A method of detecting an end point of surface treatment of a wafer includes the steps of: projecting coherent light onto an upper surface of the wafer provided with a layer to be treated; receiving superposed light caused by interference of light reflected on a surface of the layer to be treated and...http://www.google.com/patents/US4998021?utm_source=gb-gplus-sharePatent US4998021 - Method of detecting an end point of surface treatment
