MOVABLE BODY DRIVE METHOD AND MOVABLE BODY DRIVE SYSTEM, PATTERN FORMATION METHOD AND APPARATUS, EXPOSURE METHOD AND APPARATUS, POSITION CONTROL METHOD AND POSITION CONTROL SYSTEM, AND DEVICE MANUFACTURING METHOD

• US 20090027640A1
• Filed: 07/18/2008
• Published: 01/29/2009
• Est. Priority Date: 07/24/2007
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: KANAYA, Yuho, SHIBAZAKI, Yuichi
• Granted Patent: US 8,194,232 B2
• Time in Patent Office: Days
• US Class Current: 355/53
• CPC Class Codes: G03F 7/70775 Position control, e.g. interferometers or encoders for determining the stage position

Abstract

Positional information of a movement plane of a wafer stage is measured using an encoder system such as, for example, an X head and a Y head, and the wafer stage is controlled based on the measurement results. At the same time, positional information of the wafer stage is measured using an interferometer system such as, for example, an X interferometer and a Y interferometer. When abnormality of the encoder system is detected or when the wafer stage moves off from a measurement area of the encoder system, drive control is switched to a drive control based on the measurement results of the interferometer system. Accordingly, drive control of the wafer stage can be performed continuously in the entire stroke area, even at the time when abnormality occurs in the encoder system.

Claims

1. A movable body drive method in which a movable body is driven at least in a uniaxial direction, the method comprising:

a first process in which positional information of the movable body in the uniaxial direction is measured using a laser interferometer and an encoder at their respective sampling intervals, and the movable body is driven in the uniaxial direction based on measurement results of the encoder; and

a second process in which a measurement device used in position control of the movable body in the uniaxial direction is switched from the encoder to the laser interferometer whose output coordinate is corrected so that the output coordinate becomes successive to the output coordinate of the encoder just before when abnormality occurring in the encoder output is detected.

2. The movable body drive method according to claim 1, the method further comprising:

a third process in which a difference between the output coordinate by the encoder and the output coordinate by the laser interferometer is updated at every predetermined interval, wherein

in the second process when abnormality occurring in the encoder output is detected, by correcting the output coordinate of the laser interferometer at that time using the latest difference, the output coordinate of the laser interferometer is corrected to be successive to the output coordinate of the encoder just before.

3. The movable body drive method according to claim 2, the method further comprising:

a fourth process in which after the measurement device used in the position control of the movable body in the uniaxial direction has been switched from the encoder to the laser interferometer, the measurement device used in the position control of the movable body in the uniaxial direction is switched from the laser interferometer to the encoder.

4. The movable body drive method according to claim 3 wherein

in the fourth process, the measurement device used in the position control of the movable body in the uniaxial direction is switched from the laser interferometer to the encoder after reliability of the output of the encoder is evaluated.

5. The movable body drive method according to claim 3 wherein

the switching from the laser interferometer to the encoder in the fourth process is performed by computing the output coordinate of the encoder during the switching, using an offset of a measurement unit computed based on the output coordinate of the laser interferometer and an offset of the encoder equal to or less than the measurement unit that has already been set.

6. A pattern formation method to form a pattern on an object wherein

a movable body on which the object is mounted is driven using the movable body drive method according to claim 1 to perform pattern formation to the object.

7. The pattern formation method according to claim 6 wherein

the object has a sensitive layer, and a pattern is formed on the object by an exposure of the sensitive layer by irradiation of an energy beam.

8. A device manufacturing method including a pattern formation process wherein

in the pattern formation process, a pattern is formed on a substrate using the pattern formation method according to claim 6.

9. A pattern formation method to form a pattern on an object wherein

at least one of a plurality of movable bodies including a movable body on which the object is mounted is driven using the movable body drive method according to claim 1 to perform pattern formation to the object.

10. The pattern formation method according to claim 9 wherein

the object has a sensitive layer, and a pattern is formed on the object by an exposure of the sensitive layer by irradiation of an energy beam.

11. A device manufacturing method including a pattern formation process wherein

in the pattern formation process, a pattern is formed on a substrate using the pattern formation method according to claim 9.

