Guideless stage with isolated reaction stage

• US 6,841,965 B2
• Filed: 06/15/2001
• Issued: 01/11/2005
• Est. Priority Date: 04/01/1994
• Status: Expired due to Fees

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Lee, Martin E.
• Primary Examiner(s): Ro, Bentsu
• Application Number:
  US09/880,859
• Publication Number:
  US 20010030522A1
• Time in Patent Office: 1,306 Days
• Field of Search: 318/575, 318/611, 318/625, 318/626, 318/648, 318/649, 318/687
• US Class Current: 318/649
• 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. A method of making a microlithography system that forms an image onto an object, comprising the steps of:

providing an irradiation apparatus that irradiates the object with radiation to form the image on the object;

providing a movable stage associated with the irradiation apparatus, the movable stage having a first mirror;

providing a first support structure;

providing a second mirror that is connected to the irradiation apparatus;

providing a second support structure dynamically isolated from the first support structure to support the irradiation apparatus, the second support structure including a base member that supports the movable stage;

providing a drive having a first portion connected to the movable stage and a second portion connected to the first support structure to move the movable stage in a two-dimensional plane such that a reaction force exerted by the movement of the movable stage is transferred to the first support structure, the second portion of the drive not contacting the movable stage mechanically; and

providing a position detector that cooperates with the first mirror and the second mirror to detect a position of the movable stage in the two-dimensional plane, the position detector being supported by the second support structure.

2. A method according to claim 1, wherein the irradiation apparatus includes a projection system.

3. A method according to claim 2, wherein the projection system optically projects the image.

4. A method according to claim 2, wherein the movable stage is located below the projection system.

5. A method according to claim 2, wherein the position detector projects a light beam to the first mirror fixed to the movable stage and to the second mirror.

6. A method according to claim 1, wherein the irradiation apparatus includes a mask holder that holds a mask that defines the image.

7. A method according to claim 1, wherein the second support structure has a first portion that supports the movable stage and a second portion that supports the irradiation apparatus.

8. A method according to claim 7, wherein the first portion and the second portion are connected rigidly to each other.

9. A method according to claim 1, wherein the movable stage is a guideless stage having no associated guide member to guide its movement.

10. A method according to claim 9, wherein the guideless stage is movable over a surface of the base member on a bearing.

11. A method according to claim 10, wherein the bearing is a non-contact bearing that supports the guideless stage.

12. A method according to claim 11, wherein the non-contact bearing comprises an air bearing.

13. A method according to claim 11, wherein the non-contact bearing includes a magnet and a cooperating coil.

14. A method according to claim 1, wherein the movable stage is a substrate stage on which the object is supported.

15. A method according to claim 1, wherein a substrate stage is movable over a surface of the base member on a bearing.

16. A method according to claim 15, wherein the bearing is a non-contact bearing that supports the substrate stage.

17. A method according to claim 16, wherein the non-contact bearing comprises an air bearing.

18. A method according to claim 16, wherein the non-contact bearing includes a magnet and a cooperating coil.

19. A method according to claim 1, wherein the second support structure is supported on a foundation.

20. A method according to claim 19, further comprising:

providing a block between the foundation and the second support structure.

21. A method according to claim 20, wherein the block comprises a vibration absorbing assembly that prevents transmission of vibration from the foundation to the second support structure.

22. A method according to claim 19, wherein the foundation is the ground or a base structure.

23. A method according to claim 1, wherein the drive comprises a linear motor.

24. A method according to claim 23, wherein the linear motor comprises a magnet and a coil.

25. A method according to claim 24, wherein the first support structure supports one of the magnet and the coil.

26. A method according to claim 1, wherein the drive rotates the movable stage on an axis of the movable stage.

27. A method according to claim 26, wherein the drive moves the movable stage based on a detection result by the position detector so as to effect yaw correction.

28. A method according to claim 26, wherein the movable stage is a guideless stage having no associated guide member to guide its movement.

29. A method according to claim 26, wherein the movable stage is a substrate stage on which the object is supported.

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

31. A method according to claim 30, wherein the drive moves the movable stage based on a detection result by the position detector so as to effect yaw correction.

32. A method according to claim 30, wherein the movable stage is a guideless stage having no associated guide member to guide its movement.

