Patents by Inventor Yung-Ho Alex Chuang

Yung-Ho Alex Chuang 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).

  • Publication number: 20240063248
    Abstract: An image sensor is fabricated by first heavily p-type doping the thin top monocrystalline silicon substrate of an SOI wafer, then forming a relatively lightly p-doped epitaxial layer on a top surface of the top silicon substrate, where p-type doping levels during these two processes are controlled to produce a p-type dopant concentration gradient in the top silicon substrate. Sensing (circuit) elements and associated metal interconnects are fabricated on the epitaxial layer, then the handling substrate and oxide layer of the SOI wafer are at least partially removed to expose a lower surface of either the top silicon substrate or the epitaxial layer, and then a pure boron layer is formed on the exposed lower surface. The p-type dopant concentration gradient monotonically decreases from a maximum level near the top-silicon/epitaxial-layer interface to a minimum concentration level at the epitaxial layer's upper surface.
    Type: Application
    Filed: November 5, 2023
    Publication date: February 22, 2024
    Applicant: KLA Corporation
    Inventors: Abbas Haddadi, Sisir Yalamanchili, John Fielden, Yung-Ho Alex Chuang
  • Patent number: 11899338
    Abstract: A nonlinear crystal including stacked strontium tetraborate SrB4O7 (SBO) crystal plates that are cooperatively configured to create a periodic structure for quasi-phase-matching (QPM) is used in the final frequency doubling stage of a laser assembly to generate laser output light having a wavelength in the range of about 180 nm to 200 nm. One or more fundamental laser beams are frequency doubled, down-converted and/or summed using one or more frequency conversion stages to generate an intermediate frequency light with a corresponding wavelength in the range of about 360 nm to 400 nm, and then the final frequency converting stage utilizes the nonlinear crystal to double the frequency of the intermediate frequency light to generate the desired laser output light at high power. Methods, inspection systems, lithography systems and cutting systems incorporating the laser assembly are also described.
    Type: Grant
    Filed: November 21, 2022
    Date of Patent: February 13, 2024
    Assignee: KLA Corporation
    Inventors: Yung-Ho Alex Chuang, Kelly Mauser, Baigang Zhang, Xuefeng Liu, John Fielden, Yinying Xiao-Li, Elena Loginova
  • Patent number: 11879853
    Abstract: An inspection system may include an illumination source to generate an illumination beam, illumination optics to direct the illumination beam to a sample at an off-axis angle along an illumination direction, and collection optics to collect scattered light from the sample in a dark-field mode, where the scattered light from the sample includes surface haze associated with light scattered from a surface of the sample, and where at least a at least a portion of the surface haze has elliptical polarizations. The system may further include pupil-plane optics to convert the polarizations of the surface haze across the pupil to linear polarization that is aligned parallel to a selected haze orientation direction. The system may include a linear polarizer to reject the surface haze aligned parallel to this haze orientation direction and a detector to generate a dark-field image of the sample based on light passed by the linear polarizer.
    Type: Grant
    Filed: February 16, 2022
    Date of Patent: January 23, 2024
    Assignee: KLA Corporation
    Inventors: Xuefeng Liu, Jenn-Kuen Leong, Yung-Ho Alex Chuang, John Fielden
  • Patent number: 11848350
    Abstract: An image sensor is fabricated by first heavily p-type doping the thin top monocrystalline silicon substrate of an SOI wafer, then forming a relatively lightly p-doped epitaxial layer on a top surface of the top silicon substrate, where p-type doping levels during these two processes are controlled to produce a p-type dopant concentration gradient in the top silicon substrate. Sensing (circuit) elements and associated metal interconnects are fabricated on the epitaxial layer, then the handling substrate and oxide layer of the SOI wafer are at least partially removed to expose a lower surface of either the top silicon substrate or the epitaxial layer, and then a pure boron layer is formed on the exposed lower surface. The p-type dopant concentration gradient monotonically decreases from a maximum level near the top-silicon/epitaxial-layer interface to a minimum concentration level at the epitaxial layer's upper surface.
