Exposure method and apparatus, maintenance method and device manufacturing method

• US 20090066922A1
• Filed: 10/21/2008
• Published: 03/12/2009
• Est. Priority Date: 05/18/2006
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Nakano, Katsushi
• Granted Patent: US 8,514,366 B2
• Time in Patent Office: Days
• US Class Current: 355/30
• CPC Class Codes: G03F 7/70341 Details of immersion lithography aspects, e.g. exposure media or control of immersion liquid supply chemical composition of immersion liquids G03F7/2041
• CPC Class Codes: G03F 7/70925 Cleaning, i.e. actively freeing apparatus from pollutants, e.g. using plasma cleaning

Abstract

An exposure method includes holding a substrate held by a substrate holder on a substrate stage moving on an image plane side of a projection optical system; forming an immersion area the image plane side of the projection optical system by using a liquid supplied from a liquid supplying mechanism; and exposing a substrate by exposure light via the projection optical system and the immersion area. During a period when exposure of the substrate is not performed, an upper portion of the substrate holder is cleaned by moving the substrate stage relative to the immersion area, and an upper portion of a measuring stage is cleaned by moving the measuring stage relative to the immersion area. A cleaning liquid can be used as a liquid for forming the immersion area during cleaning. High-resolution immersion exposure is performed at a high throughput by suppressing entering of foreign materials into the liquid.

Claims

1. An exposure method for exposing a substrate, the exposure method comprising:

forming a liquid immersion area on the substrate held by a substrate stage to expose the substrate with an exposure light through a liquid of the liquid immersion area; and

cleaning the substrate stage by moving the substrate stage relative to the liquid immersion area during a period in which the substrate is not exposed.

2. The exposure method according to claim 1, wherein the liquid immersion area is formed by using a certain cleaning liquid.

3. The exposure method according to claim 1, wherein the substrate stage has a holding portion which holds the substrate and a flat surface which is arranged around the holding portion and which is substantially parallel to a surface of the substrate held by the holding portion;

and

the substrate stage is moved relative to the liquid immersion area in a state that at least a part of the liquid immersion area is formed on the flat surface during the cleaning.

4. The exposure method according to claim 3, wherein the holding portion holds a flat plate-shaped dummy substrate during the cleaning.

5. The exposure method according to claim 1, wherein during the cleaning, a holding portion, of the substrate stage, which holds the substrate, is covered with a dummy substrate which has an upper surface substantially parallel to a flat surface around the holding portion.

6. The exposure method according to claim 5, wherein the substrate stage is moved relative to the liquid immersion area so that at least a part of the liquid immersion area is moved substantially on only the dummy substrate.

7. The exposure method according to claim 4, wherein at least an upper surface of the dummy substrate is liquid-repellent;

and a plurality of liquid-attractive grooves are formed on the upper surface.

8. The exposure method according to claim 1, wherein the substrate stage is moved relative to the liquid immersion area during the cleaning so that at least a part of a movement range of the liquid immersion area on the substrate stage during the cleaning is different from a movement range of the liquid immersion area on the substrate stage during the exposure.

9. The exposure method according to claim 1, wherein the substrate stage is moved relative to the liquid immersion area so that at least one of a velocity and an acceleration of the movement of substrate stage relative to the liquid immersion area in a direction perpendicular to an optical axis of the exposure light is greater than that during the exposure of the substrate.

10. The exposure method according to claim 1, wherein the substrate stage is moved relative to the liquid immersion area so that at least one of a velocity and a stroke of the movement of substrate stage relative to the liquid immersion area in a direction parallel to an optical axis of the exposure light is greater than that during the exposure of the substrate.

11. The exposure method according to claim 1, further comprising forming the liquid immersion area on a measuring stage which is movable independently from the substrate stage, and moving the measuring stage relative to the liquid immersion area so as to clean the measuring stage.

12. The exposure method according to claim 11, wherein the substrate stage and the measuring stage are allowed to approach closely to each other to form the liquid immersion area at a boundary portion between the substrate stage and the measuring stage and the substrate stage and the measuring stage are vibrated relative to each other in antiphase in a direction along a boundary line so as to clean the substrate stage and the measuring stage.

13. The exposure method according to claim 1, further comprising moving the substrate stage with respect to the liquid immersion area during the cleaning along a locus different from a locus of movement along which the substrate stage is moved when the substrate is exposed.

14. The exposure method according to claim 13, further comprising moving the substrate stage during the cleaning along a movement locus of the substrate stage along which the substrate stage is moved during alignment of the substrate or before or after the exposure of the substrate.

