Method and apparatus to determine a patterning process parameter, associated with a change in a physical configuration, using measured pixel optical characteristic values

• US 10,615,084 B2
• Filed: 02/28/2017
• Issued: 04/07/2020
• Est. Priority Date: 03/01/2016
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Van Leest, Adriaan Johan, Tsiatmas, Anagnostis, Hinnen, Paul Christiaan, McNamara, Elliott Gerard, Verma, Alok, Theeuwes, Thomas, Cramer, Hugo Augustinus Joseph
• Primary Examiner(s): Doan, Nghia M
• Application Number:
  US15/445,536
• Publication Number:
  US 20170255738A1
• Time in Patent Office: 1,134 Days
• Field of Search: 716 50- 56, 430 5, 430 30
• CPC Class Codes: G01N 21/9501 Semiconductor wafers manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10
• CPC Class Codes: G03F 7/70633 Overlay, i.e. relative alignment between patterns printed by separate exposures in different layers, or in the same layer in multiple exposures or stitching
• CPC Class Codes: G03F 7/70683 Mark designs
• CPC Class Codes: G03F 9/7003 Alignment type or strategy, e.g. leveling, global alignment
• CPC Class Codes: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14

Abstract

A method of configuring a parameter determination process, the method including: obtaining a mathematical model of a structure, the mathematical model configured to predict an optical response when illuminating the structure with a radiation beam and the structure having geometric symmetry at a nominal physical configuration; using, by a hardware computer system, the mathematical model to simulate a perturbation in the physical configuration of the structure of a certain amount to determine a corresponding change of the optical response in each of a plurality of pixels to obtain a plurality of pixel sensitivities; and based on the pixel sensitivities, determining a plurality of weights for combination with measured pixel optical characteristic values of the structure on a substrate to yield a value of a parameter associated with change in the physical configuration, each weight corresponding to a pixel.

Claims

1. A method of configuring a parameter determination process, the method comprising:

obtaining a mathematical model of a structure, the mathematical model configured to predict an optical response when illuminating the structure with a radiation beam and the structure having geometric symmetry at a nominal physical configuration;

using, by a hardware computer system, the mathematical model to simulate a perturbation in the physical configuration of the structure of a certain amount to determine a corresponding change of the optical response in each of a plurality of pixels to obtain a plurality of pixel sensitivities; and

based on the pixel sensitivities, determining a plurality of weights for combination with measured pixel optical characteristic values of the structure on a substrate to yield a value of a parameter associated with change in the physical configuration, each weight corresponding to a pixel.

2. The method of claim 1, wherein the parameter is overlay and the different physical configuration is a shift of at least part of the structure relative another part of the structure.

3. The method of claim 1, wherein the optical response comprises the optical characteristic in the form of a pupil image.

4. The method of claim 1, wherein the optical response is of primarily zeroth order radiation.

5. The method of claim 1, wherein the determining the weights comprises using a Jacobian matrix.

6. The method of claim 1, wherein the determining the weights comprises using a Hessian matrix.

7. The method of claim 1, wherein the determining the weights comprises using a Moore-Penrose pseudoinverse.

8. The method of claim 1, wherein the weights are configured such that the value of the parameter can be determined using a summation, for a plurality of pixels of a detected radiation representation, of an optical characteristic value for each pixel multiplied by the weight of the plurality of weights associated with that pixel.

9. The method of claim 1, wherein the optical characteristic is intensity and/or phase.

10. The method of claim 1, wherein the structure is a device structure.

11. The method of claim 1, wherein the structure is a non-device structure within a substrate die comprising a device structure.

12. The method of claim 1, further comprises determining a set of measurement settings for obtaining the measured pixel optical characteristic values, the set of measurement settings corresponding to the plurality of weights.

13. The method of claim 12, wherein the set of measurement settings comprises one or more selected from:

a wavelength of a measurement beam, a polarization of the measurement beam, a dose of the measurement beam, and/or a number of optical characteristic readings taken by a detector sensor of a particular one illumination of the structure.

14. The method of claim 1, wherein the obtaining the mathematical model comprises performing CD measurements on one or more substrates comprising the structure and calibrating the mathematical model against the CD measurements to obtain a nominal profile of the structure for perturbation of the physical configuration of the structure.