33. A method according to claim 30, wherein the movable stage is a substrate stage on which the object is supported.

34. A method according to claim 1, wherein the first support structure at least partly supports the drive.

35. An image forming method that forms an image onto an object by an irradiation apparatus, comprising the steps of:

moving a stage in a two-dimensional plane of a base member by a driver, the driver having a first portion connected to the stage and a second portion not connected to the stage mechanically;

transferring a reaction force caused by the movement of the stage to a first support structure, the first support structure connected to the second portion of the driver;

directing a measurement beam to a first mirror of the stage and directing a reference beam to a second mirror connected to the irradiation apparatus by using a position detector;

detecting a position of the stage in the two-dimensional plane by the position detector that is supported by a second support structure dynamically isolated from the first support structure, the second support structure supports the stage, the irradiation apparatus and the base member; and

forming the image onto the object by movement of the stage.

36. A method according to claim 35, wherein the irradiation apparatus is a projection system.

37. A method according to claim 36, wherein the step of moving the stage includes aligning the stage with the projection system.

38. A method according to claim 36, wherein the projection system optically projects the image.

39. A method according to claim 36, wherein the stage is located below the projection system.

40. A method according to claim 36, wherein the second support structure has a first portion that supports the stage, and a second portion that supports the projection system.

41. A method according to claim 40, wherein the first portion and the second portion are connected rigidly to each other.

42. A method according to claim 35, wherein the stage is a guideless stage having no associated guide member to guide its movement.

43. A method according to claim 42, wherein the guideless stage is movable over a surface of the base member on a bearing.

44. A method according to claim 43, wherein the bearing is a non-contact bearing that supports the guideless stage.

45. A method according to claim 44, wherein the non-contact bearing comprises an air bearing.

46. A method according to claim 44, wherein the non-contact bearing includes a magnet and a cooperating coil.

47. A method according to claim 35, wherein the stage is a substrate stage on which the object is supported.

48. A method according to claim 47, wherein the substrate stage is movable over a surface of the base member on a bearing.

49. A method according to claim 48, wherein the bearing is a non-contact bearing that supports the substrate stage.

50. A method according to claim 49, wherein the non-contact bearing comprises an air bearing.

51. A method according to claim 49, wherein the non-contact bearing includes a magnet and a cooperating coil.

52. A method according to claim 35, wherein the second support structure is supported on a foundation.

53. A method according to claim 52, wherein the second support structure is supported on the foundation with a block between the foundation and the second support structure.

54. A method according to claim 53, wherein the block comprises a vibration absorbing assembly that prevents transmission of vibration from the foundation to the second support structure.

55. A method according to claim 52, wherein the foundation is the ground or a base structure.

56. A method according to claim 35, wherein the stage moves based on a detection result by the position detector.

57. A method according to claim 35, further comprising the step of:

effecting yaw correction of the stage.

58. A method according to claim 35, wherein the movement of the stage is carried out by cooperation with a first member that is located on the first support member, and a second member that is connected to the stage.

59. A method according to claim 58, wherein the first member is one of a magnet and a coil.

60. A method of making a positioning apparatus that positions an object, comprising the steps of:

providing a movable stage that holds the object, the movable stage having a first mirror;

providing a first support structure;

providing a second support structure dynamically isolated from the first support structure, the second support structure including a base member that supports the movable stage;

providing a second mirror that is connected to the second support structure;

providing a drive having a first portion connected to the movable stage and a second portion connected to the first support structure to move the movable stage in a two-dimensional plane such that a reaction force exerted by the movement of the movable stage is transferred to the first support structure, the second portion of the drive not in contact with the movable stage mechanically; and

providing a position detector that directs a measurement beam to the first mirror and that directs a reference beam to the second mirror to detect a positional information of the object in the two-dimensional plane, the position detector being supported by the second support structure.

61. A method according to claim 60, wherein the second support structure is supported on a foundation.

62. A method according to claim 61, further comprising:

providing a block between the foundation and the second support structure.

63. A method according to claim 62, wherein the block comprises a vibration absorbing assembly that prevents transmission of vibration from the foundation to the second support structure.

64. A method according to claim 61, wherein the foundation is the ground or a base structure.

65. A method according to claim 60, wherein the drive rotates the object on an axis of the object.

66. A method according to claim 65, wherein the drive moves the object based on a detection result by the position detector so as to effect yaw correction.

67. A method according to claim 60, wherein the drive moves the object in the two-dimensional plane, including movement in the plane in a first linear direction, in a second linear direction and in a rotative direction on an axis of the object.

68. A method according to claim 67, wherein the drive moves the object based on a detection result by the position detector so as to effect yaw correction.

69. A method according to claim 60, wherein the movable stage is a guideless stage having no associated guide member to guide its movement.

70. A method according to claim 69, wherein the guideless stage is movable over a surface of the base member on a bearing.

