摘要:
A reference frame provided in a vacuum chamber is supported by support pillars extending through and isolated from the vacuum chamber walls to isolate the reference frame from vibrations in the vacuum chamber. The gap between the support pillar and the vacuum chamber wall may be sealed by a low-stiffness seal. The low stiffness seal may be a three part seal allowing relative motion in six-degrees of freedom.
摘要:
A lithographic projection apparatus comprises a vacuum chamber having a wall enclosing at least one of first and second object tables, the or each object table within the vacuum chamber being connected to positioning means for positioning the object table with respect to a projection system of the apparatus. The positioning means is provided with a pneumatic gravity compensator comprising a piston associated with the object table; a gas-filled pressure chamber, the gas in the pressure chamber acting on the movable member to at least partially counteract the weight of the object table; a gas bearing; and evacuating means for evacuating gas escaping through a gap between the movable member and a bearing surface of a cylindrical housing towards the vacuum chamber. A partially flexible rod connects the piston to the object table.
摘要:
A lithographic projection apparatus comprises a vacuum chamber having a wall enclosing at least one of first and second object tables, the or each object table within the vacuum chamber being connected to positioning means for positioning the object table with respect to a projection system of the apparatus. The positioning means is provided with a pneumatic gravity compensator comprising a piston associated with the object table; a gas-filled pressure chamber, the gas in the pressure chamber acting on the movable member to at least partially counteract the weight of the object table; a gas bearing; and evacuating means for evacuating gas escaping through a gap between the movable member and a bearing surface of a cylindrical housing towards the vacuum chamber. A partially flexible rod connects the piston to the object table.