Vibration damping apparatus

• US 5,881,987 A
• Filed: 04/01/1997
• Issued: 03/16/1999
• Est. Priority Date: 04/02/1996
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Hara, Hiromichi
• Primary Examiner(s): Braun, Leslie A.
• Assistant Examiner(s): Nornberg, Michael D.
• Application Number:
  US08/831,760
• Time in Patent Office: 714 Days
• Field of Search: 248/550, 248/560, 248/566, 248/618, 248/637, 248/638, 248/346.01, 248/346.05, 267/136, 355/53
• US Class Current: 248/550
• CPC Class Codes: F16F 15/0275 Control of stiffness
• CPC Class Codes: G03F 7/70691 Handling of masks or workpieces
• CPC Class Codes: G03F 7/70833 Mounting of optical systems, e.g. mounting of illumination system, projection system or stage systems on base-plate or ground
• CPC Class Codes: G03F 7/709 Vibration, e.g. vibration detection, compensation, suppression or isolation

Abstract

An air-pressure vibration-damping apparatus, supporting an upper apparatus between a mounting floor and the upper apparatus. The vibration damping apparatus has four or more air springs for supporting the upper apparatus, a vibration-damping controller for controlling inner air pressures of the air springs so as to damp vibration from the mounting floor to the upper apparatus and suppress vibration of the upper apparatus, and a communicating pipe passing air between at least one couple of the air springs. When the couple of air springs mutually connected via the communicating pipe are regarded as one air spring, the number of air springs is three. Regarding this couple of air springs, the vibration-damping controller controls air pressure of at least one air spring.

Claims

1. A vibration damping apparatus, provided between an upper apparatus and a mounting floor, supporting the upper apparatus, said vibration damping apparatus comprising:

at least four air springs for supporting the upper apparatus;

pressure control means for controlling air pressures of said air springs by changing amounts of air in said air springs, so as to dampen vibration from the mounting floor to the upper apparatus, and suppress vibration of the upper apparatus; and

air communicating means for mutually passing air between at least one couple of the air springs among said air springs, said air communicating means comprising an air valve, positioned in a path of the air flow in said air communicating means, for controlling air flow through said air communicating means, whereby the difference of the air pressure between said at least one couple of the air springs is equalized by passing air through said air communicating means by the opening of said air valve, thereby creating an equilibrium of air pressures between said at least one couple of air springs.

2. The vibration damping apparatus according to claim 1, wherein said air communicating means comprises a pipe for passing the air, and said air valve comprises a variable air valve for controlling the amount of air that flows through said pipe.

3. The vibration damping apparatus according to claim 1, wherein said pressure control means comprises:

monitor means for monitoring at least one of displacement, speed and acceleration of the upper apparatus, and air pressures within said air springs;

electricity/air-pressure converting means for controlling the air pressures within said air springs; and

control means for driving said electricity/air-pressure converting means in accordance with output signals from said monitoring means.

4. The vibration damping apparatus according to claim 1, wherein, if a couple of the air springs among said air springs, connected by said air communicating means, us regarded as one air spring, the number of said air springs is three.

5. The vibration damping apparatus according to claim 1, wherein, with regard to a couple of the air springs among said air springs, connected by said air communicating means, said pressure control means controls air pressure of at least one of the couple of air springs.

6. An exposure apparatus comprising:

at least four air springs, provided on a mounting floor, for supporting said exposure apparatus;

pressure control means for controlling air pressures of said air springs by changing amounts of air in said air springs, so as to dampen vibration from the mounting floor to said exposure apparatus, and suppress vibration of said exposure apparatus;

air communicating means for mutually passing air between at least one couple of the air springs among said air springs, said air communicating means comprising an air valve, positioned in a path of the air flow in said air communicating means, for controlling air flow through said air communicating means; and

exposure means, mounted on said exposure apparatus, for projection-exposing a reticle pattern via a projection optical system onto a sensitized substrate, by a step-and-repeat method, whereby the difference of the air pressure between said at least one couple of the air springs is equalized by passing air through said air communicating means by the opening of said air valve, thereby creating an equilibrium of air pressures between said at least one couple of air springs.

7. The exposure apparatus according to claim 6, wherein said air communicating means comprises a pipe for passing the air, and said air valve comprises a variable air valve for controlling the amount of air that flows through said pipe.

8. The exposure apparatus according to claim 6, wherein said pressure control means comprises:

monitor means for monitoring at least one of displacement, speed and acceleration of said exposure apparatus, and air pressures within said air springs;

electricity/air-pressure converting means for controlling the air pressures within said air springs; and

control means for driving said electricity/air-pressure converting means in accordance with output signals from said monitoring means.

9. The exposure apparatus according to claim 6, wherein, if a couple of the air springs among said air springs, connected by said air communicating means, us regarded as one air spring, the number of said air springs is three.

10. The exposure apparatus according to claim 6, wherein, with regard to a couple of the air springs among said air springs, connected by said air communicating means, said pressure control means controls air pressure of at least one of the couple of air springs.

11. A control method for a vibration damping apparatus, provided between an upper apparatus and a mounting floor, supporting the upper apparatus with at least four air springs, said method comprising:

a damping step of controlling air pressures of the air springs based on at least one of displacement, speed, and acceleration of the upper apparatus and air pressures within the air springs so as to dampen vibration of the upper apparatus; and

a pressure-difference eliminating step of eliminating an air-pressure difference between at least one couple of air springs among the air springs, caused by said damping step, said pressure-difference eliminating step comprising controlling air flow between at least one couple of the air springs using an air valve in air communicating means, the air valve being positioned in the air flow paths, whereby the difference of the air pressure between the at least one couple of the air springs is equalized by passing air through the air communicating means by the opening of the air valve, thereby creating an equilibrium of air pressures between the at least one couple of air springs.

12. A control method according to claim 11, further comprising controlling a response time in said pressure-difference eliminating step by the air valve.

13. A device manufacturing method by using an exposure apparatus supported by at least four air springs on a mounting floor, said method comprising:

a projection-exposure step of driving stages of the exposure apparatus, and projection-exposing a reticle pattern via a projection optical system onto a sensitized substrate, by a step-and-repeat method;

an air-pressure control step of suppressing vibration caused by driving of the stages of the exposure apparatus, and controlling air pressures of the air springs so as to dampen vibration from the mounting floor to the exposure apparatus; and

a pressure-difference eliminating step of eliminating an air-pressure difference between at least one couple of the air springs among the air springs, caused by said air-pressure control step, said pressure-difference eliminating step comprising controlling air flow between at least one couple of the air springs using an air valve in air communicating means, the air valve being positioned in the air flow path, whereby the difference of the air pressure between the at least one couple of the air springs is equalized by passing air through the air communicating means by the opening of the air valve, thereby creating an equilibrium of air pressures between the at least one couple of air springs.

14. The device manufacturing method according to claim 13, further comprising controlling a response time in said pressure-difference eliminating step by the air valve.