Patents by Inventor Mohammed Tahmassebpur

Mohammed Tahmassebpur 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: 10953441
    Abstract: The present invention provides a local clean microenvironment near optical surfaces of an extreme ultraviolet (EUV) optical assembly maintained in a vacuum process chamber and configured for EUV lithography, metrology, or inspection. The system includes one or more EUV optical assemblies including at least one optical element with an optical surface, a supply of cleaning gas stored remotely from the one or more optical assemblies and a gas delivery unit comprising: a plenum chamber, one or more gas delivery lines connecting the supply of gas to the plenum chamber, one or more delivery nozzles configured to direct cleaning gas from the plenum chamber to a portion of the EUV assembly, and one or more collection nozzles for removing gas from the EUV optical assembly and the vacuum process chamber.
    Type: Grant
    Filed: April 5, 2013
    Date of Patent: March 23, 2021
    Assignee: KLA Corporation
    Inventors: Gildardo Delgado, Francis Chilese, Rudy F. Garcia, Mohammed Tahmassebpur, Salam Harb
  • Patent number: 10388489
    Abstract: A scanning electron microscopy (SEM) system includes a plurality of electron-optical columns and a plurality of electron beam sources. The electron beam sources include an emitter including one or more emitter tips configured to generate one or more electron beams of a plurality of electron beams. The electron beam sources include a stack of one or more positioners configured to adjust a position of the emitter based on one or more measurements of the electron beam generated by the emitter. The emitter is configured to scan the one or more electron beams across an area surrounding a bore of an electron-optical column of the plurality of electron-optical columns. The electron beam source array includes a carrier plate and a source tower. The source tower is configured to adjust a position of the plurality of electron beam sources relative to a position of the plurality of electron-optical columns.
    Type: Grant
    Filed: February 2, 2018
    Date of Patent: August 20, 2019
    Assignee: KLA-Tencor Corporation
    Inventor: Mohammed Tahmassebpur
  • Patent number: 10211021
    Abstract: A permanent-magnet particle beam apparatus and method incorporating a non-magnetic portion for tunability are provided. The permanent-magnet particle beam apparatus includes a particle beam emitter that emits a charged particle beam, and includes a set of permanent magnets forming a magnetic field for controlling condensing of the charged particle beam. The permanent-magnet particle beam apparatus further includes a non-magnetic electrical conductor component situated with the set of permanent magnets to control a kinetic energy of the charged particle beam moving through the magnetic field.
    Type: Grant
    Filed: February 9, 2017
    Date of Patent: February 19, 2019
    Assignee: KLA-Tencor Corporation
    Inventors: Tomas Plettner, John David Gerling, Mohammed Tahmassebpur
  • Publication number: 20180240640
    Abstract: A scanning electron microscopy (SEM) system includes a plurality of electron-optical columns and a plurality of electron beam sources. The electron beam sources include an emitter including one or more emitter tips configured to generate one or more electron beams of a plurality of electron beams. The electron beam sources include a stack of one or more positioners configured to adjust a position of the emitter based on one or more measurements of the electron beam generated by the emitter. The emitter is configured to scan the one or more electron beams across an area surrounding a bore of an electron-optical column of the plurality of electron-optical columns. The electron beam source array includes a carrier plate and a source tower. The source tower is configured to adjust a position of the plurality of electron beam sources relative to a position of the plurality of electron-optical columns.
    Type: Application
    Filed: February 2, 2018
    Publication date: August 23, 2018
    Inventor: Mohammed Tahmassebpur
  • Patent number: 9879684
    Abstract: An apparatus for shielding a controlled pressure environment, including a shield assembly with: a gate disc arranged for location in a chamber and including a first continuous surface facing an opening in the chamber and including an outer circumference extending past the opening in a radial direction orthogonal to a longitudinal axis passing through the chamber and the opening; and an at least one actuator arranged to displace the gate disc in an axial direction parallel to the longitudinal axis. The opening is arranged for connection to an inlet of a vacuum pump. In an example embodiment, the thermal system attains and maintains thermal equilibrium in the chamber and/or to shields the chamber from unwanted thermal affects by heating or cooling the gate disc to offset cooling or heat generated by the vacuum pump. For example, the gate disc is cooled to offset heat generated by a turbo-molecular pump.
