Exposure apparatus

• US 20050146693A1
• Filed: 12/09/2004
• Published: 07/07/2005
• Est. Priority Date: 12/09/2003
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Ohsaki, Yoshinori
• Granted Patent: US 7,221,431 B2
• Time in Patent Office: Days
• US Class Current: 355/30
• CPC Class Codes: G03B 27/52 Details
• 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 7/7085 Detection arrangement, e.g. detectors of apparatus alignment possibly mounted on wafers, exposure dose, photo-cleaning flux, stray light, thermal load
• CPC Class Codes: G03F 9/7096 Arrangement, mounting, housing, environment, cleaning or maintenance of apparatus

Abstract

An exposure apparatus includes a projection optical system for projecting a pattern on a reticle onto an object to be exposed, a reference mark that serves as a reference for an alignment between the reticle and the object, a first fluid that has a refractive index of 1 or greater, and fills a space between at least part of the projection optical system and the object and a space between at least part of the projection optical system and the reference mark, and an alignment mechanism for aligning the object by using the projection optical system and the first fluid.

Claims

1. An exposure apparatus comprising:

a projection optical system for projecting a pattern on a reticle onto an object to be exposed;

a reference mark that serves as a reference for an alignment between the reticle and the object;

a first fluid that has a refractive index of 1 or greater, and fills a space between at least part of said projection optical system and the object and a space between at least part of said projection optical system and the reference mark; and

an alignment mechanism for aligning the object by using said projection optical system and the first fluid.

2. An exposure apparatus according to claim 1, further comprising:

a stage for mounting the object; and

a reference plate mounted on said stage and made of a transparent material that transmits light, wherein said reference mark is provided on the reference plate.

3. An exposure apparatus according to claim 2, wherein said alignment mechanism includes a light-receiving element provided on said reference plate at a back of a surface on which said reference mark is formed, the light-receiving element receiving light that transmits the reference mark,

wherein said exposure apparatus further comprises a second fluid that has a refractive index of 1 or greater, and fills a space between said reference mark and the light-receiving element.

4. An exposure apparatus according to claim 3, wherein said alignment mechanism further includes a plane-convex lens provided between said reference mark and the light-receiving element, the plane-convex lens having a plane opposing to the back of said reference plate,

wherein the second fluid fills a space between said reference mark and the plane-convex lens.

5. An exposure apparatus according to claim 2, wherein said alignment mechanism includes a light-receiving element provided on said reference plate at a back of a surface on which said reference mark is formed, the light-receiving element receiving light that transmits the reference mark,

wherein the back of said reference plate has a convex shape having a curvature that does not cause a total reflection of the light.

6. An exposure apparatus according to claim 1, wherein said alignment mechanism has a plane-convex lens having a plane opposing to a back of a surface of said reference plate, on which surface said reference mark is formed, the plane being spaced from the back by a distance so that light that transmits the reference mark is not totally reflected on the back of said reference plate.

7. An exposure apparatus according to claim 5, wherein the distance is smaller than the wavelength of the light.

8. An exposure apparatus according to claim 1, wherein said alignment mechanism includes a light-receiving element for receiving light that transmits said reference mark,

wherein said exposure apparatus further comprises a second fluid that fills a space between the reference mark and the light-receiving element, and has a refractive index of 1 or greater.

9. An exposure apparatus according to claim 1, wherein said alignment mechanism includes an irradiating section for irradiating light that transmits said reference mark and enters said projection optical system,

wherein said exposure apparatus further comprises a second fluid that fills a space between said reference mark and the irradiating section, and has a refractive index of 1 or greater.

10. An exposure apparatus according to claim 2, wherein said alignment mechanism includes an irradiating section arranged at a back of a surface of said reference plate, on which surface said reference mark is formed,

wherein said exposure apparatus further comprises a second fluid that immerses a space between the reference mark and the irradiating section, and has a refractive index of 1 or greater.

29. A device manufacturing method comprising the steps of:

exposing an object using an exposure apparatus according to claim 1;

and

developing the object that has been exposed.

