Lithographic apparatus, alignment apparatus, device manufacturing method, and a method of converting an apparatus

• US 20050132914A1
• Filed: 12/23/2003
• Published: 06/23/2005
• Est. Priority Date: 12/23/2003
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Mulkens, Johannes Catharinus Hubertus, Loopstra, Erik Roelof, Van Den Brink, Marinus Aart
• Granted Patent: US 7,589,818 B2
• Time in Patent Office: Days
• US Class Current: 101/463.100
• CPC Class Codes: B41C 1/1075 Mechanical aspects of on-press plate preparation B41C1/1008 - B41C1/1066 take precedence
• CPC Class Codes: B41C 1/1083 Mechanical aspects of off-press plate preparation B41C1/1008 - B41C1/1066 take precedence
• CPC Class Codes: G03F 7/70258 Projection system adjustments, e.g. adjustments during exposure or alignment during assembly of projection system
• 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 9/7026 Focusing

Abstract

A detector detects liquid in the path of a projection beam or alignment beam. A controller then determines which one or more of a plurality of compensating optical elements may be provided in the optical path of the projection beam or alignment beam in order to focus the projection beam or alignment beam on the surface of the substrate. The appropriate optical element may be placed in the path of the projection beam or alignment beam directly as a final element of the projection system or alignment system respectively.

Claims

1. A method of converting a projection lens system of a lithographic projection apparatus, the method comprising at least one of exchanging a compensating optical element in the optical path of the projection lens system for another compensating optical element, adding a further compensating optical element in the optical path of the projection lens system, and removing a further compensating optical element in the optical path of the projection lens system, such that with a liquid between the projection lens system and the point of focus of the projection lens system, the distance of the point of focus of the projection lens system from a non parallel optical element will remain the same as without the liquid between the projection lens system and the point of focus of the projection lens system.

2. A method according to claim 1, wherein the compensating optical element is arranged to be a final element of the projection lens system.

3. A method according to claim 1, wherein different compensating optical elements placed in the projection lens system are placed in the optical path at different positions along the optical path.

4. A method according to claim 1, wherein the compensating optical element, when the liquid is between the projection lens system and the point of focus of the projection lens system, is placed at a distance of less than 4 mm from the point of focus of the projection lens system.

5. A method according to claim 1, wherein the thickness of the compensating optical element is between 50 μ

m and 500 μ

m.

6. A method according to claim 1, wherein the compensating optical element is a plane parallel plate.

7. A method according to claim 1, wherein different compensating optical elements have different thicknesses.

8. A method according to claim 1, wherein different compensating optical elements have different optical properties.

9. A method according to claim 8, wherein at least one of the different optical properties is different refractive indices.

10. A method according to claim 9, wherein at least one compensating optical element is hollow and filled with a fluid having a different refractive index.

11. A method according to claim 1, wherein the method is carried out by a user.

12. A method according to claim 1, wherein the method is non-automatic.

13. A method of converting a projection lens system of a lithographic projection apparatus, the method comprising at least one of exchanging a compensating optical element in the optical path of the projection lens system for another compensating optical element, adding a further compensating optical element in the optical path of the projection lens system, and removing a further compensating optical element in the optical path of the projection lens system, such that without a liquid between the projection lens system and the point of focus of the projection lens system, the distance of the point of focus of the projection lens system from a non parallel optical element will remain the same as with the liquid between the projection lens system and the point of focus of the projection lens system.

14. A method according to claim 13, wherein the compensating optical element is arranged to be a final element of the projection lens system.

15. A method according to claim 13, wherein different compensating optical elements placed in the projection lens system are placed in the optical path at different positions along the optical path.

16. A method according to claim 13, wherein the compensating optical element, when the liquid is between the projection lens system and the point of focus of the projection lens system, is placed at a distance of less than 4 mm from the point of focus of the projection lens system.

17. A method according to claim 13, wherein the thickness of the compensating optical element is between 50 μ

m and 500 μ

m.

18. A method according to claim 13, wherein the compensating optical element is a plane parallel plate.

19. A method according to claim 13, wherein different compensating optical elements have different thicknesses.

20. A method according to claim 13, wherein different compensating optical elements have different optical properties.

21. A method according to claim 20, wherein at least one of the different optical properties is different refractive indices.

22. A method according to claim 21, wherein at least one compensating optical element is hollow and filled with a fluid having a different refractive index.

23. A method according to claim 13, wherein the method is carried out by a user.

24. A method according to claim 13, wherein the method is non-automatic.

25. A method of converting a projection lens system of a lithographic projection apparatus, the method comprising at least one of exchanging a compensating optical element in the optical path of the projection lens system for another compensating optical element, adding a further compensating optical element in the optical path of the projection lens system, and removing a further compensating optical element in the optical path of the projection lens system such that the at least one of the presence and position of the compensating optical element in the optical path of the projection lens system is adjusted to ensure that the total optical path length between a patterning device and the point of focus of a patterned beam remains unchanged with a liquid between the projection lens system and a substrate from without the liquid between the projection lens system and the substrate.

