Patent ID: 6603130
Filing Date: 2003-08-05
Classification: F16C,G03F

Abstract:
A lithographic projection apparatus, comprising:a radiation system constructed to supply a projection beam of radiation; a first object table provided with a mask holder to hold a mask; a second object table provided with a substrate holder to hold a substrate; a projection system constructed and arranged to image an irradiated portion of the mask onto a target portion of the substrate; a vacuum chamber having a wall enclosing at least one of said first and second object tables, said vacuum chamber wall having an aperture therein; a moveable sealing member constructed and arranged to seal said aperture; a bearing constructed and arranged to bear said sealing member and maintain a gap between said sealing member and said vacuum chamber wall, said bearing comprising: a gas bearing adapted to provide pressurized gas into said gap thereby to generate forces tending to hold said sealing member away from said vacuum chamber wall; and an evacuation system spaced apart from said gas bearing constructed and arranged to remove said gas from said gap.