Electric motors and positioning devices having moving magnet arrays and six degrees of freedom

• US 6,208,045 B1
• Filed: 11/16/1998
• Issued: 03/27/2001
• Est. Priority Date: 11/16/1998
• Status: Expired due to Term

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Gery, Jean-Marc, Hazelton, Andrew J., Binnard, Michael B.
• Primary Examiner(s): LaBalle, Clayton
• Assistant Examiner(s): JONES, JUDSON
• Application Number:
  US09/192,813
• Time in Patent Office: 862 Days
• Field of Search: 310/12, 318/135, 33/1.M, 744/71.XY, 108/137, 108/138, 297/21, 297/60, 297/85, 414/935, 414/936
• US Class Current: 310/12.06
• CPC Class Codes: G03F 7/70716 Stages
• CPC Class Codes: G03F 7/70758 Drive means, e.g. actuators, motors for long- or short-stroke modules or fine or coarse driving
• CPC Class Codes: H01L 21/682 Mask-wafer alignment in general G03F7/70, G03F9/70
• CPC Class Codes: H02K 2201/18 Machines moving with multiple degrees of freedom
• CPC Class Codes: H02K 41/03 Synchronous motors; Motors moving step by step; Reluctance motors H02K41/035 takes precedence
• CPC Class Codes: Y10S 414/135 Associated with semiconductor wafer handling

Abstract

A two-dimensional electric motor having a moving magnet and positionable in six degrees of freedom. The electric motor has a coil array and a magnet array. The magnet array has a smaller width than the coil array in the moving magnet embodiment. The invention'"'"'s process of achieving motion of a coil array with respect to a magnet array in six degrees of freedom includes providing an electrical current distribution to a coils. The motion is controlled in a first direction and a vertical direction between a portion of the coils and a portion of the magnet array. The electrical current distribution has two wavelike components having a same period but approximately ninety degrees out of phase. The invention'"'"'s positioning devices do not require air bearings. Instead, the suspension of the support member by magnetic attraction to the frame or by interaction of the coil array and the magnet array replace the air bearings. The invention'"'"'s electric motors and positioning devices should be useful in positioning wafers during semiconductor manufacture.

Claims

1. An electric motor, comprising:

a planar magnet array having magnets with magnetic fields, the magnets being disposed in a plane; and

a planar coil array positioned adjacent to the magnet array and operable to interact with the magnetic fields to provide a force between the coil array and the magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane;

wherein the coil array has a first coil period in the first direction and a second coil period in the second direction and wherein the magnet array has a first magnet period in the first direction and a second magnet period in the second direction, the first coil period being less than the first magnet period and the second coil period being less than the second magnet period.

2. The electric motor of claim 1, wherein said magnet array and said coil array interact to further provide a torque between the coil array and the magnet array about the third direction.

3. The electric motor of claim 1, wherein said magnet array and said coil array interact to further provide a torque between the coil array and the magnet array about the first and second directions.

4. The electric motor of claim 1, further comprising a bearing attached to at least one of said magnet array and said coil array, said bearing supporting said magnet array relative to said coil array.

5. The electric motor of claim 1, wherein the coil array has a first dimension in the first direction and a second dimension in the second direction and wherein the magnet array has a first dimension in the first direction and a second dimension in the second direction, the first coil dimension being larger than the first magnet dimension and the second coil dimension being larger than the second magnet dimension.

6. The electric motor of claim 1, wherein the magnet array includes edge magnets disposed on a periphery of the magnet array and interior magnets disposed interior of the edge magnets, each edge magnet having a magnetic flux less than a magnetic flux of each interior magnet.

7. The electric motor of claim 6, wherein the magnet array has at least one corner and wherein the edge magnets include a corner magnet at each corner of the magnet array, the corner magnets having a magnetic flux less the magnetic flux of other edge magnets.

8. An electric motor, comprising:

a planar magnet array having magnets with magnetic fields, the magnets being disposed in a plane; and

a planar coil array positioned adjacent to the magnet array and operable to interact with the magnetic fields to provide a force between the coil array and the magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane, wherein the magnet array includes edge magnets disposed on a periphery of the magnet array and interior magnets disposed interior of the edge magnets, each edge magnet having a magnetic flux less than a magnetic flux of each interior magnet.

