Projection exposure apparatus, cleaning and maintenance methods of a projection exposure apparatus, and device manufacturing method

• US 20060232757A1
• Filed: 03/23/2006
• Published: 10/19/2006
• Est. Priority Date: 09/26/2003
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Tani, Yasuhisa, Shiozawa, Masaki
• Granted Patent: US 8,035,797 B2
• Time in Patent Office: Days
• US Class Current: 355/53
• CPC Class Codes: B08B 3/10 with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration
• CPC Class Codes: G03F 7/2041 in the presence of a fluid, e.g. immersion; using fluid cooling means
• 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 7/70916 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
• CPC Class Codes: G03F 7/70975 Assembly, maintenance, transport or storage of apparatus

Abstract

A projection exposure apparatus that exposes a substrate with a liquid interposed between a surface of the substrate and an optical element on the substrate side of a projection optical system; includes liquid supply and discharge mechanisms, which supply the liquid via a liquid supply tube as they recover the liquid via a liquid recovery tube, and an adhesion preventing mechanism that prevents an adhesion of impurities on member forming a flow path for the liquid.

Claims

1. A projection exposure apparatus in which a mask is illuminated with an exposure beam and transfers a pattern of the mask onto a substrate via a projection optical system and a liquid is filled in a space between a surface of the substrate and an optical element of the projection optical system on the substrate side, comprising:

a liquid supply and discharge mechanism, which supplies the liquid via a liquid supply tube, and recovers the liquid via a liquid recovery tube; and

a scale adhesion prevention mechanism provided on the liquid supply tube.

2. A projection exposure apparatus according to claim 1, further comprising a scale adhesion prevention mechanism provided on the liquid recovery tube.

3. A projection exposure apparatus according to claim 1, wherein the scale adhesion prevention mechanism prevents an adhesion of scale based on an external magnetic field applied from an outside of the liquid supply tube or the liquid recovery tube.

4. A projection exposure apparatus according to claim 1, wherein the scale adhesion prevention mechanism prevents an adhesion of scale based on electrical signals that flow through wiring wound in a coil shape on the liquid supply tube or the liquid recovery tube.

5. A projection exposure apparatus according to claim 1, wherein the exposure beam is ArF laser light.

6. A projection exposure apparatus according to claim 1, wherein a base material of the optical element is fluorite.

7. A liquid immersion type projection exposure apparatus in which a gap between an optical component and an object of exposure is filled with a liquid and the object is exposed, comprising:

a liquid supply mechanism which supplies the liquid; and

a cleaning means that removes adhering substances within a flow path of the liquid.

8. A projection exposure apparatus according to claim 7, wherein the cleaning means has a supply flow volume ascertainment unit, which ascertains a liquid supply flow volume per unit time, and a flow volume fluctuation control unit which causes a liquid supply flow volume per unit time to fluctuate.

9. A projection exposure apparatus according to claim 8, further comprising a liquid discharge mechanism which discharges the liquid, wherein

the cleaning means has a discharge flow volume ascertainment unit, which ascertains a liquid discharge flow volume per unit time, and

the flow volume fluctuation control unit controls the liquid supply mechanism and the liquid discharge mechanism so that the liquid supply flow volume per unit time and the liquid discharge flow volume per unit time become linked and fluctuate.

10. A projection exposure apparatus according to claim 8, wherein the liquid supply flow volume per unit time fluctuates at an amplitude of 0.1% or more with respect to a time average value of the liquid supply flow volume.

11. A projection exposure apparatus according to claim 7, wherein the cleaning means has a function that removes the adhering substances from inside of the flow path by mixing one or more bubbles of a volume of 1 ml or less into the liquid.

12. A projection exposure apparatus according to claim 7, wherein the cleaning means is configured to operate in correspondence with a stop of exposure so as to remove the adhering substances from the inside of the flow path.

13. A projection exposure apparatus according to claim 7, wherein the optical component is a synthetic calcium fluoride monocrystal.

14. A projection exposure apparatus according to claim 13, wherein an uppermost surface of the optical component is coated with magnesium fluoride.

15. A projection exposure apparatus according to claim 7, wherein purified water or an aqueous solution in which salts are dissolved is used as the liquid.

