Patents by Inventor John Fielden
John Fielden 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).
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Publication number: 20230161221Abstract: 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: ApplicationFiled: December 22, 2022Publication date: May 25, 2023Inventors: Yung-Ho Alex Chuang, Yinying Xiao-Li, Elena Loginova, John Fielden, Baigang Zhang, Xuefeng Liu, Kelly Ann Weekley Mauser
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Publication number: 20230034635Abstract: 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: ApplicationFiled: July 11, 2022Publication date: February 2, 2023Inventors: John Fielden, Yung-Ho Alex Chuang
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Patent number: 11567391Abstract: 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: GrantFiled: December 18, 2021Date of Patent: January 31, 2023Assignee: KLA CorporationInventors: Yung-Ho Alex Chuang, Yinying Xiao-Li, Elena Loginova, John Fielden, Baigang Zhang, Xuefeng Liu, Kelly Ann Weekley Mauser
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Patent number: 11543732Abstract: 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: GrantFiled: December 16, 2021Date of Patent: January 3, 2023Assignee: KLA CorporationInventors: Yung-Ho Alex Chuang, Yinying Xiao-Li, Elena Loginova, John Fielden, Baigang Zhang
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Publication number: 20220399694Abstract: 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: ApplicationFiled: March 23, 2022Publication date: December 15, 2022Inventors: Yung-Ho Alex CHUANG, Yinying XIAO-LI, John FIELDEN, Baigang ZHANG
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Publication number: 20220381783Abstract: The invention relates to a method for identifying a cancer that is predicted to respond to treatment with a topoisomerase 1 (TOP1) inhibitor. The invention also extends to a method of treating cancer in a subject and a method of selecting a cancer patient for treatment with a cancer therapy. The invention further extends to use of cancer cells, such as primary colon cancer cells, as a biomarker for a patients response to treatment (insensitivity or sensitivity) with a particular chemotherapeutic agent, such as a TOP1 inhibitor.Type: ApplicationFiled: July 30, 2020Publication date: December 1, 2022Inventors: Kristijan RAMADAN, John FIELDEN, Tim MAUGHAN
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Publication number: 20220336180Abstract: 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: ApplicationFiled: July 6, 2022Publication date: October 20, 2022Inventors: Edgardo Garcia Berrios, J. Joseph Armstrong, Yinying Xiao-Li, John Fielden, Yung-Ho Alex Chuang
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Publication number: 20220268710Abstract: 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: ApplicationFiled: February 16, 2022Publication date: August 25, 2022Inventors: Xuefeng Liu, Jenn-Kuen Leong, Yung-Ho Alex Chuang, John Fielden
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Patent number: 11424117Abstract: 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: GrantFiled: May 17, 2021Date of Patent: August 23, 2022Assignee: KLA CorporationInventors: Yung-Ho Alex Chuang, Yinying Xiao-Li, Edgardo Garcia-Berrios, John Fielden
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Patent number: 11417492Abstract: 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: GrantFiled: September 14, 2020Date of Patent: August 16, 2022Assignee: KLA CorporationInventors: Edgardo Garcia Berrios, J. Joseph Armstrong, Yinying Xiao-Li, John Fielden, Yung-Ho Alex Chuang
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Publication number: 20220254829Abstract: 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: ApplicationFiled: December 7, 2021Publication date: August 11, 2022Inventors: Sisir Yalamanchili, John Fielden, Francisco Kole, Yung-Ho Alex Chuang
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Patent number: 11360032Abstract: Strontium tetraborate is used as an optical coating material for optical components utilized in semiconductor inspection and metrology systems to take advantage of its high refractive indices, high optical damage threshold and high microhardness in comparison to conventional optical materials. At least one layer of strontium tetraborate is formed on the light receiving surface of an optical component's substrate such that its thickness serves to increase or decrease the reflectance of the optical component. One or multiple additional coating layers may be placed on top of or below the strontium tetraborate layer, with the additional coating layers consisting of conventional optical materials. The thicknesses of the additional layers may be selected to achieve a desired reflectance of the optical component at specific wavelengths. The coated optical component is used in an illumination source or optical system utilized in a semiconductor inspection system, a metrology system or a lithography system.Type: GrantFiled: January 8, 2021Date of Patent: June 14, 2022Assignee: KLA CorporationInventors: Yung-Ho Alex Chuang, Yinying Xiao-Li, Elena Loginova, John Fielden