9. The electric motor of claim 8, wherein the magnet array has at least one corner and wherein the edge magnets include a corner magnet at each corner of the magnet array, the corner magnets having a magnetic flux less the magnetic flux of other edge magnets.

10. A positioning device comprising:

a frame having a first surface;

a support having a first surface;

a magnet array having magnets with magnetic fields disposed in a plane on the first surface of one of the frame and support;

a coil array disposed on the first surface of the other of the frame and support, the coil array being positioned adjacent to the magnet array and operable to interact with the magnetic fields to provide a force between the coil array and the magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane; and

at least one air bearing attached to at least one of said frame and support, said bearing movably supporting said magnet array and said coil array relative to each other generally in the third direction.

11. A positioning device comprising:

a frame having a first surface;

a support having a first surface;

a magnet array having magnets with magnetic fields disposed in a plane on the first surface of one of the frame and support; and

a coil array disposed on the first surface of the other of the frame and support, the coil array being positioned adjacent to the magnet array and operable to interact with the magnetic fields to provide a force between the coil array and the magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane;

wherein said frame and support are magnetically supported relative to each other, and wherein one of the frame and support includes at least one support magnet and at least a portion of the other of the frame and support comprises a magnetically permeable material, the support magnet and the magnetically permeable material interact to support the magnet array relative to the coil array.

12. The positioning device of claim 11, wherein the support is adapted to support a wafer, the support being magnetically suspended from the frame.

13. The positioning device of claim 12, wherein the support has a second surface opposing the first surface, the second surface of the support being adapted to support the wafer, wherein the magnet array is disposed on the first surface of the support.

14. The positioning device of claim 12, wherein the support has a second surface opposing the first surface, the second surface of the support being adapted to support the wafer, wherein the coil array is disposed on the first surface of the support.

15. The positioning device of claim 11, wherein each of the frame and the support has a second surface, further comprising:

a second magnet array having second magnets with second magnetic fields disposed in a plane on one of the second frame surface and the second support surface; and

a second coil array disposed on a plane on the other of the second frame surface and the second support surface, the second coil array being positioned adjacent to the second magnet array and operable to interact with the second magnetic fields to provide a second force between the second coil array and the second magnet array in the first, second and third directions.

16. The positioning device of claim 15, wherein the force provided by the coil array and the magnet array and the second force provided by the second coil array and the second magnet array combine to position the support relative to the frame.

17. The positioning device of claim 15, wherein the magnet arrays are disposed on the first and second surfaces of the support.

18. The positioning device of claim 15, wherein the coil arrays are disposed on the first and second surfaces of the support.

19. The positioning device of claim 15, wherein the magnet arrays are disposed on one of the surfaces of the support and one of the surfaces of the frame.

20. The positioning device of claim 15, wherein the second magnet array is disposed on the second frame surface and the second coil array is disposed on the second support surface.

21. A positioning device comprising:

a frame having a first surface;

a support having a first surface;

a magnet array having magnets with magnetic fields disposed in a plane on the first surface of one of the frame and support; and

a coil array disposed on the first surface of the other of the frame and support, the coil array being positioned adjacent to the magnet array and operable to interact with the magnetic fields to provide a force between the coil array and the magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane;

wherein said frame and support are magnetically supported relative to each other, said support is magnetically suspended from said frame, said support has a second surface opposing the first surface, said second surface of said support being adapted to support a wafer, and wherein said coil array is disposed on said first surface of said support.

22. A positioning device comprising:

a frame having first and second surfaces;

a support having first and second surfaces;

a first magnet array having first magnets with first magnetic fields disposed in a plane on the first surface of the frame;

a first coil array disposed on the first surface of the support, the first coil array being positioned adjacent to the first magnet array and operable to interact with the first magnetic fields to provide a force between the first coil array and the first magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane;

a second magnet array having second magnets with second magnetic fields disposed in a plane on the second frame surface; and

a second coil array disposed on a plane on the second support surface, the second coil array being positioned adjacent to the second magnet array and operable to interact with the second magnetic fields to provide a second force between the second coil array and the second magnet array in the first, second and third directions.