12. An exposure method in which a pattern is formed on an object by an irradiation of an energy beam wherein

for relative movement of the energy beam and the object, a movable body on which the object is mounted is driven, using the movable body drive method according to claim 1.

13. A movable body drive method in which a movable body is driven in directions of three degree of freedom in a predetermined plane, the method comprising:

a first process in which the movable body is driven based on an output of an interferometer system that measures positional information in the directions of three degrees of freedom; and

a second process in which when switching from servo control of the position in the directions of three degrees of freedom of the movable body using the interferometer system to servo control of the position in the directions of three degrees of freedom of the movable body using an encoder system, the switching of the control is performed by phase linkage where an output coordinate of the encoder system at the time of the switching is computed using an offset of a measurement unit computed based on the output coordinate of the interferometer system and an of set of the encoder system equal to or less than the measurement unit that has already been set for at least about a rotational direction in the predetermined plane.

14. The movable body drive method according to claim 13 wherein

when switching from servo control of the position in the directions of three degrees of freedom of the movable body using the interferometer system to servo control of the position in the directions of three degrees of freedom of the movable body using the encoder system, the switching of the control is performed by a coordinate linkage where an initial value of the output coordinate of the encoder system is set coinciding with the output coordinate of the interferometer system for directions of two degrees of freedom, excluding the rotational direction in the predetermined plane.

15. The movable body drive method according to claim 13 wherein

in the movable body, a grating that has a grid arranged periodically in the uniaxial direction is installed, and

the encoder system has a head unit, which intersects a longitudinal direction of the grating and is placed substantially covering the whole area of the stroke of the movable body, including a plurality of head sections that are also placed at a spacing so that two adjacent head sections do not move oft from the grating, and

in the second process, on the switching of the control, the phase linkage is performed for the rotational direction in the predetermined planer after having converted rotation quantity of the movable body measured by the interferometer system into rotation quantity between two adjacent head sections of the head unit.

16. A pattern formation method to form a pattern on an object wherein

a movable body on which the object is mounted is driven using the movable body drive method according to claim 13 to perform pattern formation to the object.

17. The pattern formation method according to claim 16 wherein

the object has a sensitive layer, and a pattern is formed on the object by an exposure of the sensitive layer by irradiation of an energy beam.

18. A device manufacturing method including a pattern formation process wherein

in the pattern formation process, a pattern is formed on a substrate using the pattern formation method according to claim 16.

19. A pattern formation method to form a pattern on an object wherein

at least one of a plurality of movable bodies including a movable body on which the object is mounted is driven using the movable body drive method according to claim 13 to perform pattern formation to the object.

20. The pattern formation method according to claim 19 wherein

the object has a sensitive layer, and a pattern is formed on the object by an exposure of the sensitive layer by irradiation of an energy beam.

21. A device manufacturing method including a pattern formation process wherein

in the pattern formation process, a pattern is formed on a substrate using the pattern formation method according to claim 19.

22. An exposure method in which a pattern is formed on an object by an irradiation of an energy beam wherein

for relative movement of the energy beam and the object, a movable body on which the object is mounted is driven, using the movable body drive method according to claim 13.

23. A movable body drive method in which a movable body is driven at least in a uniaxial direction, the method comprising:

a first process in which the movable body is driven based on an output of an encoder that measures positional information in the uniaxial direction of the movable body; and

a second process in which in the case of switching from servo control of the position of the movable body using the encoder to servo control of the position of the movable body using a laser interferometer, switching of the control is performed at the point when the movable body stops or becomes stationary.

24. A pattern formation method to form a pattern on an object wherein

a movable body on which the object is mounted is driven using the movable body drive method according to claim 23 to perform pattern formation to the object.

25. The pattern formation method according to claim 24 wherein

the object has a sensitive layer, and a pattern is formed on the object by an exposure of the sensitive layer by irradiation of an energy beam.

26. A device manufacturing method including a pattern formation process wherein

in the pattern formation process, a pattern is formed on a substrate using the pattern formation method according to claim 24.

