# US 8,542,346 B2 · Optical system with an exchangeable, manipulable correction arrangement for reducing image aberrations

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- Number: US 8,542,346 B2
- Document ID: US8542346B2
- Status: Granted
- Kind: B2
- Application number: 12/409,961
- Filed: 2009-03-24
- Published: 2009-10-01
- Granted: 2013-09-24
- Earliest claimed: 2006-12-01
- Assignees: Carl Zeiss SMT GmbH
- Applicants: Guido Limbach; Franz Sorg; Armin Schoeppach; Ulrich Weber; Ulrich Loering; Dirk Hellweg; Peter Meyer; Stefan Xalter; Jens Kugler; Bernhard Gellrich; Stefan Hembacher; Bernhard Geuppert; Aksel Goehnermeier
- Inventors: Guido Limbach; Franz Sorg; Armin Schoeppach; Ulrich Weber; Ulrich Loering; Dirk Hellweg; Peter Meyer; Stefan Xalter; Jens Kugler; Bernhard Gellrich; Stefan Hembacher; Bernhard Geuppert; Aksel Goehnermeier
- Web page: https://patentgrep.com/patent/US8542346B2

## CPC

- G02B 7/004: {Manual alignment, e.g. micromanipulators}
- G02B 27/0068: {having means for controlling the degree of correction, e.g. using phase modulators, movable elements (controlling the phase of light using moving or deformable elements G02B26/06)}
- G03F 7/70191: {Optical correction elements, filters or phase plates for controlling intensity, wavelength, polarisation, phase or the like}
- G03F 7/70258: {Projection system adjustments, e.g. adjustments during exposure or alignment during assembly of projection system}
- G03F 7/70308: {Optical correction elements, filters or phase plates for manipulating imaging light, e.g. intensity, wavelength, polarisation, phase or image shift}
- G03F 7/70825: {Mounting of individual elements, e.g. mounts, holders or supports (workpiece or mask holders G03F7/707)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)

## Abstract

The disclosure relates to an optical system, such as a projection exposure apparatus for semiconductor lithography, including a manipulable correction arrangement for reducing image aberrations. In some embodiments, the system includes at least one manipulator configured to reduce image aberrations. The manipulator can include at least one optical element which can be manipulated by at least one actuator. The manipulator can be formed in changeable fashion together with an actuator.

## Claims

### Claim 1

An optical system, comprising:
a manipulator, comprising:
an actuator; and
an optical element which is manipulable by the actuator,
wherein:
the actuator and the optical element are connected with each other to provide a first unit,
the first unit is exchangeable with a second unit which is different from the first unit so that, after the first unit is exchanged with the second unit, the optical system does not include the first unit, and
the optical system is an optical system for semiconductor microlithography.

### Claim 2 (depends on 1)

The optical system as claimed in claim 1, wherein the manipulator comprises a plurality of optical elements, and the actuator is configured to position the optical elements with respect to one another.

### Claim 3 (depends on 2)

The optical system as claimed in claim 2, wherein the optical elements are exchangeable without exchanging the actuator.

### Claim 4 (depends on 2)

The optical system as claimed in claim 2, wherein at least one of the optical elements has at least one aspherically formed surface such that a deformation of a wavefront propagating in the optical system arises in the event of a displacement, rotation or tilting of the surfaces of the optical elements relative to one another.

### Claim 5 (depends on 1)

The optical system as claimed in claim 1, wherein the optical system has an optical axis, and the manipulator or at least one of its component parts is positionable in a direction of the optical axis or orthogonally with respect to the optical axis.

### Claim 6 (depends on 1)

The optical system of claim 1, wherein the optical element is an Alvarez element.

### Claim 7 (depends on 1)

The optical system of claim 1, wherein the manipulator comprises at least two adjacent optical elements which are essentially orthogonal in terms of their lateral extent with respect to an optical axis of the optical system and at each of which at least one actuator is arranged such that the dimensions of the actuators which are projected in the direction of the optical axis of the projection exposure apparatus do not overlap.

### Claim 8 (depends on 6)

The optical system as claimed in claim 6, comprising two essentially circular optical elements, at each of which three actuators are arranged respectively at an angular distance of 120°.

### Claim 9 (depends on 1)

The optical system as claimed in claim 1, comprising:
a first optical element;
a first actuator configured to move the first optical element in a direction of an optical axis of the optical system;
a second optical element; and
a second actuator configured to move the second optical element along the optical axis of the optical system and also configured to tilt the second optical element along two axes.