23. A positioning device comprising:

a frame having first and second surfaces;

a support having first and second surfaces;

a first magnet array having first magnets with first magnetic fields disposed in a plane on the first surface of one of the frame and support;

a first coil array disposed on the first surface of the other of the frame and support, the first coil array being positioned adjacent to the first magnet array and operable to interact with the first magnetic fields to provide a force between the first coil array and the first magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane;

a second magnet array having second magnets with second magnetic fields disposed in a plane on one of the second frame surface and the second support surface; and

a second coil array disposed on a plane on the other of the second frame surface and the second support surface, the second coil array being positioned adjacent to the second magnet array and operable to interact with the second magnetic fields to provide a second force between the second coil array and the second magnet array in the first, second and third directions;

wherein the magnet arrays are disposed on one of the surfaces of the support and one of the surfaces of the frame.

24. A positioning device comprising:

a frame having first and second surfaces;

a support having first and second surfaces;

a first magnet array having first magnets with first magnetic fields disposed in a plane on the first surface of one of the frame and support;

a first coil array disposed on the first surface of the other of the frame and support, the first coil array being positioned adjacent to the first magnet array and operable to interact with the first magnetic fields to provide a force between the first coil array and the first magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane;

a second magnet array having second magnets with second magnetic fields disposed in a plane on the second frame surface; and

a second coil array disposed on a plane on the second support surface, the second coil array being positioned adjacent to the second magnet array and operable to interact with the second magnetic fields to provide a second force between the second coil array and the second magnet array in the first, second and third directions.

25. An exposure apparatus, comprising:

an optical system for imaging a pattern onto an article, the optical system comprising a frame;

a stage device for positioning of the article relative to the optical system for imaging, comprising;

a stage movable relative to the optical system and having a first surface and a second surface, the second surface being adapted for supporting the article;

a magnet array having magnets with magnetic fields, the magnets being disposed in a plane; and

a planar coil array positioned adjacent to the magnet array and operable to interact with the magnetic fields to provide a force between the coil array and the magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane, one of the magnet array and the coil array being attached to the frame and the other of the magnet array and the coil array being attached to the first surface of the stage, wherein the stage is magnetically supported relative to the optical system, and wherein one of the frame and stage includes at least one support magnet and the other of the frame and stage comprises a magnetically permeable material, the support magnet and the magnetically permeable material interact to support the magnet array relative to the coil array.

26. The exposure apparatus of claim 25, wherein the magnet array is movable relative to the coil array in six degrees of freedom.

27. The exposure apparatus of claim 25, wherein the stage is magnetically suspended from the frame.

28. The exposure apparatus of claim 27, wherein the coil array is disposed on the first surface of the stage.

29. The exposure apparatus of claim 27, wherein the magnet array is disposed on the first surface of the stage.

30. The exposure apparatus of claim 29, wherein the frame comprises a magnetically permeable material such that the magnet array and the frame interact to suspend the stage and the magnet array relative to the frame.

31. An exposure apparatus, comprising:

an optical system for imaging a pattern onto an article, the optical system comprising a frame;

a stage device for positioning of the article relative to the optical system for imaging, comprising;

a stage movable relative to the optical system and having a first surface and a second surface, the second surface being adapted for supporting the article;

a magnet array having magnets with magnetic fields, the magnets being disposed in a plane; and

a planar coil array positioned adjacent to the magnet array and operable to interact with the magnetic fields to provide a force between the coil array and the magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane, one of the magnet array and the coil array being attached to the frame and the other of the magnet array and the coil array being attached to the first surface of the stage, wherein the stage is magnetically supported relative to the optical system, the stage is magnetically suspended from the frame, and the coil array is disposed on the first surface of the stage.

