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CN-122018257-A - Self-referencing integrated alignment sensor

CN122018257ACN 122018257 ACN122018257 ACN 122018257ACN-122018257-A

Abstract

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

Inventors

  • M. Swiram
  • J.L. Klerzer
  • S.Lu

Assignees

  • ASML控股股份有限公司

Dates

Publication Date
20260512
Application Date
20210609
Priority Date
20200624

Claims (20)

  1. 1. A system for determining alignment of a substrate, comprising: An illumination system configured to: generating a multi-wavelength radiation beam comprising a first set of wavelengths and a second set of wavelengths, the second set of wavelengths comprising at least one wavelength identical to the wavelengths of the first set of wavelengths, and Transmitting the multi-wavelength radiation beam towards a region of a surface of the substrate; A detection system comprising a multimode dispersion waveguide structure having a first input channel structure, a second input channel structure, a plurality of first output channel structures, and a plurality of second output channel structures and configured to: Receiving a first set of photons via a first input channel structure extending away from a longitudinal axis of the multimode dispersion waveguide structure at a first angle from the longitudinal axis, the first set of photons being at the first set of wavelengths and diffracted from the region of the surface of the substrate in response to illumination of the region by the multi-wavelength radiation beam; Receiving a second set of photons via a second input channel structure extending away from the longitudinal axis at a second angle to the longitudinal axis of the multimode dispersion waveguide structure, the second set of photons being at the second set of wavelengths 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; generating a plurality of first optical signals having different wavelengths indicative of differences between the first set of photons and the second set of photons; generating a plurality of second optical signals having different wavelengths indicative of a sum of the first set of photons and the second set of photons; transmitting a first optical signal having a different wavelength via a different first output channel structure extending at a third angle to the longitudinal axis; Transmitting a second optical signal having a different wavelength via a different second output channel structure extending at a fourth angle to the longitudinal axis, and An electronic signal is generated based on the first set of photons and the second set of photons.
  2. 2. The system for determining alignment of a substrate of claim 1, wherein the second set of wavelengths further comprises at least another wavelength different from the wavelength of the first set of wavelengths.
  3. 3. The system for determining alignment of a substrate of claim 1, wherein the area of the region of the surface of the substrate is 1.0 square millimeters.
  4. 4. The system for determining alignment of a substrate of claim 1, wherein the region of the surface of the substrate comprises a portion of an alignment grating structure.
  5. 5. The system for determining alignment of a substrate of claim 1, wherein: the first set of photons indicating a first order diffraction responsive to the irradiation of the region by the multi-wavelength radiation beam, and The second set of photons is indicative of first order diffraction responsive to the illumination of the region by the multi-wavelength radiation beam.
  6. 6. The system for determining alignment of a substrate 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.
  7. 7. The system for determining alignment of a substrate of claim 1, wherein the detection system is further configured to determine an alignment position of the substrate based on the electronic signal.
  8. 8. The system for determining alignment of a substrate of claim 1, wherein: the detection system includes optics; The optical device is configured to: collecting a first diffracted radiation beam at a first diffraction angle from the region of the surface of the substrate; collecting a second diffracted radiation beam at a second diffraction angle from the region of the surface of the substrate; the first diffracted beam of radiation includes the first set of photons; the second diffracted beam of radiation includes the second set of photons.
  9. 9. The system for determining alignment of a substrate of claim 8, wherein: the first diffracted radiation beam being indicative of a first order diffraction responsive to the irradiation of the region by the multi-wavelength radiation beam, and The second diffracted radiation beam is indicative of first order diffraction responsive to the illumination of the region by the multi-wavelength radiation beam.
  10. 10. The system for determining alignment of a substrate of claim 9, wherein the optics comprise a microlens structure.
  11. 11. The system for determining alignment of a substrate of claim 1, wherein: The detection system further comprises: a first detector, and A second detector; the multimode dispersive waveguide structure is configured to: Transmitting the first optical signal to the first detector via the first output channel structure, and The second optical signal is transmitted to the second detector via the second output channel structure.
  12. 12. The system for determining alignment of a substrate of claim 11, wherein: the first detector is configured to: Receiving the first optical signal, and Generating difference measurement data based on a first set of measurements of the first optical signal, and The second detector is configured to: Receiving the second optical signal, and Sum measurement data is generated based on a second set of measurements of the second optical signal.