26. A method of converting a projection lens system of a lithographic projection apparatus, the method comprising at least one of exchanging a compensating optical element in the optical path of the projection lens system for another compensating optical element, adding a further compensating optical element in the optical path of the projection lens system, and removing a further compensating optical element in the optical path of the projection lens system such that the at least one of the presence and position of the compensating optical element in the optical path of the projection lens system is adjusted to ensure that the total optical path length between a patterning device and the point of focus of a patterned beam remains unchanged without liquid between the projection lens system and a substrate from with the liquid between the projection lens system and the substrate.

27. A lithographic apparatus comprising:

an illumination system configured to provide a beam of radiation;

a support structure configured to hold a patterning device, the patterning device configured to impart the beam with a pattern in its cross-section;

a substrate table configured to hold a substrate;

a projection lens system configured to project the beam as patterned onto a target portion of the substrate; and

a plurality of optical elements removably positionable in the path of the beam to adjust the focal plane of the beam,

wherein the at least one of the presence and position of one or more of the plurality of optical elements in the path of the beam can be adjusted to ensure that the total optical path length of the beam remains unchanged irrespective of the presence or absence of liquid between the projection lens system and the substrate table.

28. An apparatus according to claim 27, further comprising a controller configured to control which one or more of the plurality of optical elements is placed in the path of the beam dependent on the quantity of liquid between the projection lens system and the substrate table.

29. An apparatus according to claim 27, further comprising a liquid supply system configured to at least partly fill a space between the projection lens system and the substrate table, with a liquid.

30. A lithographic apparatus comprising:

an illumination system configured to provide a beam of radiation;

a support structure configured to hold a patterning device, the patterning device configured to impart the beam with a pattern in its cross-section;

a substrate table configured to hold a substrate;

a projection lens system configured to project the beam as patterned onto a target portion of the substrate; and

a plurality of optical elements removably positionable in the path of the beam to adjust the focal plane of the beam,

wherein the at least one of the presence and position of one or more of the plurality of optical elements in the path of the beam is adjusted such that with a liquid between the projection lens system and the point of focus of the projection lens system, the point of focus of the projection lens system remains unchanged from without a liquid between the projection lens system and the point of focus of the projection lens system.

31. An apparatus according to claim 30, further comprising a controller configured to control which one or more of the plurality of optical elements is placed in the path of the beam dependent on the quantity of liquid between the projection lens system and the substrate table.

32. An apparatus according to claim 30, further comprising a liquid supply system configured to at least partly fill a space between the projection lens system and the substrate table, with a liquid.

33. A lithographic apparatus comprising:

an illumination system configured to provide a beam of radiation;

a support structure configured to hold a patterning device, the patterning device configured to impart the beam with a pattern in its cross-section;

a substrate table configured to hold a substrate;

a projection lens system configured to project the beam as patterned onto a target portion of the substrate;

a plurality of optical elements removably positionable in the path of the beam to adjust the focal plane of the beam; and

a plurality of docking stations in the path of the beam configured to hold the plurality of optical elements.

34. An apparatus according to claim 33, wherein each docking station is a predetermined distance from a final non-parallel plate element of the projection lens system.

35. An apparatus according to claim 34, wherein at least one docking station is arranged such that the focal point of the beam is on at least one of the substrate and the substrate table when no liquid is present in the path of the beam.

36. An apparatus according to claim 34, wherein at least one docking station is arranged such that the focal point of the beam is on at least one of the substrate and the substrate table when a liquid is present in the optical path of the beam.

37. An apparatus according to claim 33, further comprising a controller configured to control which one or more of the plurality of optical elements is placed in the path of the beam dependent on a quantity of liquid between the projection lens system and the substrate table.

38. An apparatus according to claim 33, further comprising a liquid supply system configured to at least partly fill a space between the projection lens system and the substrate table, with a liquid.

39. A device manufacturing method comprising:

projecting a beam as patterned by a patterning device onto a target portion of a substrate; and

adjusting the focal plane of the beam by interposing one or more of a plurality of optical elements in the path of the beam, to ensure that the focal point of the beam focuses on the same point regardless of the presence or absence of liquid in the beam.

40. A method according to claim 39, further comprising controlling which one or more of the plurality of optical elements is interposed in the path of the beam dependent on a quantity of liquid between a projection lens system and the substrate table.

41. A method according to claim 39, further comprising at least partly filling a space between a projection lens system and a substrate table, with a liquid.

