Exposure method and apparatus, maintenance method and device manufacturing method

• US 8,514,366 B2
• Filed: 10/21/2008
• Issued: 08/20/2013
• Est. Priority Date: 05/18/2006
• Status: Expired due to Fees

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Nakano, Katsushi
• Primary Examiner(s): Whitesell Gordon, Steven H
• Application Number:
  US12/289,148
• Publication Number:
  US 20090066922A1
• Time in Patent Office: 1,764 Days
• Field of Search: 355/30, 355/53, 355/72, 355/77
• 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 holding portion of a substrate stage to expose the substrate with an exposure light through an immersion liquid of the liquid immersion area; and

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

wherein during the cleaning, the holding portion holds a dummy substrate having an upper surface portion and an edge portion which is more liquid-attractive than the upper surface portion.

2. The exposure method according to claim 1, wherein the cleaning liquid is the immersion liquid.

3. The exposure method according to claim 1, wherein the substrate stage has 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 1, wherein the dummy substrate is flat plate-shaped.

5. The exposure method according to claim 1, wherein the upper surface portion of the dummy substrate is substantially parallel to a flat surface around the holding portion.

6. The exposure method according to claim 1, 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 1, wherein a plurality of liquid-attractive grooves are formed on the upper surface of the dummy substrate.

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 of the cleaning liquid 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 of the cleaning liquid 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 of the cleaning liquid 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 cleaning liquid of the liquid immersion area from above the substrate stage 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 immersion liquid;

and

an optical path space, for the exposure light, which is between the substrate and the optical member is filled with the immersion 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 immersion 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 the cleaning liquid is supplied to form the liquid immersion area during the cleaning.

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

20. The exposure method according to claim 1, wherein the cleaning liquid is obtained by mixing a certain solvent with the immersion liquid.

21. The exposure method according to claim 1, wherein the cleaning liquid is recovered on a side of the substrate stage during the cleaning.

22. The exposure method according to claim 21, wherein the cleaning 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 22, wherein the upper surface of the dummy substrate 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 cleaning liquid of the liquid immersion area during the cleaning.

27. 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.

28. The exposure method according to claim 1, wherein the cleaning liquid includes water.

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

a substrate stage having a holding portion which holds the substrate;

a liquid immersion system having a supply port; and

a controller which moves the substrate stage, the controller moving the substrate stage relative to a liquid immersion area of a cleaning liquid supplied from the supply port so as to clean the substrate stage during a period in which the substrate is not exposed,

wherein during the cleaning,

the holding portion holds a dummy substrate such that a gap is formed along an edge portion of the dummy substrate, the dummy substrate having an upper surface portion and the edge portion being more liquid-attractive than the upper surface portion,

the controller moves the substrate stage relative to the liquid immersion area of the cleaning liquid, and

the cleaning liquid, which has inflowed through the gap, is recovered from a recovery portion of the substrate stage.

30. The exposure apparatus according to claim 29, wherein the substrate stage has 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 of the cleaning liquid such that at least a part of the liquid immersion area is formed on the flat surface.

31. The exposure apparatus according to claim 30, wherein the upper surface portion of the dummy substrate is liquid-repellent and substantially flush with the flat surface.

32. The exposure apparatus according to claim 29, wherein the dummy substrate is flat plate-shaped.

33. The exposure apparatus according to claim 29, wherein at least the upper surface portion of the dummy substrate is liquid-repellent, and a plurality of liquid-attractive grooves are formed on the upper surface portion.

34. The exposure apparatus according to claim 29, 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 of the cleaning liquid 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.

35. The exposure apparatus according to claim 34, wherein the controller has a third mode in which the substrate stage is moved relative to the liquid immersion area of the cleaning liquid so that at least one of a velocity and a stroke of the movement of substrate stage relative to the liquid immersion area of the cleaning liquid in a direction parallel to the optical axis of the exposure light is grater than that in the first mode.

36. The exposure apparatus according to claim 29, 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.

37. The exposure apparatus according to claim 36, 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.

38. The exposure apparatus according to claim 29, wherein the liquid immersion system includes a liquid supply device which supplies the cleaning liquid, and a liquid recovery device which recovers the supplied cleaning liquid.

39. The exposure apparatus according to claim 38, wherein the liquid immersion system includes a liquid immersion member which performs at least one of the supply and the recovery of the cleaning liquid to form the liquid immersion area of the cleaning liquid;

and

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

40. The exposure apparatus according to claim 29, wherein the liquid immersion system includes a first liquid supply device which supplies the immersion liquid, and a second liquid supply device which supplies the cleaning liquid containing a certain solvent;

and

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

41. The exposure apparatus according to claim 40, wherein the second liquid supply device includes a mixing device which mixes the certain solvent into the immersion liquid supplied from the first liquid supply device;

and

the cleaning liquid is obtained by mixing the certain solvent into the immersion liquid.

42. The exposure apparatus according to claim 29, wherein the controller allows the exposure light to be emitted during the cleaning.

43. The exposure apparatus according to claim 29, wherein

the controller vibrates the substrate stage in a direction parallel to the optical axis during the cleaning.

44. The exposure apparatus according to claim 29, further comprising a vibrator which ultrasonically vibrates the cleaning liquid of the liquid immersion area during the cleaning.

45. A method for producing a device, comprising:

exposing a substrate by using the exposure apparatus as defined in claim 29;

developing the exposed substrate; and

processing the developed substrate.

46. The exposure apparatus according to claim 29, wherein the cleaning liquid includes water.

47. The exposure apparatus according to claim 29, wherein during the cleaning, in order to promote the inflow of the cleaning liquid through the gap into a space under the gap, the controller moves the substrate stage such that the immersion area of the cleaning liquid is moved along the edge portion of the dummy substrate.

48. The exposure apparatus according to claim 29, wherein during the cleaning, in order to promote the inflow of the cleaning liquid through the gap into a space under the gap, the controller moves the substrate stage such that the immersion area of the cleaning liquid is moved annularly along the gap.

49. A maintenance method for an exposure apparatus which forms a liquid immersion area of an immersion liquid on a substrate held by a holding portion of a substrate stage and which exposes the substrate with an exposure light through the immersion 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 immersion liquid to form the liquid immersion area; and

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

wherein during the cleaning, the holding portion holds a dummy substrate having an upper surface portion and an edge portion which is more liquid-attractive than the upper surface portion.

50. The maintenance method according to claim 49, wherein the substrate stage includes 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 such that at least a part of the liquid immersion area is formed on the flat surface.

51. The maintenance method according to claim 49, wherein the dummy substrate is flat plate-shaped.

52. The maintenance method according to claim 49, wherein the substrate stage is moved relative to the liquid immersion area of the cleaning liquid 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.

53. The maintenance method according to claim 49, wherein the substrate stage is moved relative to the liquid immersion area of the cleaning liquid 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.

54. The maintenance method according to claim 49, wherein the exposure apparatus comprises a measuring stage which is movable independently from the substrate stage;

and

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

55. The maintenance method according to claim 54, 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.

56. The maintenance method according to claim 49, wherein the exposure apparatus comprises a liquid recovery device which recovers the cleaning liquid of the liquid immersion area during the cleaning.

57. The maintenance method according to claim 49, wherein the cleaning liquid is the immersion liquid.

58. The maintenance method according to claim 49, wherein the cleaning liquid is obtained by mixing a certain solvent into the immersion liquid.

59. The maintenance method according to claim 49, wherein the cleaning liquid includes water.