Cleanup method for optics in immersion lithography using bubbles

• US 8,670,103 B2
• Filed: 12/19/2007
• Issued: 03/11/2014
• Est. Priority Date: 04/11/2003
• Status: Expired due to Fees

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Kawai, Hidemi
• Primary Examiner(s): LIU, CHIA HOW MICHAEL
• Application Number:
  US12/003,038
• Publication Number:
  US 20080100813A1
• Time in Patent Office: 2,274 Days
• Field of Search: 355/30, 355/53, 355/67, 359/665
• 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

A liquid immersion exposure apparatus includes an optical system via which a substrate is exposed with an exposure beam, and a cleaning device which performs a cleaning operation by filling a space adjacent the optical system with a liquid including bubbles.

Claims

1. A cleaning method used in a liquid immersion exposure apparatus, the method comprising:

placing an object to perform a cleanup process such that a surface of the object is opposite to a final surface of an optical system of the exposure apparatus in which a wafer is exposed with an exposure beam via the final surface of the optical system through an immersion liquid supplied from a nozzle member of the exposure apparatus during an immersion lithography process;

filling a space adjacent the optical system with a liquid supplied from the nozzle member during the cleanup process; and

moving the object under the optical system relative to the optical system in a direction substantially parallel to the final surface of the optical system during the cleanup process, while the liquid is in contact with the final surface of the optical system and the surface of the object;

wherein bubbles are generated in the liquid to clean a member of the apparatus which is in contact with the liquid during the cleanup process,

wherein the surface of the object, but not the wafer, contacts the liquid during the cleanup process.

2. The method according to claim 1, wherein the bubbles include cavitating bubbles.

3. The method according to claim 1, wherein the space includes a gap between the optical system disposed on one side and the object positioned on the other side, and wherein the member is disposed at the one side.

4. The method according to claim 1, wherein the member includes a last optical element of the optical system, the last optical element having the final surface.

5. The method according to claim 1, wherein:

the object is moved to generate the bubbles during the cleanup process.

6. The method according to claim 1, further comprising generating the bubbles in the liquid.

7. The method according to claim 1, wherein the object is horizontally moved during the cleanup process.

8. The method according to claim 1, wherein the object has no side walls.

9. A cleaning method used in a liquid immersion exposure apparatus, the method comprising:

filling a gap between an optical system disposed on one side and an object positioned on the other side with a liquid supplied from a nozzle member of the exposure apparatus during a cleanup process, a wafer being positioned on the other side of the optical system and exposed with an exposure beam via a final surface of the optical system through an immersion liquid supplied from the nozzle member during an immersion lithography process in the exposure apparatus; and

moving the object under the optical system relative to the optical system in a direction substantially parallel to the final surface of the optical system during the cleanup process, while the liquid is in contact with the final surface of the optical system and the surface of the object,

wherein bubbles are generated in the liquid in the gap to enhance a cleaning effect of the liquid during the cleanup process, and

wherein the object, but not the wafer, contacts the liquid during the cleanup process.

10. The method according to claim 9, wherein the liquid is used for cleaning a member disposed at the one side in the apparatus.

11. The method according to claim 9, wherein the liquid including the bubbles is used for cleaning a last optical element of the optical system, the last optical element having the final surface.

12. The method according to claim 9, wherein the object is horizontally moved during the cleanup process.

13. The method according to claim 9, wherein the object has no side walls.

14. A cleaning method used in a liquid immersion exposure apparatus, the method comprising:

placing an object to perform a cleanup process such that a surface of the object is opposite to a final surface of an optical system of the exposure apparatus in which a wafer is exposed with an exposure beam via the final surface of the optical system through an immersion liquid supplied from a nozzle member of the exposure apparatus in an immersion lithography process; and

moving the object under the optical system relative to the optical system in a direction substantially parallel to the final surface of the optical system during the cleanup process, while a liquid supplied from the nozzle member is in contact with the final surface of the optical system and the surface of the object,

wherein bubbles are generated in the liquid to enhance a cleaning effect of the liquid, and

wherein the surface of the object, but not the wafer, contacts the liquid during the cleanup process.

15. The method according to claim 14, wherein the liquid is supplied such that a member of the apparatus makes contact with the liquid to clean the member.

16. The method according to claim 15, wherein a gap is formed between the optical system disposed on one side and the object placed on the other side, and wherein the member is disposed at the one side.

17. The method according to claim 16, wherein the member includes a last optical element of the optical system, the last optical element having the final surface.

18. The method according to claim 14, wherein the liquid is filled in a gap between the final surface of the optical system and the surface of the object during the cleanup process.

19. The method according to claim 14, wherein the object is moved to generate the bubbles in the liquid.

20. The method according to claim 14, further comprising generating the bubbles in the liquid.

21. The method according to claim 14, wherein the object is horizontally moved during the cleanup process.

22. The method according to claim 14, wherein the object has no side walls.