Patents by Inventor Sandeep Krishnan

Sandeep Krishnan 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: 10316412
    Abstract: A wafer carrier for use in a system for growing epitaxial layers on one or more wafers by chemical vapor deposition. The wafer carrier includes wafer retention pockets recessed in its body. Each pocket includes a floor surface and a peripheral wall surface surrounding the floor surface and defining a periphery of that pocket. Each pocket has a center situated along a corresponding wafer carrier radial axis. In each of the pockets, a set of bumpers is positioned primarily at a distal portion of the wafer retention pocket opposite the central axis so as to maintain a gap of at least a predefined size between the peripheral wall surface at the distal portion and an edge of a wafer to be placed in the wafer retention pocket.
    Type: Grant
    Filed: April 18, 2012
    Date of Patent: June 11, 2019
    Assignee: Veeco Instruments Inc.
    Inventors: Sandeep Krishnan, Jeffrey Scott Montgomery, Lukas Urban, Alexander I. Gurary, Yuliy Rashkovsky
  • Publication number: 20190169745
    Abstract: A wafer carrier for use in a chemical vapor deposition (CVD) system includes a plurality of wafer retention pockets, each having a peripheral wall surface surrounding a floor surface and defining a periphery of that wafer retention pocket. Each wafer retention pocket has a periphery with a shape defined by at least a first arc having a first radius of curvature situated around a first arc center and a second arc having a second radius of curvature situated around a second arc center. The second arc is different from the first arc, either by its radius of curvature, arc center, or both.
    Type: Application
    Filed: November 30, 2018
    Publication date: June 6, 2019
    Inventors: Sandeep Krishnan, Lukas Urban
  • Patent number: 10167571
    Abstract: A wafer carrier and methods of making the same for use in a system for growing epitaxial layers on one or more wafers by chemical vapor deposition. The wafer carrier includes wafer retention pockets recessed in its body. A thermally-insulating spacer is situated at least partially in the at least one wafer retention pocket and arranged to maintain a spacing between the peripheral wall surface and the wafer, the spacer being constructed from a material having a thermal conductivity less than a thermal conductivity of the wafer carrier such that the spacer limits heat conduction from portions of the wafer carrier body to the wafer. The wafer carrier further includes a spacer retention feature that engages with the spacer and includes a surface oriented to prevent centrifugal movement of the spacer when subjected to rotation about the central axis.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: January 1, 2019
    Assignee: Veeco Instruments Inc.
    Inventors: Sandeep Krishnan, William E. Quinn, Jeffery S. Montgomery, Joshua Mangum, Lukas Urban
  • Patent number: 10145013
    Abstract: A wafer carrier for use in a chemical vapor deposition (CVD) system includes a plurality of wafer retention pockets, each having a peripheral wall surface surrounding a floor surface and defining a periphery of that wafer retention pocket. Each wafer retention pocket has a periphery with a shape defined by at least a first arc having a first radius of curvature situated around a first arc center and a second arc having a second radius of curvature situated around a second arc center. The second arc is different from the first arc, either by its radius of curvature, arc center, or both.
    Type: Grant
    Filed: January 26, 2015
    Date of Patent: December 4, 2018
    Assignee: Veeco Instruments Inc.
    Inventors: Sandeep Krishnan, Lukas Urban
  • Publication number: 20180142356
    Abstract: Systems and methods are described herein for improving the overall thickness control and the radial thickness profile of epitaxially-grown films or layers on wafers. Continuous, in situ measurement of thickness at a radially inner region and a radially outer region are used in embodiments to control corresponding precursor and/or dilution gas flow rates. Such measurements can be made using white light reflectometry through a viewport in the reactor housing.
