Method for determining a position of a structure element on a mask and microscope for carrying out the method

• US 10,089,733 B2
• Filed: 09/30/2016
• Issued: 10/02/2018
• Est. Priority Date: 09/30/2015
• Status: Active Grant

• Current Assignee: CARL Zeiss SMT GmbH (Carl-Zeiss-Stiftung)
• Original Assignee: CARL Zeiss SMT GmbH (Carl-Zeiss-Stiftung)
• Inventors: Seidel, Dirk
• Primary Examiner(s): Kassa, Yosef
• Application Number:
  US15/281,760
• Publication Number:
  US 20170091921A1
• Time in Patent Office: 732 Days
• Field of Search: 382141, 382144, 382145, 382149, 382190, 382278, 382283, 382287, 382294, 358537, 358538, 358448
• CPC Class Codes: G03F 1/84 Inspecting
• CPC Class Codes: G06T 2207/10056 Microscopic image
• CPC Class Codes: G06T 2207/30141 Printed circuit board [PCB]
• CPC Class Codes: G06T 2207/30148 Semiconductor; IC; Wafer
• CPC Class Codes: G06T 7/0004 Industrial image inspection
• CPC Class Codes: G06T 7/70 Determining position or orientation of objects or cameras camera calibration G06T7/80

Abstract

A method and a microscope for determining a position of a structure element on a mask are provide. The method comprises predefining a region on the mask which comprises at least the structure element; determining a phase image of the region, wherein the phase image comprises in a spatially resolved manner the phase of the imaging of the mask by the illumination radiation; and determining the position of the structure element within the phase image.

Claims

1. A method for determining a position of a structure element on a mask, comprising the following steps:

predefining a region on the mask which comprises at least the structure element,

determining a phase image of the region, wherein the phase image comprises in a spatially resolved manner the phase of the imaging of the mask by the illumination radiation, and

determining the position of the structure element within the phase image;

wherein, for determining the phase image, at least two aerial images of the region of the mask are recorded, wherein the at least two aerial images are recorded under diversified conditions determining the positioning error of the structure element as distance of the position of the structure element from a set point position of the structure element in the phase image.

2. The method according to claim 1, comprising the following step:

determining the setpoint position of a structure element from the position of the structure element within a simulated phase image of the region of the mask.

3. The method according to claim 1, comprising the following steps:

determining a first position of a first structure element within the phase image,

determining a second position of the first structure element within an intensity image,

determining the deviation of the first position from the second position, and

correcting a third phase image of a second structure element by the determined deviation.

4. The method according to claim 1, wherein the diversifications can be described by mathematical models.

5. The method according to claim 1, wherein the diversification is effected by the recording of the at least two aerial images in parallel planes spaced apart from one another.

6. The method according to claim 1, wherein the recording of one of the aerial images is effected in the best focal plane.

7. The method according to claim 1, wherein the diversification is effected by a spatial frequency filtering in the pupil plane of the imaging beam path of the imaging.

8. The method according to claim 1, wherein the diversification is effected by the recording of the at least two aerial images with different illumination directions.

9. The method according to claim 1, wherein determining the phase image is effected by recording an image of the region by use of a phase contrast microscopy.

10. A microscope comprising:

an imaging optical unit for recording an aerial image of a predefined region on a mask which comprises at least a structure element,

a detector for recording the aerial image, and

an image processing device configured to carry out the following steps;

predefining a region on the mask which comprises at least the structure element,

determining a phase image of the region, wherein the phase image comprises in a spatially resolved manner the phase of the imaging of the mask by the illumination radiation, and

determining the position of the structure element within the phase image,

wherein, for determining the phase image, at least two aerial images of the region of the mask are recorded, wherein the at least two aerial images are recorded under diversified conditions determining the positioning error of the structure element as distance of the position of the structure element from a set point position of the structure element in the phase image,

wherein aerial images recorded by the microscope are used.

11. The microscope of claim 10 in which the diversifications can be described by mathematical models.

12. The microscope of claim 10 in which the diversification is effected by the recording of the at least two aerial images in parallel planes spaced apart from one another.

13. The microscope of claim 10 in which the recording of one of the aerial images is effected in the best focal plane.

14. The microscope of claim 10 in which the diversification is effected by a spatial frequency filtering in the pupil plane of the imaging beam path of the imaging.

15. The microscope of claim 10 in which the diversification is effected by the recording of the at least two aerial images with different illumination directions.

16. The microscope of claim 10 in which determining the first phase image is effected by recording an image of the region by use of a phase contrast microscopy.

17. The microscope of claim 10 in which the image processing device is configured to carry out the following step:

determining the setpoint position of a structure element from the position of the structure element within a simulated phase image of the region of the mask.

18. The microscope of claim 10 in which the image processing device is configured to carry out the following steps:

determining a first position of a first structure element within the phase image,

determining a second position of the first structure element within an intensity image,

determining the deviation of the first position from the second position, and

correcting a third phase image of a second structure element by the determined deviation.

19. A microscope comprising:

an imaging optical unit for recording a phase image of a predefined region on a mask which comprises at least a structure element,

a detector for recording the phase image,

an image processing device configured to carry out the following steps;

predefining a region on the mask which comprises at least the structure element,

determining a phase image of the region, wherein the phase image comprises in a spatially resolved manner the phase of the imaging of the mask by the illumination radiation, and

determining the position of the structure element within the phase image,

wherein, for determining the phase image, at least two aerial images of the region of the mask are recorded, wherein the at least two aerial images are recorded under diversified conditions determining the positioning error of the structure element as distance of the position of the structure element from a set point position of the structure element in the phase image,

wherein phase images recorded by the microscope are used.

20. The microscope of claim 19 in which the diversifications can be described by mathematical models.

21. The microscope of claim 19 in which the diversification is effected by the recording of the at least two aerial images in parallel planes spaced apart from one another.

22. The microscope of claim 19 in which the recording of one of the aerial images is effected in the best focal plane.

23. The microscope of claim 19 in which the diversification is effected by a spatial frequency filtering in the pupil plane of the imaging beam path of the imaging.

24. The microscope of claim 19 in which the diversification is effected by the recording of the at least two aerial images with different illumination directions.

25. The microscope of claim 19 in which determining the first phase image is effected by recording an image of the region by use of a phase contrast microscopy.

26. The microscope of claim 19 in which the image processing device is configured to carry out the following step:

determining the setpoint position of a structure element from the position of the structure element within a simulated phase image of the region of the mask.

27. The microscope of claim 19 in which the image processing device is configured to carry out the following steps:

determining a first position of a first structure element within the phase image,

determining a second position of the first structure element within an intensity image,

determining the deviation of the first position from the second position, and

correcting a third phase image of a second structure element by the determined deviation.