Patent ID: 6937333

Claim:
A film thickness measurement apparatus fox measuring a thickness of a film formed on an object, comprising: a first light source for emitting a polarized light to an object; a light receiving part for receiving a reflected light of said polarized light from said abject to acquire a polarization state of said reflected light; an calculation part for obtaining a thickness of a film on said object on the basis of said polarization state; a second light source for emitting an illumination light; an optical system for guiding said illumination light to said object and guiding a reflected light of said illumination light from said object to a predetermined position; a light shielding pattern disposed at a position almost optically conjugate to an aperture stop position on an optical path from said second light source to said object; and an imaging part for acquiring an image of said light shielding pattern formed on said predetermined position, wherein said calculation part obtains a tilt angle of said object on the basis of an output from said imaging part and obtains a thickness of said film from said polarization state, by using said tilt angle.