Patent ID: 11920928
Assignee: TOKYO ELECTRON LIMITED
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 12:
13. A method of correcting an optical path length measurement error, the method comprising:
a step of emitting light to a measurement target object and causing first interference light from the measurement target object to be incident on a spectroscope under a predetermined temperature environment;
a step of calculating an optical path length of the measurement target object on the basis of the first interference light;
a step of emitting the light to a reference object configured to have a constant optical path length with respect to a temperature fluctuation, and causing second interference light from the reference object to be incident on the spectroscope under the predetermined temperature environment;
a step of calculating a measurement optical path length of the reference object on the basis of the second interference light;
a step of acquiring a reference optical path length of the reference object;
a step of calculating a fluctuation rate of the measurement optical path length with respect to the reference optical path length under the predetermined temperature environment on the basis of the measurement optical path length of the reference object calculated on the basis of the second interference light and the reference optical path length of the reference object; and
a step of correcting the optical path length of the measurement target object on the basis of the fluctuation rate.