| 摘要 |
PURPOSE: To put airflows on optical paths of interferometers in optical states by local air conditioning, regarding the interferometers which measure the position in a plurality of directions of an object of measurement provided in a space the whole of which is air-conditioned. CONSTITUTION: Ducts 25 and 26 of a local air-conditioning system are disposed respectively near optical paths 23 and 24 of laser beams of interferometer units 21 and 22 which measure the positions in directions X and Y of a wafer stage 30 provided in a chamber room air-conditioned as a whole by an airflow 42 from an outlet 41 of a main air-conditioning system. Temperature regulating devices 11 and 12 regulating the temperature of air are provided in air-sending pipes 33 and 34 sending the air from a blower 10 to the ducts 25 and 26 of the local air-conditioning system respectively, and based on measured values of temperature sensors TX and TY measuring the temperatures of the optical paths 23 and 24, the temperatures of airflows 27 and 28 sent from the ducts 25 and 26 of the local air-conditioning system are controlled discretely by an air-conditioning control system through temperature control devices 13 and 14. |
