# US 2017/0285483 A1 · Method and apparatus for using patterning device topography induced phase

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- Number: US 2017/0285483 A1
- Document ID: US20170285483A1
- Status: Published application
- Kind: A1
- Application number: 15/532,085
- Filed: 2015-11-25
- Published: 2017-10-05
- Earliest claimed: 2014-12-17
- Assignees: ASML Netherlands B.V.
- Applicants: ASML Netherlands B.V.
- Inventors: Jozef Maria FINDERS
- Web page: https://patentgrep.com/patent/US20170285483A1

## CPC

- G03F 7/706: {Aberration measurement}
- G03F 7/70125: {Use of illumination settings tailored to particular mask patterns (details of setting means G03F7/70091)}
- G03F 7/70441: {Optical proximity correction [OPC]}
- G03F 7/705: {Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions}
- 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)

## Abstract

A method including, for an illumination by radiation of a pattern of a lithographic patterning device, obtaining calculated wavefront phase information caused by three-dimensional topography of the pattern, and based on the wavefront phase information, adjusting a parameter of the illumination and/or adjusting a parameter of the pattern.

## Claims

### Claim 1

A method comprising:
for an illumination by radiation of a pattern of a lithographic patterning device, obtaining calculated wavefront phase information caused by three-dimensional topography of the pattern; and
based on the wavefront phase information and by a hardware computer processor, adjusting a parameter of the illumination and/or of the pattern.

### Claim 2 (depends on 1)

The method of claim 1, further comprising, for the adjusted illumination and/or pattern parameter, obtaining calculated wavefront phase information caused by the three-dimensional topography of the pattern and adjusting the parameter of the illumination and/or of the pattern, wherein the obtaining and adjusting is repeated until a certain termination condition is satisfied.

### Claim 3 (depends on 1)

The method of claim 1, wherein the adjusting comprises calculating, based on the wavefront phase information, a lithographic metric and, based on the lithographic metric, adjusting the parameter of the illumination and/or of the pattern.

### Claim 4 (depends on 1)

The method of claim 1, wherein the obtaining comprises obtaining the calculated wavefront phase information for a plurality of different incidence angles of illumination radiation; and wherein the adjusting comprises defining an acceptable angular range of incident illumination radiation based on the calculated wavefront phase information, and adjusting the parameter of the illumination and/or of the pattern, within the defined angular range.

### Claim 5 (depends on 1)

The method of claim 1, wherein the adjusting comprises computing a multi-variable function of a plurality of design variables that are characteristics of the lithographic process, the design variables including a characteristic of illumination for the pattern and a characteristic of the pattern, wherein the multi-variable function is a function of the calculated wavefront phase information.

### Claim 6 (depends on 1)

The method of claim 1, wherein the adjusting improves a contrast of imaging of the pattern.

### Claim 7 (depends on 1)

The method of claim 1, wherein the obtaining comprises obtaining three-dimensional topography information of the pattern and calculating the wavefront phase information caused by the three-dimensional topography based on the three-dimensional topography information.

### Claim 8 (depends on 1)

The method of claim 1, wherein the pattern is a design layout for a device and the wavefront phase information is specified only for a sub-pattern of the pattern.

### Claim 9 (depends on 1)

The method of claim 1, comprising adjusting the parameter of the illumination, wherein the adjusting the parameter of the illumination comprises adjusting an intensity distribution of the illumination.

### Claim 10 (depends on 1)

The method of claim 1, comprising adjusting the parameter of the pattern, wherein the adjusting the parameter of the pattern comprises adjusting one or more selected from: refractive index, extinction coefficient, sidewall angle, thickness, feature width, pitch, and/or a parameter of a layer stack, and/or comprises applying an optical proximity correction feature and/or a resolution enhancement technique to the pattern.

### Claim 11 (depends on 1)

The method of claim 1, wherein the wavefront phase information comprises wavefront phase information for a plurality of incident angles of radiation and/or sidewall angles of the pattern.

### Claim 12 (depends on 1)

The method of claim 1, wherein the obtaining comprises rigorously calculating the wavefront phase information.

### Claim 13 (depends on 1)

The method of claim 1, wherein the adjusting comprises tuning a parameter of a projection system of a lithography apparatus.

### Claim 14

A non-transitory computer program product comprising machine-readable instructions configured to cause a processor to:
for an illumination by radiation of a pattern of a lithographic patterning device, obtain calculated wavefront phase information caused by three-dimensional topography of the pattern; and
based on the wavefront phase information, adjust a parameter of the illumination and/or of the pattern.

### Claim 15 (depends on 1)

A method of manufacturing devices wherein a device pattern is applied to a series of substrates using a lithographic process, the method including preparing the device pattern using the method of claim 1 and exposing the device pattern onto the substrates.

### Claim 16 (depends on 14)

The computer program product of claim 14, wherein the instructions configured to adjust the parameter are further configured to calculate, based on the wavefront phase information, a lithographic metric and, based on the lithographic metric, adjust the parameter of the illumination and/or of the pattern.

### Claim 17

A method to improve a lithographic process to image at least a portion of a pattern of a lithographic patterning device onto a substrate, the method comprising:
obtaining calculated wavefront phase information caused by three-dimensional topography of the pattern;
computing, by a hardware computer, a multi-variable function of a plurality of parameters that are characteristics of the lithographic process, the parameters including a characteristic of illumination for the pattern and a characteristic of the pattern, wherein the multi-variable function is a function of the calculated wavefront phase information; and
adjusting a characteristic of the lithographic process by adjusting one or more of the parameters and re-computing the multi-variable function with the adjusted one or more parameters, until a predefined termination condition is satisfied.

### Claim 18 (depends on 17)

The method of claim 17, wherein the adjusting further comprises computing a further multi-variable function of a plurality of design variables that are characteristics of the lithographic process, wherein the further multi-variable function is not a function of the calculated wavefront phase information.

### Claim 19 (depends on 18)

The method of claim 18, wherein the multi-variable function is used for a critical area of the pattern and the further multi-variable function is used for a non-critical area.

### Claim 20 (depends on 18)

The method of claim 18, wherein the further multi-variable function is based on kernels.