Lithographic apparatus and device manufacturing method

• US 20060158626A1
• Filed: 12/12/2005
• Published: 07/20/2006
• Est. Priority Date: 12/30/2004
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Baselmans, Johannes Jacobus Matheus, Mulkens, Johannes Catharinus Hubertus, Donders, Sjoerd Nicolaas Lambertus, Streefkerk, Bob, Hoogendam, Christiaan Alexander, Mertens, Jeroen Johannes Sophia
• Granted Patent: US 7,670,730 B2
• Time in Patent Office: Days
• US Class Current: 355/53
• 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 7/70883 of optical system
• CPC Class Codes: G03F 9/7023 Aligning or positioning in direction perpendicular to substrate surface

Abstract

A method for correcting an exposure parameter of an immersion lithographic apparatus is provided. In the method, an exposure parameter is measured using a measuring beam projected through a liquid between the projection system and a substrate table of the immersion lithographic apparatus and offset is determined based on a change of a physical property impacting a measurement made using the measuring beam to at least partly correct the measured exposure parameter. Also, there is provided an apparatus and method to measure a height of an optical element connected to liquid between the projection system and the substrate table in the immersion lithographic apparatus.

Claims

1. A method for correcting an exposure parameter of an immersion lithographic apparatus, the method comprising:

measuring an exposure parameter using a measuring beam projected through a liquid between the projection system and a substrate table of the immersion lithographic apparatus; and

determining an offset based on a change of a physical property impacting a measurement made using the measuring beam to at least partly correct the measured exposure parameter.

2. The method according to claim 1, wherein the physical property comprises (a) a temperature, or (b) a pressure, or (c) a composition, or (d) any combination of (a)-(c), of the liquid.

3. The method according to claim 1, wherein the physical property comprises (a) a temperature, or (b) a pressure, or (c) a composition, or (d) any combination of (a)-(c), of a flushing gas, of or on an optical element of the projection system, or both.

4. The method according to claim 1, wherein the exposure parameter comprises a focus of a patterned beam to be projected using the projection system, a height of the substrate held on the substrate table, or both.

5. The method according to claim 1, wherein the exposure parameter comprises a lateral placement of a patterned beam to be projected using the projection system, an X-Y position of the substrate held on the substrate table, or both.

6. The method according to claim 1, wherein the physical property comprises a wavelength of the measuring beam, a wavelength of a patterned beam to be projected using the projection system, or both.

7. The method according to claim 1, wherein the offset comprises a multiplication of the change of the physical property and a rate of change of the exposure parameter with respect to the physical property.

8. The method according to claim 1, comprising projecting the measuring beam and a patterned beam for the exposure of the substrate through an optical element of the projection system.

9. The method according to claim 1, wherein determining the offset based on the change of the physical property comprises determining the offset based on the difference between the change of the physical property for a wavelength of the measuring beam and a change of the physical property for a wavelength of a patterned beam to be projected using the projection system.

10. A lithographic apparatus, comprising:

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

a substrate table configured to hold a substrate;

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

a liquid supply system configured to provide liquid to a space between the projection system and the substrate table;

a sensor configured to measure an exposure parameter using a measuring beam projected through the liquid; and

a correction system configured to determine an offset based on a change of a physical property impacting a measurement made using the measuring beam to at least partly correct the measured exposure parameter.

11. The apparatus according to claim 10, wherein the physical property comprises (a) a temperature, or (b) a pressure, or (c) a composition, or (d) any combination of (a)-(c), of the liquid.

12. The apparatus according to claim 10, wherein the physical property comprises (a) a temperature, or (b) a pressure, or (c) a composition, or (d) any combination of (a)-(c), of a flushing gas, of or on an optical element of the projection system, or both.

13. The apparatus according to claim 11, further comprising a temperature sensor configured to measure the temperature of the liquid, a pressure sensor configured to measure the pressure of the liquid, or both.

14. The apparatus according to claim 10, wherein the exposure parameter comprises a focus of the patterned beam, a height of the substrate, or both.

15. The apparatus according to claim 10, wherein the exposure parameter comprises a lateral placement of the patterned beam, an X-Y position of the substrate, or both.

16. The apparatus according to claim 10, wherein the physical property comprises a wavelength of the measuring beam, a wavelength of the patterned beam, or both.

17. The apparatus according to claim 10, wherein the offset comprises a multiplication of the change of the physical property and a rate of change of the exposure parameter with respect to the physical property.