15. The exposure method according to claim 1, further comprising recovering the liquid of the liquid immersion area during the cleaning.

16. The exposure method according to claim 1, wherein the exposure light is radiated onto the substrate via an optical member and the liquid;

and

an optical path space, for the exposure light, which is between the substrate and the optical member is filled with the liquid to form the liquid immersion area locally to include an irradiation area of the exposure light on the substrate stage.

17. The exposure method according to claim 16, wherein a liquid immersion member is used to perform at least one of supply and recovery of the liquid with respect to the liquid immersion area;

and

the liquid immersion member is also cleaned during the cleaning of the substrate stage.

18. The exposure method according to claim 1, wherein a cleaning liquid is supplied to the liquid immersion area during a period in which the substrate is not exposed.

19. The exposure method according to claim 18, wherein the cleaning liquid is a liquid for cleaning which is obtained by mixing a certain solvent with the liquid of the liquid immersion area to be formed during the exposure, or a liquid which is different from the liquid.

20. The exposure method according to claim 18, wherein the cleaning liquid is supplied to the liquid immersion area by a liquid supply mechanism which supplies the liquid.

21. The exposure method according to claim 1, wherein a holding portion, of the substrate stage, which holds the substrate is covered with a dummy substrate during the cleaning;

and the liquid is recovered on a side of the substrate stage.

22. The exposure method according to claim 21, wherein the liquid, which inflows via a gap between the dummy substrate and a flat surface around the dummy substrate, is recovered in the substrate stage.

23. The exposure method according to claim 21, wherein the dummy substrate has an upper surface which is liquid-repellent and which is substantially flush with the flat surface.

24. The exposure method according to claim 1, further comprising radiating the exposure light on a side of the substrate stage during the cleaning.

25. The exposure method according to claim 1, further comprising vibrating the substrate stage in a direction parallel to an optical axis of the exposure light during the cleaning.

26. The exposure method according to claim 1, further comprising ultrasonically vibrating the liquid of the liquid immersion area during the cleaning.

80. A method for producing a device, comprising:

exposing a substrate by using the exposure method as defined in claim 1;

developing the exposed substrate; and

processing the developed substrate.

27. An exposure method for exposing a substrate with an exposure light via an optical member and a liquid, the exposure method comprising:

arranging a movable member, which makes contact with the liquid, to be opposite to the optical member; and

moving the movable member relative to a liquid immersion area of a cleaning liquid formed between the optical member and the movable member to clean the movable member.

28. The exposure method according to claim 27, wherein the cleaning liquid is same as the liquid in a liquid immersion area to be formed between the optical member and the substrate during the exposure.

29. The exposure method according to claim 27, wherein the movable member includes a substrate stage which holds the substrate and/or a measuring stage which is movable independently from the substrate stage.

30. The exposure method according to claim 27, wherein at least a part of a locus of movement of the movable member is different between an operation of the cleaning and an operation of the exposure.

90. A method for producing a device, comprising:

exposing a substrate by using the exposure method as defined in claim 27;

developing the exposed substrate; and

processing the developed substrate.

31. An exposure apparatus which exposes a substrate with an exposure light through a liquid, the exposure apparatus comprising:

a substrate stage which holds the substrate;

a liquid immersion mechanism which supplies the liquid onto the substrate to form a liquid immersion area; and

a controller which moves the substrate stage relative to the liquid immersion area so as to clean the substrate stage during a period in which the substrate is not exposed.

32. The exposure apparatus according to claim 31, wherein the substrate stage has a holding portion which holds the substrate and a flat surface which is arranged around the holding portion and which is substantially parallel to a surface of the substrate held by the holding portion;

and

the controller moves the substrate stage relative to the liquid immersion area in a state that at least a part of the liquid immersion area is formed on the flat surface.

33. The exposure apparatus according to claim 32, wherein the holding portion is covered with a flat plate-shaped dummy substrate during the cleaning.

34. The exposure apparatus according to claim 33, wherein at least an upper surface of the dummy substrate is liquid-repellent, and a plurality of liquid-attractive grooves are formed on the upper surface.

35. The exposure apparatus according to claim 31, wherein the controller has:

a first mode in which the substrate is exposed; and

a second mode in which the substrate stage is moved relative to the liquid immersion area so that at least one of a velocity and an acceleration of the movement of substrate stage relative to the liquid immersion area in a direction perpendicular to an optical axis of the exposure light is greater than that in the first mode.

36. The exposure apparatus according to claim 35, wherein the controller has a third mode in which the substrate stage is moved relative to the liquid immersion area so that at least one of a velocity and a stroke of the movement of substrate stage relative to the liquid immersion area in a direction parallel to the optical axis of the exposure light is greater than that in the first mode.

