Patent ID: 7929139

Claim:
A spectroscopic ellipsometer, comprising: a holding part for holding an object having a measurement surface; an elevating mechanism for moving said object together with said holding part in a vertical direction perpendicular to said measurement surface; a lighting part for emitting polarized light to said measurement surface, said polarized light being inclined to said measurement surface; an analyzer where reflected light of said polarized light enters; a spectral splitting device for spectrally splitting said reflected light after passing through said analyzer, to obtain spectrally split light; a light receiving device for receiving said spectrally split light to acquire spectral intensity of said reflected light; a polarization state acquiring part for acquiring a polarization state at each wavelength of said reflected light on the basis of output of said light receiving device; an incidence restricting part which restricts incidence of said reflected light to said spectral splitting device when said measurement surface is apart from a focus position in said vertical direction; and a focus information acquiring part which obtains a total light amount in at least part of wavelength band of said reflected light on the basis of output of said light receiving device while said measurement surface moves by said elevating mechanism, to acquire a relationship between vertical position of said measurement surface and said total light amount.