Correction of optical elements by correction light irradiated in a flat manner

Patent metadata

Field	Value
Publication number	US-10054786-B2
Application number	US-201615158983-A
Country	US
Kind code	B2
Filing date	May 19, 2016
Priority date	Mar 27, 2007
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

Abstract

The disclosure relates to a correction light device for the irradiation of optical elements of an optical arrangement, in particular a lens, such a microlithography lens having a correction light, which include at least one correction light source and at least one mirror arrangement that deflects the light from the correction light source in the beam path to the optical element such that at least part of at least one surface of at least one optical element of the optical arrangement are irradiated in a locally and/or temporally variable fashion. The correction light strikes the surface of the optical element at a flat angle such that the obtuse angle between the optical axis of the optical arrangement at the location of the optical element and the correction light beam is less than or equal to 105°.

First claim

What is claimed is:

1. A projection exposure system for microlithography, comprising:
an exposure light source to provide exposure light;
a projection objective comprising a plurality of optical elements arranged along an optical axis, the optical elements being configured to direct the exposure light from a mask in an object plane of the projection objective to a substrate in an image field of the projection objective during operation of the projection exposure system for microlithography, the exposure light irradiating a first part of a surface of a first optical element of the plurality of optical elements; and
a device for heating at least the first optical element, the device comprising:
a correction light source different from the exposure light source; and
an optical arrangement configured to direct correction light from the correction light source to the first optical element of the projection objective such that at least a second part of the surface of the first optical element is irradiated with the correction light, the second part of the surface being different from the first part of the surface,
wherein the correction light strikes the second part of the surface at an angle such that an obtuse angle between the optical axis of the projection objective at the location of the first optical element and the correction light is less than or equal to 105°.

2. The projection exposure system of claim 1 , wherein the optical arrangement is configured to direct the correction light to irradiate the surface of the first optical element in a locally variable fashion to reduce unevenness in heating of the first optical element by the exposure light.

3. The projection exposure system of claim 2 , wherein the unevenness in heating of the first optical element by the exposure light is caused by non-uniform illumination of the surface of the first optical element by the exposure light.

4. The projection exposure system of claim 3 , wherein the non-uniform irradiation is due to non-rotationally symmetrical illumination of the projection exposure system.

5. The projection exposure system of claim 3 , wherein the non-uniform irradiation is due to the image field having a slit-shape.

6. The projection exposure system of claim 1 , wherein the optical arrangement comprises a mirror arrangement configured to direct the correction light from the correction light source to the first optical element of the projection objective.

7. The projection exposure system of claim 6 , wherein the mirror arrangement is configured to direct the correction light from the correction light source to the first optical element of the projection objective such that the surface of the first optical element is irradiated with the correction light in a locally variable fashion and/or a temporally variable fashion.

8. The projection exposure system of claim 6 , wherein the mirror arrangement comprises a plurality of mirror elements each arranged to direct light to a different region of the surface of the first optical element.

9. The projection exposure system of claim 8 , wherein each of the mirror elements is switchable between a first state in which the mirror directs correction light toward the surface and a second state in which the mirror does not direct light to the surface.

10. The projection exposure system of claim 9 , wherein the plurality of mirror elements are switchable between the first and second states separate from each other.

11. The projection exposure system of claim 8 , wherein the device comprises one or more additional elements positioned to direct the correction light from the mirror arrangement to the surface of the first optical element.

12. The projection exposure system of claim 6 , wherein the mirror elements are arranged side by side.

13. The projection exposure system of claim 6 , wherein the mirror arrangement comprises a multi-mirror array (MMA).

14. The projection exposure system of claim 6 , wherein the mirror arrangement comprises a polygonal mirror array.

15. The projection exposure system of claim 6 , wherein the device further comprises a grating, and wherein the grating is between the correction light source and the mirror arrangement or between the mirror arrangement and the first optical element.

16. The projection exposure system of claim 1 , wherein the correction light reduces thermal inhomogeneities of the first optical element caused by the exposure light.

17. The projection exposure system of claim 1 , wherein the correction light beam is configured to heat the first optical element for a period of time in which the first optical element is unevenly heated by the exposure light.

18. The projection exposure system of claim 1 , wherein the correction light source is a laser.

19. The projection exposure system of claim 1 , wherein the laser is a CO 2 laser.

20. The projection exposure system of claim 1 , wherein the correction light has a wavelength greater than or equal to 4 μm.

21. The projection exposure system of claim 1 , wherein the projection objective comprises a curved mirror.

22. The projection exposure system of claim 21 , wherein the projection objective comprises a plane mirror.

23. The projection exposure system of claim 1 , wherein the device is further arranged to direct correction light to a different surface of the first optical element or to a surface of a second optical element of the plurality of optical elements of the projection objective.

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Bleidistel Sascha
• Maul Manfred

Classifications

• G03F7/70308 Primary

  Optical correction elements, filters or phase plates for manipulating imaging light, e.g. intensity, wavelength, polarisation, phase or image shift · CPC title

• G02B26/0816 Primary

  by means of one or more reflecting elements · CPC title

• G02B7/028

  with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation · CPC title

• G03F7/70891

  Temperature · CPC title

• G03F7/70258 Primary

  Projection system adjustments, e.g. adjustments during exposure or alignment during assembly of projection system · CPC title