Patent ID: 6483585
Filing Date: 2002-11-19
Classification: G01B,G01N

Abstract:
A device for use in determining a film thickness of a sample, the device comprising:a substrate for supporting said sample; a light source for producing electromagnetic radiation to illuminate said sample; a first polarization element located between said light source and said sample; a detector for detecting electromagnetic radiation reflected from said sample; a second polarization element located between said detector and said sample; and a data analysis means for utilizing a signal obtained from said detector to determine film thickness, wherein the polarization state of electromagnetic radiation illuminating said sample is not changed by a component of said device between said first polarization element and said sample and the polarization state of electromagnetic radiation reflected from said sample is not changed by a component of said device between said sample and said second polarization element; and wherein at least one of said first and second polarization elements is a rotatable element which rotates during an operating mode of said device to vary an s and/or p component of said electromagnetic radiation with time, and wherein said data analysis means uses a standard function that correlates film thickness to detector signal intensity.