    Type: Grant
    Filed: March 10, 2021
    Date of Patent: December 19, 2023
    Assignee: KLA Corporation
    Inventors: Abbas Haddadi, Sisir Yalamanchili, John Fielden, Yung-Ho Alex Chuang
  • Patent number: 11815784
    Abstract: A nonlinear crystal grating assembly including two integral nonlinear crystal grating structures having inverted crystal axes and having parallel spaced-apart mesas with predetermined mesa widths arranged such that, when assembled in an interdigitated configuration, the mesas of the two grating structures form an alternating grating pattern that is aligned with a propagation direction of input light, thereby creating a periodic structure for quasi-phase-matching (QPM). The nonlinear crystal grating structures are formed using strontium tetraborate, lithium triborate or another nonlinear crystal material. The nonlinear crystal grating assembly is utilized in a laser assembly in which fundamental wavelengths are doubled and/or summed using intermediate frequency conversion stages, and then a final frequency converting stage utilizes the nonlinear crystal grating assembly to double or sum one or more intermediate light beam frequencies to generate laser output light at high power and photon energy levels.
    Type: Grant
    Filed: December 22, 2022
    Date of Patent: November 14, 2023
    Assignee: KLA Corporation
    Inventors: Yung-Ho Alex Chuang, Yinying Xiao-Li, Elena Loginova, John Fielden, Baigang Zhang, Xuefeng Liu, Kelly Ann Weekley Mauser
  • Publication number: 20230298847
    Abstract: An electron gun for an electron microscope or similar device includes a field emitter cathode having a field emitter protrusion extending from the output surface of a monocrystalline silicon substrate, and electrodes configured to enhance the emission of electrons from a tip portion of the field emitter protrusion to generate a primary electron beam. A contiguous TiN layer is disposed directly on at least the tip portion of the field emitter protrusion using a process that minimizes oxidation and defects in the TiN layer.
    Type: Application
    Filed: March 16, 2023
    Publication date: September 21, 2023
    Inventors: Yung-Ho Alex Chuang, Yinying Xiao-Li, Edgardo García Berríos, John Fielden, Lavinia Ghirardini, Masayoshi Nagao
  • Patent number: 11719652
    Abstract: Methods and systems for realizing a high radiance x-ray source based on a high density electron emitter array are presented herein. The high radiance x-ray source is suitable for high throughput x-ray metrology and inspection in a semiconductor fabrication environment. The high radiance X-ray source includes an array of electron emitters that generate a large electron current focused over a small anode area to generate high radiance X-ray illumination light. In some embodiments, electron current density across the surface of the electron emitter array is at least 0.01 Amperes/mm2, the electron current is focused onto an anode area with a dimension of maximum extent less than 100 micrometers, and the spacing between emitters is less than 5 micrometers. In another aspect, emitted electrons are accelerated from the array to the anode with a landing energy less than four times the energy of a desired X-ray emission line.
    Type: Grant
    Filed: January 27, 2021
    Date of Patent: August 8, 2023
    Assignee: KLA Corporation
    Inventors: Yung-Ho Alex Chuang, John Fielden
  • Patent number: 11715615
    Abstract: A light modulated electron source utilizes a photon-beam source to modulate the emission current of an electron beam emitted from a silicon-based field emitter. The field emitter's cathode includes a protrusion fabricated on a silicon substrate and having an emission tip covered by a coating layer. An extractor generates an electric field that attracts free electrons toward the emission tip for emission as part of the electron beam. The photon-beam source generates a photon beam including photons having an energy greater than the bandgap of silicon, and includes optics that direct the photon beam onto the emission tip, whereby each absorbed photon creates a photo-electron that combines with the free electrons to enhance the electron beam's emission current. A controller modulates the emission current by controlling the intensity of the photon beam applied to the emission tip. A monitor measures the electron beam and provides feedback to the controller.
