KR-20260064711-A - Spectral angle measurement

KR20260064711AKR 20260064711 AKR20260064711 AKR 20260064711AKR-20260064711-A

Abstract

The measurement system may include a dual-frequency comb source providing a first comb beam having a first repetition rate and a second comb beam having a second repetition rate, a beam splitter for generating one or more dual-frequency comb illumination beams from the first comb beam and the second comb beam, and a beam combiner for forming a dual-frequency comb illumination beam from the first comb beam and the second comb beam. The system may further include an illumination subsystem for illuminating a sample with a dual-frequency comb illumination beam through an objective lens, a collection subsystem for collecting sample light from the sample with an objective lens, and a detector for capturing a radio frequency signal based on the sample light. The system may also extract spectrum measurement data associated with the sample from the radio frequency signal and generate measurement values based on the spectrum measurement data.

Inventors

마나센 암논
짐다스 데이비드
피터린츠 케빈
힐 앤드류 브이
크리슈난 샹카르
바크닌 요나탄
돌레프 이도
가네산 수리아나라야난
창 차오
김 종진

Assignees

케이엘에이 코포레이션

Dates

Publication Date: 20260507
Application Date: 20240905
Priority Date: 20240903

Claims (20)

In a measurement system, A controller including one or more processors Includes, The above one or more processors execute program instructions, thereby causing the above one or more processors, Receiving a radio frequency signal from a detector associated with illuminating a sample with a dual-frequency comb illumination beam through an objective lens via an illumination subsystem, and collecting sample light from said sample responding to said dual-frequency comb illumination beam through said objective lens by a collection subsystem—said that the dual-frequency comb illumination beam comprises two frequency combs having different repetition rates—; Extracting spectrum measurement data associated with the sample from the above radio frequency signal; and Generating one or more measurement values of the sample based on the spectrum measurement data A measurement system configured to enable the implementation of a measurement recipe by
In paragraph 1, One or more of the above-mentioned measurements are, Overlay measurements, tilt measurements, and critical dimension measurements A measurement system comprising at least one of the following.
In paragraph 1, The illumination subsystem comprises an illumination polarizer and a rotatable illumination phase plate within the illumination path of the dual-frequency comb illumination beam, and the collection subsystem comprises a rotatable collection phase plate and an analyzer within the optical path of the sample light. Generating one or more measurement values of the sample based on the spectrum measurement data above is, Reconstructing data representing one or more Müller matrix elements associated with the sample based on the spectrum measurement data; and Generating one or more measurement values based on data representing one or more of the above-mentioned Müller matrix elements A measurement system that includes
In paragraph 3, A measurement system in which at least a portion of the radio frequency signal is associated with the zeroth-order diffraction from the sample, and at least a portion of the data representing one or more Müller matrix elements is associated with the zeroth-order diffraction from the sample.
In paragraph 3, The above lighting subsystem illuminates the in-die portion of the sample, and the measurement system comprises one or more measurement measurements including in-die measurements.
In paragraph 1, A measurement system wherein the illumination subsystem comprises an illumination apodizer for generating one or more off-axis illumination lobes from the dual-frequency comb illumination beam, and at least a portion of the radio frequency signal is associated with the first-order diffraction of the one or more off-axis illumination lobes by the sample.
In paragraph 6, The above-described lighting apodizer is a measuring system comprising one or more curved apertures.
In Paragraph 7, A measuring system in which one or more of the above-mentioned curved openings are shaped as one or more crescent moons.
In paragraph 6, The above lighting subsystem is a measurement system that illuminates a measurement target on the sample.
In Paragraph 9, The above measurement target is, Overlay measurement target A measurement system that includes
In Paragraph 10, The above measurement target is, Advanced imaging metrology (AIM) targets and robust AIM targets A measurement system comprising at least one of the following.
In Paragraph 10, The above measurement target is, Laying hen overlay (scatterometry overlay; SCOL) target A measurement system that includes
In Paragraph 9, The above lighting subsystem further provides an additional dual-frequency comb lighting beam, and The above lighting subsystem is, An adjustable phase modulator and an additional apodizer within the optical path of the additional dual-frequency comb illumination beam—the additional apodizer generates one or more reference lobes of the additional dual-frequency comb illumination beam—; and An additional beam combiner for superimposing the sample light with one or more reference lobes of the additional dual-frequency comb illumination beam to generate an interference pattern on the detector. Includes more, A measurement system in which the above radio frequency signal includes phase scan data associated with scanning the phase of the additional dual-frequency comb illumination beam with the above adjustable phase modulator.
In Paragraph 13, A measurement system in which the measurement target includes a scatterometer overlay (SCOL) target, and at least a portion of the phase scan data is associated with the first-order diffraction of one or more off-axis illumination lobes by the sample.
In Paragraph 13, The above measurement target is one or more moirés A measurement system comprising a structure, wherein at least a portion of the phase scan data is associated with the first-order diffraction of one or more out-of-axis illumination lobes by the one or more moiré structures.
In a measurement system, Dual Frequency Comb Source - The above dual frequency comb source is, A first frequency comb source providing a first comb beam having a first repetition rate; A second frequency comb source providing a second comb beam having a second repetition rate; and One or more beam splitters for generating one or more dual-frequency comb illumination beams from the first comb beam and the second comb beam. Includes -; A beam combiner for combining the first comb beam and the second comb beam to form a dual-frequency comb illumination beam; An illumination subsystem comprising one or more optical elements configured to illuminate a sample with a dual-frequency comb illumination beam through an objective lens, and a collection subsystem comprising one or more additional optical elements for collecting sample light from the sample responding to the dual-frequency comb illumination beam with the objective lens; A detector in the pupil plane of the collection subsystem configured to capture a radio frequency signal based on the sample light; and A controller including one or more processors Includes, The above one or more processors execute program instructions, thereby causing the above one or more processors, Receiving the radio frequency signal from the detector; Extracting spectrum measurement data associated with the sample from the above radio frequency signal; and Generating one or more measurement values of the sample based on the spectrum measurement data A measurement system configured to enable the implementation of a measurement recipe by
In Paragraph 16, One or more of the above-mentioned measurements are, Overlay measurements, tilt measurements, and critical dimension measurements A measurement system comprising at least one of the following.
In Paragraph 16, The illumination subsystem comprises an illumination polarizer and a rotatable illumination phase plate in the illumination path of the dual-frequency comb illumination beam, and the illumination subsystem comprises a rotatable collection phase plate and an analyzer in the optical path of the sample light. Generating one or more measurement values of the sample based on the spectrum measurement data above is, Reconstructing data representing one or more Müller matrix elements associated with the sample based on the spectrum measurement data; and Generating one or more measurement values based on data representing one or more of the above-mentioned Müller matrix elements A measurement system that includes
In Paragraph 18, A measurement system in which at least a portion of the radio frequency signal is associated with the zeroth-order diffraction from the sample, and at least a portion of the data representing one or more Müller matrix elements is associated with the zeroth-order diffraction from the sample.
In Paragraph 18, The above lighting subsystem illuminates the in-die portion of the sample, and the measurement system comprises one or more measurement measurements including in-die measurements.