32. An exposure apparatus, comprising:

an optical system for imaging a pattern onto an article, the optical system comprising a frame;

a stage device for positioning of the article relative to the optical system for imaging, comprising;

a stage movable relative to the optical system and having a first surface and a second surface, the second surface being adapted for supporting the article;

a magnet array having magnets with magnetic fields, the magnets being disposed in a plane; and

a planar coil array positioned adjacent to the magnet array and operable to interact with the magnetic fields to provide a force between the coil array and the magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane, one of the magnet array and the coil array being attached to the frame and the other of the magnet array and the coil array being attached to the first surface of the stage, wherein the magnet array is disposed on the first surface of the stage, and the frame comprises a magnetically permeable material such that the magnet array and the frame interact to suspend the stage and the magnet array relative to the frame.

33. An exposure apparatus, comprising:

an optical system for imaging a pattern onto an article, the optical system comprising a frame having first and second surfaces;

a stage device for positioning of the article relative to the optical system for imaging, comprising;

a stage movable relative to the optical system and having a first surface and a second surface, the second surface being adapted for supporting the article;

a first magnet array having first magnets with first magnetic fields, the first magnets being disposed in a plane and attached to the first surface of the frame; and

a first planar coil array positioned adjacent to the first magnet array and operable to interact with the first magnetic fields to provide a force between the first coil array and the first magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane, the first coil array being attached to the first surface of the stage;

a second planar magnet array having second magnets with second magnetic fields on the second surface of the frame; and

a second planar coil array disposed on the second surface of the stage, the second coil array being positioned adjacent to the second magnet array and operable to interact with the second magnetic fields to provide a second force between the second coil array and the second magnet array in the first, second and third directions.

34. The exposure apparatus of claim 33, wherein the force provided by the coil array and the magnet array and the second force provided by the second coil array and the second magnet array combine to position the stage relative to the frame.

35. An exposure apparatus, comprising:

an optical system for imaging a pattern onto an article, the optical system comprising a frame having first and second surfaces;

a stage device for positioning of the article relative to the optical system for imaging, comprising;

a stage movable relative to the optical system and having a first surface and a second surface, the second surface being adapted for supporting the article;

a first magnet array having first magnets with first magnetic fields, the first magnets being disposed in a plane; and

a first planar coil array positioned adjacent to the magnet array and operable to interact with the first magnetic fields to provide a force between the first coil array and the first magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane, one of the first magnet array and the first coil array being attached to the first surface of the frame and the other of the first magnet array and the first coil array being attached to the first surface of the stage;

a second planar magnet array having second magnets with second magnetic fields on the second surface of one of the frame and stage; and

a second planar coil array disposed on the second surface of the other of the frame and stage, the second coil array being positioned adjacent to the second magnet array and operable to interact with the second magnetic fields to provide a second force between the second coil array and the second magnet array in the first, second and third directions, wherein the magnet arrays are disposed on one of the surfaces of the stage and one of the surfaces of the frame.

36. An exposure apparatus, comprising:

an optical system for imaging a pattern onto an article, the optical system comprising a frame having first and second surfaces;

a stage device for positioning of the article relative to the optical system for imaging, comprising;

a stage movable relative to the optical system and having a first surface and a second surface, the second surface being adapted for supporting the article;

a first magnet array having first magnets with first magnetic fields, the first magnets being disposed in a plane; and

a first planar coil array positioned adjacent to the first magnet array and operable to interact with the first magnetic fields to provide a force between the first coil array and the first magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane, one of the first magnet array and the first coil array being attached to the first surface of the frame and the other of the first magnet array and the first coil array being attached to the first surface of the stage;

a second planar magnet array having second magnets with second magnetic fields on the second surface of the frame; and

a second planar coil array disposed on the second surface of the stage, the second coil array being positioned adjacent to the second magnet array and operable to interact with the second magnetic fields to provide a second force between the second coil array and the second magnet array in the first, second and third directions.

37. An electric motor, comprising:

a moving planar magnet array having an area and magnets with magnetic fields, the magnets being disposed in a plane; and

a stationary planar coil array having an area larger than the area of the magnet array, the coil array being positioned adjacent to the magnet array and operable to interact with the magnetic fields to provide a force between the coil array and the magnet array in a first and a second direction generally parallel to the plane, wherein the coil array has a first coil period in the first direction and a second coil period in the second direction and wherein the magnet array has a first magnet period in the first direction and a second magnet period in the second direction, the first coil period being less than the first magnet period and the second coil period being less than the second magnet period.

