Metrology robustness based on through-wavelength similarity

• US 10,394,132 B2
• Filed: 04/24/2017
• Issued: 08/27/2019
• Est. Priority Date: 05/17/2016
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Garcia Granda, Miguel, Leewis, Christian Marinus, Staals, Frank
• Primary Examiner(s): Riddle, Christina A
• Application Number:
  US16/096,360
• Publication Number:
  US 20190129319A1
• Time in Patent Office: 855 Days
• Field of Search: 355 52- 55, 355 67- 71, 355 77, 3562375, 3562372, 356 60, 356609, 356625, 356630, 356634-636, 356448, 356399-401, 438 16, 700121, 700108-110, 700 28- 34, 702150, 702155, 702158, 702166, 702170, 702172, 702 57, 702 66, 702 70, 702 71, 702 81- 82, 702 84, 702 94, 702 95, 702 97, 703 2
• 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 7/706831 Recipe selection or optimisation, e.g. select or optimise recipe parameters such as wavelength, polarisation or illumination modes
• CPC Class Codes: G03F 7/706839 Modelling, e.g. modelling scattering or solving inverse problems
• CPC Class Codes: G03F 9/7019 Calibration
• CPC Class Codes: G03F 9/7026 Focusing
• CPC Class Codes: G03F 9/7046 Strategy, e.g. mark, sensor or wavelength selection
• CPC Class Codes: G03F 9/7092 Signal processing

Abstract

A method including obtaining a measurement result from a target on a substrate, by using a substrate measurement recipe; determining, by a hardware computer system, a parameter from the measurement result, wherein the parameter characterizes dependence of the measurement result on an optical path length of the target for incident radiation used in the substrate measurement recipe and the determining the parameter includes determining dependence of the measurement result on a relative change of wavelength of the incident radiation; and if the parameter is not within a specified range, adjusting the substrate measurement recipe.

Claims

1. A method comprising:

obtaining a measurement result from a target on a substrate, by using a substrate measurement recipe;

determining, by a hardware computer system, a parameter value from the measurement result, wherein the parameter characterizes dependence of the measurement result on an optical path length of the target for incident radiation used in accordance with the substrate measurement recipe and the determining the parameter value comprises determining dependence of the measurement result on a relative change of wavelength of the incident radiation; and

responsive to the parameter value not being within a specified range, adjusting the substrate measurement recipe.

2. The method of claim 1, wherein the measurement result comprises an overlay error, alignment, focus, or critical dimension.

3. The method of claim 1, wherein the measurement result comprises a normalized intensity asymmetry of two diffraction orders from the target.

4. The method of claim 1, wherein the parameter is a derivative of the measurement result with respect to a relative change of the optical path length.

5. The method of claim 1, wherein determining the parameter value comprises obtaining measurement results using at least two different wavelengths.

6. The method of claim 1, wherein the parameter is a difference between two sets of measurement results obtained using two substrate measurement recipes with different wavelengths of the incident radiation.

7. The method of claim 1, wherein adjusting the substrate measurement recipe comprises adjusting a parameter of a measurement target structure associated with the substrate measurement recipe.

8. The method of claim 7, wherein the parameter of the target comprises a shape or orientation of at least part of the measurement target structure.

9. The method of claim 1, wherein adjusting the substrate measurement recipe comprises adjusting a parameter of a measurement using the substrate measurement recipe.

10. The method of claim 9, wherein the parameter of the measurement comprises polarization or wavelength of the incident measurement radiation.

11. A method comprising:

obtaining a measurement result from a target on a substrate, by using each of a plurality of substrate measurement recipes;

determining, by a hardware computer system, a parameter value from each of the measurement results, wherein the parameter characterizes dependence of the measurement result on an optical path length of the target for incident radiation used in accordance with the substrate measurement recipe to obtain the measurement result; and

selecting at least one substrate measurement recipe from the plurality of substrate measurement recipes based on the parameter values.

12. The method of claim 11, wherein determining the parameter value comprises determining dependence of the measurement result on a relative change of wavelength of the incident radiation.

13. The method of claim 11, wherein the measurement result comprises an overlay error, focus, alignment, or critical dimension.

14. A computer program product comprising a non-transitory computer readable medium having instructions recorded thereon, the instructions when executed by a computer implementing the method of claim 11.

15. A computer program product comprising a non-transitory computer readable medium having instructions recorded thereon, the instructions when executed by a computer system configured to cause the computer system to at least:

obtain a measurement result from a target on a substrate, the measurement using a substrate measurement recipe;

determine a parameter value from the measurement result, wherein the parameter characterizes dependence of the measurement result on an optical path length of the target for incident radiation used in accordance with the substrate measurement recipe and the determination of the parameter value comprises determination of dependence of the measurement result on a relative change of wavelength of the incident radiation; and

responsive to the parameter value not being within a specified range, adjust the substrate measurement recipe.

16. The computer program product of claim 15, wherein the parameter is a derivative of the measurement result with respect to a relative change of the optical path length.

17. The computer program product of claim 15, wherein determination of the parameter value comprises obtaining measurement results using at least two different wavelengths.

18. The computer program product of claim 15, wherein the parameter is a difference between two sets of measurement results obtained using two substrate measurement recipes with different wavelengths of the incident radiation.

19. The computer program product of claim 15, wherein adjustment of the substrate measurement recipe comprises adjustment of a parameter of a measurement target structure associated with the substrate measurement recipe.

20. The computer program product of claim 15, wherein adjustment of the substrate measurement recipe comprises adjustment of a parameter of a measurement using the substrate measurement recipe.