Objective with pupil obscuration

• US 20050180011A1
• Filed: 04/08/2005
• Published: 08/18/2005
• Est. Priority Date: 08/16/2001
• Status: Active Grant

• Current Assignee: CARL Zeiss SMT GmbH (Carl-Zeiss-Stiftung)
• Original Assignee: Carl Zeiss AG (Carl-Zeiss-Stiftung)
• Inventors: Ulrich, Wilhelm, Mann, Hans-Jurgen
• Granted Patent: US 7,209,286 B2
• Time in Patent Office: Days
• US Class Current: 359/499
• CPC Class Codes: G02B 17/0652 on-axis systems with at least one of the mirrors having a central aperture
• CPC Class Codes: G03F 7/70225 Optical aspects of catadioptric systems, i.e. comprising reflective and refractive elements
• CPC Class Codes: G03F 7/70233 Optical aspects of catoptric systems, i.e. comprising only reflective elements, e.g. extreme ultraviolet [EUV] projection systems
• CPC Class Codes: G03F 7/70291 Addressable masks, e.g. spatial light modulators [SLMs], digital micro-mirror devices [DMDs] or liquid crystal display [LCD] patterning devices

Abstract

An objective is configured with a first partial objective and a second partial objective. The first partial objective, which projects a first field plane onto an intermediate image, has a first, convex mirror and a second, concave mirror. The second partial objective, which projects the intermediate image onto a second field plane, has a third and a fourth mirror, both concave. All of the four mirrors have central mirror apertures. The axial distance between the first and second mirrors is in a ratio between 0.95 and 1.05 relative to the distance between the second mirror and the intermediate image. The axial distance Z_M3-IM between the third mirror and the second field plane conforms to the relationship $0.03·{\mathrm{Du}}_{\mathrm{M3}}+5.0\mathrm{mm}<Z_{\mathrm{M3}-\mathrm{IM}}<\frac{0.25·{\mathrm{Du}}_{\mathrm{M3}}}{\tan \left(\arcsin \left(\mathrm{NA}\right)\right)}.$
NA represents the numerical aperture NA in the second field plane, and DU_M3 represents the diameter of the third mirror. The objective furthermore has a Petzval radius with an absolute value larger than the distance between the first and second field planes.

Claims

1. A projection exposure apparatus comprising:

an illuminating system to illuminate a drivable micromirror array and an objective, which projects said drivable micromirror array onto photosensitive substrate;

wherein said objective comprises mirrors which are arranged coaxial with respect to a common optical axis.

2. The projection exposure apparatus according to claim 1, wherein said objective is a catoptric objective.

3. The projection exposure apparatus according to claim 1, wherein said objective has a numerical aperture at said substrate greater than 0:

1.

4. The projection exposure apparatus according to claim 1, wherein said objective has an imaging scale ratio of greater than 20:

1.

5. The projection exposure apparatus according to claim 1, wherein said objective comprises at least two partial objectives with an intermediate image plane between said at lest two partial objectives.

6. The projection exposure apparatus according to claim 5, wherein each of said at least two partial objectives has an imaging scale ratio greater than 1:

1.

7. The projection exposure apparatus according to claim 6, wherein said partial objective between said drivable micromirror array and said intermediate image has an imaging scale ration which is substantially greater by comparison with said partial objective between intermediate image and said photosensitive substrate.

8. The projection exposure apparatus according to claim 1, wherein said objective is an objective with pupil obscuration.

9. The projection exposure apparatus according to claim 1, wherein said objective comprises mirrors being coated with reflecting layers which are adapted to reflect two mutually separated operating wavelengths.

10. The projection exposure apparatus according to claim 1, wherein an axial spacing of said drivable micromirror array from said photosensitive substrate is less than or equal to 3000 mm.

11. The projection exposure apparatus according to claim 1, wherein said drivable micromirror array is arranged not centered relative to a common optical axis of said objective.

12. The projection exposure apparatus according to claim 11, wherein said drivable micromirror array is arranged outside said optical axis.

13. The projection exposure apparatus according to claim 1, wherein said illuminating system comprises a grazing-incidence mirror for coupling in the illuminating light towards said drivable micromirror array.

14. The projection exposure apparatus according to claim 13, wherein said grazing-incidence mirror has an axial spacing from said drivable micromirror array which is greater than 20% of an axial spacing of said drivable micromirror array from said photosensitive substrate.

15. A projection exposure apparatus comprising:

an illuminating system to illuminate a drivable micromirror array and an objective, which projects said drivable mircromirror array onto a photosensitive substrate;

wherein said objective is catoptric objective with an imaging scale ratio of greater than 20;

1.

16. The projection exposure apparatus according to claim 15, wherein said objective has a numerical aperture at said substrate greater than 0.1.

17. A projection exposure apparatus comprising:

an illuminating system to illuminate a drivable micromirror array and an objective, which projects said drivable micromirror array onto photosensitive substrate;

wherein said objective comprises at least two partial objectives with an intermediate image plane between said at least two partial objectives.

18. The projection exposure apparatus according to claim 17, wherein each of said at least two partial objectives has an imaging scale ratio greater than 1:

1.

19. The projection exposure apparatus according to claim 18, wherein said partial objective between said drivable micromirror array and said intermediate image has an imaging scale ration which is substantially greater by comparison with said partial objective between said intermediate image and said photosensitive substrate.

20. A projection exposure apparatus comprising:

an illuminating system to illuminate a drivable micromirror array and an objective, which projects said drivable micromirror array onto a photosensitive substrate;

wherein said objective is an objective with pupil obscuration.

21. A projection exposure apparatus comprising:

an illuminating system to illuminate a drivable micromirror array and an objective, which projects said drivable micromirror array onto a photosensitive substrate;

wherein said objective consists of mirrors being coated with reflecting layers which are adapted to reflect two mutually separated operating wavelengths.