38. The electric motor of claim 37, wherein the coil array is positioned and operable to interact with the magnetic fields of the magnet array to provide a torque between the coil array and the magnet array about a third direction generally orthogonal to the plane.

39. The electric motor of claim 38, wherein said magnet array and said coil array interact to further provide a torque between the coil array and the magnet array about the first and second directions.

40. The electric motor of claim 37, further comprising a bearing attached to at least one of said magnet array and said coil array, said bearing supporting said magnet array relative to said coil array.

41. An electric motor, comprising:

a moving planar magnet array having an area and magnets with magnetic fields, the magnets being disposed in a plane, wherein the magnet array includes edge magnets disposed on a periphery of the magnet array and interior magnets disposed interior of the edge magnets, each edge magnet having a magnetic flux less than a magnetic flux of each interior magnet; and

a stationary planar coil array having an area larger than the area of the magnet array, the coil array being positioned adjacent to the magnet array and operable to interact with the magnetic fields to provide a force between the coil array and the magnet array in a first and a second direction generally parallel to the plane.

42. The electric motor of claim 41, wherein the magnetic flux of each edge magnet is approximately one half the magnetic flux of each interior magnet.

43. The electric motor of claim 41, wherein the magnet array has at least one corner and wherein the edge magnets include a corner magnet at each corner of the magnet array, the corner magnets having a magnetic flux less the magnetic flux of other edge magnets.

44. The electric motor of claim 43, wherein the magnetic flux of each edge magnet is approximately one half the magnetic flux of each interior magnet and the magnetic flux of each corner magnet is approximately one quarter the magnetic flux of each interior magnet.

45. A positioning device comprising:

a frame having a first surface;

a support having a first surface;

a moving magnet array having magnets with magnetic fields disposed in a plane on the first surface of the support;

a stationary coil array disposed on the first surface of the frame, the coil array being positioned adjacent to the magnet array and operable to interact with the magnetic fields to provide a force between the coil array and the magnet array in a first and second direction generally parallel to the plane; and

at least one air bearing attached to at least one of said frame and support, said air bearing movably supporting said magnet array and said coil array relative to each other generally in the third direction generally orthogonal to the plane.

46. The positioning device of claim 45, wherein the coil array is positioned and operable to interact with the magnetic fields of the magnet array to provide a torque between the coil array and the magnet array about a third direction generally orthogonal to the plane.

47. The positioning device of claim 45, wherein the coil array is positioned and operable to interact with the magnetic fields of the magnet array to provide a force in a third direction generally orthogonal to the plane.

48. The positioning device of claim 47, wherein the coil array is positioned and operable to interact with the magnetic fields of the magnet array to provide a torque about the first and second directions.

49. A positioning device comprising:

a frame having a first surface;

a support having a first surface;

a moving magnet array having magnets with magnetic fields disposed in a plane on the first surface of the support; and

a stationary coil array disposed on the first surface of the frame, the coil array being positioned adjacent to the magnet array and operable to interact with the magnetic fields to provide a force between the coil array and the magnet array in a first and second direction generally parallel to the plane, wherein said frame and support are magnetically supported relative to each other, one of said frame and support including at least one support magnet and at least a portion of the other of the frame and support comprising a magnetically permeable material, the support magnet and the magnetically permeable material interacting to support the magnet array relative to the coil array.

50. The positioning device of claim 49, wherein the support is adapted to support a wafer, the support being magnetically suspended from the frame.

51. The positioning device of claim 49, wherein the support has a second surface opposing the first surface, the second surface of the support being adapted to support the wafer, wherein the magnet array is disposed on the first surface of the support.

52. A positioning device comprising:

a frame having a first surface;

a support having a first surface;

a moving magnet array having magnets with magnetic fields disposed in a plane on the first surface of the support, said magnet array including edge magnets disposed on a periphery of the magnet array and interior magnets disposed interior of the edge magnets, each edge magnet having a magnetic flux less than a magnetic flux of each interior magnet; and

a stationary coil array disposed on the first surface of the frame, the coil array being positioned adjacent to the magnet array and operable to interact with the magnetic fields to provide a force between the coil array and the magnet array in a first and second direction generally parallel to the plane.