16. A cleaning method of a liquid immersion type projection exposure apparatus in which a gap between an optical component and an object of exposure is filled with a liquid and the object is exposed, the method comprising:

causing, when supplying the liquid, a liquid supply volume and a liquid discharge flow volume to fluctuate to remove an adhering substances in a flow path of the liquid.

17. A cleaning method of the projection exposure apparatus according to claim 16, wherein the adhering substances in the flow path are removed by causing fluctuation at an amplitude of 0.1% or more for the liquid supply volume per unit time with respect to a time average value of the liquid supply flow volume.

18. A cleaning method of a liquid immersion type projection exposure apparatus in which a gap between an optical component and an object of exposure is filled with a liquid to increase a resolution, comprising:

mixing, when supplying the liquid, one or more bubbles of a volume of 1 ml or less into the liquid to clean inside of a flow path.

19. A projection exposure apparatus in which a space between a first object and a second object is filled with a liquid and exposure light is projected on an object of exposure via the liquid, comprising:

a liquid supply and discharge mechanism which supplies the liquid via a liquid supply tube and recovers the liquid via a liquid recovery tube; and

an adhesion prevention mechanism which prevents an adhesion of impurities to a member that forms a flow path of the liquid.

20. A projection exposure apparatus according to claim 19, wherein the member forming the flow path of the liquid includes the liquid supply tube of the liquid supply and discharge mechanism.

21. A projection exposure apparatus according to claim 19, wherein the member forming the flow path of the liquid includes the liquid recovery tube of the liquid supply and discharge mechanism.

22. A projection exposure apparatus according to claim 19, wherein the member forming the flow path of the liquid includes nozzles.

23. A projection exposure apparatus according to claim 19, wherein the adhesion of impurities is prevented by a magnetic field generated by the adhesion prevention mechanism.

24. A projection exposure apparatus according to claim 19, wherein the second object is the object of exposure.

25. A projection exposure apparatus according to claim 19, wherein the first object includes an optical element, and the exposure light is irradiated to the object of exposure via the optical element and the liquid.

26. A projection exposure apparatus according to claim 25, wherein the base material of the optical element is fluorite.

37. A device manufacturing method that uses a projection exposure apparatus as recited in claim 19.

27. A liquid immersion type projection exposure apparatus that fills a space between a first object and a second object with a liquid and irradiates exposure light on an object of exposure via the liquid, comprising:

a liquid supply mechanism which supplies the liquid;

a liquid discharge mechanism which discharges the liquid; and

a cleaning mechanism that cleans a flow path of the liquid.

28. A projection exposure apparatus according to claim 27, wherein the first object includes an optical component, and the exposure light is irradiated to the object of exposure via the optical component and the liquid.

29. A projection exposure apparatus according to claim 27, wherein the second object is the object of exposure.

30. A projection exposure apparatus according to claim 27, wherein the flow path includes a liquid supply flow path for supplying the liquid.

31. A projection exposure apparatus according to claim 27, wherein the flow path includes a liquid discharge flow path for discharging the liquid.

32. A projection exposure apparatus according to claim 27, wherein the cleaning mechanism removes impurities within the flow path.

33. A projection exposure apparatus according to claim 27, wherein the cleaning mechanism performs cleaning of the flow path by causing the liquid flow volume within the flow path to fluctuate.

34. A projection exposure apparatus according to claim 27, wherein the cleaning mechanism performs cleaning of the flow path by causing a liquid into which bubbles have been mixed to flow in the flow path.

35. A projection exposure apparatus according to claim 27, wherein the cleaning mechanism operates in correspondence with a stop of exposure.

36. A projection exposure apparatus according to claim 27, wherein purified water or an aqueous solution in which salts are dissolved is used as the liquid.

38. A maintenance method of a liquid immersion type projection exposure apparatus in which a gap between a first object and a second object is filled with a liquid and an object of exposure is exposed, comprising:

cleaning a flow path of the liquid, when exposure of the object is not being performed.

39. A maintenance method according to claim 38, wherein the cleaning of the flow path is performed by causing a liquid flow volume within the flow path to fluctuate.

40. A maintenance method according to claim 38, wherein the cleaning is performed by causing a liquid into which bubbles have been mixed to flow within the flow path.

41. A device manufacturing method that uses the maintenance method of a projection exposure apparatus as recited in claim 38.