Patent Number: 
Section: claims

1. A magnetic shunt assembly for an apparatus, the apparatus including an optical assembly, a gap near the optical assembly, a stage, and a mover assembly that moves the stage along an axis in the gap, the mover assembly generating a magnetic field, the magnetic shunt assembly comprising: a first magnetic shunt positioned approximately between the optical assembly and the mover assembly, the first magnetic shunt being made of a magnetic permeable material, the first magnetic shunt providing a low magnetic reluctance path that redirects at least a portion of the magnetic field away from the gap. 2. The magnetic shunt assembly of  claim 1  wherein the first magnetic shunt is spaced apart from the stage. claim 1 3. The magnetic shunt assembly of  claim 1  wherein the first magnetic shunt is spaced apart from the optical assembly. claim 1 4. The magnetic shunt assembly of  claim 1  wherein the first magnetic shunt is substantially tubular shaped and substantially encircles at least a portion of the optical assembly. claim 1 5. The magnetic shunt assembly of  claim 1  wherein the first magnetic shunt is generally flat plate shaped. claim 1 6. The magnetic shunt assembly of  claim 1  wherein the first magnetic shunt has a substantially xe2x80x9cLxe2x80x9d shaped cross-section. claim 1 7. The magnetic shunt assembly of  claim 1  wherein the first magnetic shunt redirects at least approximately 10 percent of the magnetic field away from the gap. claim 1 8. The magnetic shunt assembly of  claim 1  wherein the first magnetic shunt redirects the at least approximately 50 percent of the magnetic field away from the gap. claim 1 9. The magnetic shunt assembly of  claim 1  further comprising a second magnetic shunt positioned approximately between the optical assembly and the mover assembly, the second magnetic shunt being made of a magnetically permeable material. claim 1 10. The magnetic shunt assembly of  claim 9  wherein the first magnetic shunt and the second magnetic shunt are positioned on opposite sides of the stage. claim 9 11. The magnetic shunt assembly of  claim 9  wherein the first magnetic shunt and the second magnetic shunt are positioned on opposite sides of the optical assembly. claim 9 12. The magnetic shunt assembly of  claim 1  wherein the first magnetic shunt does not move relative to the optical assembly during operation of the stage assembly. claim 1 13. A stage assembly comprising a stage, a mover assembly, a container that encloses the stage and the magnetic shunt assembly of  claim 1 , wherein the first magnetic shunt is coupled to the container. claim 1 14. The stage assembly of  claim 13  wherein the magnetic shunt assembly includes at least one container magnetic shunt that is positioned along a wall of the container. claim 13 15. An apparatus including the magnetic shunt assembly of  claim 1  and an illumination source. claim 1 16. An object on which an image has been formed with the apparatus of  claim 15 . claim 15 17. A semiconductor wafer on which an image has been formed with the exposure apparatus of  claim 15 . claim 15 18. A stage assembly for moving a device for an apparatus, the apparatus including an optical assembly, a gap near the optical assembly, the stage assembly comprising: a stage that retains the device;  a mover assembly that moves the stage along an axis in the gap, the mover assembly generating a magnetic field; and  a first magnetic shunt positioned approximately between the optical assembly and the mover assembly, the first magnetic shunt being spaced apart from the stage, the first magnetic shunt being made of a magnetic permeable material, the first magnetic shunt providing a low magnetic reluctance path that redirects at least a portion of the magnetic field away from the gap. 19. The stage assembly of  claim 18  wherein the first magnetic shunt is spaced apart from the optical assembly. claim 18 20. The stage assembly of  claim 18  wherein the first magnetic shunt is substantially tubular shaped and substantially encircles at least a portion of the optical assembly. claim 18 21. The stage assembly of  claim 18  wherein the first magnetic shunt is generally flat plate shaped. claim 18 22. The stage assembly of  claim 18  wherein the first magnetic shunt has a substantially xe2x80x9cLxe2x80x9d shaped cross-section. claim 18 23. The stage assembly of  claim 18  wherein the first magnetic shunt redirects at least approximately 10 percent of the magnetic field away from the gap. claim 18 24. The stage assembly of  claim 18  wherein the first magnetic shunt redirects at least approximately 