Anti-vibration system for exposure apparatus
An anti-vibration system includes air dampers of high natural frequency, in a compact space. A pair of air dampers are disposed with their driving directions opposed to each other, and inside pressures of these dampers are variably controlled so as to set the natural vibration frequency.
1. An anti-vibration system, comprising:
a plurality of frames disposed on a first object;
a pair of gas dampers which generate respective forces applied to one of the plurality of frames, directions of the forces being opposed to each other; and
a controller which increases or decreases both of internal pressures of said gas dampers in accordance with a motion state of a second object which is supported by and moved relative to the first object.
2. An anti-vibration system according to claim 1 , wherein the motion state corresponds to acceleration of the second object.
3. An anti-vibration system according to claim 1 , further comprising a linear motor which generates a driving force applied to a frame disposed on the first object in a direction parallel to directions of the respective forces.
4. An anti-vibration system according to claim 3 , further comprising a first supporting member which supports said pair of gas dampers on a floor, and a second supporting member which supports said linear motor on the floor.
5. An anti-vibration system according to claim 4 , wherein said second supporting member includes a resilient member.
6. An anti-vibration system according to claim 3 , wherein said linear motor generates the driving force in accordance with at least one of a motion state of the second object, a position of the second object and a motion state of the first object.
7. An exposure apparatus, comprising:
a stage which supports an object to be exposed;
a stage base which supports said stage; and
an anti-vibration system which comprises:
(i) a plurality of frames disposed on said stage base,
(ii) a pair of gas dampers which generate respective forces applied to one of the plurality of frames, directions of the forces being opposed to each other; and
(iii) a controller which increases or decreases both of internal pressures of said gas dampers in accordance with a motion state of said stage which is moved relative to said stage base.
8. A device manufacturing method comprising the steps of:
exposing an object to a pattern using an exposure apparatus as recited in claim 7 ; and
developing the object exposed in said exposing step.