Patent ID: 6663791
Filing Date: 2003-12-16
Classification: G01B,G01N,H01J

Abstract:
A method for detecting a thickness of coating film, comprising the steps of:providing a coating material forming a coating film comprising a low conductive material having a conductivity that is lower than that of aluminum; providing a disk having a wafer support device for mounting a wafer thereon, wherein a surface of said disk is coated by said coating material; providing an electrical measurement sensor which is fixed on said surface of said disk; said electrical measurement sensor has electrodes covered with said coating film of generally the same material that coats said disk; irradiating said wafer, said disk and said sensor with an irradiating beam of ions while said disk is being rotated; and outputting an electrical change as a sensor signal when ions from said beam strike said sensor to detect a decrease of said coating film thickness on the disk surface during ion beam treatment of said wafer.