    Type: Grant
    Filed: July 6, 2022
    Date of Patent: August 1, 2023
    Assignee: KLA Corporation
    Inventors: Edgardo Garcia Berrios, J. Joseph Armstrong, Yinying Xiao-Li, John Fielden, Yung-Ho Alex Chuang
  • Publication number: 20230185158
    Abstract: A nonlinear crystal including stacked strontium tetraborate SrB4O7 (SBO) crystal plates that are cooperatively configured to create a periodic structure for quasi-phase-matching (QPM) is used in the final frequency doubling stage of a laser assembly to generate laser output light having a wavelength in the range of about 180 nm to 200 nm. One or more fundamental laser beams are frequency doubled, down-converted and/or summed using one or more frequency conversion stages to generate an intermediate frequency light with a corresponding wavelength in the range of about 360 nm to 400 nm, and then the final frequency converting stage utilizes the nonlinear crystal to double the frequency of the intermediate frequency light to generate the desired laser output light at high power. Methods, inspection systems, lithography systems and cutting systems incorporating the laser assembly are also described.
    Type: Application
    Filed: November 21, 2022
    Publication date: June 15, 2023
    Inventors: Yung-Ho Alex Chuang, Kelly Mauser, Baigang Zhang, Xuefeng Liu, John Fielden, Yinying Xiao-Li, Elena Loginova
  • Patent number: 11662646
    Abstract: Systems and methods for measuring or inspecting semiconductor structures using broadband infrared radiation are disclosed. The system may include an illumination source comprising a pump source configured to generate pump light and a nonlinear optical (NLO) assembly configured to generate broadband IR radiation in response to the pump light. The system may also include a detector assembly and a set of optics configured to direct the IR radiation onto a sample and direct a portion of the IR radiation reflected and/or scattered from the sample to the detector assembly.
    Type: Grant
    Filed: October 26, 2017
    Date of Patent: May 30, 2023
    Assignee: KLA Corporation
    Inventors: Yung-Ho Alex Chuang, Vahid Esfandyarpour, John Fielden, Baigang Zhang, Yinying Xiao Li
  • Publication number: 20230161221
    Abstract: A nonlinear crystal grating assembly including two integral nonlinear crystal grating structures having inverted crystal axes and having parallel spaced-apart mesas with predetermined mesa widths arranged such that, when assembled in an interdigitated configuration, the mesas of the two grating structures form an alternating grating pattern that is aligned with a propagation direction of input light, thereby creating a periodic structure for quasi-phase-matching (QPM). The nonlinear crystal grating structures are formed using strontium tetraborate, lithium triborate or another nonlinear crystal material. The nonlinear crystal grating assembly is utilized in a laser assembly in which fundamental wavelengths are doubled and/or summed using intermediate frequency conversion stages, and then a final frequency converting stage utilizes the nonlinear crystal grating assembly to double or sum one or more intermediate light beam frequencies to generate laser output light at high power and photon energy levels.
    Type: Application
    Filed: December 22, 2022
    Publication date: May 25, 2023
    Inventors: Yung-Ho Alex Chuang, Yinying Xiao-Li, Elena Loginova, John Fielden, Baigang Zhang, Xuefeng Liu, Kelly Ann Weekley Mauser
  • Publication number: 20230034635
    Abstract: An amorphous layer is used as a protective coating for hygroscopic nonlinear optical crystals. The amorphous layer consists of one or more alkali metal borates and/or alkali earth metal borates. The amorphous layer slows or prevents water and/or oxygen from diffusing into the hygroscopic nonlinear optical crystal, thus simplifying handling, storage and operating environmental requirements. One or multiple additional coating layers may be placed on top of the amorphous layer, with the additional coating layers including conventional optical materials. The thicknesses of the amorphous layer and/or additional layers may be chosen to reduce reflectance of the optical component at one or more specific wavelengths. The coated nonlinear optical crystal is used in an illumination source utilized in a semiconductor inspection system, a metrology system, or a lithography system.
