Patent ID: 8199336

Claim:
An optical measurement apparatus for measuring a film thickness or an optical constant of a sample, comprising: a storage processing part storing into a storage part a plurality of main reference positions where measurement is to be performed and at least one movement value relative to each main reference position; a main measuring part moving a measurement position to one of the main reference positions stored in the storage part, then irradiating light, and then measuring a change in a state of reflected light; an auxiliary measuring part moving the measurement position to an auxiliary reference position based on the movement value relative to one of the main reference positions stored in the storage part, then irradiating light, and then measuring a change in a state of reflected light; a main calculating part performing analysis on the basis of a main model corresponding to the main reference position stored in the storage part and the change in the state of light measured by the main measuring part, and calculating a film thickness or an optical constant; and an auxiliary calculating part performing analysis on the basis of an auxiliary model corresponding to the auxiliary reference position stored in the storage part and the change in the state of light measured by the auxiliary measuring part, and calculating a film thickness or an optical constant.