Patent ID: 7377992
Filing Date: 2008-05-27
Classification: G03F,H01J

Abstract:
1. An apparatus for detecting an end point used in processing a to-be-processed layer using a mask layer formed on the to-be-processed layer, said apparatus comprising; a light source for irradiating the mask layer and the to-be-processed layer with light; a spectroscope for measuring interference light formed of reflected lights from the mask layer and reflected lights from the to-be-processed later under the light from the light source; arithmetic means for removing an interference component brought by the mask later from the interference light measured by the spectroscope to calculate the waveform of the interference light brought by the to-be-produced later; and end-point detection means for determining the thickness of the remaining to-be-processed layer based on the waveform of the interference light calculated by the arithmetic means and comparing the determined thickness of the remaining to-be-processes layer to a desired thickness thereof, thereby detecting the end point of the processing on the to-be-processed layer, wherein the arithmetic means determines the ratio of the intensity of the measured interference light for at least one kind of specific wavelength to the sum of the intensities of the measured interference light for at least ten or more kinds of wavelengths to remove the interference component brought by the mask layer from the measured interference light.