    Type: Application
    Filed: July 11, 2022
    Publication date: February 2, 2023
    Inventors: John Fielden, Yung-Ho Alex Chuang
  • Patent number: 11567391
    Abstract: A nonlinear crystal grating assembly including two integral nonlinear crystal grating structures having inverted crystal axes and having parallel spaced-apart mesas with predetermined mesa widths arranged such that, when assembled in an interdigitated configuration, the mesas of the two grating structures form an alternating grating pattern that is aligned with a propagation direction of input light, thereby creating a periodic structure for quasi-phase-matching (QPM). The nonlinear crystal grating structures are formed using strontium tetraborate, lithium triborate or another nonlinear crystal material. The nonlinear crystal grating assembly is utilized in a laser assembly in which fundamental wavelengths are doubled and/or summed using intermediate frequency conversion stages, and then a final frequency converting stage utilizes the nonlinear crystal grating assembly to double or sum one or more intermediate light beam frequencies to generate laser output light at high power and photon energy levels.
    Type: Grant
    Filed: December 18, 2021
    Date of Patent: January 31, 2023
    Assignee: KLA Corporation
    Inventors: Yung-Ho Alex Chuang, Yinying Xiao-Li, Elena Loginova, John Fielden, Baigang Zhang, Xuefeng Liu, Kelly Ann Weekley Mauser
  • Patent number: 11543732
    Abstract: An optical element includes Strontium tetraborate SrB4O7 (SBO) crystal plates that are cooperatively configured to create a periodic structure for quasi-phase-matching (QPM) is used in the final frequency converting stage of a laser assembly to generate laser output light having a wavelength in the range of 125 nm to 183 nm. One or more fundamental light beams having fundamental wavelengths between 1 and 1.1 ?m are doubled and/or summed using multiple intermediate frequency conversion stages to generate one or more intermediate light beam frequencies (e.g., second through eighth harmonics, or sums thereof), and then the final frequency converting stage utilizes the optical element to either double a single intermediate light beam frequency or to sum two intermediate light beam frequencies to generate the desired laser output light at high power and photon energy levels. A method and inspection system incorporating the laser assembly is also described.
    Type: Grant
    Filed: December 16, 2021
    Date of Patent: January 3, 2023
    Assignee: KLA Corporation
    Inventors: Yung-Ho Alex Chuang, Yinying Xiao-Li, Elena Loginova, John Fielden, Baigang Zhang
  • Publication number: 20220399694
    Abstract: A tunable laser assembly uses a fundamental wavelength between 1 ?m and 1.1 ?m to alternately generate laser output light at two or more output wavelengths within the range of 184 nm to 200 nm by directing the fundamental light through different regions of a fan-out periodically poled nonlinear crystal to generate corresponding different down-converted signals, and using different nonlinear summing crystals to mix the different down-converted signals with a fifth harmonic of the fundamental wavelength. Each nonlinear summing crystal has a crystal axis aligned at an angle relative to the light propagation direction to facilitate the efficient transmission and summing of the fifth harmonic with an associated down-converted signal.
    Type: Application
    Filed: March 23, 2022
    Publication date: December 15, 2022
    Inventors: Yung-Ho Alex CHUANG, Yinying XIAO-LI, John FIELDEN, Baigang ZHANG
  • Publication number: 20220336180
    Abstract: A light modulated electron source utilizes a photon-beam source to modulate the emission current of an electron beam emitted from a silicon-based field emitter. The field emitter's cathode includes a protrusion fabricated on a silicon substrate and having an emission tip covered by a coating layer. An extractor generates an electric field that attracts free electrons toward the emission tip for emission as part of the electron beam. The photon-beam source generates a photon beam including photons having an energy greater than the bandgap of silicon, and includes optics that direct the photon beam onto the emission tip, whereby each absorbed photon creates a photo-electron that combines with the free electrons to enhance the electron beam's emission current. A controller modulates the emission current by controlling the intensity of the photon beam applied to the emission tip. A monitor measures the electron beam and provides feedback to the controller.
