Lithographic projection apparatus, supporting assembly and device manufacturing method

A supporting assembly comprising:

• a moveable member associated with a supported structure;
• a housing in which said moveable member is journalled, said journalling being such that substantially no vibration forces are transmitted between said moveable member and said housing;
• a gas-filled pressure chamber, the gas in said pressure chamber acting on said moveable member so as to at least partially counteract the force due to the weight of the supported structure;
• and
• a gas supply to supply gas to said pressure chamber;
• the supporting assembly being constructed and arranged such that substantially no gas flows through the pressure chamber when said moveable member is substantially stationary.

A method of manufacturing a device using a lithographic projection apparatus comprising:

• providing a substrate that is at least partially covered by a layer of radiation-sensitive material;
• projecting an image of at least part of a mask pattern onto a target portion of the layer of radiation-sensitive material;
• providing a moveable member associated with a supported structure;
• providing a housing in which said moveable member is journalled such that substantially no vibration forces are transmitted between said moveable member and said housing;
• providing a gas-filled pressure chamber, the gas in said pressure chamber acting on said moveable member so as to at least partially counteract the force due to the weight of the supported structure;
• supplying gas to the pressure chamber;
• and
• preventing gas from flowing through said pressure chamber when said moveable member is substantially stationary.

A lithographic projection apparatus comprising:

• a radiation system to supply a projection beam of radiation;
• a first object table provided with a first object holder to hold a mask;
• a second object table provided with a second object holder to hold a substrate;
• and
• a projection system to image an irradiated portion of the mask onto a target portion of the substrate;
• at least one of said first and second object tables being connected to positioning structure constructed and arranged to position said one object table with respect to the projection system, wherein the apparatus further comprises a supporting assembly comprising:
• a moveable member associated with a supported structure;
• a housing in which said moveable member is journalled such that substantially no vibration forces are transmitted between said moveable member and said housing;
• a gas-filled pressure chamber, the gas in said pressure chamber acting on said moveable member so as to at least partially counteract a force due to weight of the supported structure;
• and
• a gas supply to supply gas to said pressure chamber;
• the supporting assembly including means for preventing gas from flowing through the pressure chamber when said moveable member is substantially stationary.