27. A pattern formation method to form a pattern on an object wherein

at least one of a plurality of movable bodies including a movable body on which the object is mounted is driven using the movable body drive method according to claim 23 to perform pattern formation to the object.

28. The pattern formation method according to claim 27 wherein

the object has a sensitive layer, and a pattern is formed on the object by an exposure of the sensitive layer by irradiation of an energy beam.

29. A device manufacturing method including a pattern formation process wherein

in the pattern formation process, a pattern is formed on a substrate using the pattern formation method according to claim 27.

30. An exposure method in which a pattern is formed on an object by an irradiation of an energy beam wherein

for relative movement of the energy bean and the object, a movable body on which the object is mounted is driven, using the movable body drive method according to claim 23.

31. A movable body drive method in which a movable body is driven at least in a uniaxial direction, the method comprising:

a first process in which the movable body is driven based on an output of an encoder that measures positional information in the uniaxial direction of the movable body; and

a second process in which a coordinate linkage is performed in the case of switching from servo control of the position of the movable body using the encoder to servo control of the position of the movable body using the laser interferometer, when abnormality occurring in the encoder output is detected, where an initial value of the output of the laser interferometer is set to coincide with the output coordinate of the encoder just before.

32. A pattern formation method to form a pattern on an object wherein

a movable body on which the object is mounted is driven using the movable body drive method according to claim 31 to perform pattern formation to the object.

33. The pattern formation method according to claim 32 wherein

the object has a sensitive layer, and a pattern is formed on the object by an exposure of the sensitive layer by irradiation of an energy beam.

34. A device manufacturing method including a pattern formation process wherein

in the pattern formation process, a pattern is formed on a substrate using the pattern formation method according to claim 32.

35. A pattern formation method to form a pattern on an object wherein

at least one of a plurality of movable bodies including a movable body on which the object is mounted is driven using the movable body drive method according to claim 31 to perform pattern formation to the object.

36. The pattern formation method according to claim 35 wherein

the object has a sensitive layer, and a pattern is formed on the object by an exposure of the sensitive layer by irradiation of an energy beam.

37. A device manufacturing method including a pattern formation process wherein

in the pattern formation process, a pattern is formed on a substrate using the pattern formation method according to claim 35.

38. An exposure method in which a pattern is formed on an object by an irradiation of an energy beam wherein

for relative movement of the energy beam and the object, a movable body on which the object is mounted is driven, using the movable body drive method according to claim 31.

39. A position control method in which a position of a movable body is controlled in at least a uniaxial direction wherein

the position of the movable body is controlled using at least one of an output from an encoder that generates information corresponding to the position in the uniaxial direction of the movable body and an output from a laser interferometer that irradiates a laser beam to the movable body in the uniaxial direction and generates a signal corresponding to an optical path length of the laser beam in the uniaxial direction to the movable body, and

relation information between positional information of the movable body using the output from the encoder and positional information of the movable body using the output from the laser interferometer is obtained, whereby

when abnormality occurs in one of the output from the encoder and the output from the laser interferometer used for the control of the movable body, the other output and the relation information are used to control the position of the movable body.

40. The position control method according to claim 39 wherein

as the relation information, a difference information between positional information of the movable body using the output from the encoder and positional information of the movable body using the output from the laser interferometer is obtained.

41. The position control method according to claim 39 wherein

the abnormality is a state where there is no output from one of the encoder and the laser interferometer.

42. A position control method of a movable body in which a position of a movable body is controlled in at least a uniaxial direction wherein

when starting position control of the movable body using an output from an encoder that generates information corresponding to the position in the uniaxial direction of the movable body, after controlling the position of the movable body using an output from a laser interferometer that irradiates a laser beam to the movable body in the uniaxial direction and generates a signal corresponding to an optical path length of the laser beat in the uniaxial direction to the movable body,

positional information based on the output from the encoder is adjusted using positional information based on the output from the laser interferometer.

43. The position control method according to claim 42 wherein

when starting the position control using the output from the encoder, a first coordinate information which is obtained using the output from the encoder is adjusted to coincide with a second coordinate information which is obtained using the output of the laser interferometer.