    Type: Grant
    Filed: September 10, 2013
    Date of Patent: January 30, 2018
    Assignee: KLA-Tencor Corporation
    Inventors: Mohammed Tahmassebpur, Salam Harb
  • Patent number: 9874512
    Abstract: A computer-implemented method for determining an optimized purge gas flow in a semi-conductor inspection metrology or lithography apparatus, comprising receiving a permissible contaminant mole fraction, a contaminant outgassing flow rate associated with a contaminant, a contaminant mass diffusivity, an outgassing surface length, a pressure, a temperature, a channel height, and a molecular weight of a purge gas, calculating a flow factor based on the permissible contaminant mole fraction, the contaminant outgassing flow rate, the channel height, and the outgassing surface length, comparing the flow factor to a predefined maximum flow factor value, calculating a minimum purge gas velocity and a purge gas mass flow rate from the flow factor, the contaminant mass diffusivity, the pressure, the temperature, and the molecular weight of the purge gas, and introducing the purge gas into the semi-conductor inspection metrology or lithography apparatus with the minimum purge gas velocity and the purge gas flow rate.
    Type: Grant
    Filed: August 22, 2014
    Date of Patent: January 23, 2018
    Assignees: KLA-Tencor Corporation, National Technology & Engineering Solutions of Sandia, LLC
    Inventors: Gildardo Delgado, Terry Johnson, Marco Arienti, Salam Harb, Lennie Klebanoff, Rudy Garcia, Mohammed Tahmassebpur, Sarah Scott
  • Publication number: 20170294286
    Abstract: A permanent-magnet particle beam apparatus and method incorporating a non-magnetic portion for tunability are provided. The permanent-magnet particle beam apparatus includes a particle beam emitter that emits a charged particle beam, and includes a set of permanent magnets forming a magnetic field for controlling condensing of the charged particle beam. The permanent-magnet particle beam apparatus further includes a non-magnetic electrical conductor component situated with the set of permanent magnets to control a kinetic energy of the charged particle beam moving through the magnetic field.
    Type: Application
    Filed: February 9, 2017
    Publication date: October 12, 2017
    Inventors: Tomas Plettner, John David Gerling, Mohammed Tahmassebpur
  • Publication number: 20140362366
    Abstract: A computer-implemented method for determining an optimized purge gas flow in a semi-conductor inspection metrology or lithography apparatus, comprising receiving a permissible contaminant mole fraction, a contaminant outgassing flow rate associated with a contaminant, a contaminant mass diffusivity, an outgassing surface length, a pressure, a temperature, a channel height, and a molecular weight of a purge gas, calculating a flow factor based on the permissible contaminant mole fraction, the contaminant outgassing flow rate, the channel height, and the outgassing surface length, comparing the flow factor to a predefined maximum flow factor value, calculating a minimum purge gas velocity and a purge gas mass flow rate from the flow factor, the contaminant mass diffusivity, the pressure, the temperature, and the molecular weight of the purge gas, and introducing the purge gas into the semi-conductor inspection metrology or lithography apparatus with the minimum purge gas velocity and the purge gas flow rate.
    Type: Application
    Filed: August 22, 2014
    Publication date: December 11, 2014
    Inventors: Gildardo Delgado, Terry Johnson, Marco Arienti, Salam Harb, Lennie Klebanoff, Rudy Garcia, Mohammed Tahmassebpur, Sarah Scott
  • Publication number: 20140261568
    Abstract: The present invention provides a local clean microenvironment near optical surfaces of an extreme ultraviolet (EUV) optical assembly maintained in a vacuum process chamber and configured for EUV lithography, metrology, or inspection. The system includes one or more EUV optical assemblies including at least one optical element with an optical surface, a supply of cleaning gas stored remotely from the one or more optical assemblies and a gas delivery unit comprising: a plenum chamber, one or more gas delivery lines connecting the supply of gas to the plenum chamber, one or more delivery nozzles configured to direct cleaning gas from the plenum chamber to a portion of the EUV assembly, and one or more collection nozzles for removing gas from the EUV optical assembly and the vacuum process chamber.
    Type: Application
    Filed: April 5, 2013
    Publication date: September 18, 2014
    Applicant: KLA-Tencor Corporation
    Inventors: Gildardo Delgado, Francis Chilese, Rudy F. Garcia, Mohammed Tahmassebpur, Salam Harb
  • Publication number: 20140072452
    Abstract: An apparatus for shielding a controlled pressure environment, including a shield assembly with: a gate disc arranged for location in a chamber and including a first continuous surface facing an opening in the chamber and including an outer circumference extending past the opening in a radial direction orthogonal to a longitudinal axis passing through the chamber and the opening; and an at least one actuator arranged to displace the gate disc in an axial direction parallel to the longitudinal axis. The opening is arranged for connection to an inlet of a vacuum pump. In an example embodiment, the thermal system attains and maintains thermal equilibrium in the chamber and/or to shields the chamber from unwanted thermal affects by heating or cooling the gate disc to offset cooling or heat generated by the vacuum pump. For example, the gate disc is cooled to offset heat generated by a turbo-molecular pump.
