公开(公告)号：US11971665B2

公开(公告)日：2024-04-30

申请号：US17432019

申请日：2020-02-06

Applicant: ASML Holding N.V.

Inventor： Joshua Adams ,  Yuxiang Lin ,  Krishanu Shome ,  Gerrit Johannes Nijmeijer ,  Igor Matheus Petronella Aarts

IPC: G03F9/00

CPC classification number: G03F9/7065 ,  G03F9/7076 ,  G03F9/7088

Abstract: An alignment method includes directing an illumination beam with a first polarization state to form a diffracted beam with a second polarization state from an alignment target, and passing the diffracted beam through a polarization analyzer. The alignment method further includes measuring a polarization state of the diffracted beam and determining a location of the alignment target from the measured polarization state relative to its initial polarization state. The alignment target includes a plurality of diffraction gratings with a single pitch and two or more duty cycles, wherein the pitch is smaller than a wavelength of the illumination beam, and the location of the alignment target corresponds to the duty cycle of the diffraction grating.

公开(公告)号：US11899380B2

公开(公告)日：2024-02-13

申请号：US17770575

申请日：2020-09-28

Applicant: ASML Holding N.V.

Inventor： Krishanu Shome ,  Igor Matheus Petronella Aarts ,  Junwon Lee

IPC: G03F7/20 ,  G03F9/00 ,  G01J9/02

CPC classification number: G03F9/7046 ,  G01J9/02 ,  G03F9/7049 ,  G03F9/7088 ,  G01J2009/028

Abstract: An apparatus for and method of sensing alignment marks in which a self-referencing interferometer based sensor outputs standing images of the alignment marks and camera device is used to capture the images as output by the sensor and a detector is used to obtain phase information about the alignment marks from the images as output by the sensor.

公开(公告)号：US11513446B2

公开(公告)日：2022-11-29

申请号：US17297691

申请日：2019-11-26

Applicant: ASML Holding N.V.

Inventor： Greger Göte Andersson ,  Krishanu Shome ,  Zahrasadat Dastouri ,  Igor Matheus Petronella Aarts

IPC: G03F9/00 ,  G03F7/20

Abstract: A method of applying a measurement correction includes determining an orthogonal subspace used to characterize a first principal component of the measurement and a second principal component of the measurement, and rotating the orthogonal subspace by a first angle such that the first principle component rotates to become a first factor vector and the second principle component rotates to become a second factor vector. An asymmetry vector is generated by rotating the second factor vector by a second angle, where the asymmetry vector and the first factor vector define a non-orthogonal subspace. An asymmetry contribution is determined in the measurement based on the projection of the measurement onto the first factor vector in the non-orthogonal subspace. The method also includes subtracting the asymmetry contribution from the measurement.

公开(公告)号：US10732524B2

公开(公告)日：2020-08-04

申请号：US15746164

申请日：2016-07-19

Applicant: ASML Holding N.V.

Inventor： Krishanu Shome ,  Justin Lloyd Kreuzer

IPC: G02B5/30 ,  G03F9/00 ,  G02B27/09

Abstract: An optical system for improving alignment measurement accuracy is discussed. The optical system includes first and second optical elements. The first optical element may be configured to change a first beam having a first polarization state into a second beam having a second polarization state. The second optical element may be configured to provide total internal reflection of the second beam and to change the second beam into a third beam having a third polarization state. The first, second, and third polarization states may be different from each other.

公开(公告)号：US20190243254A1

公开(公告)日：2019-08-08

申请号：US16389208

申请日：2019-04-19

Applicant: ASML Holding N.V.

Inventor： Krishanu Shome ,  Justin Lloyd Kreuzer

IPC: G03F7/20 ,  G03F9/00

Abstract: A metrology system includes a radiation source that generates light, an optical modulation unit, a reflector, an interferometer, and a detector. The optical modulating unit temporally separates a first polarization mode of the light from a second polarization mode of the light. The reflector directs the light towards a substrate. The interferometer interferes the diffracted light from a pattern on the substrate, or reflected light from the substrate, and produces output light from the interference. The detector receives the output light from the interferometer. The first and second polarization modes of the output light are temporally separated at the detector. Additionally, an optical rotator can be configured to receive the first polarized light and rotate the polarization of the first polarized light.

公开(公告)号：US10338481B2

公开(公告)日：2019-07-02

申请号：US15766427

申请日：2016-10-06

Applicant: ASML Holding N.V.

Inventor： Krishanu Shome ,  Justin Lloyd Kreuzer

IPC: G03F9/00 ,  G03F7/20

Abstract: A metrology system includes a radiation source that generates light, an optical modulation unit, a reflector, an interferometer, and a detector. The optical modulating unit temporally separates a first polarization mode of the light from a second polarization mode of the light. The reflector directs the light towards a substrate. The interferometer interferes the diffracted light from a pattern on the substrate, or reflected light from the substrate, and produces output light from the interference. The detector receives the output light from the interferometer. The first and second polarization modes of the output light are temporally separated at the detector.