# US 2020/0401054 A1 · Measuring a Process Parameter for a Manufacturing Process Involving Lithography

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- Number: US 2020/0401054 A1
- Document ID: US20200401054A1
- Status: Published application
- Kind: A1
- Application number: 17/012,705
- Filed: 2020-09-04
- Published: 2020-12-24
- Earliest claimed: 2014-02-21
- Assignees: ASML Netherlands B.V.
- Applicants: ASML Netherlands B.V.
- Inventors: Maurits Van Der Schaar; Arie Jeffrey Den Boef; Omer Abubaker Omer Adam; Te-Chih Huang; Youping Zhang
- Web page: https://patentgrep.com/patent/US20200401054A1

## 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 21/47: Scattering, i.e. diffuse reflection (G01N21/25, G01N21/41 take precedence {G01N21/55 takes precedence})
- G01N 21/8806: {Specially adapted optical and illumination features}
- G03F 7/70683: {Mark designs}
- G03F 9/70: {for microlithography (measuring printed patterns for monitoring overlay G03F7/70633 or focus G03F7/70641; projection system adjustment G03F7/70258; position control G03F7/70775)}
- G03F 9/7076: {Mark details, e.g. phase grating mark, temporary mark}
- G01N 2201/12: Circuits of general importance; Signal processing
- 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)

## Abstract

There is disclosed a method of measuring a process parameter for a manufacturing process involving lithography. In a disclosed arrangement the method comprises performing first and second measurements of overlay error in a region on a substrate, and obtaining a measure of the process parameter based on the first and second measurements of overlay error. The first measurement of overlay error is designed to be more sensitive to a perturbation in the process parameter than the second measurement of overlay error by a known amount.

## Claims

### Claim 1

A method comprising:
designing a metrology target design pattern by a computing device comprising at least one processor, a memory, and a plurality of functional modules;
determining, by the at least one processor, a layout of a patterning device based on the metrology target design pattern;
modeling, by the plurality of functional modules, a performance of the metrology target design pattern based on at least one of physical properties of the patterning device, optical components of a lithography system, a resist used in a lithographic process, post-resist processes, and a properties of a metrology system; and
determining, by the at least one processor, a metrology target parameter of the metrology target design pattern based on the modelling.

### Claim 2 (depends on 1)

The method of claim 1, wherein the plurality of functional modules comprises a design layout module, a patterning device layout module, a patterning device model module, an optical model module, a resist model module, a process model module, and/or a metrology module.

### Claim 3 (depends on 1)

The method of claim 1, wherein the modeling the performance of the metrology target design pattern further comprises predicting edge placements and critical dimension of the metrology target design pattern.

### Claim 4 (depends on 1)

The method of claim 1, wherein the metrology target parameter comprises at least one of a target coefficient, stack sensitivity, and overlay error.

### Claim 5 (depends on 1)

The method of claim 1, further comprising:
determining the metrology target parameter based on a process parameter for the manufacturing process.

### Claim 6 (depends on 5)

The method of claim 5, wherein the process parameter comprises side wall angle of a metrology target, material thickness of the metrology target, material relative permittivity, material refractive index, metrology radiation wavelength, an etch parameter, floor tilt, extinction coefficient, coating asymmetry, or chemical-mechanical polish erosion.

### Claim 7 (depends on 1)

The method of claim 1, further comprising:
forming first and second target structures on a substrate based on the metrology target design pattern and the metrology target parameter.

### Claim 8

A non-transitory computer readable product comprising machine-readable instructions for causing a processor to perform the operations comprising:
designing a metrology target design pattern using a plurality of functional modules;
determining a layout of a patterning device based on the metrology target design pattern;
modeling, by the plurality of functional modules, a performance of the metrology target design pattern based on at least one of physical properties of the patterning device, optical components of a lithography system, a resist used in a lithographic process, post-resist processes, and a properties of a metrology system; and
determining a metrology target parameter of the metrology target design pattern based on the modelling.

### Claim 9 (depends on 8)

The non-transitory computer readable product of claim 8, wherein the plurality of functional modules comprises a design layout module, a patterning device layout module, a patterning device model module, an optical model module, a resist model module, a process model module, and/or a metrology module.

### Claim 10 (depends on 8)

The non-transitory computer readable product of claim 8, wherein the modeling the performance of the metrology target design pattern further comprises predicting edge placements and critical dimension of the metrology target design pattern.

### Claim 11 (depends on 8)

The non-transitory computer readable product of claim 8, wherein the metrology target parameter comprises at least one of a target coefficient, stack sensitivity, and overlay error.

### Claim 12 (depends on 8)

The non-transitory computer readable product of claim 8, the operations performed by the processor further comprising:
determining the metrology target parameter based on a process parameter for the manufacturing process.

### Claim 13 (depends on 12)

The non-transitory computer readable product of claim 12, wherein the process parameter comprises side wall angle of a metrology target, material thickness of the metrology target, material relative permittivity, material refractive index, metrology radiation wavelength, an etch parameter, floor tilt, extinction coefficient, coating asymmetry, or chemical-mechanical polish erosion.

### Claim 14

A system comprising:
a memory; and
at least one processor coupled to the memory, wherein the at least one processor is configured to:
design a metrology target design pattern using a plurality of functional modules;
determine a layout of a patterning device based on the metrology target design pattern;
model, by the plurality of functional modules, a performance of the metrology target design pattern based on at least one of physical properties of the patterning device, optical components of a lithography system, a resist used in a lithographic process, post-resist processes, and a properties of a metrology system; and
determine a metrology target parameter of the metrology target design pattern based on the modelling.

### Claim 15 (depends on 14)

The system of claim 14, wherein the plurality of functional modules comprises a design layout module, a patterning device layout module, a patterning device model module, an optical model module, a resist model module, a process model module, and/or a metrology module.

### Claim 16 (depends on 14)

The system of claim 14, wherein the modeling the performance of the metrology target design pattern further comprises predicting edge placements and critical dimension of the metrology target design pattern.

### Claim 17 (depends on 14)

The system of claim 14, wherein the metrology target parameter comprises at least one of a target coefficient, stack sensitivity, and overlay error.

### Claim 18 (depends on 14)

The system of claim 14, wherein the at least one processor is further configured to:
determine the metrology target parameter based on a process parameter for the manufacturing process.

### Claim 19 (depends on 18)

The system of claim 18, wherein the process parameter comprises side wall angle of a metrology target, material thickness of the metrology target, material relative permittivity, material refractive index, metrology radiation wavelength, an etch parameter, floor tilt, extinction coefficient, coating asymmetry, or chemical-mechanical polish erosion.

### Claim 20 (depends on 14)

The system of claim 14, wherein the at least one processor is further configured to:
generate instructions to form first and second target structures on a substrate based on the metrology target design pattern and the metrology target parameter.