Optical imaging device and method for reducing dynamic fluctuations in pressure difference

Patent metadata

Field	Value
Publication number	US-9817322-B2
Application number	US-201113229114-A
Country	US
Kind code	B2
Filing date	Sep 9, 2011
Priority date	May 19, 2006
Publication date	Nov 14, 2017
Grant date	Nov 14, 2017

Abstract

There is provided an optical imaging device, in particular for microlithography, comprising at least one optical element and at least one holding device associated to the optical element ( 109 ), wherein the holding device holds the optical element and a first part ( 109.1 ) of the optical element contacts a first atmosphere and a second part ( 109.2 ) of the optical element at least temporarily contacts a second atmosphere. There is provided a reduction device at least reducing dynamic fluctuations in the pressure difference between the first atmosphere and the second atmosphere.

First claim

What is claimed is:

1. An optical imaging device, comprising:
a first optical element;
a second optical element; and
a reduction device comprising a control device and an adjustment device connected to the control device,
wherein:
the first and second optical elements cooperate during use of the optical imaging device in an optical imaging process;
the control device is configured to capture a variable representative of a pressure disturbance which acts on the first optical element at a frequency above 10 Hz and which adversely influences an imaging error of the optical imaging process; and
the control device is configured to control the adjustment device to adjust a position of the second optical element at a control bandwidth above 10 Hz to modify a pressure between the first and second optical elements to counteract the pressure disturbance.

2. The optical imaging device according to claim 1 , wherein the control device comprises a capturing device configured to capture the variable, and the capturing device is located in a vicinity of the first optical element.

3. The optical imaging device according to claim 2 , wherein the capturing device is located at a holding structure which holds the first optical element.

4. The optical imaging device according to claim 1 , wherein the first optical element is a last optical element along a path that imaging light follows from an object plane of the optical imaging device to an image plane of the optical imaging device during use of the optical imaging device, and the second optical element is a penultimate optical element along the path that the imaging light follows from the object plane of the optical imaging device to the image plane of the optical imaging device during use of the optical imaging device.

5. The optical imaging device according to claim 4 , wherein the first optical element comprises a first lens, and the second optical element comprises a second lens.

6. The optical imaging device according to claim 4 , wherein the first optical element is configured to contact an immersion medium located between the first optical element and the image plane during the optical imaging process.

7. The optical imaging device according to claim 4 , wherein a first part of the first optical element contacts a first atmosphere, a second part of the first optical element at least temporarily contacts a second atmosphere, and the reduction device is configured to at least reduce dynamic fluctuations in a pressure difference between the first and second atmospheres.

8. The optical imaging device according to claim 7 , wherein the control device is configured to determine a pressure difference deviation which is a deviation between an actual value and a selectable setpoint value of the pressure difference between the first and second atmospheres, and a first adjustment device controlled by the control device is configured to influence a pressure in the first atmosphere as a function of the pressure difference deviation determined by the control device so that the pressure difference deviation is counteracted.

9. The optical imaging device according to claim 8 , wherein the control device is configured to establish an actual value of the pressure difference deviation using an actual value of at least one operating parameter of the optical imaging device and a stored model, the model is a model of a behavior of the pressure difference between the first atmosphere and second atmospheres as a function of the at least one operating parameter, and the model is previously established for the optical imaging device.

10. The optical imaging device according to claim 9 , wherein the at least one operating parameter is a quantity that influences a pressure in the first atmosphere and/or a quantity that influences a pressure in the second atmosphere.

11. The optical imaging device according to claim 8 , wherein the first atmosphere prevails within a first space, the first space is delimited at least by the first part of the optical element, and the adjustment device is configured to influence a pressure in the first atmosphere by modifying a volume of the first space.

12. The optical imaging device according to claim 11 , wherein the adjustment device comprises an actuation device connected to one of the first and second optical elements, and the actuation device is configured to alter a position of one of the first and second optical elements.

13. The optical imaging device according to claim 7 , wherein the control device is configured to determine pressure fluctuations in the second atmosphere, and the adjustment device controlled by the control device is configured to influence a pressure in the second atmosphere so that the pressure fluctuations in the second atmosphere are counteracted.

14. The optical imaging device according to claim 13 , wherein the control device is configured to establish an actual value of the pressure fluctuations in the second atmosphere using an actual value of at least one operating parameter of the optical imaging device and a stored model, the model is a model of a behavior of the pressure fluctuations in the second atmosphere as a function of the at least one operating parameter, the model is previously established for the optical imaging device, and the at least one operating parameter is a quantity influencing the pressure in the second atmosphere.

15. The optical imaging device according to claim 13 , wherein:
the control device is configured to determine a frequency and an amplitude of first pressure waves within the second atmosphere;
the adjustment device is configured to generate, as a function of the frequency and the amplitude of the first pressure waves as well as controlled by the control device, second pressure waves in the second atmosphere so that the second and first pressure waves interfere to form resulting pressure waves with a resulting amplitude; and
the resulting amplitude is smaller than the first amplitude or substantially zero.

16. The optical imaging device according to claim 15 , wherein:
the adjustment device comprises at least one loudspeaker, or the optical imaging device comprises a capturing device to determine the frequency and the first amplitude of the first pressure waves; and
when present, the capturing device is connected to the control device, the capturing device is configured to capture the frequency and the amplitude of the first pressure waves, and the capturing device comprises at least one microphone.

17. The optical imaging device according to claim 15 , further comprising an adjustment structure, wherein:
the adjustment structure is located adjacent to at least one of the optical element and/or the adjustment structure is located adjacent to a holding device holding the optical element and being a tubular structure surrounding the optical element and/or at least a part of the holding device;
the control device comprises at least one sensing device and/or the adjustment device comprises at least one pressure wave generating device;
the at least one sensing device is mechanically connected to the adjacent structure;
the at least one sensing device is configured to sense a variable representative of the frequency and the amplitude of the first pressure waves within the second atmosphere; and
the at least one pressure wave generating device is mechanically connected to the adjacent structure and generating the second pressure waves.

18. The optical imaging device according to claim 4 , wherein there are no lenses or mirrors between the first

Assignees

• Hembacher Stefan
• Gellrich Bernhard
• Kugler Jens
• Bleidistel Sascha
• Zeiss Carl Smt Gmbh

Inventors

• Hembacher Stefan
• Gellrich Bernhard
• Kugler Jens
• Bleidistel Sascha

Classifications

• G03F7/70241

  Optical aspects of refractive lens systems, i.e. comprising only refractive elements · CPC title

• G03F7/70825

  Mounting of individual elements, e.g. mounts, holders or supports (workpiece or mask holders G03F7/707) · CPC title

• G03F7/70883 Primary

  of optical system · CPC title

• G03F7/70341

  Details of immersion lithography aspects, e.g. exposure media or control of immersion liquid supply (chemical composition of immersion liquids G03F7/2041) · CPC title