INTERFEROMETER AND EXPOSURE APPARATUS INCLUDING THE SAME

摘要

An interferometer comprises: an optical unit; an environment measurement unit to measure an environmental condition in a chamber; and a signal processing unit to measure a position of a stage. The optical unit separates a first light having a first wavelength into a reference light and a measurement light to generate a first interference signal based on a first reflected light as the reflected reference light from a reference mirror and a second reflected light as the reflected measurement light from a stage mirror. The signal processing unit calculates a correction factor of the chamber based on the environmental conditions; corrects the first interference signal into a second interference signal based on a correction factor; and measures a position of the stage based on the second interference signal.