US Patent 7145629 Exposure technique

An atmosphere control technique for an exposure apparatus. An exposure apparatus to which this technique is applied includes, for example, a chamber which contains a space through which exposure light passes, a circulation system which has a path and circulates an inert gas through the path and the chamber, at least one valve provided in the path, a supply system which has a supply port at one end of a zone of the path defined by the at least one valve and supplies an inert gas to the supply port, and an exhaust system which has an exhaust port at the other end of the zone and exhausts a gas from the exhaust port.