Metrology method, target and substrate

Patent metadata

Field	Value
Publication number	US-10718604-B2
Application number	US-201916507297-A
Country	US
Kind code	B2
Filing date	Jul 10, 2019
Priority date	Aug 29, 2014
Publication date	Jul 21, 2020
Grant date	Jul 21, 2020

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 a measurement target on a substrate with radiation, wherein:
the measurement target comprises at least a first sub-target and a second sub-target,
each of the first sub-target and the second sub-target has a first periodic structure having features extending in a first direction and a second periodic structure having features extending in a second different direction,
the first sub-target at least partly overlays a third sub-target and the second sub-target at least partly overlays a fourth sub-target, and
the first sub-target has a different design than the third sub-target and/or the second sub-target has a different design than the fourth sub-target; and

detecting radiation scattered by at least the first and second sub-targets to obtain for the measurement target a measurement representing a parameter of a lithographic process.

2. The method of claim 1 , wherein the first sub-target has a different pitch, feature width, or space width than the third sub-target and/or the second sub-target has a different pitch, feature width, or space width than the fourth sub-target.

3. The method of claim 1 , wherein the first sub-target has a different design than the second sub-target.

4. The method of claim 3 , wherein the first sub-target has a different pitch, feature width, or space width than the second sub-target.

5. The method of claim 1 , wherein the third sub-target has a different design than the fourth sub-target.

6. The method of claim 5 , wherein the third sub-target has a different pitch, feature width, or space width than the fourth sub-target.

7. The method of claim 1 , wherein the first and second periodic structures of the second sub-target meet at a center of the measurement target and the 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.

8. The method of claim 7 , wherein a length and width of each of the first and second periodic structures of the first sub-target is substantially the same as a length and width of each of the first and second periodic structures of the second sub-target.

9. The method of claim 1 , wherein the first direction and the second different direction are substantially perpendicular.

10. The method of claim 1 , wherein the parameter of the lithographic process is overlay.

11. The method of claim 1 , wherein a bias difference is provided between the first sub-target and the second sub-target.

12. The method of claim 1 , wherein the illuminating comprising illuminating a measurement spot on the measurement target that covers at one time at least part of each of the first and second periodic structures of the first sub-target and the first and second periodic structures of the second sub-target.

13. The method of claim 1 , wherein the third and fourth sub-targets each comprise periodic structures.

14. The method of claim 1 , wherein the detecting comprises detecting radiation scattered by at least the first, second, third and fourth sub-targets to obtain for the measurement target a measurement representing the parameter of the lithographic process.

15. The method of claim 1 , wherein the detecting radiation comprises forming a dark field image of at least the first and second sub-targets.

16. 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 performance of the method of claim 1 .

17. 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:
obtain a result from detection of radiation scattered by a measurement target on a substrate, wherein:
the measurement target comprises at least a first sub-target and a second sub-target,
each of the first sub-target and the second sub-target has a first periodic structure having features extending in a first direction and a second periodic structure having features extending in a second different direction,
the first sub-target at least partly overlays a third sub-target and the second sub-target at least partly overlays a fourth sub-target, and
the first sub-target has a different design than the third sub-target and/or the second sub-target has a different design than the fourth sub-target; and

determine, from the result and for the measurement target, a measurement representing a parameter of a lithographic process.

18. A measurement target for determination of a parameter of a lithographic process, the target comprising:
at least a first sub-target and a second sub-target, wherein:
each of the first sub-target and the second sub-target has a first periodic structure having features extending in a first direction and a second periodic structure having features extending in a second different direction,
the first sub-target at least partly overlays a third sub-target and the second sub-target at least partly overlays a fourth sub-target, and
the first sub-target has a different design than the third sub-target and/or the second sub-target has a different design than the fourth sub-target.

19. The target of claim 18 , wherein the first sub-target and/or second sub-target has a different pitch, feature width, or space width than the third sub-target and/or fourth sub-target.

20. The target of claim 18 , wherein the first sub-target has a different design than the second sub-target.

21. The target of claim 18 , wherein the target is a dark-field image-based target.

22. A substrate comprising the target of claim 18 .

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