Description

Spectral angle measurement Cross-reference regarding related applications This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 63/536,703 filed September 6, 2023 [Title of invention: SPECTRAL ANGULAR METROLOGY; Inventors: Kevin Peterlinz, Andrew V. Hill, Shankar Krishnan, Yonatan Vaknin, Ido Dolev, Suryarayanan Ganesan, Chao Chang, Jongjin Kim, and David Zimdars], the full text of which is incorporated herein by reference. Technology field The present disclosure generally relates to spectrum measurement, and more specifically to spectrum measurement using a dual comb frequency source. Overlay metrology continues to serve as a Moore's Law enabler. However, to sustain this, an increasing number of sites per wafer are required for overlay monitoring and control to enable higher-order model corrections. Specifically, Correction Per Exposure (CPE) is increasingly utilized, requiring in-field target measurements, which ultimately increases the need for on-product target measurements. Therefore, there is a need to develop systems and methods to address the aforementioned limitations. Many advantages of the present disclosure can be better understood by those skilled in the art by referring to the accompanying drawings: FIG. 1a illustrates a block diagram of a dual comb spectroscopy (DCS) measurement system according to one or more embodiments of the present disclosure. FIG. 1b illustrates a schematic diagram of a DCS measurement system configured for spectral ellipsometry (SE) measurement according to one or more embodiments of the present disclosure. FIG. 1c illustrates a schematic diagram of a DCS measurement system configured for multispectral first-order diffraction measurement of a scattering overlay (SCOL) target according to one or more embodiments of the present disclosure. FIG. 1d illustrates a schematic diagram of a DCS measurement system configured for multispectral first-order diffraction measurement of measurement targets in a phase scanning configuration according to one or more embodiments of the present disclosure. FIG. 1e illustrates a schematic diagram of a DCS measurement system configured for multispectral moiré-based measurement of measurement targets in a phase scanning configuration according to one or more embodiments of the present disclosure. FIG. 2 is a side view of a SCOL overlay target suitable for scatterometer overlay measurement by a DCS measurement system according to one or more embodiments of the present disclosure. FIG. 3a is a plan view of a cell of a moiré overlay target having a moiré structure (304) according to one or more embodiments of the present disclosure. FIG. 3b is a side view of a single cell of the moiré overlay target in FIG. 3a on a substrate according to one or more embodiments of the present disclosure. FIG. 4 is a flowchart illustrating steps performed in a method for measurement based on dual comb spectroscopy according to one or more embodiments of the present disclosure. From now on, the content of the present invention as illustrated and disclosed in the attached drawings will be described in detail. The present disclosure has been illustrated and described particularly in relation to specific embodiments and specific features thereof. The embodiments described herein are to be considered illustrative rather than restrictive. It will be readily apparent to those skilled in the art that various changes and modifications of form and detail may be made without departing from the spirit and scope of the present disclosure. Embodiments of the present disclosure relate to a system and method for providing spectral measurements using dual-comb spectroscopy (DCS) techniques. In some embodiments, the DCS measurement system directs one or more lobes of a dual-frequency comb illumination beam toward a sample and generates one or more measurements from the associated sample light, and the dual-frequency comb illumination beam is formed from two frequency combs having different repetition rates. In this configuration, the two frequency combs generate bit signals in a detector that encodes optical spectroscopic data. In particular, optical spectroscopic data associated with the optical spectrometry of the sample can be retrieved through frequency analysis (e.g., Fourier transform analysis, etc.) of the radio frequency (RF) signal generated by the detector. Dual-comb spectroscopy is described in "Dual-comb spectroscopy" by Ian Coddington, Nathan Newbury, and William Swann (Optica 3, 414-426 (2016)); and Pique en Hensch T.W. (Picqu , N., H It is generally described in "Frequency comb spectroscopy" (Nature Photon 13, 146-157 (2019)) by nsch, TW); the full text of both is merged here by reference. It is considered herein that the system and method disclosed herein can support a wide range of metrological measurements using a single tool. In some embodiments, the DCS measurement system may generate spectral ellipsometer (SE) measure