Method and apparatus for analyzing and for removing a defect of an EUV photomask

1. An apparatus, comprising:

an ultra-violet radiation source configured to determine first data of a defect of an optical element for an extreme ultra-violet wavelength range, the optical element comprising a substrate and a multi-layer structure;

a scanning probe microscope configured to determine second data of the defect;

a scanning particle microscope configured to determine third data of the defect;

a combining unit adapted to combine the first data, the second data and the third data, and to transform at least one member selected from the group consisting of the first data, the second data and the third data so that a pixel of the first data is associated with a pixel of the second data and a pixel of the third data, and

a device configured to generate a mark by locally depositing material on at least one element selected from the group consisting of the multi-layer structure and an absorber structure of the optical element; and/or a device configured to generate a mark by etching a local depression into an absorber structure of the optical element,

wherein the combining unit is configured to compensate deviations with respect to at least one member selected from the group consisting of the mark, a scale of the first data, a scale of the second data, a scale of the third data.

2. The apparatus of claim 1 , wherein:

the scanning probe microscope comprises at least one member selected from the group consisting of a scanning force microscope, a scanning tunneling microscope, a magnetic field force microscope, an optical near-field microscope, and an acoustic scanning near-filed microscope; and

the scanning particle microscope comprises at least one member selected from the group consisting of a scanning electron microscope, a focused ion-beam microscope and an interferometer.

3. The apparatus of claim 1 , wherein the optical element comprises a photolithographic mask.

4. The apparatus of claim 1 , wherein the combining unit is configured to adapt parameters of a model for the defect to the combined first, second and third data.

5. The apparatus of claim 4 , wherein the model comprises a rotationally symmetrical Gaussian profile which is parameterized by a height and a half-width.

6. The apparatus of claim 4 , wherein the model comprises at least two parameters with respect to a position of the defect relative to a mark.

7. A method of analyzing a defect of an optical element for an extreme ultra-violet wavelength range, the optical element comprising a substrate and a multi-layer structure, the method comprising:

determining first data by exposing the defect to ultra-violet radiation;

determining second data by scanning the defect with a scanning probe microscope;

determining third data by scanning the defect with a scanning particle microscope;

combining the first, the second and the third data;

generating a mark by locally depositing material on at least one element selected from the group consisting of the multi-layer structure and an absorber structure of the optical element; and/or

generating a mark by etching a local depression into an absorber structure of the optical element;

wherein combining the first, the second and the third data comprises compensating deviations with respect to at least one member selected from the group consisting of the mark, a scale of the first data, a scale of the second data, a scale of the third data; and

wherein combining the first, the second, and the third data further comprises transforming at least one member selected from the group consisting of the first data, the second data and the third data so that each pixel of the first data is associated with a pixel of the second data and a pixel of the third data.

8. The method according to claim 7 , further comprising using the scanning particle microscope to at least partially compensate the defect.

9. The method according to claim 7 , wherein exposing the defect to ultra-violet radiation further comprises recording an aerial image of the defect and/or exposing a wafer.

10. The method according to claim 9 , wherein recording an aerial image of the defect comprises recording an aerial image in a focus and/or recording an aerial image stack by changing a focus relative to the optical element for the extreme ultra-violet wavelength range.

11. The method according to claim 7 , wherein:

the scanning probe microscope comprises at least one member selected from the group consisting of a scanning force microscope, a scanning tunneling microscope, a magnetic field force microscope, an optical near-field microscope, and an acoustic scanning near-filed microscope; and

the scanning particle microscope comprises at least one member selected from the group consisting of a scanning electron microscope, a focused ion-beam microscope and an interferometer.

12. The method according to claim 7 , wherein the defect comprises a buried defect arranged in the multi-layer structure and/or in the substrate.

13. The method according to claim 7 , further comprising adapting parameters of a model for the defect to the combined first, second and third data.

14. The method according to claim 13 , wherein the model comprises a rotationally symmetrical Gaussian profile which is parameterized by a height and a half-width.

15. The method of claim 13 , wherein the model comprises at least two parameters with respect to a position of the defect relative to a mark.

16. A method of analyzing a defect of an optical element for an extreme ultra-violet wavelength range, the optical element comprising a substrate and a multi-layer structure, the method comprising:

determining first data by exposing the defect to ultra-violet radiation;

determining second data by scanning the defect with a scanning probe microscope;

determining third data by scanning the defect with a scanning particle microscope;

combining the first, the second and the third data; and

adapting parameters of a model for the defect to the combined first, second and third data;

wherein the model comprises a rotationally symmetrical Gaussian profile which is parameterized by a height and a half-width.

17. The method according to claim 16 , further comprising: a) generating a mark by locally depositing material on at least one element selected from the group consisting of the multi-layer structure and an absorber structure of the optical element; and/or b) generating a mark by etching a local depression into an absorber structure of the optical element.

18. The method according to claim 17 , further comprising using the scanning particle microscope to generate the mark.

19. The method according to claim 17 , wherein combining the first, the second and the third data comprises compensating deviations with respect to at least one member selected from the group consisting of the mark, a scale of the first data, a scale of the second data, a scale of the third data.

20. The method according to claim 19 , wherein combining the first, the second, and the third data further comprises transforming at least one member selected from the group consisting of the first data, the second data and the third data so that each pixel of the first data is associated with a pixel of the second data and a pixel of the third data.

21. An apparatus, comprising:

an ultra-violet radiation source configured to determine first data of a defect of an optical element for an extreme ultra-violet wavelength range, the optical element comprising a substrate and a multi-layer structure;

a scanning probe microscope configured to determine second data of the defect;

a scanning particle microscope configured to determine third data of the defect;

a combining unit configured to combine the first, the second and the third data, and adapt parameters of a model for the defect to the combined first, second and third data, wherein the model comprises a rotationally symmetrical Gaussian profile which is parameterized by a height and a half-width.

22. The apparatus of claim 21 , wherein:

the scanning probe microscope comprises at least one member selected from the group consisting of a scanning force microscope, a scanning tunneling microscope, a magnetic field force microscope, an optical near-field microscope, and an acoustic scanning near-filed microscope; and

the scanning particle microscope comprises at least one member selected from the group consisting of a scanning electron microscope, a focused ion-beam microscope and an interferometer.

23. The apparatus of claim 21 , wherein the optical element comprises a photolithographic mask.

24. The apparatus of claim 21 , wherein the defect comprises a buried defect arranged in the multi-layer structure and/or in the substrate.

25. The apparatus of claim 21 , further comprising a device configured to record an aerial image of the defect and/or exposing a wafer.