Device and method for characterizing a microlithographic mask

Patent metadata

Field	Value
Publication number	US-11112702-B2
Application number	US-202017007751-A
Country	US
Kind code	B2
Filing date	Aug 31, 2020
Priority date	Sep 4, 2019
Publication date	Sep 7, 2021
Grant date	Sep 7, 2021

Abstract

The invention relates to a device and a method for characterizing a microlithographic mask. A device according to the invention has an illumination optical unit for illuminating structures of a mask intended for use in a lithography process in a microlithographic projection exposure apparatus, a detector unit, and an evaluation unit for evaluating the data recorded by the detector unit, wherein the detector unit is configured for the spatially resolved determination of both the intensity and the polarization state of the respectively impinging light emanating from the mask.

First claim

What is claimed is:

1. A device for characterizing a microlithographic mask, comprising:
an illumination optical unit for illuminating structures of a mask configured for use in a lithography process in a microlithographic projection exposure apparatus;
a detector unit; and
an evaluation unit for evaluating the data recorded by the detector unit;
wherein the detector unit is configured for the spatially resolved determination of both the intensity and the polarization state of the respectively impinging light emanating from the mask, and the spatially resolved determination of both the intensity and the polarization state using the detector unit is effected in one single exposure step.

2. The device of claim 1 , wherein the detector unit has a sensor arrangement composed of a plurality of intensity sensors and a polarizer arrangement composed of a plurality of polarizers, said polarizer arrangement being situated in the optical path upstream of the sensor arrangement, wherein polarizers of the polarizer arrangement are respectively assigned to different intensity sensors of the sensor arrangement.

3. The device of claim 2 , wherein the sensor arrangement is configured as a periodic array of intensity sensors.

4. The device of claim 2 , wherein the polarizer arrangement is configured as a periodic array of polarizers.

5. The device of claim 2 , wherein the polarizer arrangement has polarizers having mutually different polarization transmission directions.

6. The device of claim 5 , wherein polarization transmission directions of different polarizers differ from one another by an integer multiple of 22.5°, in particular by an integer multiple of 45°, or by an integer multiple of 30°, in particular by an integer multiple of 60°.

7. The device of claim 2 , wherein the sensor arrangement also has intensity sensors on which, during the operation of the device, light impinges without previously passing through one of the polarizers of the polarizer arrangement.

8. The device of claim 2 , wherein the polarizer arrangement is designed for an operating wavelength in a range from 13 nm to 250 nm, in particular for an operating wavelength in a range from 190 nm to 200 nm.

9. The device of claim 1 , wherein the device is designed for emulating polarization-dependent effects in the form of a polarization dependence of the interference of electromagnetic radiation that takes place in a wafer plane during the operation of the microlithographic projection exposure apparatus, wherein the data used for emulating the polarization-dependent effects are recorded by the detector unit in a single exposure step.

10. The device of claim 1 , further comprising an imaging optical unit for imaging the mask onto the detector unit.

11. The device of claim 1 , wherein the evaluation unit is configured to reconstruct an image of the mask with the application of an iterative Fourier retrieval algorithm.

12. A device for characterizing an object, comprising:
an illumination optical unit for illuminating the object with light having an operating wavelength in a range from 13 nm to 250 nm;
a detector unit; and
an evaluation unit for evaluating the data recorded by the detector unit;
wherein the detector unit is configured for the spatially resolved determination of both the intensity and the polarization state of the respectively impinging light emanating from the object, and the spatially resolved determination of both the intensity and the polarization state using the detector unit is effected in one single exposure step.

13. The device of claim 12 , wherein the detector unit comprises a sensor arrangement composed of a plurality of intensity sensors and a polarizer arrangement composed of a plurality of polarizers, said polarizer arrangement being situated in the optical path upstream of the sensor arrangement, wherein polarizers of the polarizer arrangement are respectively assigned to different intensity sensors of the sensor arrangement.

14. A method for characterizing a microlithographic mask,
wherein structures of a mask intended for use in a lithography process in a microlithographic projection exposure apparatus are illuminated by an illumination optical unit; and
wherein a spatially resolved determination of both the intensity and the polarization state of the respectively impinging light emanating from the mask is carried out by at least one detector unit, and the spatially resolved determination of both the intensity and the polarization state is performed by the at least one detector unit in one single exposure step.

15. The method of claim 14 , wherein the detector unit has a sensor arrangement composed of a plurality of intensity sensors and a polarizer arrangement composed of a plurality of polarizers, said polarizer arrangement being situated in the optical path upstream of the sensor arrangement, wherein polarizers of the polarizer arrangement are respectively assigned to different intensity sensors of the sensor arrangement.

16. The method of claim 15 , wherein the respective extinction factor of the polarizers is taken into account during the evaluation of the data recorded by the detector unit.

17. The method of claim 14 , wherein for a respective polarized illumination setting which is set in the illumination optical unit and which, both in terms of the intensity distribution and in terms of the polarization distribution, at least approximately corresponds to the illumination setting predefined in the microlithographic projection exposure apparatus, the data used for emulating the polarization-dependent effects are recorded by the detector unit in a single exposure step.

18. The method of claim 14 , wherein data recorded by the detector unit are evaluated in an evaluation unit, wherein polarization-dependent effects in the form of a polarization dependence of the interference of electromagnetic radiation that takes place in a wafer plane during the operation of the microlithographic projection exposure apparatus are emulated during this evaluation.

19. The method of claim 14 , wherein the mask is imaged onto the at least one detector unit by an imaging optical unit.

20. The method of claim 14 , wherein an image of the mask is reconstructed with the application of an iterative Fourier retrieval algorithm.

Assignees

• Zeiss Carl Smt Gmbh

Inventors

• Martin Sven
• Frank Thomas
• Matejka Ulrich

Classifications

• G03F7/706837

  Data analysis, e.g. filtering, weighting, flyer removal, fingerprints or root cause analysis · CPC title

• G03F7/706849

  Irradiation branch, e.g. optical system details, illumination mode or polarisation control · CPC title

• G03F7/70566 Primary

  Polarisation control · CPC title

• G03F7/70591

  Testing optical components · CPC title

• G03F1/84 Primary

  Inspecting · CPC title