    Type: Application
    Filed: September 10, 2013
    Publication date: March 13, 2014
    Inventors: Mohammed Tahmassebpur, Salam Harb
  • Patent number: 8664594
    Abstract: The present disclosure provides an electron beam column with substantially improved resolution and/or throughput for inspecting manufactured substrates. The electron beam column comprises an electron gun, a scanner, an objective lens, and a detector. In accordance with one embodiment, the electron gun includes a gun lens having a flip-up pole piece configuration. In accordance with another embodiment, the scanner comprises a dual scanner having a pre-scanner and a main scanner, and the detector may be configured between the electron gun and the pre-scanner. In accordance with another embodiment, the electron beam column includes a continuously-variable aperture configured to select a beam current. Other embodiments relate to methods of using an electron beam column for automated inspection of manufactured substrates. In one embodiment, for example, an aperture size is adjusted to achieve a minimum spot size given a selected beam current and a column-condition domain being used.
    Type: Grant
    Filed: April 27, 2011
    Date of Patent: March 4, 2014
    Assignee: KLA-Tencor Corporation
    Inventors: Xinrong Jiang, Liqun Han, Mohammed Tahmassebpur, Salam Harb, John D. Greene
  • Patent number: 8278623
    Abstract: A novel technique is disclosed for varying a size of an aperture within a vacuum chamber. A drive mechanism within the vacuum chamber is used to adjust a partial horizontal overlap between at least two blades, wherein a perimeter of the aperture opening is defined by edges of said blades. In one embodiment, a variable aperture mechanism includes first and second blades attached to a first support, and third and fourth blades attached to a second support. The first blade is spaced vertically above the second blade on the first support; a second support, and the fourth blade is spaced vertically above the third blade on the second support. There is a partial horizontal overlap between the first and third blades and between the fourth and second blades, and the aperture opening has a perimeter defined by edges of the four blades. Other embodiments are also disclosed.
    Type: Grant
    Filed: January 14, 2011
    Date of Patent: October 2, 2012
    Assignee: KLA-Tencor Corporation
    Inventor: Mohammed Tahmassebpur
  • Publication number: 20120181444
    Abstract: A novel technique is disclosed for varying a size of an aperture within a vacuum chamber. A drive mechanism within the vacuum chamber is used to adjust a partial horizontal overlap between at least two blades, wherein a perimeter of the aperture opening is defined by edges of said blades. In one embodiment, a variable aperture mechanism includes first and second blades attached to a first support, and third and fourth blades attached to a second support. The first blade is spaced vertically above the second blade on the first support; a second support, and the fourth blade is spaced vertically above the third blade on the second support. There is a partial horizontal overlap between the first and third blades and between the fourth and second blades, and the aperture opening has a perimeter defined by edges of the four blades. Other embodiments are also disclosed.
    Type: Application
    Filed: January 14, 2011
    Publication date: July 19, 2012
    Inventor: Mohammed TAHMASSEBPUR
  • Patent number: 8169768
    Abstract: An electrostatic chuck for retaining a substrate. The chuck has a clamping surface for receiving the substrate, where the clamping surface is formed of a hard polymeric material filled with carbon nanotubes. Electrodes are disposed beneath the clamping surface, for inducing localized electrostatic charges in the substrate and thereby retaining the substrate against the clamping surface. A base supports the clamping surface and the electrodes.
    Type: Grant
    Filed: May 21, 2009
    Date of Patent: May 1, 2012
    Assignee: KLA-Tencor Corporation
    Inventors: Mohammed Tahmassebpur, Salam Harb
  • Patent number: 8092927
    Abstract: A method of forming a gate valve for use in a high vacuum environment of an electron gun by machining a core of non-magnetic nickel-chromium-molybdenum-iron-tungsten-silicon-carbon alloy that is weldable with nickel alloys and has a tensile strength of about 750 megapascals, machining a cladding of nickel-iron, welding the core to the cladding to form the gate valve, and machining the gate valve so as to remove any dimensional differences at an interface between the core and the cladding. In this manner, because the final mechanical tolerance is controlled by machining instead of part assembling, extremely high alignment accuracy is obtained. The final part provides field shielding as provided by the nickel alloy shell, low stray field provided by the non-magnetic alloy, good vacuum performance, and tight mechanical tolerance control.
