Position measurement system, zeroing method, lithographic apparatus and device manufacturing method

    公开(公告)号:US10883816B2

    公开(公告)日:2021-01-05

    申请号:US16489439

    申请日:2018-02-06

    Abstract: A position measurement system configured to measure a position of an object, the system including: a displacement interferometer having a first capture range; a time-of-flight sensor having a second capture range that is larger than the first capture range and having an inaccuracy that is smaller than the first capture range; and a processing unit, wherein the position measurement system has a zeroing mode in which the processing unit is configured to determine a coarse position of the object within the second capture range based on an output from the time-of-flight sensor, and in which the processing unit is configured to determine a fine position of the object based on the determined coarse position and an output from the displacement interferometer.

    Method for calibration of an optical measurement system and optical measurement system

    公开(公告)号:US12270647B2

    公开(公告)日:2025-04-08

    申请号:US17920751

    申请日:2021-03-22

    Abstract: The invention provides a method for calibration of an optical measurement system, which may be a heterodyne interferometer system, wherein a first optical axis and a second optical axis have a different optical path length, the method comprises: ∘measuring a first measurement value along the first optical axis using a first measurement beam, ∘measuring a second measurement value along the second optical axis using a second measurement beam, ∘changing a wavelength of the first measurement beam and the second measurement beam, ∘measuring a further first measurement value along the first optical axis using the first measurement beam with changed wavelength, measuring a further second measurement value along the second optical axis using the second measurement beam with changed wavelength, ∘determining a cyclic error of the optical measurement system on the basis of the measured values, and ∘storing a corrective value based on the cyclic error.

    Compact dual pass interferometer for a plane mirror interferometer

    公开(公告)号:US12270644B2

    公开(公告)日:2025-04-08

    申请号:US18023482

    申请日:2021-07-20

    Abstract: A compact dual pass interferometer for a plane mirror interferometer configured to receive an input radiation beam from a light source. An optical component has a partially reflective surface arranged to reflect a first portion of the input radiation beam to follow a first optical path directed towards an output terminal and further arranged to transmit a second portion of the input radiation beam to follow a second optical path, directed towards a first location on a reflective target surface and back to the partially reflective surface, then to a second location on the reflective target surface and back to the partially reflective surface, whereupon the second optical path is directed through the partially reflective surface to be recombined with the first optical path to provide a recombined optical path configured to provide an output radiation beam. The output terminal configured to deliver the output radiation beam to a detector.

    Stage system and lithographic apparatus

    公开(公告)号:US11556066B2

    公开(公告)日:2023-01-17

    申请号:US17434309

    申请日:2020-01-30

    Abstract: The invention provides a stage system comprising a stage (ST) which is movable in respect of a reference structure. One of the stage and the reference structure comprises a reflective surface (REFS). An optical position sensor (IF1) is arranged at the other one of the stage and the reference structure and is configured to determine a position of the reflective surface relative to the optical position sensor. An optical shape sensor (IF2) is configured to determine a shape of the reflective surface. The stage system further comprises a position measurement controller configured to derive a stage position of the stage from the position of the reflective surface relative to the optical position sensor and from the shape of the reflective surface as determined by the optical shape sensor.

    Wavelength tracking system, method to calibrate a wavelength tracking system, lithographic apparatus, method to determine an absolute position of a movable object, and interferometer system

    公开(公告)号:US11525737B2

    公开(公告)日:2022-12-13

    申请号:US16965753

    申请日:2019-01-15

    Abstract: The invention provides a wavelength tracking system comprising a wavelength tracking unit and an interferometer system. The wavelength tracking unit has reflection surfaces at stabile positions providing a first reflection path with a first path length and a second reflection path with a second path length. The first path length is substantially larger than the second path length. The interferometer system comprises: a beam splitter to split a light beam in a first measurement beam and a second measurement beam; at least one optic element to guide the first measurement beam, at least partially, along the first reflection path and the second measurement beam, at least partially, along the second reflection path; a first light sensor arranged at an end of the first reflection path to receive the first measurement beam and to provide a first sensor signal on the basis of the first measurement beam; a second light sensor arranged at an end of the second reflection path to receive the second measurement beam and to provide a second sensor signal on the basis of the second measurement beam; and a processing unit to determine a wavelength or change in wavelength on the basis of the first sensor signal and the second sensor signal.

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