71. A method according to claim 70, wherein the bearing is a non-contact bearing that supports the guideless stage.

72. A method according to claim 71, wherein the non-contact bearing comprises an air bearing.

73. A method according to claim 71, wherein the non-contact bearing includes a magnet and a cooperating coil.

74. A method according to claim 60, wherein the drive comprises a magnet and a coil.

75. A method according to claim 74, wherein the first support structure supports one of the magnet and the coil.

76. A method according to claim 60, wherein the first support structure at least partly supports the drive.

77. A positioning method that positions an object, comprising the steps of:

moving a stage that holds the object in a two-dimensional plane of a base member by a driver, the driver having a first portion connected to the stage and a second portion not connected to the stage mechanically;

transferring a reaction force caused by movement of the object to a first support structure, the first support structure connected with the second portion of the driver;

directing a measurement beam to a first mirror of the stage and directing a reference beam to a second mirror connected to a second support structure by using a position detector, the second support structure being dynamically isolated from the first support structure;

detecting a position information of the object in the two-dimensional plane by the position detector supported by the second support structure, the second support structure supports the stage and the base member; and

positioning the object based on a detection result by the position detector.

78. A method according to claim 77, wherein the second support structure is supported on a foundation.

79. A method according to claim 78, wherein the second support structure is supported on the foundation with a block between the foundation and the second support structure.

80. A method according to claim 79, wherein the block comprises a vibration absorbing assembly that prevents transmission of vibration from the foundation to the second support structure.

81. A method according to claim 78, wherein the foundation is the ground or a base structure.

82. A method according to claim 77, wherein the step of moving the stage includes rotating the stage on an axis of the stage.

83. A method according to claim 82, wherein the step of positioning the object comprises moving the object based on a detection result by the position detector so as to effect yaw correction.

84. A method according to claim 77, wherein the step of moving the stage includes moving the object in first and second linear directions and rotating the object on an axis of the object.

85. A method according to claim 84, wherein the step of positioning the object comprises moving the object based on a detection result by the position detector so as to effect yaw correction.

86. A method according to claim 77, wherein the stage is a guideless stage having no associated guide member to guide its movement.

87. A method according to claim 86, wherein the guideless stage is movable over a surface of the base member on a bearing.

88. A method according to claim 87, wherein the bearing is a non-contact bearing that supports the guideless stage.

89. A method according to claim 88, wherein the non-contact bearing comprises an air bearing.

90. A method according to claim 88, wherein the non-contact bearing includes a magnet and a cooperating coil.

91. A method according to claim 77, wherein the step of positioning the object comprises moving the stage based on a detection result by the position detector.

92. A method according to claim 77, wherein the first portion is one of a magnet and a coil.

93. A method of making a microlithography system that exposes a pattern of a mask onto an object by a projection system, comprising the steps of:

providing an object stage that holds the object in association with the projection system, the object stage having a first mirror;

providing a second mirror that is connected to the protection system;

providing a support structure that supports the projection system and the object stage, the support structure having a base member disposed below the projection system to support the object stage;

providing a vibration absorbing assembly that holds the support structure to prevent transmission of vibration from a foundation to the support structure, a holding surface of the vibration absorbing assembly being higher than a surface of the base member and lower than a holding surface of the mask;

providing a drive having a first portion connected to the object stage and a second portion not connected to the object stage to move the object stage;

providing a reaction frame dynamically isolated from the support structure, the reaction frame connected to the second portion of the drive;

providing a position detector that cooperates with the first mirror and the second mirror to detect a position of the object stage, the position detector being supported by the support structure.

94. A method according to claim 93, wherein the reaction frame is supported on the foundation.

95. A method according to claim 93, wherein the foundation is one of a floor and a base structure.

96. A method according to claim 93, wherein the holding surface of the vibration absorbing assembly is higher than a holding surface of the object.

97. A method according to claim 93, wherein the second portion of the drive is movable on the reaction frame.

98. A method according to claim 97, wherein the second portion of the drive is one of a coil member and a magnet member.

99. A method according to claim 98, wherein the base member comprises a horizontal planar surface and the drive moves the object stage in a horizontal plane.

100. A method according to claim 99, wherein the support structure supports the mask.

101. A method according to claim 100, wherein the support structure supports a condenser lens located above the mask.

102. A method according to claim 101, wherein the reaction frame does not receive the weight of the base member.

103. A method according to claim 93, wherein the base member comprises a horizontal planar surface and the drive moves the object stage in a horizontal plane.

104. A method according to claim 93, wherein the support structure supports the mask.

105. A method according to claim 93, wherein the support structure supports a condenser lens located above the mask.

106. A method according to claim 93, wherein the reaction frame does not receive the weight of the base member.