    Type: Application
    Filed: November 20, 2017
    Publication date: May 24, 2018
    Inventors: Sandeep KRISHNAN, Michael CHANSKY, Daewon KWON, Earl MARCELO
  • Patent number: 9816184
    Abstract: A structure for a chemical vapor deposition reactor desirably includes a reaction chamber having an interior, a spindle mounted in the reaction chamber, and a wafer carrier releasably mounted onto the spindle for rotation therewith. The spindle desirably has a shaft extending along a vertical rotational axis and a key projecting outwardly from the shaft. The wafer carrier preferably has a body defining oppositely-facing top and bottom surfaces and at least one wafer-holding feature configured so that a wafer can be held therein with a surface of the wafer exposed at the top surface of the body. The wafer carrier desirably further has a recess extending into the body from the bottom surface of the body and a keyway projecting outwardly from a periphery of the recess along a first transverse axis. The shaft preferably is engaged in the recess and the key preferably is engaged into the keyway.
    Type: Grant
    Filed: March 20, 2012
    Date of Patent: November 14, 2017
    Assignee: Veeco Instruments Inc.
    Inventors: Sandeep Krishnan, Keng Moy, Alexander I. Gurary, Matthew King, Vadim Boguslavskiy, Steven Krommenhoek
  • Publication number: 20170191157
    Abstract: A structure for a chemical vapor deposition reactor desirably includes a reaction chamber having an interior, a spindle mounted in the reaction chamber, and a wafer carrier releasably mounted onto the spindle for rotation therewith. The spindle desirably has a shaft extending along a vertical rotational axis and a key projecting outwardly from the shaft. The wafer carrier preferably has a body defining oppositely-facing top and bottom surfaces and at least one wafer-holding feature configured so that a wafer can be held therein with a surface of the wafer exposed at the top surface of the body. The wafer carrier desirably further has a recess extending into the body from the bottom surface of the body and a keyway projecting outwardly from a periphery of the recess along a first transverse axis. The shaft preferably is engaged in the recess and the key preferably is engaged into the keyway.
    Type: Application
    Filed: March 21, 2017
    Publication date: July 6, 2017
    Inventors: Sandeep Krishnan, Keng Moy, Alex Gurary, Matthew King, Vadim Boguslavskiy, Steven Krommenhoek
  • Publication number: 20170121847
    Abstract: A wafer carrier assembly for use in a system for growing epitaxial layers on one or more wafers by chemical vapor deposition (CVD), the wafer carrier assembly includes a wafer carrier body formed symmetrically about a central axis, and including a generally planar top surface that is situated perpendicularly to the central axis and a planar bottom surface that is parallel to the top surface. At least one wafer retention pocket is recessed in the wafer carrier body from the top surface. Each of the at least one wafer retention pocket includes a floor surface and a peripheral wall surface that surrounds the floor surface and defines a periphery of that wafer retention pocket. At least one thermal control feature includes an interior cavity or void formed in the wafer carrier body and is defined by interior surfaces of the wafer carrier body.
    Type: Application
    Filed: January 11, 2017
    Publication date: May 4, 2017
    Inventors: Eric Armour, Sandeep Krishnan, Alex Zhang, Bojan Mitrovic, Alexander Gurary
  • Publication number: 20170076972
    Abstract: A wafer carrier for a plurality of wafers, the wafer carrier having a platen with a plurality of openings and a plurality of wafer retention platforms, the platen configured to rotate about a first axis, the plurality of wafer retention platforms configured to rotate about respective second axes, each of the wafer retention platforms rotatably coupled to one of the plurality of openings by friction reducing bearings, the platen and the plurality of wafer retention platforms and the friction reducing bearings all being constructed of the same material.
    Type: Application
    Filed: September 15, 2016
    Publication date: March 16, 2017
    Inventors: Sandeep Krishnan, Lukas Urban, Alexander Gurary, Keng Moy, Ajit Paranjpe
  • Publication number: 20170053049
    Abstract: Improvements to the heating uniformity of a wafer carrier for a chemical vapor deposition (CVD) system can be made based on a computational thermal model built according physical and operational characteristics of the CVD system. Operation of the thermal model is simulated, where a process recipe to be carried out on the CVD system is modeled, including heat transfers taking place in the virtual CVD system, to produce a set of thermal-spatial non-uniformities in at least one region of interest of a virtual wafer carrier. Structural corrections to be made to the pocket floor of each of the at least one wafer retention pocket are determined based on the set of thermal-spatial non-uniformities and on a predefined thermal-pocket floor relation that defines at least one design rule for correcting the pocket floor to achieve an increase in thermal uniformity throughout the at least one region of interest.