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Publication number: 20220136981Abstract: Strontium tetraborate can be used as an optical material. Strontium tetraborate exhibits high refractive indices, high optical damage threshold, and high microhardness. The transmission window of strontium tetraborate covers a very broad range of wavelengths, from 130 nm to 3200 nm, making the material particularly useful at VUV wavelengths. An optical component made of strontium tetraborate can be incorporated in an optical system, such as a semiconductor inspection system, a metrology system, or a lithography system. These optical components may include mirrors, lenses, lens arrays, prisms, beam splitters, windows, lamp cells or Brewster-angle optics.Type: ApplicationFiled: January 14, 2022Publication date: May 5, 2022Inventors: Yung-Ho Alex Chuang, Yinying Xiao-Li, Elena Loginova, John Fielden
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Publication number: 20220107544Abstract: 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: ApplicationFiled: December 16, 2021Publication date: April 7, 2022Inventors: Yung-Ho Alex Chuang, Yinying Xiao-Li, Elena Loginova, John Fielden, Baigang Zhang
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Patent number: 11255797Abstract: Strontium tetraborate can be used as an optical material. Strontium tetraborate exhibits high refractive indices, high optical damage threshold, and high microhardness. The transmission window of strontium tetraborate covers a very broad range of wavelengths, from 130 nm to 3200 nm, making the material particularly useful at VUV wavelengths. An optical component made of strontium tetraborate can be incorporated in an optical system, such as a semiconductor inspection system, a metrology system, or a lithography system. These optical components may include mirrors, lenses, lens arrays, prisms, beam splitters, windows, lamp cells or Brewster-angle optics.Type: GrantFiled: July 6, 2020Date of Patent: February 22, 2022Assignee: KLA CorporationInventors: Yung-Ho Alex Chuang, Yinying Xiao-Li, Elena Loginova, John Fielden
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Patent number: 11243175Abstract: A system may include illumination optics to direct an illumination beam to a sample at an off-axis angle, collection optics to collect scattered light from the sample, and a phase mask located at a first pupil plane to provide different phase shifts for light in two or more pupil regions of a collection area to reshape a point spread function of light scattered from one or more particles on a surface of the sample. The system may further include a polarization rotator located at a second pupil plane, where the polarization rotator provides a spatially-varying polarization rotation angle selected to rotate light scattered from the surface of the sample to a selected polarization angle, a polarizer to reject light polarized along the selected polarization angle, and a detector to generate a dark-field image of the sample based on light passed by the polarizer.Type: GrantFiled: February 12, 2021Date of Patent: February 8, 2022Assignee: KLA CorporationInventors: Xuefeng Liu, Jenn-Kuen Leong, Daniel Kavaldjiev, John Fielden
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Patent number: 11239048Abstract: An electron beam inspection system is disclosed, in accordance with one or more embodiments of the present disclosure. The inspection system may include an electron beam source configured to generate one or more primary electron beams. The inspection system may also include an electron-optical column including a set of electron-optical elements configured to direct the one or more primary electron beams to a sample. The inspection system may further include a detection assembly comprising: a scintillator substrate configured to collect electrons emanating from the sample, the scintillator substrate configured to generate optical radiation in response to the collected electrons; one or more light guides; one or more reflective surfaces configured to receive the optical radiation and direct the optical radiation along the one or more light guides; and one or more detectors configured to receive the optical radiation from the light guide.Type: GrantFiled: March 9, 2020Date of Patent: February 1, 2022Assignee: KLA CorporationInventors: Alan D. Brodie, Lawrence P. Muray, John Fielden
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Patent number: 11237455Abstract: 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 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 nonlinear crystal 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: GrantFiled: April 24, 2021Date of Patent: February 1, 2022Assignee: KLA CorporationInventors: Yung-Ho Alex Chuang, Yinying Xiao-li, Elena Loginova, John Fielden, Baigang Zhang
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Publication number: 20210389643Abstract: 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 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 nonlinear crystal 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: ApplicationFiled: April 24, 2021Publication date: December 16, 2021Inventors: Yung-Ho Alex Chuang, Yinying Xiao-li, Elena Loginova, John Fielden, Baigang Zhang
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Publication number: 20210320144Abstract: 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: ApplicationFiled: March 10, 2021Publication date: October 14, 2021Inventors: Abbas Haddadi, Sisir Yalamanchili, John Fielden, Yung-Ho Alex Chuang