  13. 13. The system for determining alignment of a substrate of claim 12, wherein: the detection system is configured to: the electronic signal is generated based on the difference measurement data and the sum measurement data.
  14. 14. The system for determining alignment of a substrate of claim 1, wherein: The system includes an optical coupler; the optical coupler is configured to: receiving the first set of photons; Receiving the second set of photons; Transmitting the first set of photons to the detection system, and Transmitting the second set of photons to the detection system.
  15. 15. An integrated optical device comprising: a radiation source configured to: emitting a multi-wavelength radiation beam towards a region of a surface of a substrate, wherein the multi-wavelength radiation beam comprises a first set of wavelengths and a second set of wavelengths, the second set of wavelengths comprising at least one wavelength identical to the wavelengths of the first set of wavelengths, and A metrology system comprising a multimode dispersion waveguide structure having a first input channel structure, a second input channel structure, a plurality of first output channel structures, and a plurality of second output channel structures and configured to: Measuring a first diffracted radiation beam indicative of first order diffraction at the first set of wavelengths in response to irradiation of the region by the multi-wavelength radiation beam and receiving the first diffracted radiation beam via a first input channel structure extending away from a longitudinal axis of the multimode, dispersive waveguide structure at a first angle to the longitudinal axis; Measuring a second diffracted radiation beam indicative of first order diffraction at the second set of wavelengths in response to the irradiation of the region by the multi-wavelength radiation beam and receiving the second diffracted radiation beam via a second input channel structure extending away from the longitudinal axis at a second angle to the longitudinal axis of the multimode dispersive waveguide structure; generating a plurality of first optical signals having different wavelengths indicative of a difference between the first and second diffracted beams of radiation; Generating a plurality of second optical signals having different wavelengths indicative of a sum of the first and second diffracted beams of radiation; transmitting a first optical signal having a different wavelength via a different first output channel structure extending at a third angle to the longitudinal axis; Transmitting a second optical signal having a different wavelength via a different second output channel structure extending at a fourth angle to the longitudinal axis, and An electronic signal is generated based on the measured first diffracted radiation beam and the measured second diffracted radiation beam.
  16. 16. 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.
  17. 17. 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.
  18. 18. A method for determining alignment of a substrate, comprising: Generating, by a radiation source, a multi-wavelength radiation beam having a first set of wavelengths and a second set of wavelengths, the second set of wavelengths including at least one wavelength that is the same as the wavelengths of the first set of wavelengths; transmitting the multi-wavelength radiation beam through the radiation source toward a region of the surface of the substrate; Measuring, by a metrology system comprising a multimode dispersion waveguide structure having a first input channel structure, a second input channel structure, a plurality of first output channel structures, and a plurality of second output channel structures, a first diffracted radiation beam indicative of first order diffraction at the first set of wavelengths in response to irradiation of the region by the multi-wavelength radiation beam and receiving, by the metrology system, the first diffracted radiation beam via a first input channel structure extending away from a longitudinal axis of the multimode dispersion waveguide structure at a first angle to the longitudinal axis; Measuring, by the metrology system, a second diffracted radiation beam indicative of first order diffraction at the second set of wavelengths in response to the irradiation of the region by the multi-wavelength radiation beam and receiving, by the metrology system, the second diffracted radiation beam via a second input channel structure extending away from the longitudinal axis of the multimode, dispersive waveguide structure at a second angle to the longitudinal axis; generating a plurality of first optical signals having different wavelengths indicative of a difference between the first and second diffracted beams of radiation; Generating a plurality of second optical signals having different wavelengths indicative of a sum of the first and second diffracted beams of radiation; transmitting a first optical signal having a different wavelength via a different first output channel structure extending at a third angle to the longitudinal axis; Transmitting a second optical signal having a different wavelength via a different second output channel structure extending at a fourth angle to the longitudinal axis, and An electronic signal is generated by the metrology system based on the measured first diffracted radiation beam and the measured second diffracted radiation beam.
  19. 19. The method for determining alignment of a substrate 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.
  20. 20. The method for determining alignment of a substrate of claim 18, further comprising determining, by the metrology system, an alignment position of the substrate based on the electronic signal.