50 percent of the magnetic field away from the gap. claim 18 25. The stage assembly of  claim 18  further comprising a second magnetic shunt positioned approximately between the optical assembly and the mover assembly, the second magnetic shunt being made of a magnetically permeable material. claim 18 26. The stage assembly of  claim 25  wherein the first magnetic shunt and the second magnetic shunt are positioned on opposite sides of the stage. claim 25 27. The stage assembly of  claim 25  wherein the first magnetic shunt and the second magnetic shunt are positioned on opposite sides of the optical assembly. claim 25 28. The stage assembly of  claim 18  wherein the first magnetic shunt does not move relative to the optical assembly during operation of the stage assembly. claim 18 29. The stage assembly of  claim 18  further comprising a container that encloses the stage, wherein the first magnetic shunt is coupled to the container. claim 18 30. The stage assembly of  claim 18  wherein the magnetic shunt assembly includes at least one container magnetic shunt that is positioned along a wall of the container. claim 18 31. An exposure apparatus including the magnetic shunt assembly of  claim 18  and an illumination source. claim 18 32. An object on which an image has been formed with the exposure apparatus of  claim 31 . claim 31 33. A semiconductor wafer on which an image has been formed with the exposure apparatus of  claim 31 . claim 31 34. A method for reducing stray magnetic fields in a gap of an apparatus, the apparatus including an optical assembly, a stage, and a mover assembly that moves the stage along an axis in the gap, the mover assembly generating a magnetic field, the method comprising the step of: positioning a first magnetic shunt positioned approximately between the optical assembly and the mover assembly, the first magnetic shunt being made of a magnetic permeable material, the first magnetic shunt providing a low magnetic reluctance path that redirects at least a portion of the magnetic field away from the gap. 35. The method of  claim 34  wherein the step of positioning the first magnetic shunt includes the step of spacing the first magnetic shunt apart from the stage. claim 34 36. The method of  claim 34  wherein the step of positioning the first magnetic shunt includes the step of spacing the first magnetic shunt apart from the optical assembly. claim 34 37. The method of  claim 34  wherein the step of positioning the first magnetic shunt includes the step of providing a first magnetic shunt that is substantially tubular shaped, the first magnetic shunt substantially encircling at least a portion of the optical assembly. claim 34 38. The method of  claim 34  wherein the step of positioning the first magnetic shunt includes the step of prQviding a first magnetic shunt that is substantially flat plate shaped. claim 34 39. The method of  claim 34  wherein the step of positioning the first magnetic shunt includes the step of providing a first magnetic shunt that has a substantially xe2x80x9cLxe2x80x9d shaped cross-section. claim 34 40. The method of  claim 34  further comprising the step of positioning a second magnetic shunt approximately between the optical assembly and the mover assembly, the second magnetic shunt being made of a magnetically permeable material. claim 34 41. The method of  claim 40  wherein the step of positioning the second magnetic shunt includes the step of positioning the second magnetic shunt on the opposite side of the stage from the first magnetic shunt. claim 40 42. The method of  claim 40  wherein the step of positioning the second magnetic shunt includes the step of positioning the second magnetic shunt on the opposite side of the optical assembly from the first magnetic shunt. claim 40 43. A method for making an exposure apparatus that transfers a pattern from a first object onto a second object, the method comprising the steps of: providing an illumination system that illuminates the first object supported by a stage to form the image on the second object, the first object being positioned in a gap; and  reducing stray magnetic fields in the gap with the method of  claim 34 .  