Optical imaging device with image defect determination

Patent metadata

Field	Value
Publication number	US-9996014-B2
Application number	US-201614993076-A
Country	US
Kind code	B2
Filing date	Jan 11, 2016
Priority date	Jul 1, 2008
Publication date	Jun 12, 2018
Grant date	Jun 12, 2018

Abstract

An optical imaging device, including an imaging unit and a measuring device. The imaging unit includes a first optical element group having at least one first optical element, which contributes to the imaging. The measuring device determines an imaging error, which occurs during the imaging, using a capturing signal. The measuring device includes a measurement light source, a second optical element group and a capturing unit. The measurement light source emits at least one measurement light bundle, The second optical element group includes an optical reference element and a second optical element, which guide the measurement light bundle onto the capturing unit, to generate the capturing signal. Each second optical element has a defined spatial relationship with a respective one of the first optical elements, The second optical elements differ from the first optical elements. The measuring device determines the imaging error with the capturing signal.

First claim

What is claimed is:

1. An optical imaging device, comprising
an imaging unit configured to image an object point onto an image point, wherein the imaging unit comprises a first optical element group, and
a measuring device, wherein:
the measuring device is configured to determine at least one imaging error resulting from the object point being imaged onto the image point,
the measuring device comprises: at least one measurement light source, a second optical element group having at least one optical element, and at least one capturing unit,
the measurement light source is configured to emit at least one measurement light bundle,
the second optical element group is configured to direct the at least one measurement light bundle onto the at least one capturing unit, to generate at least one capturing signal, and
passive thermal shielding is provided for the at least one optical element of the second optical element group.

2. The optical imaging device according to claim 1 , wherein the thermal shielding is configured to not interfere with a beam profile of the at least one measurement light bundle; and
wherein the thermal shield comprises a metal foil or metal shell.

3. The optical imaging device according to claim 1 , further comprising an active temperature control device for the thermal shielding.

4. The optical imaging device according to claim 1 , further comprising a passive temperature control device for the thermal shielding.

5. The optical imaging device according to claim 1 , wherein the measurement light source is configured to emit a plurality of measurement light bundles.

6. The optical imaging device according to claim 1 , configured as a scanner.

7. The optical imaging device according to claim 1 , wherein
the first optical element group comprises at least one imaging optical element, and
the measuring device is configured to determine state changes of the at least one imaging optical element during transport of the optical imaging device and to register the determined state changes in a log.

8. The optical imaging device according to claim 7 , wherein the measuring device is configured to determine changes in position and/or in orientation and/or in geometry of the at least one imaging optical element with respect to at least one reference.

9. The optical imaging device according to claim 7 , further comprising:
a correction device, wherein
the correction device is configured to connect to the measuring device, and
the correction device is configured to modify the position and/or the orientation and/or the geometry of the at least one imaging optical element with respect to the at least one reference as a function of the log of the measuring device.

10. The optical imaging device according to claim 1 , wherein
the first optical element group comprises at least one imaging optical element, and
the imaging unit is configured to image the object point onto the image point using extreme ultraviolet light, and
the imaging unit comprises a support structure having at least one structural element, configured to support the at least one imaging optical element, and
the at least one structural element comprises a material or material combination having a coefficient of thermal expansion of more than 0.6·10 −6 K −1 .

11. The optical imaging device according to claim 10 , wherein the at least one structural element comprises a material or material combination having a coefficient of thermal expansion of more than 1.2·10 −6 K −1 .

12. The optical imaging device according to claim 10 , wherein the imaging unit is configured to image the object point onto the image point using light having a wavelength in a 5 nm to 20 nm range.

13. The optical imaging device according to claim 10 , further comprising:
a correction device, wherein
the correction device is configured to connect to the measuring device,
the measuring device is configured to output at least one signal representative of a position and/or an orientation and/or a geometry of the at least one imaging optical element with respect to at least one reference, and
the correction device is configured to modify the position and/or the orientation and/or the geometry of the at least one imaging optical element with respect to the at least one reference as a function of the at least one signal.

14. The optical imaging device according to claim 10 , wherein the at least one structural element is made at least partially of an Invar material.

15. The optical imaging device according to claim 1 , configured for executing a microlithography process.

16. The optical imaging method according to claim 1 , wherein the thermal shielding is configured to not interfere with a beam profile of the at least one measurement light bundle.

17. The optical imaging according to claim 1 , wherein the thermal shielding is configured with a passage cross section dimensioned no larger than sufficient to pass the at least one measurement light bundle without interference by the thermal shielding.

18. An optical imaging method comprising
imaging an object point onto an image point with an imaging unit comprising a first optical element group; and
determining at least one imaging error resulting from said imaging of the object point onto the image point,
wherein said determining comprises:
emitting at least one measurement light bundle, and
directing the at least one measurement light bundle with a second optical element group of a measuring device, wherein the second optical element group comprises at least one thermally shielded optical element, onto at least one capturing unit, to generate at least one capturing signal, wherein thermal shielding is spatially associated to the thermally shielded optical element to provide passive shielding of the thermally shielded optical element.

19. The optical imaging method according to claim 18 , wherein the thermal shielding of the at least one optical element comprises a temperature control.

20. The optical imaging method according to claim 18 , wherein said first optical element group comprises at least one imaging optical element, and
wherein said determining further comprises:
during transport of the optical imaging device prior to imaging the object point onto the image point, determining changes in position and/or in orientation and/or in geometry of the at least one imaging optical element with respect to at least one reference and registering the changes in a log.

21. The optical imaging method according to claim 20 , further comprising:
modifying the position and/or the orientation and/or the geometry of the at least one imaging optical element with respect to the at least one reference in accordance with the registered changes.

22. The optical imaging method according to claim 18 , wherein the thermal shielding is configured to not interfere with a beam profile of the at least one measurement light bundle.

23. An optical imaging device, comprising
an imaging unit configured to image an object point onto an image point, wherein the imaging unit comprises a first optical element group, and
a measuring device, wherein:
the measuring device is configured to determine at least one imaging error resulting from the object point being imaged onto the image point,
the measuring device comprises: at least one measurement light source, a second optical element group having at least one optical element, and at least one capturing unit,
th

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Freimann Rolf
• Wegmann Ulrich

Classifications

• G03F7/7085

  Detection arrangement, e.g. detectors of apparatus alignment possibly mounted on wafers, exposure dose, photo-cleaning flux, stray light, thermal load · CPC title

• G01B9/02065

  using a second interferometer before or after measuring interferometer · CPC title

• G01N21/95607

  using a comparative method · CPC title

• G01B11/002

  for measuring two or more coordinates · CPC title

• G01N2021/95676

  Masks, reticles, shadow masks · CPC title