘要

The present invention provides a method and apparatus for detecting the end point of a process by monitoring the position of a valve during the process. In one aspect, a cleaning process is performed in the chamber, and a controller monitors the valve position to determine the end point of the process which corresponds to a decrease in the number of steps in the valve position required to achieve a stable throttle valve position after the cleaning process is complete.