Patent ID: 7612889
Filing Date: 2009-11-03
Classification: G01B,G03F

Abstract:
1. A method of measuring a displacement of a sample to be inspected, comprising: splitting a light beam emitted from a light source into a first light beam and a second light beam; detecting the first light beam with a first sensor; irradiating a reference mirror having a diffraction grating for reflecting a first polarization state light beam and passing a second polarization state light beam with light having the first polarization state among the split second light beam, and reflecting the light having a first polarization state by the reference mirror; irradiating a sample with light having the second polarization state among the split second light beam, and reflecting the light having the second polarization state by the sample; generating an interference light by overlapping light reflected by the reference mirror with light reflected from the sample, and passing the overlapped lights through a polarizing plate; detecting the interference light with a second sensor; and extracting displacement information of the sample by processing a signal output from the first sensor corresponding to the first light beam and a signal output from the second sensor corresponding to the interference light.