| 摘要 |
PROBLEM TO BE SOLVED: To provide a technology which is advantageous in measuring a position of a surface to be inspected with high accuracy using a plurality of wavelengths.SOLUTION: The measuring device for measuring a position of a surface to be inspected includes: an irradiation part for irradiating a light beam containing a first wavelength which is set using a first wavelength reference element and a second wavelength which is set using a second wavelength reference element whose wavelength dependency on the change of the ambient environment is larger than that of the first wavelength reference element, to the surface to be inspected and a reference surface; a detection part for detecting a phase difference between a light beam to be inspected from the surface to be inspected irradiated by the light beam and a reference light beam from the reference surface irradiated by the light beam; and a control part for deciding a position of the surface to be inspected using a synthetic wavelength with the first wavelength and the second wavelength. The control part obtains the wavelength of the second wavelength on the basis of a variation of the phase difference in the first wavelength, a variation of the phase difference in the second wavelength, a refractive index on the optical path of the light beam to be inspected in the first wavelength, and a refractive index on the optical path in the second wavelength before/after an optical path length difference between the light beam to be inspected and the reference light beam is changed. |
