Cleanup method for optics in immersion lithography supplying cleaning liquid onto a surface of object below optical element, liquid supply port and liquid recovery port

• US 8,493,545 B2
• Filed: 03/09/2009
• Issued: 07/23/2013
• Est. Priority Date: 04/11/2003
• Status: Expired due to Fees

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Kawai, Hidemi, Novak, W. Thomas
• Primary Examiner(s): Ton, Toan
• Assistant Examiner(s): LIU, CHIA HOW MICHAEL
• Application Number:
  US12/382,078
• Publication Number:
  US 20090174872A1
• Time in Patent Office: 1,597 Days
• Field of Search: 355/30, 355/53, 355/67
• US Class Current: 355/30
• CPC Class Codes: B08B 3/04 Cleaning involving contact with liquid
• CPC Class Codes: B08B 3/12 by sonic or ultrasonic vibrations washing or rinsing machines for crockery or tableware using sonic or ultrasonic waves A47L15/13; of natural teeth, of prostheses using ultrasonic techniques similar to those used for natural teeth A61C17/20; application of ultrasonic vibrations to chemical, physical or physico-chemical processes in general B01J19/10
• 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 7/70891 Temperature
• CPC Class Codes: G03F 7/70916 Pollution mitigation, i.e. mitigating effect of contamination or debris, e.g. foil traps
• CPC Class Codes: G03F 7/70925 Cleaning, i.e. actively freeing apparatus from pollutants, e.g. using plasma cleaning

Abstract

An immersion lithography apparatus and cleanup method used for the immersion lithography apparatus in which an immersion liquid is supplied to a gap between an optical element of a projection optics and a workpiece during an immersion lithography process. A surface of an object, which is different from the workpiece, is provided below the optical element, a supply port and a recovery port. During a cleanup process, a cleaning liquid is supplied onto the object such that the cleaning liquid covers only a portion of the surface of the object.

Claims

1. A method used in an immersion lithography apparatus in which an immersion liquid is supplied to a gap between an optical element of a projection optics and a workpiece during an immersion lithography process, the method comprising:

supplying, during the immersion lithography process, the immersion liquid to the gap through a first channel without passing through a second channel; and

supplying, during a cleanup process, a cleaning liquid onto a surface of an object, which is different from the workpiece, provided directly vertically below the optical element, a liquid supply port and a liquid recovery port, the cleaning liquid being supplied from above the object from the liquid supply port by delivering flow from the second channel such that only a portion of the surface of the object is covered by the cleaning liquid and at least a part of a remainder of the surface of the object is not covered by the cleaning liquid nor the immersion liquid,

wherein the workpiece is moved directly vertically below and relative to the optical element, the liquid supply port and the liquid recovery port during the immersion lithography process, and

wherein during the immersion lithography process, the immersion liquid is locally disposed on an upper surface of the workpiece, at least a part of a remainder of the upper surface of the workpiece not being covered by the immersion liquid nor the cleaning liquid.

2. The method according to claim 1, wherein the cleaning liquid covers only a portion of the surface of the object such that a surface of the cleaning liquid extends between the surface of the object and a liquid supply member which has the supply port.

3. The method according to claim 1, wherein the liquid supply port supplies the immersion liquid during the immersion lithography process.

4. The method according to claim 1, further comprising moving the object relative to the optical element in the cleanup process.

5. The method according to claim 1, wherein the cleanup process is performed with ultraviolet light.

6. The method according to claim 1, wherein the cleaning liquid fills a space between the optical element and the object in the cleanup process.

7. The method according to claim 1, wherein the object is provided directly vertically below a member to be cleaned during the cleanup process.

8. The method according to claim 7, wherein the cleaning liquid is retained between the member to be cleaned and the object in the cleanup process.

9. The method according to claim 7, wherein the member to be cleaned includes the optical element.

10. The method according to claim 9, wherein liquid absorbed by the optical element is removed in the cleanup process.

11. The method according to claim 1, wherein the workpiece includes a wafer for fabricating a semiconductor device.

12. An immersion lithography apparatus comprising:

a liquid supply port;

a liquid recovery port; and

a projection optics having an optical element, the projection optics projecting a pattern image onto a workpiece through an immersion liquid supplied to a gap between the final surface and the workpiece during an immersion lithography process;

wherein during the immersion lithography process, the immersion liquid is supplied through a first channel without passing through a second channel and the workpiece is moved directly vertically below and relative to the projection optics, the liquid supply port and the liquid recovery port,

wherein during a cleanup process, an object having a surface, which is different from the workpiece, is placed directly vertically below the liquid supply port, the liquid recovery port and the projection optics, and a cleaning liquid is supplied onto the object from above the object from the liquid supply port by delivering flow from the second channel such that only a portion of the surface of the object is covered by the cleaning liquid and at least a part of a remainder of the surface of the object is not covered by the cleaning liquid nor the immersion liquid, and

wherein during the immersion lithography process, the immersion liquid is locally disposed on an upper surface of the workpiece, at least a part of a remainder of the upper surface of the workpiece not being covered by the immersion liquid nor the cleaning liquid.