37. The exposure apparatus according to claim 31, further comprising a measuring stage which is movable independently from the substrate stage;

wherein the controller forms the liquid immersion area on the measuring stage during the period in which the substrate is not exposed, and moves the measuring stage relative to the liquid immersion area to execute cleaning of the measuring stage.

38. The exposure apparatus according to claim 37, wherein the controller allows the substrate stage and the measuring stage to approach closely to each other to form the liquid immersion area at a boundary portion between the substrate stage and the measuring stage and vibrates the substrate stage relative to the measuring stage in antiphase in a direction along a boundary line defining the boundary portion so as to clean the substrate stage and the measuring stage.

39. The exposure apparatus according to claim 31, wherein the liquid immersion mechanism includes a liquid supply mechanism which supplies the liquid, and a liquid recovery mechanism which recovers the supplied liquid.

40. The exposure apparatus according to claim 39, wherein the liquid immersion mechanism includes a liquid immersion member which performs at least one of the supply and the recovery of the liquid with respect to the liquid immersion area;

and

the liquid immersion member is also cleaned during the cleaning of the substrate stage.

41. The exposure apparatus according to claim 31, wherein the liquid immersion mechanism includes a first liquid supply mechanism which supplies the liquid, and a second liquid supply mechanism which supplies a cleaning liquid containing a certain solvent;

and

the second liquid supply mechanism supplies the cleaning liquid onto the substrate stage during the cleaning.

42. The exposure apparatus according to claim 41, wherein the second liquid supply mechanism includes a mixing mechanism which mixes the certain solvent into the liquid supplied from the first liquid supply mechanism;

and

the cleaning liquid is obtained by mixing the certain solvent into the liquid of the liquid immersion area to be formed during the exposure.

43. The exposure apparatus according to claim 31, wherein the substrate stage has a holding portion which holds the substrate;

and

a flat plate-shaped dummy substrate is provided exchangeably with the substrate to cover the holding portion during the cleaning.

44. The exposure apparatus according to claim 31, wherein the substrate stage has a holding portion which holds the substrate, the holding portion being covered with a dummy substrate during the cleaning;

and

a recovery portion, which recovers the liquid inflowing through a gap between the dummy substrate and a flat surface disposed around the dummy substrate, is provided, the recovery portion having at least a part which is arranged in the substrate stage.

45. The exposure apparatus according to claim 43, wherein an upper surface of the dummy substrate is liquid-repellent and substantially flush with the flat surface.

46. The exposure apparatus according to claim 31, wherein the controller allows the exposure light to be emitted during an operation of the cleaning.

47. The exposure apparatus according to claim 31, wherein the substrate stage has a holding portion which holds the substrate and a flat surface which is provided around the holding portion, the substrate stage including a table which is movable in a direction parallel to an optical axis of the exposure light;

and

the controller vibrates the table in a direction parallel to the optical axis during an operation of the cleaning.

48. The exposure apparatus according to claim 31, further comprising a vibrator which ultrasonically vibrates the liquid of the liquid immersion area during the cleaning.

89. A method for producing a device, comprising:

exposing a substrate by using the exposure apparatus as defined in claim 31;

developing the exposed substrate; and

processing the developed substrate.

49. An exposure apparatus which exposes a substrate with an exposure light via an optical member and a liquid, the exposure apparatus comprising:

a movable member which is arranged to be opposite to the optical member and which makes contact with the liquid;

a liquid immersion mechanism which forms a liquid immersion area of a cleaning liquid between the optical member and the movable member; and

a controller which moves the movable member relative to the liquid immersion area to clean the movable member.

50. The exposure apparatus according to claim 49, wherein the cleaning liquid is same as the liquid in the liquid immersion area formed between the optical member and the substrate during the exposure.

51. The exposure apparatus according to claim 49, wherein the movable member includes a substrate stage which holds the substrate and/or a measuring stage which is movable independently from the substrate stage.

52. The exposure apparatus according to claim 51, wherein the substrate stage holds a cover member by a holding portion holding the substrate during a period in which the substrate stage is cleaned.

53. The exposure apparatus according to claim 49, wherein the controller allows at least a part of a locus of movement of the movable member to differ between an operation of the cleaning and an operation of the exposure.

54. The exposure apparatus according to claim 49, wherein the controller executes an operation of the cleaning during a period in which the substrate is not exposed.

94. A method for producing a device, comprising:

exposing a substrate by using the exposure apparatus as defined in claim 49;

developing the exposed substrate; and

processing the developed substrate.