42. A method of converting an alignment lens system of an alignment apparatus, said method comprising at least one of exchanging a compensating optical element in the optical path of the alignment lens system for another compensating optical element, adding a further compensating optical element in the optical path of the alignment lens system, and removing a further compensating optical element in the optical path of the alignment lens system, such that with a liquid between the alignment lens system and the point of focus of the alignment lens system, the distance of the point of focus of the alignment lens system from a non parallel optical element will remain the same as without the liquid between the alignment lens system and the point of focus of the alignment lens system.

43. A method according to claim 42, wherein the alignment lens system is a projection alignment lens system and the compensating optical element is arranged to form a final element of the projection alignment lens system.

44. A method according to claim 42, wherein different compensating optical elements placed in the alignment lens system are placed in the optical path at different positions along the optical path.

45. A method according to claim 42, wherein the compensating optical element, when the liquid is between the alignment lens system and the point of focus of the alignment lens system, is placed at a distance of less than 4 mm from the point of focus of the alignment lens system.

46. A method according to claim 42, wherein the thickness of the compensating optical element is between 50 μ

m and 500 μ

m.

47. A method according to claim 42, wherein the compensating optical element is a plane parallel plate.

48. A method according to claim 42, wherein different compensating optical elements have different thicknesses.

49. A method according to claim 42, wherein different compensating optical elements have different optical properties.

50. A method according to claim 49, wherein at least one of the different optical properties is different refractive indices.

51. A method according to claim 50, wherein at least one compensating optical element is hollow and filled with a fluid having a different refractive index.

52. A method according to claim 42, wherein the method is carried out by a user.

53. A method according to claim 42, wherein the method is non-automatic.

54. A method of converting an alignment lens system of an alignment apparatus, the method comprising at least one of exchanging a compensating optical element in the optical path of the alignment lens system for another compensating optical element, adding a further compensating optical element in the optical path of the alignment lens system, and removing a further compensating optical element in the optical path of the alignment lens system, such that without a liquid between the alignment lens system and the point of focus of the alignment lens system, the distance of the point of focus of the alignment lens system from a non parallel optical element will remain the same as with the liquid between the alignment lens system and the point of focus of the alignment lens system.

55. A method according to claim 54, wherein the alignment lens system is a projection alignment lens system and the compensating optical element is arranged to form a final element of the projection alignment lens system.

56. A method according to claim 54, wherein different compensating optical elements placed in the alignment lens system are placed in the optical path at different positions along the optical path.

57. A method according to claim 54, wherein the compensating optical element, when the liquid is between the alignment lens system and the point of focus of the alignment lens system, is placed at a distance of less than 4 mm from the point of focus of the alignment lens system.

58. A method according to claim 54, wherein the thickness of the compensating optical element is between 50 μ

m and 500 μ

m.

59. A method according to claim 54, wherein the compensating optical element is a plane parallel plate.

60. A method according to claim 54, wherein different compensating optical elements have different thicknesses.

61. A method according to claim 54, wherein different compensating optical elements have different optical properties.

62. A method according to claim 61, wherein at least one of the different optical properties is different refractive indices.

63. A method according to claim 62, wherein at least one compensating optical element is hollow and filled with a fluid having a different refractive index.

64. A method according to claim 54, wherein the method is carried out by a user.

65. A method according to claim 54, wherein the method is non-automatic.

66. A method of converting an alignment lens system of an alignment apparatus, the method comprising at least one of exchanging a compensating optical element in the optical path of the alignment lens system for another compensating optical element, adding a further compensating optical element in the optical path of the alignment lens system, and removing a further compensating optical element in the optical path of the alignment lens system such that the at least one of the presence and position of the compensating optical element in the optical path of the alignment lens system is adjusted to ensure that the total optical path length between a reference mark and the point of focus of an alignment beam remains unchanged with a liquid between the alignment lens system and a substrate from without the liquid between the alignment lens system and the substrate table.

67. A method of converting an alignment lens system of an alignment apparatus, the method comprising at least one of exchanging a compensating optical element in the optical path of the alignment lens system for another compensating optical element, adding a further compensating optical element in the optical path of the alignment lens system, and removing a further compensating optical element in the optical path of the alignment lens system such that the at least one of the presence and position of the compensating optical element in the optical path of the alignment lens system is adjusted to ensure that the total optical path length between a reference mark and the point of focus of an alignment beam remains unchanged without liquid between the alignment lens system and a substrate from with the liquid between the alignment lens system and the substrate table.

68. An alignment apparatus comprising:

a substrate table configured to hold a substrate, the substrate having a substrate mark;

an alignment lens system configured to detect alignment between a reference mark and the substrate mark using an alignment beam of radiation; and

a plurality of optical elements removably positionable in the path of the alignment beam configured to adjust the focal plane of the alignment lens system when detecting alignment,

wherein the at least one of the presence and position of one or more of the plurality of optical elements in the path of the alignment beam can be adjusted to ensure that the total optical path length of the alignment beam remains unchanged irrespective of the quantity of liquid between the alignment lens system and the substrate table.

