# US 12,216,414 B2 · Self-referencing integrated alignment sensor

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- Number: US 12,216,414 B2
- Document ID: US12216414B2
- Status: Granted
- Kind: B2
- Application number: 18/012,799
- Filed: 2021-06-09
- Published: 2023-08-24
- Granted: 2025-02-04
- Earliest claimed: 2020-06-24
- Assignees: ASML Holding N.V.
- Applicants: ASML Holding N.V.
- Inventors: Mohamed Swillam; Justin Lloyd Kreuzer; Stephen Roux
- Web page: https://patentgrep.com/patent/US12216414B2

## CPC

- G03F 9/7019: {Calibration}
- G03F 9/7088: {Alignment mark detection, e.g. TTR, TTL, off-axis detection, array detector, video detection}
- G03F 9/7049: {Technique, e.g. interferometric}
- G03F 9/7065: {Production of alignment light, e.g. light source, control of coherence, polarization, pulse length, wavelength}
- 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

Systems, apparatuses, and methods are provided for determining the alignment of a substrate. An example method can include emitting a multi-wavelength radiation beam including a first wavelength and a second wavelength toward a region of a surface of a substrate. The example method can further include measuring a first diffracted radiation beam indicative of first order diffraction at the first wavelength in response to an irradiation of the region by the multi-wavelength radiation beam. The example method can further include measuring a second diffracted radiation beam indicative of first order diffraction at the second wavelength in response to the irradiation of the region by the multi-wavelength radiation beam. Subsequently, the example method can include generating, based on the measured first set of photons and the measured second set of photons, an electronic signal for use in determining an alignment position of the substrate.

## Claims

### Claim 1

A system, comprising:
an illumination system configured to:
generate a multi-wavelength radiation beam comprising a first wavelength and a second wavelength; and
transmit the multi-wavelength radiation beam toward a region of a surface of a substrate;
a detection system comprising a multimode dispersion waveguide structure and first and second detectors,
wherein the multimode dispersion waveguide structure is configured to:
receive and propagate a first set of photons at the first wavelength and diffracted from the region of the surface of the substrate in response to an illumination of the region by the multi-wavelength radiation beam;
receive and propagate a second set of photons at the second wavelength and diffracted from the region of the surface of the substrate in response to the illumination of the region by the multi-wavelength radiation beam; and
wherein at least one of the first and second detectors is configured to generate an electronic signal based on the received first and second set of photons.

### Claim 2 (depends on 1)

The system of claim 1, wherein the second wavelength is different from the first wavelength.

### Claim 3 (depends on 1)

The system of claim 1, wherein an area of the region of the surface of the substrate is about 1.0 square millimeter.

### Claim 4 (depends on 1)

The system of claim 1, wherein the region of the surface of the substrate comprises a portion of an alignment grating structure.

### Claim 5 (depends on 1)

The system of claim 1, wherein:
the first set of photons is indicative of first order diffraction in response to the illumination of the region by the multi-wavelength radiation beam; and
the second set of photons is indicative of first order diffraction in response to the illumination of the region by the multi-wavelength radiation beam.

### Claim 6 (depends on 1)

The system of claim 1, wherein the electronic signal is indicative of a phase difference between the first set of photons and the second set of photons.

### Claim 7 (depends on 1)

The system of claim 1, wherein the detection system is further configured to determine an alignment position of the substrate based on the electronic signal.

### Claim 8 (depends on 1)

The system of claim 1, wherein:
the detection system further comprises an optic;
the optic is configured to:
collect a first diffracted radiation beam from the region of the surface of the substrate at a first diffraction angle;
collect a second diffracted radiation beam from the region of the surface of the substrate at a second diffraction angle;
the first diffracted radiation beam comprises the first set of photons; and
the second diffracted radiation beam comprises the second set of photons.

### Claim 9 (depends on 8)

The system of claim 8, wherein:
the first diffracted radiation beam is indicative of first order diffraction in response to the illumination of the region by the multi-wavelength radiation beam; and
the second diffracted radiation beam is indicative of first order diffraction in response to the illumination of the region by the multi-wavelength radiation beam.