55. A maintenance method for an exposure apparatus which forms a liquid immersion area on a substrate held by a substrate stage and which exposes the substrate with an exposure light through a liquid of the liquid immersion area, the maintenance method comprising:

arranging the substrate stage to be opposite to a liquid immersion member which performs at least one of supply and recovery of the liquid with respect to the liquid immersion area; and

moving the substrate stage relative to the liquid immersion area to clean at least one of the liquid immersion member and the substrate stage during a period in which the substrate is not exposed.

56. The maintenance method according to claim 55, wherein the substrate stage includes a holding portion which holds the substrate, and a flat surface which is arranged around the holding portion and which is substantially parallel to a surface of the substrate held by the holding portion;

and

during the cleaning, the substrate stage is moved relative to the liquid immersion area in a state that at least a part of the liquid immersion area is formed on the flat surface.

57. The maintenance method according to claim 56, wherein the holding portion holds a flat plate-shaped dummy substrate during the cleaning.

58. The maintenance method according to claim 55, wherein the substrate stage is moved relative to the liquid immersion area during the cleaning so that at least one of a velocity and an acceleration of the movement of substrate stage relative to the liquid immersion area in a direction perpendicular to an optical axis of the exposure light is greater than that during the exposure of the substrate.

59. The maintenance method according to claim 55, wherein the substrate stage is moved relative to the liquid immersion area during the cleaning so that at least one of a velocity and a stroke of the movement of substrate stage relative to the liquid immersion area in a direction parallel to an optical axis of the exposure light is greater than that during the exposure of the substrate.

60. The maintenance method according to claim 55, wherein the exposure apparatus comprises a measuring stage which is movable independently from the substrate stage;

and

the liquid immersion area is formed on the measuring stage, and the measuring stage is moved relative to the liquid immersion area to clean the measuring stage.

61. The maintenance method according to claim 60, wherein the substrate stage and the measuring stage are allowed to approach closely to each other to form the liquid immersion area at a boundary portion between the substrate stage and the measuring stage and the substrate stage is vibrated relative to the measuring stage in antiphase in a direction provided along a boundary line so that the substrate stage and the measuring stage are cleaned.

62. The maintenance method according to claim 55, wherein the exposure apparatus comprises a liquid recovery mechanism which recovers the liquid of the liquid immersion area;

and

the liquid of the liquid immersion area is recovered during the cleaning.

63. The maintenance method according to claim 55, wherein a cleaning liquid is supplied to the liquid immersion area during a period in which the substrate is not exposed.

64. The maintenance method according to claim 63, wherein the cleaning liquid is a cleaning liquid which is obtained by mixing a certain solvent into the liquid of the liquid immersion area to be formed during the exposure, or a liquid which is different from the liquid.

65. A maintenance method for an exposure apparatus which exposes a substrate with an exposure light via an optical member and a liquid, the maintenance method comprising:

arranging a movable member, which makes contact with the liquid, to be opposite to the optical member; and

moving the movable member relative to a liquid immersion area of a cleaning liquid, formed between the optical member and the movable member, to clean the movable member.

66. The maintenance method according to claim 65, wherein the cleaning liquid is same as the liquid in the liquid immersion area formed between the optical member and the substrate during the exposure.

67. The maintenance method according to claim 65, wherein the movable member includes a substrate stage which holds the substrate and/or a measuring stage which is movable independently from the substrate stage.

68. The maintenance method according to claim 67, wherein during the cleaning of the substrate stage, a holding portion of the substrate stage which holds the substrate is covered with a cover member.

69. The maintenance method according to claim 65, wherein at least a part of a locus of movement of the movable member is allowed to differ between an operation of the cleaning and an operation of the exposure.

70. The maintenance method according to claim 65, wherein an operation of the cleaning is executed during a period in which the substrate is not exposed.

71. An exposure method for exposing a substrate, the exposure method comprising:

filling, with a liquid, an optical path space for an exposure light on the substrate held by a substrate stage;

exposing the substrate with the exposure light through the liquid; and

supplying an ultrasonically vibrated cleaning liquid onto the substrate stage during a period in which the substrate is not exposed.

91. A method for producing a device, comprising:

exposing a substrate by using the exposure method as defined in claim 71;

developing the exposed substrate; and

processing the developed substrate.

72. An exposure method for exposing a substrate, the exposure method comprising:

filling an optical path space for an exposure light with a liquid by a liquid immersion mechanism on the substrate held by a substrate stage;

exposing the substrate with the exposure light through the liquid; and

supplying a cleaning liquid to at least one of a supply port and a recovery port for the liquid of the liquid immersion mechanism during a period in which the substrate is not exposed.

