An exposure apparatus includes a reticle stage which holds a reticle, a reticle surface plate which supports the reticle stage, a projection optical system which projects a pattern of the reticle onto a substrate, a shield, and a gas supply. The shield surrounds a space, between the reticle stage and...http://www.google.es/patents/US6757048?utm_source=gb-gplus-sharePatente US6757048 - Exposure apparatus, maintenance method therefor, semiconductor device manufacturing method using the apparatus, and semiconductor manufacturing factory