53. The positioning device of claim 52, wherein the magnetic flux of each edge magnet is approximately one half the magnetic flux of each interior magnet.

54. The positioning device of claim 52, wherein the magnet array has at least one corner and wherein the edge magnets include a corner magnet at each corner of the magnet array, the corner magnets having a magnetic flux less the magnetic flux of other edge magnets.

55. The positioning device of claim 54, wherein the magnetic flux of each edge magnet is approximately one half the magnetic flux of each interior magnet and the magnetic flux of each corner magnet is approximately one quarter the magnetic flux of each interior magnet.

56. An exposure apparatus, comprising:

an optical system for imaging a pattern onto an article, the optical system comprising a frame;

a stage device for positioning of the article relative to the optical system for imaging, comprising;

a stage movable relative to the optical system and having a first surface and a second surface, the second surface being adapted for supporting the article;

a magnet array having magnets with magnetic fields, the magnets being disposed in a plane on the first stage surface, wherein the magnet array includes edge magnets disposed on a periphery of the magnet array and interior magnets disposed interior of the edge magnets, each edge magnet having a magnetic flux less than a magnetic flux of each interior magnet; and

a planar coil array positioned on the frame adjacent to the magnet array and operable to interact with the magnetic fields to provide a force between the coil array and the magnet array in first and second directions generally parallel to the plane.

57. The exposure apparatus of claim 56, wherein the magnetic flux of each edge magnet is approximately one half the magnetic flux of each interior magnet.

58. The exposure apparatus of claim 56, wherein the magnet array has at least one corner and wherein the edge magnets include a corner magnet at each corner of the magnet array, the corner magnets having a magnetic flux less the magnetic flux of other edge magnets.

59. The exposure apparatus of claim 58, wherein the magnetic flux of each edge magnet is approximately one half the magnetic flux of each interior magnet and the magnetic flux of each corner magnet is approximately one quarter the magnetic flux of each interior magnet.

60. A method for positioning an object, comprising:

providing a planar magnet array having magnets with magnetic fields and disposing the magnets in a plane;

providing a planar coil array adjacent to the magnet array and with a first coil period in a first direction generally parallel to the plane and a second coil period in a second direction generally parallel to the plane and wherein providing the planar magnet array includes providing the magnet array with a first magnet period in the first direction greater than the first coil period and a second magnet period in the second direction greater than the second coil period; and

applying one or more currents to one or more coils of the coil array to interact with the magnetic fields to generate a force between the coil array and the magnet array in the first, second and a third direction, the third direction being generally orthogonal to the plane.

61. The method of claim 60, wherein the applying one or more currents further interacts with the magnetic fields to generate a torque between the coil array and the magnet array about the first, second and third directions.

62. The method of claim 60, further comprising providing a bearing attached to at least one of said magnet array and said coil array to support said magnet array relative to said coil array.

63. A method for positioning an object, comprising:

providing a planar magnet array having magnets with magnetic fields and disposing the magnets in a plane;

providing a planar coil array adjacent to the magnet array, such that the planar coil array has a first dimension in a first direction and a second dimension in a second direction and the magnet array includes a first dimension in the first direction less than the first coil dimension and a second dimension in the second direction less than the second coil dimension; and

applying one or more currents to one or more coils of the coil array to interact with the magnetic fields to generate a force between the coil array and the magnet array in the first, second and a third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane.

64. A method for positioning an object, comprising:

providing a planar magnet array having magnets with magnetic fields and disposing the magnets in a plane, wherein the magnets include edge magnets disposed on a periphery of the magnet array and interior magnets disposed interior of the edge magnets and having a magnetic flux greater than a magnetic flux of each edge magnet;

providing a planar coil array adjacent to the magnet array; and

applying one or more currents to one or more coils of the coil array to interact with the magnetic fields to generate a force between the coil array and the magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane.

65. A method for positioning an object, comprising:

providing a planar magnet array having magnets with magnetic fields and disposing the magnets in a plane, wherein the magnet array includes edge magnets and at least one corner, and providing a corner magnet at each corner of the magnet array having a magnetic flux less the magnetic flux of the edge magnets;

providing a planar coil array adjacent to the magnet array; and

applying one or more currents to one or more coils of the coil array to interact with the magnetic fields to generate a force between the coil array and the magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane.