73. The exposure method according to claim 72, wherein the cleaning liquid is ultrasonically vibrated.

74. The exposure method according to claim 72, wherein the substrate stage is moved during a period in which the substrate stage is cleaned with the cleaning liquid.

92. A method for producing a device, comprising:

exposing a substrate by using the exposure method as defined in claim 72;

developing the exposed substrate; and

processing the developed substrate.

75. An exposure method for exposing a plurality of areas on a substrate with an exposure light through a liquid, the exposure method comprising:

exposing the plurality of areas respectively through the liquid while moving a movable member which holds the substrate along a first route; and

cleaning the movable member with the liquid or a cleaning liquid by moving the movable member which holds a dummy substrate along a second route different from the first route.

76. The exposure method according to claim 75, wherein the second route is determined so that an area, on the movable member, with which the liquid makes contact during the exposure is cleaned with the liquid or the cleaning liquid.

77. The exposure method according to claim 75, wherein the second route is a route which includes at least one of the first route.

78. The exposure method according to claim 75, wherein the exposure light is not radiated onto the dummy substrate when the movable member is cleaned with the liquid or the cleaning liquid.

79. The exposure method according to claim 75, wherein the liquid or the cleaning liquid is substantially retained in an area which is smaller than a total areal size of the substrate and which is greater than one area on the substrate.

93. A method for producing a device, comprising:

exposing a substrate by using the exposure method as defined in claim 75;

developing the exposed substrate; and

processing the developed substrate.

81. An exposure apparatus which exposes a substrate, comprising:

a liquid immersion mechanism which fills an optical path space for an exposure light with a liquid on the substrate held by a substrate stage;

an ultrasonic vibrator which is provided in the vicinity of a supply port, for the liquid, of the liquid immersion mechanism; and

a controller which controls the ultrasonic vibrator so that a cleaning liquid, which is vibrated by an ultrasonic wave generated by the ultrasonic vibrator, is supplied onto the substrate stage during a period in which the substrate is not exposed.

95. A method for producing a device, comprising:

exposing a substrate by using the exposure apparatus as defined in claim 81;

developing the exposed substrate; and

processing the developed substrate.

82. An exposure apparatus which exposes a substrate, comprising:

a liquid immersion mechanism including a first liquid supply mechanism which supplies a liquid to an optical path space for an exposure light on the substrate held by a substrate stage;

a second liquid supply mechanism which is provided on a side of the substrate stage and which supplies a cleaning liquid;

an ultrasonic vibrator which vibrates the cleaning liquid by an ultrasonic wave; and

a controller which controls the ultrasonic vibrator so that the cleaning liquid, which is vibrated by the ultrasonic wave generated by the ultrasonic vibrator, is supplied to at least one of a supply port and a recovery port, for the liquid, of the liquid immersion mechanism during a period in which the substrate is not exposed.

96. A method for producing a device, comprising:

exposing a substrate by using the exposure apparatus as defined in claim 82;

developing the exposed substrate; and

processing the developed substrate.

83. An exposure apparatus which exposes a substrate through a liquid, comprising:

a liquid immersion mechanism which fills an optical path space for an exposure light with the liquid on the substrate held by a substrate stage; and

a device which supplies a cleaning liquid to at least one of a supply port and a recovery port, for the liquid, of the liquid immersion mechanism during a period in which the substrate is not exposed.

84. The exposure apparatus according to claim 83, further comprising an ultrasonic vibrator which vibrates the cleaning liquid by an ultrasonic wave.

85. The exposure apparatus according to claim 83, further comprising a controller which moves the substrate stage during a period in which the substrate stage is cleaned with the cleaning liquid.

97. A method for producing a device, comprising:

exposing a substrate by using the exposure apparatus as defined in claim 83;

developing the exposed substrate; and

processing the developed substrate.

86. An exposure apparatus which exposes a substrate with an exposure light via an optical member and a liquid, the exposure apparatus comprising:

a movable member which is arranged to be opposite to the optical member; and

a cleaning device which includes a vibrator provided on the movable member and which cleans a member making contact with the liquid with a cleaning liquid vibrated by the vibrator.

87. The exposure apparatus according to claim 86, wherein the cleaning liquid includes the liquid.

88. The exposure apparatus according to claim 86, further comprising a liquid immersion member which is used to form a liquid immersion area of the liquid, wherein the member making contact with the liquid includes at least the liquid immersion member.

98. A method for producing a device, comprising:

exposing a substrate by using the exposure apparatus as defined in claim 86;

developing the exposed substrate; and

processing the developed substrate.