# US 2022/0035255 A1 · Target for measuring a parameter of a lithographic process

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- Number: US 2022/0035255 A1
- Document ID: US20220035255A1
- Status: Published application
- Kind: A1
- Application number: 17/299,531
- Filed: 2019-12-04
- Published: 2022-02-03
- Earliest claimed: 2018-12-04
- Assignees: ASML Netherlands B.V.
- Applicants: ASML Netherlands B.V.
- Inventors: Maurits VAN DER SCHAAR; Olger Victor ZWIER; Patrick WARNAAR
- Web page: https://patentgrep.com/patent/US20220035255A1

## CPC

- 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}
- G01N 21/17: Systems in which incident light is modified in accordance with the properties of the material investigated (where the material investigated is optically excited causing a change in wavelength of the incident light G01N21/63)
- G01N 21/4788: {Diffraction (for sizing particles G01N15/0205)}
- G03F 7/70683: {Mark designs}
- H10P 74/277: {Circuits for electrically characterising or monitoring manufacturing processes, e.g. circuits in tested chips or circuits in testing wafers}
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A target for determining a performance parameter of a lithographic process, the target comprising a first sub-target formed by at least two overlapping gratings, wherein the underlying grating of the first sub-target has a first pitch and the top lying grating of the first sub-target has a second pitch, at least a second sub-target formed by at least two overlapping gratings, wherein the underlying grating of the second sub-target has a third pitch and the top lying grating of the second sub-target has a fourth pitch.

## Claims

### Claim 1

A target for determining a performance parameter of a lithographic process, the target comprising:
a first sub-target formed by at least two overlapping gratings, wherein an underlying grating of the first sub-target has a first pitch and a top lying grating of the first sub-target has a second pitch; and
at least a second sub-target formed by at least two overlapping gratings, wherein an underlying grating of the second sub-target has a third pitch and a top lying grating of the second sub-target has a fourth pitch.

### Claim 2 (depends on 1)

The target of claim 1, wherein the first pitch and the third pitch are the same.

### Claim 3 (depends on 1)

The target of claim 1, wherein the third pitch and the fourth pitch are the same.

### Claim 4 (depends on 1)

The target of claim 1, wherein the target further comprises:
a third sub-target formed by at least two overlapping gratings, wherein an underlying grating of the third sub-target has the first pitch and a top lying grating of the third sub-target has the second pitch, and
a fourth sub-target formed by at least two overlapping gratings, wherein an underlying grating of the fourth sub-target has the third pitch and a top lying grating of the fourth sub-target has the fourth pitch.

### Claim 5 (depends on 4)

The target of claim 4, wherein the third sub-target and the first sub-target have an overlay bias that increases in a first direction, and the second sub-target and the fourth sub-target have an overlay bias that decreases in the first direction.

### Claim 6 (depends on 5)

The target of claim 5, wherein the increasing overlay bias has a continuous variation.

### Claim 7 (depends on 5)

The target of claim 5, wherein the decreasing overlay bias has a continuous variation.

### Claim 8 (depends on 1)

The target of claim 1, wherein the target is formed on a substrate, the substrate comprising a major surface in an X-Y plane.

### Claim 9 (depends on 8)

The target of claim 8, wherein the first and second sub-targets have a same X and Y dimension.

### Claim 10 (depends on 4)

The target of claim 4, wherein the target is formed on a substrate, the substrate comprising a major surface in an X-Y plane, and wherein the first, second, third and fourth sub-targets each has a same X and Y dimension.

### Claim 11

A method of making a target for determining a performance parameter of a lithographic process, comprising:
forming a first sub-target having at least two overlapping gratings, wherein an underlying grating of the first sub-target has a first pitch and a top lying grating of the first sub-target has a second pitch; and
forming at least a second sub-target having at least two overlapping gratings, wherein an underlying grating of the second sub-target has a third pitch and a top lying grating of the second sub-target has a fourth pitch.

### Claim 12 (depends on 11)

The method of claim 11, further comprising forming the first pitch and the third pitch with a same pitch.

### Claim 13 (depends on 11)

The method of claim 11, further comprising forming the third pitch and the fourth pitch with a same pitch.

### Claim 14 (depends on 11)

The method of claim 11, further comprises:
forming a third sub-target having at least two overlapping gratings, wherein an underlying grating of the third sub-target has the first pitch and a top lying grating of the third sub-target has the second pitch, and
forming a fourth sub-target having at least two overlapping gratings, wherein an underlying grating of the fourth sub-target has the third pitch and a top lying grating of the fourth sub-target has the fourth pitch.

### Claim 15 (depends on 14)

The method of claim 14, further comprising forming the third sub-target and the first sub-target with an overlay bias that increases in a first direction, and the second sub-target and the fourth sub-target with an overlay bias that decreases in the first direction.

### Claim 16 (depends on 15)

The method of claim 15, further comprising forming the increasing overlay bias with a continuous variation.

### Claim 17 (depends on 15)

The method of claim 15, further comprising forming the decreasing overlay bias with a continuous variation.

### Claim 18 (depends on 11)

The method of claim 11, further comprising forming the target on a substrate, the substrate comprising a major surface in an X-Y plane.

### Claim 19 (depends on 18)

The method of claim 18, further comprising forming the first and second sub-targets with a same X and Y dimension.

### Claim 20 (depends on 14)

The method of claim 14, further comprising forming the target on a substrate, the substrate comprising a major surface in an X-Y plane, and further comprising forming the first, second, third and fourth sub-targets with a same X and Y dimension.