    Type: Grant
    Filed: February 25, 2011
    Date of Patent: January 10, 2012
    Assignee: KLA-Tencor Corporation
    Inventors: Mohammed Tahmassebpur, Salam Harb, Liqun Han, Marian Mankos
  • Publication number: 20110142382
    Abstract: A method of forming a gate valve for use in a high vacuum environment of an electron gun by machining a core of non-magnetic nickel-chromium-molybdenum-iron-tungsten-silicon-carbon alloy that is weldable with nickel alloys and has a tensile strength of about 750 megapascals, machining a cladding of nickel-iron, welding the core to the cladding to form the gate valve, and machining the gate valve so as to remove any dimensional differences at an interface between the core and the cladding. In this manner, because the final mechanical tolerance is controlled by machining instead of part assembling, extremely high alignment accuracy is obtained. The final part provides field shielding as provided by the nickel alloy shell, low stray field provided by the non-magnetic alloy, good vacuum performance, and tight mechanical tolerance control.
    Type: Application
    Filed: February 25, 2011
    Publication date: June 16, 2011
    Applicant: KLA-TENCOR TECHNOLOGIES CORPORATION
    Inventors: Mohammed Tahmassebpur, Salam Harb, Liqun Han, Marian Mankos
  • Patent number: 7919193
    Abstract: A component for use in a high vacuum environment, the component including a core of non-magnetic Hastelloy with a cladding of nickel-iron covering the core at least in part. The component can be, for example, at least one of a gate valve for use in a high vacuum environment of an electron gun, a bearing, a slide way, a gate valve bearing, a rotary slide, a linear slide, an electron beam column, and electron beam chamber, and a vacuum chamber. In this manner, because the final mechanical tolerance is controlled by machining instead of part assembling, extremely high alignment accuracy is obtained. The final part provides field shielding as provided by the nickel alloy shell, low stray field provided by the non-magnetic Hastelloy, good vacuum performance, and tight mechanical tolerance control. Also, because Hastelloy has the advantage of a low oxidation rate in comparison to stainless steel and titanium, there is less contamination buildup due to conditions such as electron beam bombardment.
    Type: Grant
    Filed: October 24, 2007
    Date of Patent: April 5, 2011
    Assignee: KLA-Tencor Corporation
    Inventors: Mohammed Tahmassebpur, Salam Harb, Liqun Han, Marian Mankos
  • Patent number: 5748449
    Abstract: An electrical enclosure for a circuit board includes a top part and a bottom part. Substantially rigid compression fingers extend downwardly from a top wall of the top part and are disposed inwardly from a top side wall of the top part. One or more shield springs extend upwardly from a bottom wall of the bottom part and are disposed inwardly from a bottom side wall of the bottom part. The top part and the bottom part are attachable and detachable such that the top and bottom shells define a chamber, the compression fingers and the shield springs contacting top and bottom surfaces of the circuit board, respectively, to thereby suspend the circuit board in the chamber. A coaxial cable grounding arrangement and an electrical connector shielding arrangement are also disclosed.
    Type: Grant
    Filed: April 20, 1995
    Date of Patent: May 5, 1998
    Assignee: Sierra Wireless, Inc.
    Inventor: Mohammed Tahmassebpur
  • Patent number: 5617106
    Abstract: In a pivotable antenna assembly, a pivot rod is provided having an axial opening therein at a first end thereof and a radial opening extending to the axial opening. An antenna is provided, the antenna having an antenna element and a portion through which a portion of the pivot rod extends such that the axial opening of the pivot rod is inside the portion of the antenna. A coaxial cable having a first end is provided, the coaxial cable including a central conductor, a dielectric material around the conductor, a shielding material around the dielectric material, and a jacket around the dielectric material, the first end of the coaxial cable extending into the axial opening of the pivot rod, the shielding being attached to an interior wall of the pivot rod, and the conductor extending through the radial opening and being attached to the antenna element. A method for making a pivotable antenna assembly is also disclosed.
    Type: Grant
    Filed: April 20, 1995
    Date of Patent: April 1, 1997
    Assignee: Sierra Wireless, Inc.
    Inventor: Mohammed Tahmassebpur
  • Patent number: D372701
    Type: Grant
    Filed: June 29, 1995
    Date of Patent: August 13, 1996
    Assignee: Sierra Wireless, Inc.
    Inventor: Mohammed Tahmassebpur