44. A movable body drive system in which a movable body is driven at least in a uniaxial direction, the system comprising:

a laser interferometer which measures positional information of the movable body in the uniaxial direction at a first sampling interval;

an encoder which measures positional information of the movable body in the uniaxial direction at a second sampling interval;

a drive device which drives the movable body; and

a controller which drives the movable body in the uniaxial direction via the drive device based on measurement results of the encoder, and when detecting abnormality S occurring in the encoder output, switches a measurement device used in position control of the movable body in the uniaxial direction from the encoder to the laser interferometer whose output coordinate has been corrected to be successive to an output of the encoder just before.

45. The movable body drive system according to claim 44, the system further comprising:

an update device which updates a difference between an output coordinate by the encoder and an output coordinate by the laser interferometer at every sampling interval of the encoder, wherein

when the controller detects abnormality occurring in the encoder output, by correcting the output coordinate of the laser interferometer at that time using the latest difference, the output coordinate of the laser interferometer is corrected to be successive to the output coordinate of the encoder just before.

46. The movable body drive system according to claim 44 wherein

after switching the measurement device used in the position control of the movable body in the uniaxial direction from the encoder to the laser interferometer, when the output of the encoder returns to a reliable degree, the controller switches the measurement device used in the position control of the movable body in the uniaxial direction from the laser interferometer to the encoder.

47. The movable body drive system according to claim 46 wherein

the controller performs the switching from the laser interferometer to the encoder by computing the output coordinate of the encoder during the switching, using an offset of a measurement unit computed based on the output coordinate of the laser interferometer and an offset of the encoder equal to or less than the measurement unit that has already been set.

48. The movable body drive system according to claim 44 wherein

when abnormality occurring in the encoder output is detected, an error-processing method to be performed can be specified to the controller.

49. The movable body drive system according to claim 48 wherein

as the error-processing method, one of showing a display encouraging manual assist, showing an alarm display that switching from the encoder to the laser interferometer has been performed, and not performing anything in particular can be specified alternatively.

50. A pattern formation apparatus that forms a pattern on an object, the apparatus comprising:

a patterning device which generates a pattern on the object; and

a movable body drive system according to claim 44, wherein

drive of a movable body on which the object is mounted is performed by the movable body drive system for pattern formation on the object.

51. The pattern formation apparatus according to claim 50 wherein

the object has a sensitive layer, and a pattern is generated on the object by an exposure of the sensitive layer by irradiation of an energy beam.

52. An exposure apparatus that forms a pattern on an object by an irradiation of an energy beam, the apparatus comprising:

a patterning device that irradiates the energy beam on the object; and

a movable body drive system according to claim 44, wherein

the movable body drive system drives the movable body on which the object is mounted for relative movement of the energy beam and the object.

53. A movable body drive system in which a movable body is driven in directions of three degree of freedom in a predetermined plane, the system comprising:

an interferometer system that measures positional information of the movable body in the directions of three degrees of freedom;

an encoder system that measures positional information of the movable body in the directions of three degrees of freedom;

a drive device which drives the movable body; and

a controller which performs a switching from servo control via the drive device of the position in the directions of three degrees of freedom of the movable body using the interferometer system to servo control via the drive device of the position in the directions of three degrees of freedom of the movable body using an encoder system by a phase linkage, where an output coordinate of the encoder system at the time of the switching is computed using an offset of a measurement unit computed based on the output coordinate of the interferometer system and an offset of the encoder system equal to or less than the measurement unit that has already been set for at least a rotational direction in the predetermined plane.

54. The movable body drive system according to claim 53 wherein

the controller performs a switching of the control by a coordinate linkage where an initial value of the output coordinate of the encoder system is set to coincide with the output coordinate of the interferometer system for directions of two degrees of freedom, excluding the rotational direction in the predetermined plane.