11. An exposure apparatus comprising:

a projection optical system for projecting a pattern on a reticle onto an object;

a reference mark that serves as a reference for an alignment between the reticle and the object;

a light-receiving element for receiving light that transmits said reference mark; and

a fluid that has a refractive index of 1 or greater, and fills a space between said reference mark and said light-receiving element.

12. An exposure apparatus according to claim 11, further comprising:

a stage for mounting the object; and

a reference plate mounted on said stage and made of a transparent material that transmits light, wherein said reference mark is provided on the reference plate.

13. An exposure apparatus according to claim 12, wherein said alignment mechanism further includes a plane-convex lens provided between said reference mark and the light-receiving element, the plane-convex lens having a plane opposing to the back of said reference plate,

wherein the fluid fills a space between said reference mark and the plane-convex lens.

14. An exposure apparatus according to claim 11, wherein said projection optical system has a numerical aperture of 0.8 or greater.

15. An exposure apparatus comprising:

a projection optical system for projecting a pattern on a reticle onto an object;

a reference mark that serves as a reference for an alignment between the reticle and the object;

an irradiating section for irradiating light that transmits said reference mark and enters said projection optical system; and

a fluid that has a refractive index of 1 or greater, and fills a space between said reference mark and said irradiating section.

16. An exposure apparatus according to claim 15, further comprising:

a stage for mounting the object; and

a reference plate mounted on said stage and made of a transparent material that transmits light, wherein said reference mark is provided on the reference plate.

17. An exposure apparatus according to claim 16, wherein said alignment mechanism further includes a plane-convex lens provided between said reference mark and the light-receiving element, the plane-convex lens having a plane opposing to the back of said reference plate,

wherein the fluid fills a space between said reference mark and the plane-convex lens.

18. An exposure apparatus comprising:

a projection optical system for projecting a pattern on a reticle onto an object;

a reference mark that serves as a reference for an alignment between the reticle and the object; and

an anti-reflection member for preventing a total reflection of light that has passed said reference mark and has not yet been received by said light-receiving element.

19. An exposure apparatus according to claim 18, further comprising:

a stage for mounting the object; and

a reference plate mounted on said stage and made of a transparent material that transmits light, wherein said reference mark is provided on the reference plate,

wherein said antireflection member has a convex shape that has a curvature that does not cause a total reflection of the light, and is formed on a back of a surface of said reference plate, on which surface said reference mark is formed.

20. An exposure apparatus according to claim 18, further comprising:

a stage for mounting the object; and

a reference plate mounted on said stage and made of a transparent material that transmits light, wherein said reference mark is provided on the reference plate,

wherein said antireflection member includes a plane-convex lens that has a plane that opposes a back of a surface of the reference plate, on which surface said reference mark is formed, and is spaced from the back by a distance so that light that passes the reference mark is not totally reflected on the back of the reference plate.

21. An exposure apparatus according to claim 18, wherein the light-receiving element is a light intensity sensor for detecting a light intensity change of the light.

22. An exposure apparatus according to claim 21, further comprising a calculating section for calculating a positional relationship between the reticle and the object in an optical-axis direction of said projection optical system, based on the light intensity change detected by the light intensity sensor.

23. An exposure apparatus according to claim 21, further comprising a calculating section for calculating an aberration of said projection optical system based on the light intensity change detected by said light intensity sensor.

24. An exposure apparatus comprising:

a projection optical system for projecting a pattern on a reticle onto an object;

a light-receiving element for receiving light that transmits said reference mark; and

an adjuster, arranged between said reference mark and the light-receiving element, for adjusting an numerical aperture of the light.

25. An exposure apparatus according to claim 24, wherein said adjuster has a fluid that has a refractive index of 1 or greater, and fills a space between said reference mark and said light-receiving element.

26. An exposure apparatus according to claim 24, wherein said exposure apparatus is an immersion type exposure apparatus that immerses at least part of said projection optical system in a fluid that has a refractive index of 1 or greater.

27. An exposure method for exposing a pattern on a reticle onto an object, said exposure method comprising the step of:

aligning the reticle and the object with each other by using light having a numerical aperture of 1 or greater.

28. An exposure method according to claim 27, wherein at least part of the projection optical system is filled with the fluid having a refractive index of 1 or greater.