IP Library › Granted Patent US 12698962
Granted Patent B2
US 12698962 · App. 18/144,540 · Granted Aug 4, 2026

Metrology target for one-dimensional measurement of periodic misregistration

Inventors: Yoel Feler (Haifa, IL); Mark Ghinovker (Yoqneam Ilit, IL)
Assignee: KLA Corporation
G01B11/272G06T7/0004G06T2207/30148
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Quick Facts
Patent No.
US 12698962
App. No.
18/144,540
Granted
Aug 4, 2026
Kind
B2
Abstract

A metrology target includes a first target structure set having one or more first target structures formed within at least one of a first working zone or a second working zone of a sample. The metrology target includes a second target structure set having one or more second target structures formed within at least one of the first working zone or the second working zone. The first working zone may include a center of symmetry that overlaps with a center of symmetry of the second working zone when an overlay error of one or more layers of the sample is not present. The metrology target may additionally include a third target structure set, a fourth target structure set, or a fifth target structure set.

Claims (29)

1 . A system comprising:

a controller communicatively couplable a metrology sub-system, wherein the controller includes one or more processors, wherein the one or more processors are configured to execute a set of program instructions maintained in memory, wherein the set of program instructions is configured to cause the one or more processors to:

receive, from the metrology sub-system, one or more images of a metrology target on a sample, wherein the metrology target comprises:

two or more sets of working zones, wherein each of the sets of working zones includes features having periodicity along one or more directions, wherein each of the sets of working zones is at least two-fold rotationally symmetric about a respective center of rotational symmetry, wherein the centers of rotational symmetry of the two or more sets of working zones are designed to overlap at a common point, wherein one of the two or more sets of working zones is a single central working zone centered on and including the common point and is at least two-fold rotationally symmetric with itself, wherein at least the single central working zone includes features in two or more sample layers, the features comprising a two-dimensional periodic structure having periodicity along two directions and configured for measurement of overlay error along a first measurement direction and a second measurement direction; and

determine overlay error between two or more layers of the sample including the features of the two or more working zones based on differences between the centers of rotational symmetry of any of the two or more sets of working zones.

2 . The system of claim 1 , wherein at least some of the features of the two or more sets of working zones are disposed on a first layer of the sample, wherein at least some of the features of the two or more sets of working zones are disposed on a second layer of the sample.

3 . The system of claim 1 , wherein the features of at least one of two or more sets of working zones are located in a different layer of a sample including the metrology target than the features of at least one other of the two or more sets of working zones.

4 . The system of claim 1 , wherein the features of the two or more sets of working zones are disposed on common layers of the sample.

5 . The system of claim 1 , wherein the metrology sub-system comprises:

an advanced imaging metrology (AIM) tool, wherein the two or more sets of working zones provide an AIM target.

6 . The system of claim 1 , wherein the metrology sub-system comprises:

a robust advanced imaging metrology (rAIM) tool, wherein the two or more sets of working zones provide an rAIM target.

7 . The system of claim 1 , wherein the working zones of all of the two or more sets of working zones have at least one of a common size or a common shape.

8 . The system of claim 1 , wherein the working zones of at least one of the two or more sets of working zones have at least one of a different size or shape than the working zones of at least one other of the two or more sets of working zones.

9 . The system of claim 1 , wherein the differences between the centers of rotational symmetry of any of the two or more sets of working zones are indicative of overlay error between one or more layers of the sample including the features of the two or more working zones along the two directions.

10 . A metrology target comprising:

two or more sets of working zones, wherein each of the sets of working zones includes features having periodicity along one or more directions, wherein each of the sets of working zones is at least two-fold rotationally symmetric about a respective center of rotational symmetry, wherein the centers of rotational symmetry of the two or more sets of working zones are designed to overlap at a common point, wherein one of the two or more sets of working zones is a single central working zone centered on and including the common point and is at least two-fold rotationally symmetric with itself, wherein at least the single central working zone includes features in two or more sample layers, the features comprising a two-dimensional periodic structure having periodicity along two directions and configured for measurement of overlay error along a first measurement direction and a second measurement direction; wherein differences between the centers of rotational symmetry of any of the two or more sets of working zones are indicative of overlay error between two or more layers of the sample including the features of the two or more working zones.

11 . The metrology target of claim 10 , wherein the working zones of all of the two or more sets of working zones have at least one of a common size or a common shape.

12 . The metrology target of claim 10 , wherein the working zones of at least one of the two or more sets of working zones have at least one of a different size or shape than the working zones of at least one other of the two or more sets of working zones.

13 . The metrology target of claim 10 , wherein the features of at least one of two or more sets of working zones are located in a different layer of a sample than the features of at least one other of the two or more sets of working zones.

14 . The metrology target of claim 10 , wherein the two or more sets of working zones provide an advanced imaging metrology (AIM) target compatible with a selected AIM tool.

15 . The metrology target of claim 10 , wherein the two or more sets of working zones provide a robust advanced imaging metrology (AIM) target compatible with a selected rAIM tool.

16 . The metrology target of claim 10 , wherein the differences between the centers of rotational symmetry of any of the two or more sets of working zones are indicative of overlay error between one or more layers of the sample including the features of the two or more working zones along the two directions.

17 . A metrology method comprising:

generating one or more images of a metrology target on a sample, wherein the metrology target comprises:

two or more sets of working zones, wherein each of the sets of working zones includes features having periodicity along one or more directions, wherein each of the sets of working zones is at least two-fold rotationally symmetric about a respective center of rotational symmetry, wherein the centers of rotational symmetry of the two or more sets of working zones are designed to overlap at a common point, wherein one of the two or more sets of working zones is a single central working zone centered on and including the common point and is at least two-fold rotationally symmetric with itself, wherein at least the single central working zone includes features in two or more sample layers, the features comprising a two-dimensional periodic structure having periodicity along two directions and configured for measurement of overlay error along a first measurement direction and a second measurement direction; and

determining overlay error between two or more layers of the sample including the features of the two or more working zones based on differences between the centers of rotational symmetry of any of the two or more sets of working zones.

18 . The method of claim 17 , wherein at least some of the features of the two or more sets of working zones are disposed on a first layer of the sample, wherein at least some of the features of the two or more sets of working zones are disposed on a second layer of the sample.

19 . The method of claim 17 , wherein the features of at least one of two or more sets of working zones are located in a different layer of a sample including the metrology target than the features of at least one other of the two or more sets of working zones.