Description

Self-referencing integrated alignment sensor The application is a divisional application of patent application with the application number 202180044426.5 of 'ASML control stock Co., ltd.' entering China and the date of 12 months, 21 days in China, with the application number of 'self-reference integrated alignment sensor' (International application date of 2021, 6 months, 9 days in International application number of PCT/EP 2021/065537). Cross Reference to Related Applications The present application claims priority from U.S. provisional patent application No. 63/043,543, filed 24 at 6/2020, the entire contents of which are incorporated herein by reference. Technical Field The present disclosure relates to an optical sensor and a sensing system for a lithographic apparatus. Background A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. Lithographic apparatus can be used, for example, in Integrated Circuit (IC) manufacturing. In that case, a patterning device (which is alternatively referred to as a mask or a reticle) may be used to generate a circuit pattern to be formed on an individual layer of the formed IC. Such a pattern may be transferred onto a target portion (e.g., a portion including one or several dies) on a substrate (e.g., a silicon (Si) wafer). Transfer of the pattern is typically performed via imaging onto a layer of radiation-sensitive material (e.g., resist) disposed on the substrate. Typically, a single substrate will contain a network of adjacent target portions that are continuously patterned. Conventional lithographic apparatus include so-called steppers, in which each target portion is irradiated by exposing an entire pattern onto the target portion at one time, and so-called scanners, in which each target portion is irradiated by scanning the pattern through the radiation beam in a given direction (the "scanning" -direction) while synchronously scanning the target portion parallel or anti-parallel (i.e. opposite) to such a scanning direction. The pattern may also be transferred from the patterning device to the substrate by imprinting the pattern onto the substrate. As semiconductor fabrication processes continue to advance, the size of circuit elements has been continually reduced over several decades, while the amount of functional elements (such as transistors) per device has steadily increased, following a trend commonly referred to as "moore's law. To keep pace with moore's law, the semiconductor industry is pursuing technologies that enable smaller and smaller features to be produced. To project a pattern onto a substrate, a lithographic apparatus may use electromagnetic radiation. The wavelength of this radiation determines the minimum size of the features that are patterned on the substrate. Typical wavelengths currently in use are 365 nm (i-line), 248 nm, 193 nm and 13.5 nm. Extreme Ultraviolet (EUV) radiation, such as electromagnetic radiation having a wavelength of about 50 nanometers (nm) or less (also sometimes referred to as soft x-rays) and including light having a wavelength of about 13 nm, may be used in or with a lithographic apparatus to produce very small features in or on a substrate (e.g., a silicon wafer). A lithographic apparatus using EUV radiation having a wavelength in the range of 4 nm to 20 nm (e.g., 6.7 nm or 13.5 nm) may be used to form smaller features on a substrate than a lithographic apparatus using radiation having, for example, 193 nm. Methods for generating EUV light include, but are not necessarily limited to, converting a material having an element such as xenon (Xe), lithium (Li), or tin (Sn) into a plasma state using an emission line in the EUV range. For example, in one such method, referred to as Laser Produced Plasma (LPP), a plasma may be produced by irradiating a target material, for example in the form of droplets, plates, ribbons, streams or clusters of material, which may be interchangeably referred to as fuel in the context of an LPP source, with an amplified light beam, which may be referred to as a drive laser. For such processes, a plasma is typically generated in a sealed container, such as a vacuum chamber, and various types of metrology equipment are used to monitor the plasma. Disclosure of Invention The present disclosure describes various aspects of systems, apparatus, methods, and computer program products for determining alignment of a substrate (e.g., wafer) using a substrate alignment sensing system that includes a self-referencing integrated alignment sensor. In some aspects, the self-referencing integrated alignment sensor may be configured to utilize on-axis illumination and off-axis detection (e.g., as described with reference to fig. 4-9). In other aspects, the self-referencing integrated alignment sensor may be configured to utilize off-axis illumination and on-axis detection (e.g., as described with reference to fig. 10-12). The term