55. The movable body drive system according to claim 53 wherein

the movable body has a grating that has a grid arranged periodically in the uniaxial direction, and the encoder system has a head unit, which intersects a longitudinal direction of the grating and is placed substantially covering the whole area of the stroke of the movable body, including a plurality of head sections that are also placed at a spacing so that two adjacent head sections do not move off from the grating, whereby

the controller performs the phase linkage for the rotational direction in the predetermined plane, after having converted rotation quantity of the movable body measured by the interferometer system into rotation quantity between the two adjacent head sections of the head unit on the switching of the control.

56. A pattern formation apparatus that forms a pattern on an object, the apparatus comprising:

a patterning device which generates a pattern on the object; and

a movable body drive system according to claim 53, wherein

drive of a movable body on which the object is mounted is performed by the movable body drive system for pattern formation on the object.

57. The pattern formation apparatus according to claim 56 wherein

the object has a sensitive layer, and the patterning device generates a pattern on the object by an exposure of the sensitive layer by irradiation of an energy beam.

58. An exposure apparatus that forms a pattern on an object by an irradiation of an energy beam, the apparatus comprising:

a patterning device that irradiates the energy beam on the object; and

a movable body drive system according to claim 53, wherein

the movable body drive system drives the movable body on which the object is mounted for relative movement of the energy beam and the object.

59. A movable body drive system in which a movable body is driven at least in a uniaxial direction, the system comprising:

a laser interferometer which measures positional information of the movable body in the uniaxial direction;

an encoder which measures positional information of the movable body in the uniaxial direction;

a drive device which drives the movable body; and

a controller which performs switching form servo control via the drive device of the position of the movable body using the encoder to a control via the drive device of the position of the movable body using the laser interferometer at a point when the movable body stops or becomes stationary.

60. A pattern formation apparatus that forms a pattern on an object, the apparatus comprising:

a patterning device which generates a pattern on the object; and

a movable body drive system according to claim 59, wherein

drive of a movable body on which the object is mounted is performed by the movable body drive system for pattern formation on the object.

61. The pattern formation apparatus according to claim 60 wherein

the object has a sensitive layer, and the patterning device generates a pattern on the object by an exposure of the sensitive layer by irradiation of an energy beam.

62. An exposure apparatus that forms a pattern on an object by an irradiation of an energy beam, the apparatus comprising:

a patterning device that irradiates the energy beam on the object; and

a movable body drive system according to claim 59, wherein

the movable body drive system drives the movable body on which the object is mounted for relative movement of the energy beam and the object.

63. A movable body drive system in which a movable body is driven at least in a uniaxial direction, the system comprising:

a laser interferometer which measures positional information of the movable body in the uniaxial direction;

an encoder which measures positional information of the movable body in the uniaxial direction;

a drive device which drives the movable body; and

a controller which performs a coordinate linkage In the case of switching from servo control via the drive device of the position of the movable body using the encoder to control via the drive device of the position of the movable body using the laser interferometer, when abnormality occurring in the encoder output is detected, where an initial value of the output of the laser interferometer is set to coincide with the output coordinate of the encoder just before.

64. A pattern formation apparatus that forms a pattern on an object, the apparatus comprising:

a patterning device which generates a pattern on the object; and

a movable body drive system according to claim 63, wherein

drive of a movable body on which the object is mounted is performed by the movable body drive system for pattern formation on the object.

65. The pattern formation apparatus according to claim 64 wherein

the object has a sensitive layer, and the patterning device generates a pattern on the object by an exposure of the sensitive layer by irradiation of an energy beam.

66. An exposure apparatus that forms a pattern on an object by an irradiation of an energy beam, the apparatus comprising:

a patterning device that irradiates the energy beam on the object; and

a movable body drive system according to claim 63, wherein

the movable body drive system drives the movable body on which the object is mounted for relative movement of the energy beam and the object.