66. A method for positioning a wafer in a lithography system, comprising:

providing a frame;

providing a stage for supporting the wafer and movable to position the wafer relative to the frame;

providing a planar magnet array having magnets with magnetic fields disposed in a plane and attached to one of the frame and stage;

providing a planar coil array adjacent to the magnet array and attached to the other of the frame and stage;

providing one of the frame and stage with at least one support magnet;

providing at least a portion of the other of the frame and stage with a magnetically permeable material such that the support magnet and the magnetically permeable material interact to support the magnet array relative to the coil array; and

applying one or more currents to one or more coils of the coil array to interact with the magnetic fields to generate a force between the coil array and the magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane.

67. The method of claim 66, wherein providing the stage includes providing a first stage surface and a second stage surface, the second stage surface being adapted for supporting the wafer and wherein one of the providing the magnet array and providing the coil array includes providing one of the magnet array and the coil array on the first surface of the stage.

68. The method of claim 67, wherein the providing the magnet array includes providing the magnet array on the first stage surface.

69. The method of claim 67, wherein the providing the frame includes providing at least a portion of the frame with a magnetically permeable material such that the magnet array and the magnetically permeable material interact to support the magnet array and the stage relative to the frame.

70. The method of claim 67, wherein the providing the coil array includes providing the coil array on the first stage surface.

71. The method of claim 67, wherein providing the frame includes providing a frame with a first surface having one of the magnet array and the coil array disposed thereon and a second surface, further comprising:

providing a second planar magnet array having second magnets with second magnetic fields disposed on the second surface of one of the frame and stage;

providing a second coil array adjacent to the second magnet array and disposed in a plane on the second surface of the other of the frame and stage; and

applying one or more currents to one or more coils of the second coil array to interact with the second magnetic fields to generate a second force between the second coil array and the second magnet array in the first, second and third directions.

72. A method for positioning a wafer in a lithography system, comprising:

providing a frame;

providing a stage for supporting the wafer and movable to position the wafer relative to the frame;

providing a planar magnet array having magnets with magnetic fields disposed in a plane and attached to one of the frame and stage;

providing a planar coil array adjacent to the magnet array and attached to the other of the frame and stage;

providing an air bearing on the stage to suspend the stage relative to the frame; and

applying one or more currents to one or more coils of the coil array to interact with the magnetic fields to generate a force between the coil array and the magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane.

73. A method for positioning a wafer in a lithography system, comprising:

providing a frame, including providing at least a portion of the frame with a magnetically permeable material such that the magnet array and the magnetically permeable material interact to support the magnet array and the stage relative to the frame;

providing a stage for supporting the wafer and movable to position the wafer relative to the frame, including providing a first stage surface and a second stage surface, the second stage surface being adapted for supporting the wafer and;

providing a planar magnet array having magnets with magnetic fields disposed in a plane and attached to one of the frame and stage;

providing a planar coil array adjacent to the magnet array and attached to the other of the frame and stage; and

applying one or more currents to one or more coils of the coil array to interact with the magnetic fields to generate a force between the coil array and the magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane;

wherein one of the providing the magnet array and providing the coil array includes providing one of the magnet array and the coil array on the first surface of the stage.

74. A method for positioning a wafer in a lithography system, comprising:

providing a frame;

providing a stage for supporting the wafer and movable to position the wafer relative to the frame, including providing a first stage surface and a second stage surface, the second stage surface being adapted for supporting the wafer and;

providing a planar magnet array having magnets with magnetic fields disposed in a plane and attached to one of the frame and stage;

providing a planar coil array adjacent to the magnet array and attached to the other of the frame and stage, including providing the coil array on the first stage surface; and

applying one or more currents to one or more coils of the coil array to interact with the magnetic fields to generate a force between the coil array and the magnet array in a first, second and third direction, the first and second directions being generally parallel to the plane and the third direction being generally orthogonal to the plane;

wherein one of the providing the magnet array and providing the coil array includes providing one of the magnet array and the coil array on the first surface of the stage.