OPTICAL SYSTEM FOR A MICROLITHOGRAPHIC PROJECTION EXPOSURE APPARATUS AND MICROLITHOGRAPHIC EXPOSURE METHOD

• US 20130077077A1
• Filed: 10/25/2012
• Published: 03/28/2013
• Est. Priority Date: 05/27/2010
• Status: Active Grant

• Current Assignee: CARL Zeiss SMT GmbH (Carl-Zeiss-Stiftung)
• Original Assignee: CARL Zeiss SMT GmbH (Carl-Zeiss-Stiftung)
• Inventors: Saenger, Ingo, Scharnweber, Ralf, Dittmann, Olaf, Gruner, Toralf, Weiss, Gundula, Major, Andras G., Deguenther, Markus, Wangler, Johannes, Vogt, Martin, Korb, Thomas
• Granted Patent: US 9,946,161 B2
• Time in Patent Office: Days
• US Class Current: 355/71
• CPC Class Codes: G03F 7/70116 Off-axis setting using a programmable means, e.g. liquid crystal display [LCD], digital micromirror device [DMD] or pupil facets
• CPC Class Codes: G03F 7/70566 Polarisation control

Abstract

An optical system for a microlithographic projection exposure apparatus and a microlithographic exposure method are disclosed. In an embodiment an optical system for a microlithographic projection exposure apparatus includes at least one mirror arrangement having a plurality of mirror elements which are displaceable independently of each other for altering an angular distribution of the light reflected by the mirror arrangement. The optical system also includes at least one manipulator downstream of the mirror arrangement in the light propagation direction. The manipulator has a raster arrangement of manipulator elements so that light incident on the manipulator during operation of the optical system is influenced differently in its polarization state and/or in its intensity in dependence on the incidence location.

Claims

1. An optical system having a pupil plane, the optical comprising:

a mirror arrangement comprising a plurality of mirror elements which are displaceable independently of each other to alter an angular distribution of light reflected by the mirror arrangement during use of the optical system; and

a manipulator downstream of the mirror arrangement along a light propagation path through the optical system, the manipulator comprising a raster arrangement of manipulator elements configured so that light interacting with the manipulator during use of the optical system is influenced differently in its polarization state and/or in its intensity depending on an incidence location of the light on the manipulator,

wherein;

when the mirror elements are arranged in a first configuration, light reflected by the mirror arrangement results in a first illumination setting in the pupil plane;

when the mirror elements are arranged in a second configuration, light reflected by the mirror arrangement results in a second illumination setting in the pupil plane;

the first and second illumination settings illuminate identical regions of the pupil plane;

a polarization state of the light in the pupil plane in the first illumination setting is different from a polarization state of the light in the pupil plane in the second illumination setting;

the raster arrangement of manipulator elements has an arrangement of regions which differently influence the polarization state and/or the intensity of light that interacts with the manipulator elements;

the arrangement of regions alternates periodically in two perpendicular spatial directions;

a period length of the periodically alternating arrangement in a given spatial direction corresponds to a period length of the mirror arrangement in that spatial direction or to an integral multiple of the period length in that spatial direction; and

the optical system is configured to be used in a microlithographic projection exposure apparatus.

2. The optical system of claim 1, wherein a maximum extent of the manipulator elements in one of the two perpendicular spatial directions is at most one tenth of a maximum extent of the optically usable area of the manipulator in that spatial direction.

3. The optical system of claim 1, further comprising a manipulator configured to change a position of a manipulator element.

4. The optical system of claim 1, further comprising a manipulator configured to change a position of each manipulator element.

5. The optical system of claim 1, wherein the mirror arrangement is at a first position of the optical system, the manipulator is at a second position of the optical system, and a paraxial subaperture ratio of the first position differs from a paraxial subaperture ratio of the second position by at most 0.15.

6. The optical system of claim 1, wherein the mirror arrangement is at a position in the optical system having a paraxial subaperture ratio greater than 0.8, and/or the manipulator is arranged at a position in the optical system having a paraxial subaperture ratio greater than 0.8.

7. The optical system of claim 1, wherein the mirror arrangement is at a position in the optical system having a paraxial subaperture ratio less than 0.3, and/or the manipulator is arranged at a position in the optical system having a paraxial subaperture ratio less than 0.3.

8. The optical system of claim 1, further comprising a second mirror arrangement comprising a plurality of mirror elements displaceable independently of each to alter an angular distribution of the light reflected by the second mirror arrangement, wherein the manipulator is between the mirror arrangements along the light propagation path.

