Imaging optical system

Patent metadata

Field	Value
Publication number	US-9298100-B2
Application number	US-201414329076-A
Country	US
Kind code	B2
Filing date	Jul 11, 2014
Priority date	Jan 17, 2007
Publication date	Mar 29, 2016
Grant date	Mar 29, 2016

Abstract

The disclosure generally relates to imaging optical systems that include a plurality of mirrors, which image an object field lying in an object plane in an image field lying in an image plane, where at least one of the mirrors has a through-hole for imaging light to pass through. The disclosure also generally relates to projection exposure installations that include such im-aging optical systems, methods of using such projection exposure installa-tions, and components made by such methods.

First claim

What is claimed is:

1. An imaging optical system having a pupil plane, the imaging optical system comprising:
a plurality of mirrors configured to image an object field lying in an object plane into a rectangular image field lying in an image plane,
wherein during use of the imaging optical system:
surfaces of the pupil plane are illuminated; and
at least part of the illuminated surfaces of the pupil plane is obscured.

2. The imaging optical system according to claim 1 , wherein at most 24.6% of the illuminated surfaces of the pupil plane are obscured.

3. The imaging optical system according to claim 2 , wherein at most 17% of the illuminated surfaces of the pupil plane are obscured.

4. The imaging optical system according to claim 2 , wherein at most 11.6% of the illuminated surfaces of the pupil plane are obscured.

5. The imaging optical system according to claim 1 , wherein:
at least one of the mirrors comprises a first reflective region, a second reflective region and a through-hole configured between the first and second regions; and
during use of the imaging optical system:
the first and second regions reflect imaging light; and
imaging light passes through the through-hole.

6. The imaging optical system according to claim 1 , wherein a reflection surface of at least one of the mirrors is a free-form surface which cannot be described by a rotationally symmetrical function.

7. The imaging optical system according to claim 1 , wherein the image plane is arranged parallel to the object plane.

8. The imaging optical system according to claim 1 , wherein the imaging optical system is configured so that the imaging light is reflected by the mirrors with a maximum angle of reflection of 25°.

9. The imaging optical system according to claim 8 , wherein a quotient of a maximum angle of reflection of the imaging light within the imaging optical system and a numerical aperture thereof on the image side is at most 40°.

10. The imaging optical system according to claim 1 , wherein the imaging optical system is configured so that the imaging light is reflected by the mirrors with a maximum angle of reflection of 20°.

11. The imaging optical system according to claim 1 , wherein the imaging optical system is configured so that the imaging light is reflected by the mirrors with a maximum angle of reflection of 16°.

12. The imaging optical system according to claim 1 , wherein a mirror, which is arranged before a last mirror in an imaging light path in the region of a pupil plane, has a convex basic shape.

13. The imaging optical system according to claim 1 , wherein the plurality of mirrors comprises at least four mirrors.

14. The imaging optical system according to claim 1 , wherein the plurality of mirrors consists of six mirrors.

15. The imaging optical system according to claim 1 , wherein at least two of the plurality of mirrors have negative angular magnification of the principal ray.

16. The imaging optical system according to claim 15 , wherein a mirror with positive angular magnification of the principal ray is arranged between two mirrors with negative angular magnification of the principal ray.

17. The imaging optical system according to claim 1 , wherein, during use of the imaging optical system, a central imaging beam, directed through a last mirror and centrally through a pupil, of a central object point encloses an angle of greater than 85° relative to the image plane.

18. The imaging optical system according to claim 17 , wherein the imaging light path directed through the last mirror has an intermediate image in an intermediate image plane in the region of the through-hole in the mirror, a portion of the optical system between the object plane and the intermediate image plane having a reducing magnification level of at least 2×.

19. The imaging optical system according to claim 1 , wherein a mirror, which is arranged so as to be the penultimate mirror in the imaging light path, and from which the imaging light is reflected to the last mirror, has a through-hole for imaging light to pass through, the image plane being arranged behind the penultimate mirror so as to be off-centre by not more than a fifth of the diameter of the penultimate mirror.

20. The imaging optical system according to claim 1 , wherein a mirror, which is arranged so as to be the penultimate mirror in the imaging light path, and from which the imaging light is reflected to the last mirror, has a through-hole configured to allow imaging light to pass therethrough, the image plane being arranged behind the penultimate mirror so as to be central, relative to the penultimate mirror.

21. The imaging optical system according to claim 1 , wherein an area of the image field is greater than 1 mm 2 .

22. The imaging optical system according to claim 1 , wherein the imaging optical system has a numerical aperture on the image side of at least 0.4.

23. The imaging optical system according to claim 1 , wherein the imaging optical system has a numerical aperture on the image side of at least 0.45.

24. The imaging optical system according to claim 1 , wherein the imaging optical system has a numerical aperture on the image side of at least 0.5.

25. The imaging optical system according to claim 1 , wherein the imaging optical system has a numerical aperture on the image side of at least 0.55.

26. The imaging optical system according to claim 1 , wherein the imaging optical system has a numerical aperture on the image side of at least 0.6.

27. The imaging optical system according to claim 1 , wherein the imaging optical system has a numerical aperture on the image side of at least 0.65.

28. The imaging optical system according to claim 1 , wherein the imaging optical system has a numerical aperture on the image side of at least 0.7.

29. The imaging optical system according to claim 1 , wherein the imaging optical system is telecentric on the image side.

30. The imaging optical system according to claim 1 , wherein the imaging optical system has an object-image shift of less than 100 mm.

31. The imaging optical system according to claim 1 , wherein the imaging optical system has an object-image shift of less than 10 mm.

32. The imaging optical system according to claim 1 , wherein the imaging optical system has an object-image shift of less than 1 mm.

33. The imaging optical system according to claim 1 , comprising at least one pair of adjacent mirrors which are at a distance from one another, perpendicular to at least one of the object plane and the image plane, of more than 40% of the distance between the object field and the image field.

34. The imaging optical system according to claim 1 , wherein at least one mirror has a minimum distance of less than 25 mm from the reflection surface used to the closest imaging light path not acting upon the mirror.

35. The imaging optical system according to claim 1 , wherein during use the imaging light is reflected to the image field by the mirror, which comprises the through-hole configured to image light to pass through and is the last mirror in the imaging light path.

36. A projection exposure installation, comprising:
an imaging optical system; and
a lens system,
wherein:
the imaging o

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Mann Hans-Juergen

Classifications

• G03F7/70191

  Optical correction elements, filters or phase plates for controlling intensity, wavelength, polarisation, phase or the like · CPC title

• G02B17/0647

  using more than three curved mirrors (G02B17/0668, G02B17/0694 take precedence) · CPC title

• G02B17/0663 Primary

  off-axis or unobscured systems in which not all of the mirrors share a common axis of rotational symmetry, e.g. at least one of the mirrors is warped, tilted or decentered with respect to the other elements · CPC title

• A47J37/0786

  Accessories · CPC title

• A47J36/025

  Vessels with non-stick features, e.g. coatings · CPC title