    Type: Application
    Filed: August 16, 2016
    Publication date: February 23, 2017
    Inventors: Lukas Urban, Sandeep Krishnan
  • Publication number: 20160372321
    Abstract: A self-centering wafer carrier system for a chemical vapor deposition (CVD) reactor includes a wafer carrier comprising an edge. The wafer carrier at least partially supports a wafer for CVD processing. A rotating tube comprises an edge that supports the wafer carrier during processing. An edge geometry of the wafer carrier and an edge geometry of the rotating tube being chosen to provide a coincident alignment of a central axis of the wafer carrier and a rotation axis of the rotating tube during process at a desired process temperature.
    Type: Application
    Filed: June 10, 2016
    Publication date: December 22, 2016
    Applicant: Veeco Instruments, Inc.
    Inventors: Sandeep Krishnan, Alexander I. Gurary, Chenghung Paul Chang, Earl Marcelo
  • Patent number: 9273413
    Abstract: Wafer carrier arranged to hold a plurality wafers and to inject a fill gas into gaps between the wafers and the wafer carrier for enhanced heat transfer and to promote uniform temperature of the wafers. The apparatus is arranged to vary the composition, flow rate, or both of the fill gas so as to counteract undesired patterns of temperature non-uniformity of the wafers. In various embodiments, the wafer carrier utilizes at least one plenum structure contained within the wafer carrier to source a plurality of weep holes for passing a fill gas into the wafer retention pockets of the wafer carrier. The plenum(s) promote the uniformity of the flow, thus providing efficient heat transfer and enhanced uniformity of wafer temperatures.
    Type: Grant
    Filed: March 14, 2013
    Date of Patent: March 1, 2016
    Assignee: Veeco Instruments Inc.
    Inventors: Sandeep Krishnan, Alexander I. Gurary, Keng Moy
  • Patent number: D793971
    Type: Grant
    Filed: March 27, 2015
    Date of Patent: August 8, 2017
    Assignee: Veeco Instruments Inc.
    Inventors: Sandeep Krishnan, Raghu Moorkannaiah
  • Patent number: D793972
    Type: Grant
    Filed: March 27, 2015
    Date of Patent: August 8, 2017
    Assignee: Veeco Instruments Inc.
    Inventors: Sandeep Krishnan, Keng Moy
  • Patent number: D810705
    Type: Grant
    Filed: April 1, 2016
    Date of Patent: February 20, 2018
    Assignee: Veeco Instruments Inc.
    Inventors: Sandeep Krishnan, Alexander I. Gurary, Chenghung Paul Chang, Earl Marcelo
  • Patent number: D819580
    Type: Grant
    Filed: April 1, 2016
    Date of Patent: June 5, 2018
    Assignee: Veeco Instruments, Inc.
    Inventors: Sandeep Krishnan, Alexander I. Gurary, Chenghung Paul Chang, Earl Marcelo
  • Patent number: D852762
    Type: Grant
    Filed: August 1, 2017
    Date of Patent: July 2, 2019
    Assignee: Veeco Instruments Inc.
    Inventors: Sandeep Krishnan, Raghu Chikkanayakanahalli Moorkannaiah
  • Patent number: D854506
    Type: Grant
    Filed: March 26, 2018
    Date of Patent: July 23, 2019
    Assignee: Veeco Instruments Inc.
    Inventors: Sandeep Krishnan, Yuliy Rashkovsky, Alexander Gurary, Leo Chin, Mandar Deshpande
  • Patent number: D858469
    Type: Grant
    Filed: March 26, 2018
    Date of Patent: September 3, 2019
    Assignee: Veeco Instruments Inc.
    Inventors: Sandeep Krishnan, Yuliy Rashkovsky, Alexander Gurary, Leo Chin, Mandar Deshpande
  • Patent number: D860146
    Type: Grant
    Filed: November 30, 2017
    Date of Patent: September 17, 2019
    Assignee: Veeco Instruments Inc.
    Inventors: Yuliy Rashkovsky, Mandar Deshpande, Alexander Gurary, Sandeep Krishnan, Aniruddh Parekh