69. An apparatus according to claim 68, further comprising a controller configured to control which one or more of the plurality of optical elements is placed in the alignment beam dependent on the quantity of liquid between the alignment lens system and the substrate table.

70. An apparatus according to claim 68, further comprising a liquid supply system configured to at least partly fill a space between the alignment lens system and the substrate table, with a liquid.

71. A lithographic projection apparatus comprising an illumination system configured to provide a beam of radiation, a support structure configured to hold a patterning device that serves to pattern the beam according to a desired pattern, a projection system configured to project the patterned beam onto a target portion of the substrate, and an alignment apparatus according to claim 68.

72. An apparatus according to claim 71, wherein the alignment beam traverses at least part of the projection system.

73. An alignment apparatus comprising:

a substrate table configured to hold a substrate, the substrate having a substrate mark;

an alignment lens system configured to detect alignment between a reference mark and the substrate mark using an alignment beam of radiation; and

a plurality of optical elements removably positionable in the path of the alignment beam configured to adjust the focal plane of the alignment lens system when detecting alignment,

wherein the at least one of the presence and position of one or more of the plurality of optical elements in the path of the alignment beam is adjusted such that with a liquid between the alignment lens system and the point of focus of the alignment lens system, the point of focus of the alignment lens system remains unchanged from without a liquid between the alignment lens system and the point of focus of the alignment lens system.

74. An apparatus according to claim 73, further comprising a controller configured to control which one or more of the plurality of optical elements is placed in the alignment beam dependent on the quantity of liquid between the alignment lens system and the substrate table.

75. An apparatus according to claim 73, further comprising a liquid supply system configured to at least partly fill a space between the alignment lens system and the substrate table, with a liquid.

76. A lithographic projection apparatus comprising an illumination system configured to provide a beam of radiation, a support structure configured to hold a patterning device that serves to pattern the beam according to a desired pattern, a projection system configured to project the patterned beam onto a target portion of the substrate, and an alignment apparatus according to claim 73.

77. An apparatus according to claim 75, wherein the alignment beam traverses at least part of the projection system.

78. An alignment apparatus comprising:

a substrate table configured to hold a substrate, the substrate having a substrate mark;

an alignment lens system configured to detect alignment between a reference mark and the substrate mark using an alignment beam of radiation;

a plurality of optical elements removably positionable in the path of the alignment beam configured to adjust the focal plane of the alignment lens system when detecting alignment; and

a plurality of docking stations in the path of the alignment beam configured to hold the plurality of optical elements.

79. An apparatus according to claim 78, wherein each docking station is a predetermined distance from a final non-parallel plate element of the alignment lens system.

80. An apparatus according to claim 79, wherein at least one docking station is arranged such that the focal point of the alignment beam is on at least one of the substrate and the substrate table when no liquid is present in the path of the alignment beam.

81. An apparatus according to claim 79, wherein at least one docking station is arranged such that the focal point of the alignment beam is on at least one of the substrate and the substrate table when a liquid is present in the optical path of the alignment beam.

82. An apparatus according to claim 78, further comprising a controller configured to control which one or more of the plurality of optical elements is placed in the path of the alignment beam dependent on a quantity of liquid between the alignment lens system and the substrate table.

83. An apparatus according to claim 78, further comprising a liquid supply system configured to at least partly fill a space between the alignment lens system and the substrate table, with a liquid.

84. A lithographic projection apparatus comprising an illumination system configured to provide a beam of radiation, a support structure configured to hold a patterning device that serves to pattern the beam according to a desired pattern, a projection system configured to project the patterned beam onto a target portion of the substrate, and an alignment apparatus according to claim 78.

85. An apparatus according to claim 84, wherein the alignment beam traverses at least part of the projection system.

86. An alignment apparatus comprising:

a substrate table configured to hold a substrate, the substrate having a substrate mark;

an alignment lens system configured to detect alignment between a reference mark and the substrate mark using an alignment beam of radiation;

a plurality of optical elements removably positionable in the path of the alignment beam configured to adjust the focal plane of the alignment lens system when detecting alignment;

a detector configured to detect the presence of liquid between the alignment lens system and the substrate table; and

a controller configured to control which one or more of the plurality of optical elements is placed in the path of the alignment beam on the basis of results from the detector.

87. An apparatus according to claim 86, further comprising a liquid supply system configured to at least partly fill a space between the alignment lens system and the substrate table, with a liquid.

88. A lithographic projection apparatus comprising an illumination system configured to provide a beam of radiation, a support structure configured to hold a patterning device that serves to pattern the beam according to a desired pattern, a projection system configured to project the patterned beam onto a target portion of the substrate, and an alignment apparatus according to claim 86.

89. An apparatus according to claim 88, wherein the alignment beam traverses at least part of the projection system.