13. The apparatus according to claim 12, further comprising a liquid supply member which has the supply port,

wherein the cleaning liquid covers only a portion of the surface of the object such that a surface of the cleaning liquid extends between the surface of the object and the liquid supply member.

14. The apparatus according to claim 12, wherein the liquid supply port supplies the immersion liquid during the immersion lithography process.

15. The apparatus according to claim 12, wherein the object is moved relative to the optical element in the cleanup process.

16. The apparatus according to claim 12, wherein the cleanup process is performed with ultraviolet light.

17. The apparatus according to claim 12, wherein the cleaning liquid fills a space between the optical element and the object in the cleanup process.

18. The apparatus according to claim 12, wherein the object is provided directly vertically below a member to be cleaned during the cleanup process.

19. The apparatus according to claim 18, wherein the cleaning liquid is retained between the member to be cleaned and the object in the cleanup process.

20. The apparatus according to claim 18, wherein the member to be cleaned includes an optical element of the projection optics, the optical element having the final surface.

21. The apparatus according to claim 12, wherein the object includes a pad.

22. A device manufacturing method comprising:

exposing a workpiece through the projection optics of the immersion lithography apparatus of claim 12; and

developing the exposed workpiece.

23. The apparatus according to claim 12, wherein the workpiece includes a wafer for fabricating a semiconductor device.

24. A method used in an immersion lithography apparatus in which an immersion liquid is supplied onto a workpiece during an immersion lithography process, the method comprising:

supplying, during the immersion lithography process, the immersion liquid through a first channel without passing through a second channel; and

supplying, during a cleanup process, a cleaning liquid onto a surface of an object, which is different from the workpiece, provided directly vertically below a liquid supply port, the cleaning liquid being supplied from above the object from the liquid supply port by delivering flow from the second channel such that only a portion of the object surface is covered by the cleaning liquid and at least a part of a remainder of the object surface is not covered by the cleaning liquid nor the immersion liquid,

wherein the workpiece is moved directly vertically below and relative to the liquid supply port during the immersion lithography process, and

wherein during the immersion lithography process, the immersion liquid is locally disposed on an upper surface of the workpiece, at least a part of a remainder of the upper surface of the workpiece not being covered by the immersion liquid nor the cleaning liquid.

25. The method according to claim 24, wherein the cleaning liquid covers only the portion of the surface of the object such that a surface of the cleaning liquid extends between the surface of the object and a liquid supply member which has the liquid supply port.

26. The method according to claim 24, further comprising moving the object relative to the liquid supply port in the cleanup process.

27. The method according to claim 24, wherein the cleanup process is performed with ultraviolet light.

28. The method according to claim 24, wherein the object is provided directly vertically below a member to be cleaned during the cleanup process.

29. The method according to claim 28, wherein the cleaning liquid is retained between the member to be cleaned and the object in the cleanup process.

30. The method according to claim 28, wherein the member to be cleaned includes an optical element of a projection optics, and wherein the immersion liquid is supplied to a gap between the workpiece and the optical element during the immersion lithography process.

31. The method according to claim 30, wherein liquid absorbed by the optical element is removed in the cleanup process.

32. The method according to claim 24, wherein the workpiece includes a wafer for fabricating a semiconductor device.

33. A method used in an immersion lithography apparatus, the method comprising:

placing an object to perform a cleanup process directly vertically below a liquid supply port of the apparatus, the apparatus being an apparatus in which an immersion liquid is supplied onto a workpiece through a first channel without passing through a second channel during an immersion lithography process; and

supplying, during the cleanup process, a cleaning liquid onto a surface of the object, which is different from the workpiece, placed directly vertically below the liquid supply port, the cleaning liquid being supplied from above the object from the liquid supply port by delivering flow from the second channel, a portion of the surface of the object being covered by the cleaning liquid during the cleanup process and at least a part of a remainder of the surface of the object is not covered by the cleaning liquid nor the immersion liquid,

wherein the workpiece is moved directly vertically below and relative to the liquid supply port during the immersion lithography process; and

wherein during the immersion lithography process, the immersion liquid is locally disposed on an upper surface of the workpiece, at least a part of a remainder of the upper surface of the workpiece not being covered by the immersion liquid nor the cleaning liquid.

34. The method according to claim 33, wherein the cleaning liquid covers only the portion of the surface of the object such that a surface of the cleaning liquid extends between the surface of the object and a liquid supply member which has the liquid supply port.

35. The method according to claim 33, further comprising moving the object relative to the liquid supply port in the cleanup process.

36. The method according to claim 33, wherein the cleanup process is performed with ultraviolet light.

37. The method according to claim 33, wherein the object is provided directly vertically below a member to be cleaned during the cleanup process.

38. The method according to claim 37, wherein the cleaning liquid is retained between the member to be cleaned and the object in the cleanup process.

39. The method according to claim 37, wherein the member to be cleaned includes an optical element of a projection optics, and wherein the immersion liquid is supplied to a gap between the workpiece and the optical element during the immersion lithography process.

40. The method according to claim 39, wherein liquid absorbed by the optical element is removed in the cleanup process.

41. The method according to claim 33, wherein the workpiece includes a wafer for fabricating a semiconductor device.