Patent ID: 6553335
Filing Date: 2003-04-22
Classification: H01J,H01L

Abstract:
A method for determining end-point in a chamber cleaning process comprising the steps of:providing a chamber having a cavity for conducting a semiconductor fabrication process therein; mounting a crystal sensor on a surface of said chamber cavity at a position that the crystal sensor is exposed to gases or liquids used or generated by said fabrication process; conducting said semiconductor fabrication process in said chamber; flowing a cleaning fluid into and in-situ cleaning said surface of said chamber cavity; inputting an oscillating frequency into said crystal sensor and monitoring an output frequency of oscillation from said crystal sensor; and comparing said output frequency of oscillation to an output frequency from a crystal sensor having a clean surface and defining an end-point of said chamber cleaning process when said output frequency of oscillation is not more than 20% smaller than said output frequency from said crystal sensor that has a clean surface.