Metrology method, target and substrate

Patent metadata

Field	Value
Publication number	US-12429328-B2
Application number	US-202217873406-A
Country	US
Kind code	B2
Filing date	Jul 26, 2022
Priority date	Aug 29, 2014
Publication date	Sep 30, 2025
Grant date	Sep 30, 2025

Abstract

A diffraction measurement target that has at least a first sub-target and at least a second sub-target, and wherein (1) the first and second sub-targets each include a pair of periodic structures and the first sub-target has a different design than the second sub-target, the different design including the first sub-target periodic structures having a different pitch, feature width, space width, and/or segmentation than the second sub-target periodic structure or (2) the first and second sub-targets respectively include a first and second periodic structure in a first layer, and a third periodic structure is located at least partly underneath the first periodic structure in a second layer under the first layer and there being no periodic structure underneath the second periodic structure in the second layer, and a fourth periodic structure is located at least partly underneath the second periodic structure in a third layer under the second layer.

First claim

The invention claimed is:

1. A method comprising:
illuminating with radiation a diffraction measurement target on a substrate, the measurement target comprising at least a first sub-target, a second sub-target, a third sub-target and a fourth sub-target, wherein the first, second, third and fourth sub-targets are different in design with at least one sub-target of the first to fourth sub-targets being at least partly on a different layer than the other of the first to fourth sub-targets and at least two sub-targets of the first to fourth sub-targets being at least partly on a same layer.

2. The method of claim 1 , wherein the different design comprises one of the first to fourth sub-targets having a different pitch, feature width, space width, and/or segmentation than another of the first to fourth sub-targets.

3. The method of claim 1 , wherein the first sub-target at least partly overlays a first periodic structure, the second sub-target at least partly overlays a second periodic structure, and the third sub-target at least partly overlays a third periodic structure, wherein the first periodic structure is at a different layer on the substrate than the second and third periodic structures and the second periodic structure is at a different layer on the substrate than the first and third periodic structures.

4. The method of claim 1 , wherein the illuminating comprises illuminating a measurement spot on the diffraction measurement target that covers at one time at least part of each of a periodic structure of the first to fourth sub-targets.

5. The method of claim 1 , wherein at least part of a periodic structure of each of the first to fourth sub-targets is within a contiguous area of less than or equal to 400 μm 2 on the substrate.

6. The method of claim 1 , wherein each of the first to fourth sub-targets is designed for a different process stack for the substrate.

7. The method of claim 1 , wherein each of the first to fourth sub-targets is designed for a different layer-pair for multiple layer overlay measurement.

8. A diffraction metrology target comprising at least a first sub-target, a second sub-target, a third sub-target and a fourth sub-target, wherein the first, second, third and fourth sub-targets are different in design with at least one sub-target of the first to fourth sub-targets being at least partly on a different layer than the other of the first to fourth sub-targets and at least two sub-targets of the first to fourth sub-targets being at least partly on a same layer.

9. The target of claim 8 , wherein the different design comprises one of the first to fourth sub-targets having a different pitch, feature width, space width, and/or segmentation than another of the first to fourth sub-targets.

10. The target of claim 8 , wherein at least part of a periodic structure of each of the first to fourth sub-targets is within a contiguous area of less than or equal to 400 μm 2 .

11. The target of claim 8 , wherein each of the first to fourth sub-targets is designed for a different process stack for a substrate.

12. The target of claim 8 , wherein each of the first to fourth sub-targets is designed for a different layer-pair for multiple layer overlay measurement.

13. A method comprising:
illuminating a first sub-target of a measurement target on a substrate with radiation having a first wavelength, and illuminating a second sub-target of the measurement target on the substrate with radiation having a second wavelength different from the first wavelength, wherein the first wavelength is selected for the first sub-target and the second wavelength is selected for the second sub-target; and
detecting at least some of the radiation coming from the first sub-target and at least some of the radiation coming from the second sub-target to obtain for the measurement target a measurement representing a parameter of a lithographic process,
wherein a value of the parameter is obtained from the first sub-target using the first wavelength without using the second wavelength and from the second sub-target using the second wavelength without using the first wavelength.

14. The method of claim 13 , wherein the first and second sub-targets are different in design.

15. The method of claim 13 , wherein first and second periodic structures of the second sub-target meet at a central portion of the measurement target and first and second periodic structures of the first sub-target are arranged around a periphery of the first and second periodic structures of the second sub-target.

16. The method of claim 13 , wherein the illuminating comprises illuminating the first sub-target with radiation having a first polarization and illuminating the second sub-target of the measurement target on the substrate with radiation having a second polarization, wherein the first polarization is different from the second polarization.

17. The method of claim 13 , wherein at least part of the first sub-target is located on a different layer than at least part of the second sub-target.

18. The method of claim 13 , wherein the measurement target has an area of less than or equal to 1000 μm 2 on the substrate.

19. The method of claim 13 , wherein the parameter of the lithographic process is overlay.

20. A non-transitory computer program product comprising machine-readable instructions therein, the instructions, upon execution by a computer system, configured to cause the computer system to at least:
cause illumination of a first sub-target of a measurement target on a substrate with radiation having a first wavelength, and illumination of a second sub-target of the measurement target on the substrate with radiation having a second wavelength different from the first wavelength, wherein the first wavelength is selected for the first sub-target and the second wavelength is selected for the second sub-target; and
cause detection of at least some of the radiation coming from the first sub-target and at least some of the radiation coming from the second sub-target to obtain for the measurement target a measurement representing a parameter of a lithographic process,
wherein a value of the parameter is obtained from the first sub-target using the first wavelength without using the second wavelength and from the second sub-target using the second wavelength without using the first wavelength.

Assignees

• Asml Netherlands Bv

Inventors

• Bhattacharyya Kaustuve
• Van Buel Henricus Wilhelmus Maria
• Fouquet Christophe David
• Smilde Hendrik Jan Hidde
• Van Der Schaar Maurits
• Den Boef Arie Jeffrey
• Van Haren Richard Johannes Franciscus
• Liu xing lan
• Beltman Johannes Marcus Maria
• Fuchs Andreas
• Adam Omer Abubaker Omer
• Kubis Michael
• Jak Martin Jacobus Johan

Classifications

• G03F7/706847

  Production of measurement radiation, e.g. synchrotron, free-electron laser, plasma source or higher harmonic generation [HHG] · CPC title

• G03F7/70683

  Mark designs · CPC title

• G03F7/70633 Primary

  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 title

• G01B11/14 Primary

  for measuring distance or clearance between spaced objects or spaced apertures (G01B11/26 takes precedence; rangefinders G01C3/00) · CPC title

• G03F7/70608

  Monitoring the unpatterned workpiece, e.g. measuring thickness, reflectivity or effects of immersion liquid on resist · CPC title