18. The apparatus according to claim 10, wherein the sensor is configured to project the measuring beam through an optical element of the projection system through which the patterned beam is to be projected.

19. The apparatus according to claim 10, wherein the correction system is configured to determine the offset based on the difference between a change of the physical property for a wavelength of the measuring beam and a change of the physical property for a wavelength of the patterned beam.

20. A computer program product for correcting an exposure parameter of an immersion lithographic apparatus, comprising:

software code configured to measure an exposure parameter using a measuring beam projected through a liquid between the projection system and a substrate table of the immersion lithographic apparatus; and

software code configured to determine an offset based on a change of a physical property impacting a measurement made using the measuring beam to at least partly correct the measured exposure parameter.

21. The computer program product according to claim 20, wherein the physical property comprises (a) a temperature, or (b) a pressure, or (c) a composition, or (d) any combination of (a)-(c), of the liquid.

22. The computer program product according to claim 20, wherein the physical property comprises (a) a temperature, or (b) a pressure, or (c) a composition, or (d) any combination of (a)-(c), of a flushing gas, of or on an optical element of the projection system, or both.

23. The computer program product according to claim 20, wherein the exposure parameter comprises a focus of a patterned beam to be projected using the projection system, a height of a substrate held on the substrate table, or both.

24. The computer program product according to claim 20, wherein the exposure parameter comprises a lateral placement of a patterned beam to be projected using the projection system, an X-Y position of a substrate held on the substrate table, or both.

25. The computer program product according to claim 20, wherein the physical property comprises a wavelength of the measuring beam, a wavelength of a patterned beam to be projected using the projection system, or both.

26. The computer program product according to claim 20, comprising software code configured to determine the offset by multiplication of the change of the physical property and a rate of change of the exposure parameter with respect to the physical property.

27. The computer program product according to claim 20, comprising software code configured to determine the offset based on the difference between a change of the physical property for a wavelength of the measuring beam and a change of the physical property for a wavelength of a patterned beam to be projected using the projection system.

28. A lithographic apparatus, comprising:

a substrate table configured to hold a substrate;

a projection system configured to project a patterned beam onto a target portion of the substrate, the projection system having an optical element;

a liquid supply system configured to provide liquid to a space between the projection system and the substrate table, the optical element configured to be connected to the liquid; and

a sensor configured to measure a height of the optical element.

29. The apparatus according to claim 28, wherein the optical element is moveable and further comprising a correction system configured to move the optical element to at least partly correct for a change in height of the optical element.

30. The apparatus according to claim 28, further comprising a correction system configured to move the substrate table to at least partly correct for a change in height of the optical element.

31. The apparatus according to claim 28, wherein the sensor is configured to detect a measuring beam traveling from the optical element to measure the height of the optical element.

32. The apparatus according to claim 31, wherein sensor is further configured to project the measuring beam at the optical element.

33. The apparatus according to claim 28, wherein the sensor is configured to detect a measuring beam that reflects from the optical element and configured to measure the height of the optical element by evaluating fringes created by interference between the measuring beam and a beam reflected from the substrate or substrate table.

34. The apparatus according to claim 28, wherein the sensor is a level sensor configured to measure a height of the substrate or substrate table.

35. The apparatus according to claim 28, wherein a change in the height of the optical element is a measure of focus error, spherical aberration, or both, and further comprising a correction system configured to at least partly correct such focus error, spherical aberration, or both.

36. A method of correcting for an imaging error of an immersion lithographic apparatus, comprising:

measuring a height of an optical element of a projection system in the immersion lithographic apparatus, the optical element connected to a liquid between the projection system and a substrate table of the projection system; and

at least partly correcting the image error by moving the optical element, moving the substrate table, or both.

37. The method according to claim 36, wherein the imaging error is a focus error, a spherical aberration, or both.

38. The method according to claim 36, wherein measuring the height comprises projecting a measuring beam at the optical element and detecting a measuring beam traveling from the optical element.

39. The method according to claim 36, wherein measuring the height comprises detecting a measuring beam that reflects from the optical element and evaluating fringes created by interference between the measuring beam and a beam reflected from the substrate table or a substrate held on the substrate table.

40. The method according to claim 36, wherein measuring the height is performed using a level sensor configured to measure a height of the substrate table or a substrate held on the substrate table.