15. The method of claim 1, further comprising:

measuring optical characteristic values of radiation redirected by a plurality of structures with known different physical configurations and associated expected values of the parameter;

combining the weights and the measured optical characteristic values to determine a value of the parameter for each of the known different physical configurations; and

evaluating the determined values of the parameter with the expected values of the parameter; and

responsive to the evaluation, adjusting a parameter of the mathematical model and/or adjusting one or more of the weights.

16. A non-transitory computer-readable medium comprising instructions therein, the instructions, when executed by a computer system, configured to cause the computer system to at least:

obtain a mathematical model of a structure, the mathematical model configured to predict an optical response when illuminating the structure with a radiation beam and the structure having geometric symmetry at a nominal physical configuration;

use the mathematical model to simulate a perturbation in the physical configuration of the structure of a certain amount to determine a corresponding change of the optical response in each of a plurality of pixels to obtain a plurality of pixel sensitivities; and

based on the pixel sensitivities, determine a plurality of weights for combination with measured pixel optical characteristic values of the structure on a substrate to yield a value of a parameter associated with change in the physical configuration, each weight corresponding to a pixel.

17. The computer-readable medium of claim 16, wherein the parameter is overlay and the different physical configuration is a shift of at least part of the structure relative another part of the structure.

18. The computer-readable medium of claim 16, wherein the optical response comprises the optical characteristic in the form of a pupil image.

19. The computer-readable medium of claim 16, wherein the optical response is of primarily zeroth order radiation.

20. The computer-readable medium of claim 16, wherein the determination of the weights comprises use of a Jacobian matrix.

21. The computer-readable medium of claim 16, wherein the determination of the weights comprises use of a Hessian matrix.

22. The computer-readable medium of claim 16, wherein the determination of the weights comprises use of a Moore-Penrose pseudoinverse.

23. The computer-readable medium of claim 16, wherein the weights are configured such that the value of the parameter can be determined using a summation, for a plurality of pixels of a detected radiation representation, of an optical characteristic value for each pixel multiplied by the weight of the plurality of weights associated with that pixel.

24. The computer-readable medium of claim 16, wherein the optical characteristic is intensity and/or phase.

25. The computer-readable medium of claim 16, wherein the structure is a device structure.

26. The computer-readable medium of claim 16, wherein the structure is a non-device structure within a substrate die comprising a device structure.

27. The computer-readable medium of claim 16, wherein the instructions are further configured to determine a set of measurement settings for obtaining the measured pixel optical characteristic values, the set of measurement settings corresponding to the plurality of weights.

28. A non-transitory computer-readable medium comprising instructions therein, the instructions, when executed by a computer system, configured to cause the computer system to at least:

use a mathematical model to simulate a perturbation in a physical configuration of a structure of a certain amount to determine a corresponding change of an optical response, when illuminating the structure with a radiation beam, in each of a plurality of measurement pixels of a pupil of an optical measurement machine; and

based on the simulated perturbation results, determine a plurality of weights for combination with measured pixel optical characteristic values of the structure on a substrate to yield a value of a parameter associated with change in the physical configuration, each weight corresponding to a pixel.

29. The computer-readable medium of claim 28, wherein the parameter is overlay of a patterning process to form the structure and the different physical configuration is a shift of at least part of the structure relative another part of the structure.

30. The computer-readable medium of claim 28, wherein the optical response is of primarily zeroth order radiation.

31. The computer-readable medium of claim 28, wherein the determination of the weights comprises use of a Jacobian and/or Hessian matrix.

32. The computer-readable medium of claim 28, wherein the determination of the weights comprises use of a Moore-Penrose pseudoinverse.

33. The computer-readable medium of claim 28, wherein the weights are configured such that the value of the parameter can be determined using a summation, for a plurality of pixels of a detected radiation representation, of an optical characteristic value for each pixel multiplied by the weight of the plurality of weights associated with that pixel.

34. The computer-readable medium of claim 28, wherein the structure is a device structure or a non-device structure within a substrate die comprising a device structure.