### Claim 10 (depends on 9)

The system of claim 9, wherein the optic comprises a microlens structure.

### Claim 11 (depends on 1)

The system of claim 1, wherein:
the multimode dispersion waveguide structure comprises:
a first input channel structure;
a second input channel structure;
a first output channel structure; and
a second output channel structure; and
the multimode dispersion waveguide structure is configured to:
receive the first set of photons from the first input channel structure;
receive the second set of photons from the second input channel structure;
generate a first optical signal indicative of a difference between the first set of photons and the second set of photons;
generate a second optical signal indicative of a summation of the first set of photons and the second set of photons;
transmit the first optical signal to the first detector via the first output channel structure; and
transmit the second optical signal to the second detector via the second output channel structure.

### Claim 12 (depends on 11)

The system of claim 11, wherein:
the first detector is configured to:
receive the first optical signal; and
generate difference measurement data based on a first set of measurements of the first optical signal; and
the second detector is configured to:
receive the second optical signal; and
generate summation measurement data based on a second set of measurements of the second optical signal.

### Claim 13 (depends on 12)

The system of claim 12, wherein:
the detection system is configured to:
generate the electronic signal based on the difference measurement data and the summation measurement data.

### Claim 14 (depends on 1)

The system of claim 1, wherein:
the system comprises an optical coupler;
the optical coupler is configured to:
receive the first set of photons;
receive the second set of photons;
transmit the first set of photons to the detection system; and
transmit the second set of photons to the detection system.

### Claim 15

An integrated optical device, comprising:
a radiation source configured to:
emit a multi-wavelength radiation beam toward a region of a surface of a substrate, wherein the multi-wavelength radiation beam comprises a first wavelength and a second wavelength; and
a metrology system comprising a multimode dispersion waveguide structure and a detector,
wherein the multimode dispersion waveguide structure is configured to:
receive and propagate a first diffracted radiation beam indicative of first order diffraction at the first wavelength in response to an irradiation of the region by the multi-wavelength radiation beam; and
receive and propagate a second diffracted radiation beam indicative of first order diffraction at the second wavelength in response to the irradiation of the region by the multi-wavelength radiation beam;
wherein the metrology system is configured to measure the first and second diffracted radiation beams, and
wherein the detector is configured to generate an electronic signal based on the measured first diffracted radiation beam and the measured second diffracted radiation beam.

### Claim 16 (depends on 15)

The integrated optical device of claim 15, wherein the electronic signal is indicative of a phase difference between the measured first diffracted radiation beam and the measured second diffracted radiation beam.

### Claim 17 (depends on 15)

The integrated optical device of claim 15, wherein the metrology system is further configured to determine an alignment position of the substrate based on the generated electronic signal.

### Claim 18

A method, comprising:
generating, by a radiation source, a multi-wavelength radiation beam having a first wavelength and a second wavelength;
transmitting, by the radiation source, the multi-wavelength radiation beam toward a region of a surface of a substrate;
receiving, by a multimode dispersion waveguide structure in a metrology system, a first diffracted radiation beam indicative of first order diffraction at the first wavelength in response to an irradiation of the region by the multi-wavelength radiation beam;
receiving, by the multimode dispersion waveguide structure in the metrology system, a second diffracted radiation beam indicative of first order diffraction at the second wavelength in response to the irradiation of the region by the multi-wavelength radiation beam;
measuring, by the metrology system, the first diffracted radiation beam;
measuring, by the metrology system, the second diffracted radiation beam; and
generating, by a detector in the metrology system, an electronic signal based on the measured first and second diffracted radiation beams.

### Claim 19 (depends on 18)

The method of claim 18, wherein the electronic signal is indicative of a phase difference between the first diffracted radiation beam and the second diffracted radiation beam.

### Claim 20 (depends on 18)

The method of claim 18, further comprising determining, by the metrology system, an alignment position of the substrate based on the electronic signal.