Patents by Inventor Hamid Tavassoli

Hamid Tavassoli 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: 20070091539
    Abstract: A plasma reactor having a reactor chamber and an electrostatic chuck with a surface for holding a workpiece inside the chamber includes a backside gas pressure source coupled to the electrostatic chuck for applying a thermally conductive gas under a selected pressure into a workpiece-surface interface formed whenever a workpiece is held on the surface and an evaporator inside the electrostatic chuck and a refrigeration loop having an expansion valve for controlling flow of coolant through the evaporator. The reactor further includes a temperature sensor in the electrostatic chuck and a memory storing a schedule of changes in RF power or wafer temperature.
    Type: Application
    Filed: April 21, 2006
    Publication date: April 26, 2007
    Inventors: Douglas Buchberger, Paul Brillhart, Richard Fovell, Hamid Tavassoli, Douglas Burns, Kallol Bera, Daniel Hoffman
  • Publication number: 20070081295
    Abstract: A plasma reactor for processing a workpiece includes a reactor chamber, an electrostatic chuck within the chamber for supporting a workpiece, an RF plasma bias power generator coupled to apply RF power to the electrostatic chuck and a refrigeration loop having an evaporator inside the electrostatic chuck with a refrigerant inlet and a refrigerant outlet. Preferably, the evaporator includes a meandering passageway distributed in a plane beneath a top surface of the electrostatic chuck. Preferably, refrigerant within the evaporator is apportioned between a vapor phase and a liquid phase. As a result, heat transfer between the electrostatic chuck and the refrigerant within the evaporator is a constant-temperature process. This feature improves uniformity of temperature distribution across a diameter of the electrostatic chuck.
    Type: Application
    Filed: April 21, 2006
    Publication date: April 12, 2007
    Inventors: Paul Brillhart, Richard Fovell, Hamid Tavassoli, Douglas Buchberger, Douglas Burns, Kallol Bera, Daniel Hoffman
  • Publication number: 20070081294
    Abstract: A plasma reactor for processing a workpiece includes a reactor chamber, an electrostatic chuck within the chamber having a top surface for supporting a workpiece and having indentations in the top surface that form enclosed gas flow channels whenever covered by a workpiece resting on the top surface. The reactor further includes thermal control apparatus thermally coupled to the electrostatic chuck, an RF plasma bias power generator coupled to apply RF power to the electrostatic chuck, a pressurized gas supply of a thermally conductive gas, a controllable gas valve coupling the pressurized gas supply to the indentations to facilitate filling the channels with the thermally conductive gas for heat transfer between a backside of a workpiece and the electrostatic chuck at a heat transfer rate that is a function of the pressure against the backside of the workpiece of the thermally conductive gas.
    Type: Application
    Filed: April 21, 2006
    Publication date: April 12, 2007
    Inventors: Douglas Buchberger, Paul Brillhart, Richard Fovell, Hamid Tavassoli, Douglas Burns, Kallol Bera, Daniel Hoffman
  • Publication number: 20050224180
    Abstract: Apparatus for controlling the flow of a gas between a process region and an exhaust port in a semiconductor substrate processing chamber is provided. The apparatus includes at least one restrictor plate supported within the semiconductor processing chamber and at least partially circumscribing a substrate support pedestal. The restrictor plate is adapted to control the flow of at least one gas flowing between the process region and the exhaust port.
    Type: Application
    Filed: April 8, 2004
    Publication date: October 13, 2005
    Inventors: Kallol Bera, Heeyeop Chae, Hamid Tavassoli, Yan Ye
  • Publication number: 20050167051
    Abstract: A plasma reactor for processing a workpiece, includes a vacuum chamber defined by a sidewall and ceiling, and a workpiece support pedestal having a workpiece support surface in the chamber and facing the ceiling and including a cathode electrode. An RF power generator is coupled to the cathode electrode. Plasma distribution is controlled by an external annular inner electromagnet in a first plane overlying the workpiece support surface, an external annular outer electromagnet in a second plane overlying the workpiece support surface and having a greater diameter than the inner electromagnet, and an external annular bottom electromagnet in a third plane underlying the workpiece support surface. D.C. current supplies are connected to respective ones of the inner, outer and bottom electromagnets.
    Type: Application
    Filed: January 28, 2005
    Publication date: August 4, 2005
    Inventors: Daniel Hoffman, Roger Lindley, Michael Kutney, Martin Salinas, Hamid Tavassoli, Keiji Horioka, Douglas Buchberger
  • Publication number: 20040040664
    Abstract: Various embodiments of the present invention are generally directed to a plasma etch reactor. In one embodiment, the reactor includes a chamber, a pedestal disposed within the chamber, a gas distribution plate disposed within the chamber overlying the pedestal, a ring surrounding the pedestal, and an upper electrically conductive mesh layer and a lower electrically conductive mesh layer disposed within the pedestal. The ring has a raised portion. The upper electrically conductive mesh layer is disposed substantially above the lower electrically conductive mesh layer and is substantially the same size as a substrate configured to be disposed on the pedestal. The lower electrically conductive mesh layer is substantially annular in shape and is disposed around the periphery of the upper electrically conductive mesh layer and below the raised portion of the ring.
    Type: Application
    Filed: June 2, 2003
    Publication date: March 4, 2004
    Inventors: Jang Gyoo Yang, Daniel J. Hoffman, Brian C. Lue, Tetsuya Ishikawa, Douglas A. Buchberger, Semyon L. Kats, Hamid Tavassoli, Kang-Lie Chiang, Heeyeop Chae