Exposure apparatus, exposure method, and device manufacturing method

Abstract

The exposure apparatus comprises a gas supply system that supplies a low absorptive gas with a predetermined purity to the illumination system housing and the barrel of the projection optical system and collects the gas exhausted from these closed spaces and supplies the gas to the mask chamber which houses the mask stage and the substrate chamber which houses the substrate stage. The illumination system housing, the barrel of the projection optical system, the mask chamber, and the substrate chamber are respectively located on the optical path of the exposure light. Accordingly, the low absorptive gas that has circulated the illumination system housing and the barrel of the projection optical system is used as the replacement gas of the mask chamber and the substrate chamber, while sufficiently satisfying the purity of the low absorptive gas and maintaining the transmittance of the exposure light required in each chamber. Thus, the usage efficiency of the low absorptive gas can be improved, and wasteful consumption of the low absorptive gas can be suppressed.

Dependencies are inferred from the claim text.