claim 34 44. A method for making a device utilizing the exposure apparatus made by the method of  claim 43 . claim 43 45. A method for exposing a semiconductor wafer utilizing the exposure apparatus made by the method of  claim 43 . claim 43 46. A method for making a stage assembly that moves a device for an apparatus, the apparatus including an optical assembly, and a gap near the optical assembly, the method comprising the steps of: providing a stage that retains the device;  moving the stage along an axis in the gap with a mover assembly, the mover assembly generating a magnetic field; and  positioning a first magnetic shunt approximately between the optical assembly and the mover assembly, the first magnetic shunt being spaced apart from the stage, the first magnetic shunt being made of a magnetic permeable material, the first magnetic shunt providing a low magnetic reluctance path that redirects at least a portion of the magnetic field away from the gap. 47. The method of  claim 46  wherein the step of positioning the first magnetic shunt includes the step of spacing the first magnetic shunt apart from the optical assembly. claim 46 48. The method of  claim 46  wherein the step of positioning the first magnetic shunt includes the step of providing a first magnetic shunt that is substantially tubular shaped, the first magnetic shunt substantially encircling at least a portion of the optical assembly. claim 46 49. The method of  claim 46  wherein the step of positioning the first magnetic shunt includes the step of providing a first magnetic shunt that is substantially flat plate shaped. claim 46 50. The method of  claim 46  wherein the step of positioning the first magnetic shunt includes the step of providing a first magnetic shunt that has a substantially xe2x80x9cLxe2x80x9d shaped cross-section. claim 46 51. The method of  claim 46 , further comprising the step of positioning a second magnetic shunt approximately between the optical assembly and the mover assembly, the second magnetic shunt being made of a magnetically permeable material. claim 46 52. The method of  claim 51  wherein the step of positioning the second magnetic shunt includes the step of positioning the second magnetic shunt on the opposite side of the stage from the first magnetic shunt. claim 51 53. The method of  claim 51  wherein the step of positioning the second magnetic shunt includes the step of positioning the second magnetic shunt on the opposite side of the optical assembly from the first magnetic shunt. claim 51 54. The method of  claim 46  further comprising the step of enclosing the stage with a container and the step of securing the first magnetic shunt to the container. claim 46 55. A method for making an exposure apparatus that transfers a pattern from a first object onto a second object, the method comprising the steps of: providing an illumination system that illuminates the device; and  moving the device with a stage assembly made by the method of  claim 46 .  claim 46 56. A method for making a device utilizing the exposure apparatus made by the method of  claim 55 . claim 55 57. A method for exposing a semiconductor wafer utilizing the exposure apparatus made by the method of  claim 55 . claim 55 58. A stage assembly for moving a device for an apparatus, the apparatus including an optical assembly and a gap near the optical assembly, the stage assembly comprising: a stage that retains the device;  a mover assembly that moves the stage along a first axis in the gap, the mover assembly generating a magnetic field; and  a first magnetic shunt positioned near the stage, the first magnetic shunt being fixedly positioned relative to the first axis, the first magnetic shunt being made from a magnetically permeable material, the first magnetic shunt providing a low magnetic reluctance path that redirects at least a portion of the magnetic field away from the gap. 59. The stage assembly of  claim 58  wherein the mover assembly moves the stage along a second axis that is substantially perpendicular to the first axis, and wherein the first magnetic shunt is fixedly positioned along the second axis. claim 58 60. The stage assembly of  claim 58  wherein the optical assembly includes a first subassembly and a spaced apart second subassembly, and wherein at least a portion of the stage moves between the first subassembly and the second subassembly. claim 58 61. The stage assembly of  claim 58  wherein the first magnetic shunt is positioned approximately between the optical assembly and the mover assembly. claim 58 62. The stage assembly of  claim 58  wherein the first magnetic shunt is oriented substantially perpendicularly to the stage. claim 58 63. The stage assembly of  claim 58  wherein the first magnetic shunt is fixed relative to the optical assembly. claim 58 64. The stage assembly of  claim 58  wherein the first magnetic shunt is substantially tubular shaped and substantially encircles at least a portion of the optical assembly. claim 58 65. The stage assembly of  claim 58  wherein the first magnetic