Abstract: A bearing for use in a vacuum chamber comprises a gas bearing discharging pressurised gas into a gap between two members to maintain a predetermined separation between those members.

Abstract: A long-stroke movement is fed-through into a vacuum chamber by providing a sliding seal over an aperture in the vacuum chamber wall. The object to be moved, which may be a mask or wafer table in a lithographic apparatus, within the vacuum chamber is connected to or mounted on the sliding seal and moved by movement of the sliding seal. The sliding seal may be a plate, a bowl or a labyrinth of interleaved plates.

Abstract: A bearing for use in a vacuum chamber comprises a gas bearing discharging pressurised gas into a gap between two members to maintain a predetermined separation between those members.

Abstract: An object table is supported in a vacuum chamber by an elongate beam or beams extending through elongate slots in opposite walls of the vacuum chamber. Displacement of the beam in two orthogonal directions is achieved by displacing the beam laterally and longitudinally. The elongate slots are sealed by sliding plates supported by a gas bearing. The beam is driven longitudinally by linear motors acting against between a balance mass and the beam. The beam is driven laterally by linear motors acting between a balance mass and the sliding plates. The two balance masses may be separate or combined.

Abstract: A bearing for use in a vacuum chamber comprises a gas bearing discharging pressurised gas into a gap between two members to maintain a predetermined separation between those members. To avoid the gas forming the gas bearing being an unacceptable leak into the vacuum chamber, a vacuum pump is provided between the vacuum chamber and the gas bearing.

Abstract: A lithographic apparatus for step-and-scan operation has a three stage structure for the wafer stage. During step-and-scan operation, the long-stroke stage is moved steadily along the row or column of dies to be exposed sequentially. An intermediate scanning stage moves in a figure-of-eight motion relative to the long-stroke stage so that the net movement of the fine stage, which is carried by the scanning stage, is a meander path.

Abstract: In a lithographic projection apparatus, a slider is provided for motion of the substrate table or mask table. The slider is supported on a gas-bearing and separates a region at atmospheric pressure from a vacuum space region. A differential pressure pump is provided to maintain the pressure difference in the presence of the gas-bearing. A pressure compensation vessel is provided on top of the slider and also contains a vacuum. Over most of the area of the slider, the pressure on its opposed first and second sides is the same and so deformation of the slider is avoided. The sidewalls of the pressure compensation vessel transmit the external gas pressure to the slider such that they are in line with the forces of the gas-bearing.

Abstract: A long-stroke movement is fed-through into a vacuum chamber by providing a sliding seal over an aperture in the vacuum chamber wall. The object to be moved, which may be a mask or wafer table in a lithographic apparatus, within the vacuum chamber is connected to or mounted on the sliding seal and moved by movement of the sliding seal. The sliding seal may be a plate, a bowl or a labyrinth of interleaved plates.

Abstract: An object table is supported in a vacuum chamber by an elongate beam or beams extending though elongate slots in opposite walls of the vacuum chamber. Displacement of the beam in two orthogonal directions is achieved by displacing the beam laterally and longitudinally. The elongate slots are sealed by sliding plates supported by a gas bearing. The beam is driven longitudinally by linear motors acting against between a balance mass and the beam. The beam is driven laterally by linear motors acting between a balance mass and the sliding plates. The two balance masses may be separate or combined.

Abstract: A long-stroke movement is fed-through into a vacuum chamber by providing a sliding seal over an aperture in the vacuum chamber wall. The object to be moved, which may be a mask or wafer table in a lithographic apparatus, within the vacuum chamber is connected to or mounted on the sliding seal and moved by movement of the sliding seal. The sliding seal may be a plate, a bowl or a labyrinth of interleaved plates.

Abstract: An object table is supported in a vacuum chamber by an elongate beam or beams extending though elongate slots in opposite walls of the vacuum chamber. Displacement of the beam in two orthogonal directions is achieved by displacing the beam laterally and longitudinally. The elongate slots are sealed by sliding plates supported by a gas bearing. The beam is driven longitudinally by linear motors acting against between a balance mass and the beam. The beam is driven laterally by linear motors acting between a balance mass and the sliding plates. The two balance masses may be separate or combined.