Exposure apparatus having reaction frame

• US 6,271,640 B1
• Filed: 11/10/1999
• Issued: 08/07/2001
• Est. Priority Date: 04/01/1994
• Status: Expired due to Term

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Lee, Martin E.
• Primary Examiner(s): Ro, Bentsu
• Assistant Examiner(s): Smith, Tyrone W
• Application Number:
  US09/437,608
• Time in Patent Office: 636 Days
• Field of Search: 318/560-579, 318/625, 318/648, 318/649, 744/790.1, 744/80.R, 744/900--49, 108/137-143, 248/638, 248/651, 248/656, 248/657, 248/913, 269/55, 269/56, 269/58, 269/60, 269/71, 269/73, 250/492.1, 250/492.2, 250/492.22, 378/177, 378/178, 378/195, 378/196, 378/201, 378/208, 378/209, 378/34, 378/35, 356/357, 356/358, 356/399-401, 414/282, 414/331, 414/618, 414/627, 414/743, 414/749, 414/750, 355/53, 355/55, 355/43
• US Class Current: 318/560
• CPC Class Codes: G03F 7/70716 Stages
• CPC Class Codes: G03F 7/709 Vibration, e.g. vibration detection, compensation, suppression or isolation
• CPC Class Codes: H01L 21/68 for positioning, orientation or alignment
• CPC Class Codes: H01L 21/682 Mask-wafer alignment in general G03F7/70, G03F9/70
• CPC Class Codes: Y10T 74/20207 Multiple controlling elements for single controlled element

Abstract

A guideless stage for aligning a wafer in a microlithography system is disclosed, and a reaction frame is disclosed which isolates both external vibrations as well as vibrations caused by reaction forces from an object stage. In the guideless stage an object stage is disclosed for movement in at least two directions and two separate and independently movable followers move and follow the object stage and cooperating linear force actuators are mounted on the object stage and the followers for positioning the object stage in the first and second directions. The reaction frame is mounted on a base structure independent of the base for the object stage so that the object stage is supported in space independent of the reaction frame. At least one follower is disclosed having a pair of arms which are respectively movable in a pair of parallel planes with the center of gravity of the object stage therebetween. The linear positioning forces of the actuator drive means are mounted and controlled so that the vector sum of the moments of force at the center of gravity of the object stage due to the positioning forces of the drive means is substantially equal to zero. The actuator mounting means can include at least two thin flexible members mounted in series with the primary direction of flex of the members being orthogonal to one another.

Claims

1. An exposure apparatus that transfers an image onto an object, comprising:

a support structure;

an exposure device, supported on the support structure, to expose the image onto the object;

a stage movably supported by the support structure;

a reaction frame that is dynamically isolated from the support structure; and

a drive, connected at least partly to the reaction frame, to move the stage, wherein a reaction force caused by the movement of the stage is transferred substantially to the reaction frame.

2. An apparatus according to claim 1, wherein the support structure and the reaction frame are supported on a foundation.

3. An apparatus according to claim 2, wherein the support structure is mounted on the foundation with a block between the support structure and the foundation.

4. An apparatus according to claim 3, wherein the block comprises a vibration absorbing assembly that prevents transmission of vibration from the foundation to the support structure.

5. An apparatus according to claim 2, wherein the foundation is the ground or a base structure.

6. An apparatus according to claim 5, wherein the stage is located between the exposure device and the foundation;

and

the drive has a first portion, located between the exposure device and the foundation, that is connected to the stage, and a second portion, located other than between the exposure device and the foundation, that is connected to the reaction frame.

7. An apparatus according to claim 6, wherein the support structure includes at least three spaced apart blocks on the foundation.

8. An apparatus according to claim 6, wherein the first portion of the drive is electromagnetically coupled to the stage.

9. An apparatus according to claim 6, wherein the exposure device includes a projection system that projects the image.

10. An apparatus according to claim 9, wherein the projection system optically projects the image.

11. An apparatus according to claim 6, wherein the exposure device includes a mask holder that holds a mask which defines the image.

12. An apparatus according to claim 6, wherein the reaction frame has at least one support post that extends downward to rest on the foundation, and the second portion of the drive is connected to the at least one support post.

13. An apparatus according to claim 1, wherein the exposure device includes a mask holder that holds a mask which defines the image.

14. An apparatus according to claim 1, wherein the exposure device includes a projection system that projects the image.

15. An apparatus according to claim 14, wherein the projection system optically projects the image.

16. An apparatus according to claim 14, wherein the exposure device includes a mask holder that holds a mask which defines the image.

17. An apparatus according to claim 16, wherein the projection system is disposed between the mask and the object.

18. An apparatus according to claim 1, wherein the stage is a wafer stage on which the object is supported.

19. An apparatus according to claim 1, wherein the stage is a guideless stage having no associated guide member to guide its movement.

20. An apparatus according to claim 19, wherein the support structure includes a base, and the guideless stage is two-dimensionally movable over a surface of the base on a bearing.

21. An apparatus according to claim 20, wherein the bearing is a non-contact bearing that supports the guideless stage.

22. An apparatus according to claim 21, wherein the bearing comprises an air bearing.

23. An apparatus according to claim 21, wherein the bearing includes a magnet and a cooperating coil.

24. An apparatus according to claim 1, wherein the drive comprises a linear motor.

25. An apparatus according to claim 1, wherein the drive rotates the stage on an axis of the stage.

26. An apparatus according to claim 1, wherein the drive moves the stage in a two-dimensional plane, including movement in a first linear direction, a second linear direction and a rotative direction on an axis of the stage.

27. An apparatus according to claim 1, wherein the drive includes a first portion mounted on the reaction frame, and a second portion connected to the stage and movable relative to the first portion.

28. An apparatus according to claim 27, further comprising a drive mechanism that moves the first portion.

29. An apparatus according to claim 27, wherein the first portion comprises a drive track, and the second portion comprises a drive coil.

30. An exposure apparatus that transfers an image onto an object, comprising

a base having a surface and no guide member;

a stage movably supported by the base to move above the surface, the stage having no associated member to guide its movement on the base;

a drive that drives the stage in a two-dimensional plane including movement in a first linear direction, a second linear direction and a rotative direction about an axis of the stage; and

a reaction frame that is different from the base, wherein a reaction force caused by the movement of the stage is transferred to the reaction frame.

31. An apparatus according to claim 30, wherein the stage is a wafer stage on which the object is supported.

32. An apparatus according to claim 30, wherein the drive comprises a plurality of actuators.

33. An apparatus according to claim 30, wherein the drive includes a first portion connected to the reaction frame and a second portion connected to the stage and movable relative to the first portion.

34. An apparatus according to claim 30, further comprising a mask holder that holds a mask which defines the image.

35. An apparatus according to claim 30, further comprising a projection system that projects the image.

36. An apparatus according to claim 35, wherein the projection system optically projects the image.