Patents by Inventor Helen (Heng) Liu

Helen (Heng) Liu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11668557
    Abstract: An inspection system is disclosed. In one embodiment, the inspection system includes an interferometer sub-system configured to acquire an interferogram of a sample. The inspection system may further include a controller communicatively coupled to the interferometer sub-system. The controller is configured to: receive the interferogram from the interferometer sub-system; generate a phase map of the sample based on the received interferogram, wherein the phase map includes a plurality of pixels; select a sub-set of pixels of the plurality of pixels of the phase map to be used for phase unwrapping procedures; perform one or more phase unwrapping procedures on the sub-set of pixels of the phase map to generate an unwrapped phase map; and generate a surface height map of the sample based on the unwrapped phase map.
    Type: Grant
    Filed: May 14, 2021
    Date of Patent: June 6, 2023
    Assignee: KLA Corporation
    Inventors: Helen (Heng) Liu, Guoqing Zhang
  • Publication number: 20210270598
    Abstract: An inspection system is disclosed. In one embodiment, the inspection system includes an interferometer sub-system configured to acquire an interferogram of a sample. The inspection system may further include a controller communicatively coupled to the interferometer sub-system. The controller is configured to: receive the interferogram from the interferometer sub-system; generate a phase map of the sample based on the received interferogram, wherein the phase map includes a plurality of pixels; select a sub-set of pixels of the plurality of pixels of the phase map to be used for phase unwrapping procedures; perform one or more phase unwrapping procedures on the sub-set of pixels of the phase map to generate an unwrapped phase map; and generate a surface height map of the sample based on the unwrapped phase map.
    Type: Application
    Filed: May 14, 2021
    Publication date: September 2, 2021
    Inventors: Helen (Heng) Liu, Guoqing Zhang
  • Patent number: 11035665
    Abstract: An inspection system is disclosed. In one embodiment, the inspection system includes an interferometer sub-system configured to acquire an interferogram of a sample. The inspection system may further include a controller communicatively coupled to the interferometer sub-system. The controller is configured to: receive the interferogram from the interferometer sub-system; generate a phase map of the sample based on the received interferogram, wherein the phase map includes a plurality of pixels; select a sub-set of pixels of the plurality of pixels of the phase map to be used for phase unwrapping procedures; perform one or more phase unwrapping procedures on the sub-set of pixels of the phase map to generate an unwrapped phase map; and generate a surface height map of the sample based on the unwrapped phase map.
    Type: Grant
    Filed: November 19, 2019
    Date of Patent: June 15, 2021
    Assignee: KLA Corporation
    Inventors: Helen (Heng) Liu, GuoQing Zhang
  • Patent number: 11017520
    Abstract: An inspection system may include a controller coupled to a differential interference contrast imaging tool for generating images of a sample based on illumination with two sheared illumination beams. The controller may determine a first defect-induced phase shift based on a first set of images of a defect on the sample with a first selected illumination spectrum and two or more selected induced phase differences between the two sheared illumination beams, determine a second defect-induced phase shift based a second set of images of the defect with a second selected illumination spectrum and two or more selected induced phase differences between the two sheared illumination beams, and classify the defect as a metal or a non-metal based on a comparison of the first phase shift to the second phase shift.
    Type: Grant
    Filed: August 26, 2019
    Date of Patent: May 25, 2021
    Assignee: KLA Corporation
    Inventors: Andrew Zeng, Helen Heng Liu
  • Publication number: 20210033386
    Abstract: An inspection system is disclosed. In one embodiment, the inspection system includes an interferometer sub-system configured to acquire an interferogram of a sample. The inspection system may further include a controller communicatively coupled to the interferometer sub-system. The controller is configured to: receive the interferogram from the interferometer sub-system; generate a phase map of the sample based on the received interferogram, wherein the phase map includes a plurality of pixels; select a sub-set of pixels of the plurality of pixels of the phase map to be used for phase unwrapping procedures; perform one or more phase unwrapping procedures on the sub-set of pixels of the phase map to generate an unwrapped phase map; and generate a surface height map of the sample based on the unwrapped phase map.
    Type: Application
    Filed: November 19, 2019
    Publication date: February 4, 2021
    Inventors: Helen (Heng) Liu, GuoQing Zhang
  • Patent number: 10585049
    Abstract: A system includes a controller with one or more processors and memory configured to store one or more sets of program instructions. The one or more processors are configured to execute the one or more sets of program instructions. The one or more sets of program instructions are configured to cause the one or more processors to apply filtering to a semiconductor wafer map; separate the filtered semiconductor wafer map into a plurality of dies; generate a set of die comparison statistics for the plurality of dies; generate at least one excursion map by applying at least one inspection threshold to the set of die comparison statistics; and detect at least one excursion within the at least one excursion map.
    Type: Grant
    Filed: February 12, 2019
    Date of Patent: March 10, 2020
    Assignee: KLA-Tencor Corporation
    Inventors: Helen (Heng) Liu, Aye Aung, GuoQing Zhang
  • Publication number: 20200074617
    Abstract: An inspection system may include a controller coupled to a differential interference contrast imaging tool for generating images of a sample based on illumination with two sheared illumination beams. The controller may determine a first defect-induced phase shift based on a first set of images of a defect on the sample with a first selected illumination spectrum and two or more selected induced phase differences between the two sheared illumination beams, determine a second defect-induced phase shift based a second set of images of the defect with a second selected illumination spectrum and two or more selected induced phase differences between the two sheared illumination beams, and classify the defect as a metal or a non-metal based on a comparison of the first phase shift to the second phase shift.
    Type: Application
    Filed: August 26, 2019
    Publication date: March 5, 2020
    Inventors: Andrew Zeng, Helen Heng Liu
  • Publication number: 20190277777
    Abstract: A system includes a controller with one or more processors and memory configured to store one or more sets of program instructions. The one or more processors are configured to execute the one or more sets of program instructions. The one or more sets of program instructions are configured to cause the one or more processors to apply filtering to a semiconductor wafer map; separate the filtered semiconductor wafer map into a plurality of dies; generate a set of die comparison statistics for the plurality of dies; generate at least one excursion map by applying at least one inspection threshold to the set of die comparison statistics; and detect at least one excursion within the at least one excursion map.
    Type: Application
    Filed: February 12, 2019
    Publication date: September 12, 2019
    Inventors: Helen (Heng) Liu, Aye Aung, GuoQing Zhang