### Claim 10 (depends on 1)

The optical system as claimed in claim 1, wherein the optical element is exchangeable without exchanging the actuator.

### Claim 11 (depends on 1)

The optical system as claimed in claim 1, further comprising a movement guidance system, wherein the manipulator has at least two optical elements connected to one another by the movement guidance system.

### Claim 12 (depends on 1)

The optical system as claimed in claim 1, wherein the manipulator has at least one basic mount with at least one inner mount arranged in the basic mount and in which the at least one optical element is arranged.

### Claim 13 (depends on 12)

The optical system as claimed in claim 12, wherein the inner mount is formed such that it is essentially rotationally symmetrical with respect to an optical axis of the optical system.

### Claim 14 (depends on 12)

The optical system as claimed in claim 12, wherein the actuator is arranged on the inner mount.

### Claim 15 (depends on 14)

The optical system of claim 14, comprising four actuators arranged at an angular distance of approximately 90° on the inner mount.

### Claim 16 (depends on 1)

The optical system as claimed in claim 1, wherein the actuator is formed as a member selected from the group consisting of a thin-walled metal bellows, a piezoactuator, a Lorentz actuator, a thermal actuator and a hydraulic actuator.

### Claim 17 (depends on 15)

The optical system as claimed in claim 15, wherein at least one additional bearing element is arranged on the inner mount.

### Claim 18 (depends on 17)

The optical system as claimed in claim 17, wherein the bearing element is not formed integrally with the inner mount.

### Claim 19 (depends on 1)

The optical system of claim 1, wherein the manipulator has a structural height of less than 20 millimeters in a direction of an optical axis of the optical system.

### Claim 20 (depends on 14)

The optical system as claimed in claim 14, wherein the actuator is a bellows connected to the basic mount via a feed line in a manner such that the feed line leads into the bellows without being in direct mechanical contact with the inner mount.

### Claim 21 (depends on 20)

The optical system as claimed in claim 20, wherein the feed line is arranged essentially centrally between two opposite parts of the bellows, the opposite parts of the bellows being supported on the inner mount.

### Claim 22 (depends on 1)

The optical system as claimed in claim 1, wherein the optical system is an illumination system of the projection exposure apparatus, or the optical system is a projection objective of the projection exposure apparatus.

### Claim 23 (depends on 1)

The optical system as claimed in claim 1, wherein the manipulator is arranged at a distance from a pupil which corresponds to a subaperture ratio of a magnitude of less than 0.25.

### Claim 24 (depends on 1)

The optical system as claimed in claim 1, wherein the actuator is capable of deforming the optical element.

### Claim 25 (depends on 1)

The optical system as claimed in claim 1, wherein the actuator influences a temperature of regions of the optical element.

### Claim 26 (depends on 1)

The optical system as claimed in claim 1, wherein the actuator heats regions of the optical element.

### Claim 27 (depends on 25)

The optical system as claimed in claim 25, wherein the actuator has at least one electromagnetic radiation source configured to heat the optical element.

### Claim 28 (depends on 1)

The optical system as claimed in claim 1, wherein the manipulator is arranged in place of a non-manipulable exchangeable optical correction element in the optical system.

### Claim 29 (depends on 1)

The optical system as claimed in claim 1, wherein the manipulator is capable of being arranged in place of a manipulator with a number or type of degrees of freedom which is different from that of the manipulator in the optical system, and the type of degrees of freedom is selected from the group consisting of linear translations, rotations and combinations thereof.

### Claim 30 (depends on 12)

The optical system as claimed in claim 12, wherein the inner mount is connected to the basic mount via at least three connecting points formed as elastic articulations.

### Claim 31

A system, comprising:
an optical system, comprising:
a manipulator, comprising:
an actuator; and
an optical element which which is manipulable by the actuator,
wherein:
the actuator and the optical element are connected with each other to provide a first unit
the first unit is exchangeable with a second unit which is different from the first unit so that, after the first unit is exchanged with the second unit, the optical system does not include the first unit, and
the system is a semiconductor microlithography projection exposure apparatus.

### Claim 32 (depends on 31)

The system of claim 31, wherein the optical system is a projection objective.

### Claim 33 (depends on 1)

The optical system of claim 1, wherein the first unit comprises two optical elements.