shunt is generally flat plate shaped. claim 58 66. The stage assembly of  claim 58  wherein the first magnetic shunt has a substantially xe2x80x9cLxe2x80x9d shaped cross-section. claim 58 67. The stage assembly of  claim 58  wherein the first magnetic shunt redirects at least approximately 10 percent of the magnetic field away from the gap. claim 58 68. The stage assembly of  claim 58  wherein the optical assembly has a longitudinal axis, and wherein the first axis is substantially perpendicular to the longitudinal axis. claim 58 69. The stage assembly of  claim 58  wherein the optical assembly has a longitudinal axis, and wherein the first magnetic shunt is positioned substantially parallel to the longitudinal axis. claim 58 70. The stage assembly of  claim 58  further comprising a second magnetic shunt that is fixedly positioned relative to the first axis, the second magnetic shunt being made of a magnetically permeable material. claim 58 71. The stage assembly of  claim 70  wherein the first magnetic shunt and the second magnetic shunt are positioned on opposite sides of the stage. claim 70 72. An apparatus including the stage assembly of  claim 58  and an illumination source positioned near the stage assembly. claim 58 73. An object on which an image has been formed with the apparatus of  claim 72 . claim 72 74. A semiconductor wafer on which an image has been formed with the apparatus of  claim 72 . claim 72 75. A stage assembly for moving a device for an apparatus, the apparatus including an optical assembly having a first optical subassembly and a spaced apart second optical subassembly with a gap between the first optical subassembly and the second optical subassembly, the stage assembly comprising: a stage that retains the device;  a mover assembly that moves at least a portion of the stage between the first optical subassembly and the second optical subassembly, the mover assembly generating a magnetic field; and  a first magnetic shunt positioned near the stage, the first magnetic shunt being made from a magnetically permeable material, the first magnetic shunt providing a low magnetic reluctance path that redirects at least a portion of the magnetic field away from the gap. 76. The stage assembly of  claim 75  wherein the optical assembly has a longitudinal axis, and wherein the first magnetic shunt is positioned substantially parallel to the longitudinal axis. claim 75 77. The stage assembly of  claim 75  wherein the optical assembly has a longitudinal axis, and wherein the mover assembly moves the stage along a first axis that is substantially perpendicular to the longitudinal axis. claim 75 78. The stage assembly of  claim 77  wherein the first magnetic shunt is fixedly positioned relative to the first axis. claim 77 79. The stage assembly of  claim 77  wherein the mover assembly moves the stage along a second axis that is substantially perpendicular to the first axis and the longitudinal axis, and wherein the first magnetic shunt is fixedly positioned relative to the first and second axes. claim 77 80. The stage assembly of  claim 75  wherein the first magnetic shunt is positioned approximately between the optical assembly and the mover assembly. claim 75 81. The stage assembly of  claim 75  wherein the first magnetic shunt is fixed relative to the optical assembly. claim 75 82. The stage assembly of  claim 75  wherein the first magnetic shunt is substantially tubular shaped and substantially encircles at least a portion of the optical assembly. claim 75 83. BAK The stage assembly of  claim 75  wherein the first magnetic shunt is generally flat plate shaped. claim 75 84. The stage assembly of  claim 75  wherein the first magnetic shunt has a substantially  75  shaped cross-section. claim 75 85. The stage assembly of  claim 75  wherein the first magnetic shunt redirects at least approximately 10 percent of the magnetic field away from the gap. claim 75 86. The stage assembly of  claim 75  further comprising a second magnetic shunt that is fixedly positioned relative to the first axis, the second magnetic shunt being made of a magnetically permeable material. claim 75 87. The stage assembly of  claim 86  wherein the first magnetic shunt and the second magnetic shunt are positioned on opposite sides of the stage. claim 86 88. An apparatus including the stage assembly of  claim 75  and an illumination source positioned near the stage assembly. claim 75 89. An object on which an image has been formed with the apparatus of  claim 88 . claim 88 90. A semiconductor wafer on which an image has been formed with the apparatus of  claim 88 . claim 88