9. The optical system of claim 1, wherein, during use of the optical system, mutually adjacent manipulator elements produce mutually orthogonal polarization states for light that interacts with the manipulator.

10. The optical system of claim 1, wherein the manipulator elements are configured so that the manipulator elements mutually cancel each other in their influence on the polarization state when the entire optically usable area of the manipulator is illuminated during use of the optical system.

11. The optical system of claim 1, wherein at least two mutually different illumination settings are adjustable by varying an angular distribution of the light reflected by the mirror arrangement.

12. The optical system of claim 1, further comprising an actuation unit to actuate a displacement of the mirror elements.

16. The optical system of claim 1, wherein at least two different dipole illumination settings are adjustable with mutually orthogonal polarization states.

17. The optical system of claim 1, wherein at least one illumination setting is adjustable with an at least approximately tangential polarization distribution or an at least approximately radial polarization distribution.

18. The optical system of claim 1, wherein the manipulator elements comprise gray filters.

19. The optical system of claim 1, wherein at least some of the manipulator elements have a different reflectivity for the light or a different transmissivity for the light.

20. An apparatus, comprising:

an illumination system comprising an optical system according to claim 1; and

a projection objective,

wherein the apparatus is a microlithographic projection exposure apparatus.

21. A method, comprising:

using an illumination system of a microlithographic projection exposure apparatus to illuminate a mask comprising structures; and

using a projection objective of the microlithographic projection exposure apparatus to project the structures of the mask onto a light-sensitive material,

wherein the microlithographic projection exposure apparatus comprises an optical system according to claim 1.

22. An optical system, comprising:

a mirror arrangement comprising a plurality of mirror elements which are displaceable independently of each other to alter an angular distribution of light reflected by the mirror arrangement during use of the optical system; and

a manipulator comprising a raster arrangement of manipulator elements so that light interacting with the manipulator during use of the optical system is influenced differently in its polarization state depending on an incidence location of the light on the manipulator,

wherein at least one of the manipulator elements comprises a Kerr cell or a Pockels cell, and the optical system is configured to be used in a microlithographic projection exposure apparatus.

23. The optical system of claim 22, wherein:

when the mirror elements are arranged in a first configuration, light reflected by the mirror arrangement results in a first illumination setting in the pupil plane;

when the mirror elements are arranged in a second configuration, light reflected by the mirror arrangement results in a second illumination setting in the pupil plane;

the second illumination setting in the pupil plane is different from the first illumination setting in the pupil plane;

the first and second illumination settings illuminate identical regions of the pupil plane; and

a polarization state of the light in the pupil plane in the first illumination setting is different from a polarization state of the light in the pupil plane in the second illumination setting;

24. The optical system of claim 23, wherein the first and second illumination settings differ from each other in that identical regions of the pupil plane are illuminated with different intensities.

25. The optical system of claim 24, wherein the first illumination setting is from the group consisting of a dipole illumination setting, a quadrupole illumination setting, an annular illumination setting and a conventional illumination setting.

26. The optical system of claim 25, wherein the first illumination setting is adjustable.

27. An optical system, comprising:

a manipulator configured so that light interacting with the manipulator during use of the optical system is influenced differently in its polarization state and/or in its intensity depending on an incidence location of the light on the manipulator; and

first and second mirror arrangements, each mirror arrangement comprising a plurality of mirror elements which are displaceable independently of each other to alter an angular distribution of light reflected by the mirror arrangement,

wherein the manipulator is between the first and second mirror arrangements along a light propagation path through the optical system.

28. A method of operating a microlithograpic projection exposure apparatus comprising an illumination system and a projection objective, the illumination setting comprising a manipulator comprising a raster arrangement of manipulator elements, the method comprising:

interacting light with a first region of the manipulator elements to provide a first illumination setting in a pupil plane of the illumination system; and

interacting light with a second region of the manipulator elements to provide a second illumination setting in the pupil plane of the illumination system,

wherein the first region of the manipulator elements differs from the second region of the manipulator elements, and the first illumination setting in the pupil plane differs from the second illumination setting in the pupil plane.

29. The method of claim 28, wherein, after passing through the manipulator, two beam portions of the light have mutually different polarization states.

30. The method of claim 29, wherein the illumination system comprises a mirror arrangement comprising mirror elements, the mirror arrangement is upstream of the manipulator along a light propagation path through the illumination system, and the two beam portions are deflected in different directions by the mirror elements.