    Type: Application
    Filed: July 6, 2022
    Publication date: October 20, 2022
    Inventors: Edgardo Garcia Berrios, J. Joseph Armstrong, Yinying Xiao-Li, John Fielden, Yung-Ho Alex Chuang
  • Publication number: 20220268710
    Abstract: An inspection system may include an illumination source to generate an illumination beam, illumination optics to direct the illumination beam to a sample at an off-axis angle along an illumination direction, and collection optics to collect scattered light from the sample in a dark-field mode, where the scattered light from the sample includes surface haze associated with light scattered from a surface of the sample, and where at least a at least a portion of the surface haze has elliptical polarizations. The system may further include pupil-plane optics to convert the polarizations of the surface haze across the pupil to linear polarization that is aligned parallel to a selected haze orientation direction. The system may include a linear polarizer to reject the surface haze aligned parallel to this haze orientation direction and a detector to generate a dark-field image of the sample based on light passed by the linear polarizer.
    Type: Application
    Filed: February 16, 2022
    Publication date: August 25, 2022
    Inventors: Xuefeng Liu, Jenn-Kuen Leong, Yung-Ho Alex Chuang, John Fielden
  • Patent number: 11424117
    Abstract: A broadband ultraviolet illumination source for a characterization system is disclosed. The broadband ultraviolet illumination source includes an enclosure having one or more walls, the enclosure configured to contain a gas, and a plasma discharge device based on a graphene-dielectric-semiconductor (GOS) planar-type structure. The GOS structure includes a silicon substrate having a top surface, a dielectric layer disposed on the top surface of the silicon substrate, and at least one layer of graphene disposed on a top surface of the dielectric layer. A metal contact may be formed on the top surface of the graphene layer. The GOS structure has several advantages for use in an illumination source, such as low operating voltage (below 50 V), planar surface electron emission, and compatibility with standard semiconductor processes. The broadband ultraviolet illumination source further includes electrodes placed inside the enclosure or magnets placed outside the enclosure to increase the current density.
    Type: Grant
    Filed: May 17, 2021
    Date of Patent: August 23, 2022
    Assignee: KLA Corporation
    Inventors: Yung-Ho Alex Chuang, Yinying Xiao-Li, Edgardo Garcia-Berrios, John Fielden
  • Patent number: 11417492
    Abstract: A light modulated electron source utilizes a photon-beam source to modulate the emission current of an electron beam emitted from a silicon-based field emitter. The field emitter's cathode includes a protrusion fabricated on a silicon substrate and having an emission tip covered by a coating layer. An extractor generates an electric field that attracts free electrons toward the emission tip for emission as part of the electron beam. The photon-beam source generates a photon beam including photons having an energy greater than the bandgap of silicon, and includes optics that direct the photon beam onto the emission tip, whereby each absorbed photon creates a photo-electron that combines with the free electrons to enhance the electron beam's emission current. A controller modulates the emission current by controlling the intensity of the photon beam applied to the emission tip. A monitor measures the electron beam and provides feedback to the controller.
    Type: Grant
    Filed: September 14, 2020
    Date of Patent: August 16, 2022
    Assignee: KLA Corporation
    Inventors: Edgardo Garcia Berrios, J. Joseph Armstrong, Yinying Xiao-Li, John Fielden, Yung-Ho Alex Chuang
  • Publication number: 20220254829
    Abstract: Back-illuminated DUV/VUV/EUV radiation or charged particle image sensors are fabricated using a method that utilizes a plasma atomic layer deposition (plasma ALD) process to generate a thin pinhole-free pure boron layer over active sensor areas. Circuit elements are formed on a semiconductor membrane's frontside surface, and then an optional preliminary hydrogen plasma cleaning process is performed on the membrane's backside surface. The plasma ALD process includes performing multiple plasma ALD cycles, with each cycle including forming an adsorbed boron precursor layer during a first cycle phase, and then generating a hydrogen plasma to convert the precursor layer into an associated boron nanolayer during a second cycle phase. Gasses are purged from the plasma ALD process chamber after each cycle phase. The plasma ALD cycles are repeated until the resulting stack of boron nanolayers has a cumulative stack height (thickness) that is equal to a selected target thickness.
    Type: Application
    Filed: December 7, 2021
    Publication date: August 11, 2022
    Inventors: Sisir Yalamanchili, John Fielden, Francisco Kole, Yung-Ho Alex Chuang