67. A position control system of a movable body in which a position of a movable body is controlled in at least a uniaxial direction, the system comprising:

a first measurement device which includes an encoder that generates information according to a position of the movable body in the uniaxial direction, and outputs a first positional information using an output from the encoder;

a second measurement device which includes a laser interferometer that irradiates a laser beam to the movable body in the uniaxial direction and generates a signal corresponding to an optical path length of the laser beam to the movable body in the uniaxial direction, and outputs a second positional information using an output from the laser interferometer;

a computing unit which obtains relation information between the first positional information and the second positional information; and

a controller which controls a position of the movable body using at least one of the first positional information and the second positional information, and when abnormality occurs in one of the first positional information and the second positional information used for the control of the movable body, the other positional information and the relation information obtained by the computing unit are used to control the position of the movable body.

68. The position control system according to claim 67 wherein

the computing unit obtains difference information of the first positional information and the second positional information as the relation information.

69. The position control system according to claim 67 wherein

the abnormality is a state where there is no output from one of the encoder and the laser interferometer.

70. The position control system according to claim 67 wherein

when abnormality occurs in one of the first positional information and the second positional information used for the control of the movable body, the controller begins position control of the movable body using the other positional information and the relation information obtained by the computing unit, and also begins the position control using the one positional information again at a predetermined timing.

71. The position control system according to claim 70 wherein

the controller includes a judgment section which judges abnormality cancellation of the one positional information after abnormality has occurred in one of the first positional information and the second positional information used for the control of the movable body, and

the predetermined timing in which the position control using the one positional information is started again is after when the judgment section judges abnormality cancellation in the one positional information.

72. The position control system according to claim 67 wherein

when abnormality occurs in one of the first positional information and the second positional information used for the control of the movable body, the controller encourages to select the control method of the movable body from a plurality of operation methods.

73. The position control system according to claim 67, the system further comprising;

an output device which outputs warning information when abnormality occurs in one of the first positional information and the second positional information used for the control of the movable body.

74. A position control system of a movable body in which a position of a movable body is controlled in at least a uniaxial direction, the system comprising:

a first measurement device which includes an encoder that generates information according to a position of the movable body in the uniaxial direction and outputs positional information using an output from the encoder;

a second measurement device which includes a laser interferometer that irradiates a laser beam to the movable body in the uniaxial direction and generates a signal corresponding to an optical path length of the laser beam to the movable body in the uniaxial direction, and outputs positional information using an output from the laser interferometer; and

a controller which controls the position of the movable body using positional information output from the first measurement device, after having controlled the position of the movable body using positional information output from the second measurement device, whereby

when starting the position control of the movable body using the positional information output form the first measurement device, the controller adjusts the positional information output by the first measurement device using the positional information output from the second measurement device.

75. The position control system according to claim 74 wherein

the first measurement device and the second measurement device output a first coordinate information and a second coordinate information as the positional information, respectively, and

the controller adjusts the first coordinate information from the first measurement device which is obtained by using the output from the encoder so as to coincide with the second coordinate information from the second measurement device which is obtained by using the output from the laser interferometer.

76. The position control system according to claim 74 wherein

when starting the position control of the movable body using the positional information output form the first measurement device, the controller adjusts the positional information output by the first measurement device for at least a rotational direction within a movement plane of the movable body, using an offset of a measurement unit output from the second measurement device and an offset of the encoder system equal to or less than the measurement unit that has already been set.

77. The position control system according to claim 74 wherein

the first measurement device comprises a plurality of the encoders, and

as the output of the encoder used when starting the output of the positional information, the output from a specific encoder among the plurality of encoders is used.

78. An exposure method in which an object is exposed with an energy heart, the method comprising:

moving a movable body that can hold the object, while measuring positional information of the movable body using one of a first measurement device including an encoder and a second measurement device including an interferometer; and

deciding positional information of the other of the first and second measurement devices based on positional information of the one of the measurement devices, in order to control the movement by switching the one of the measurement devices to the other of the measurement devices during the movement.

79. An exposure apparatus that exposes an object held by a movable body with an energy beam, the apparatus comprising:

a first measurement device including an encoder which measures positional information of the movable body;

a second measurement device including an interferometer, which measures positional information of the movable body; and

a controller that moves the movable body using one of the first and second measurement devices, and also decides positional information of the other of the measurement devices based on positional information of the one of the measurement devices, in order to control the movement by switching the one of the measurement devices to the other of the measurement devices during the movement.