Patents by Inventor Padmanabhan Krishnaraj

Padmanabhan Krishnaraj 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: 20030036272
    Abstract: A method of cleaning a semiconductor fabrication processing chamber involves recirculation of cleaning gas components. Consequently, input cleaning gas is utilized efficiently, and undesirable emissions are reduced. The method includes flowing a cleaning gas to an inlet of a processing chamber, and exposing surfaces of the processing chamber to the cleaning gas to clean the surfaces, thereby producing a reaction product. The method further includes removing an outlet gas including the reaction product from an outlet of the processing chamber, separating at least a portion of the reaction product from the outlet gas, and recirculating a portion of the outlet gas to the inlet of the processing chamber.
    Type: Application
    Filed: May 30, 2002
    Publication date: February 20, 2003
    Applicant: APPLIED MATERIALS, INC.
    Inventors: Shamouil Shamouilian, Canfeng Lai, Michael Santiago Cox, Padmanabhan Krishnaraj, Tsutomu Tanaka, Sebastien Raoux, Peter I. Porshnev, Thomas Nowak
  • Patent number: 6511922
    Abstract: Methods and apparatus of the present invention deposit fluorinated silicate glass (FSG) in such a manner that it strongly adheres to an overlying or underlying barrier layer or etch stop layer, and has a lower dielectric constant, among other benefits. In one embodiment, silicon tetrafluoride (SiF4), oxygen (O2), and argon (Ar) are used as the reactant gases, with the ratio of oxygen to silicon controlled to be at between about 2:1 to 6:1. Such O2 levels help reduce the amount of degradation of ceramic chamber components otherwise caused by the elimination of silane from the process recipe.
    Type: Grant
    Filed: March 26, 2001
    Date of Patent: January 28, 2003
    Assignee: Applied Materials, Inc.
    Inventors: Padmanabhan Krishnaraj, Robert Duncan, Joseph D'Souza, Alan W. Collins, Nasreen Chopra, Kimberly Branshaw
  • Patent number: 6486081
    Abstract: The present invention provides an apparatus for depositing a film on a substrate comprising a processing chamber, a substrate support member disposed within the chamber, a first gas inlet, a second gas inlet, a plasma generator and a gas exhaust. The first gas inlet provides a first gas at a first distance from an interior surface of the chamber, and the second gas inlet provides a second gas at a second distance that is closer than the first distance from the interior surface of the chamber. Thus, the second gas creates a higher partial pressure adjacent the interior surface of the chamber to significantly reduce deposition from the first gas onto the interior surface.
    Type: Grant
    Filed: November 24, 1999
    Date of Patent: November 26, 2002
    Assignee: Applied Materials, Inc.
    Inventors: Tetsuya Ishikawa, Padmanabhan Krishnaraj, Feng Gao, Alan W. Collins, Lily Pang
  • Publication number: 20020173167
    Abstract: Methods and apparatus of the present invention deposit fluorinated silicate glass (FSG) in such a manner that it strongly adheres to an overlying or underlying barrier layer or etch stop layer, and has a lower dielectric constant, among other benefits. In one embodiment, silicon tetrafluoride (SiF4), oxygen (O2), and argon (Ar) are used as the reactant gases, with the ratio of oxygen to silicon controlled to be at between about 2:1 to 6:1. Such O2 levels help reduce the amount of degradation of ceramic chamber components otherwise caused by the elimination of silane from the process recipe.
    Type: Application
    Filed: March 26, 2001
    Publication date: November 21, 2002
    Applicant: Applied Materials, Inc.
    Inventors: Padmanabhan Krishnaraj, Robert Duncan, Joseph D'Souza, Alan W. Collins, Nasreen Chopra, Kimberly Branshaw
  • Publication number: 20020151186
    Abstract: Apparatus for processing semiconductor wafers includes a processing chamber, a chuck within the chamber for supporting a wafer during processing, a fiberoptic cable having a first end positioned at the surface of the chuck, and an optical pyrometer connected to a second end of the cable. The optical pyrometer measures the temperature of a wafer during processing and measures in situ temperature of plasma-excited cleaning gas introduced into the chamber during subsequent cleaning from walls thereof of unwanted solid deposits within the chamber. The pyrometer is connected to a computer which controls the flow of cleaning gases. When the temperature of the plasma-excited gas reaches a steady-state value the computer stops the flow of cleaning gases into the chamber and thereby stops the cleaning operation.
    Type: Application
    Filed: April 11, 2001
    Publication date: October 17, 2002
    Inventors: Zhenjiang Cui, Padmanabhan Krishnaraj, Shamouil Shamouilian
  • Patent number: 6274058
    Abstract: A processing chamber cleaning method is described which utilizes microwave energy to remotely generate a reactive species to be used alone or in combination with an inert gas to remove deposits from a processing chamber. The reactive species can remove deposits from a first processing region at a first pressure and then remove deposits from a second processing region at a second pressure. Also described is a cleaning process utilizing remotely generated reactive species in a single processing region at two different pressures. Additionally, different ratios of reactive gas and inert gas may be utilized to improve the uniformity of the cleaning process, increase the cleaning rate, reduce recombination of reactive species and increase the residence time of reactive species provided to the processing chamber.
    Type: Grant
    Filed: July 2, 1999
    Date of Patent: August 14, 2001
    Assignee: Applied Materials, Inc.
    Inventors: Ravi Rajagopalan, Patricia M. Liu, Pravin K. Narwankar, Huyen Tran, Padmanabhan Krishnaraj, Alan Ablao, Tim Casper
  • Patent number: 6189483
    Abstract: The present invention provides an HDP-CVD tool using simultaneous deposition and sputtering of doped and undoped silicon dioxide capable of excellent gap fill and blanket film deposition on wafers. The tool of the present invention includes: a dual RF zone inductively coupled plasma source; a dual zone gas distribution system; temperature controlled surfaces within the tool; a symmetrically shaped turbomolecular pumped chamber body; a dual cooling zone electrostatic chuck; an all ceramic/aluminum alloy chamber; and a remote plasma chamber cleaning system.
    Type: Grant
    Filed: May 29, 1997
    Date of Patent: February 20, 2001
    Assignee: Applied Materials, Inc.
    Inventors: Tetsuya Ishikawa, Padmanabhan Krishnaraj, Kaveh Niazi, Hiroji Hanawa
  • Patent number: 6175485
    Abstract: The present invention provides an electrostatic chuck having a dielectric layer with improved porosity and electrical properties, and a method for fabricating the dielectric layer and applying the layer to a pedestal to form a portion of an electrostatic chuck. The dielectric layer is formed by a detonation gun process which includes igniting a fuel gas mixture to form a detonation wave and propelling aluminum oxide powder onto the pedestal at high speeds. The dielectric layer has a porosity of less than 1 percent of its total volume, which improves the electrical properties of the chuck, such as its dielectric strength and the dielectric constant. In addition, the low porosity decreases the adsorption of moisture and other gases into the dielectric layer, which further enhances the electrical properties of the chuck.
    Type: Grant
    Filed: July 19, 1996
    Date of Patent: January 16, 2001
    Assignee: Applied Materials, Inc.
    Inventors: Padmanabhan Krishnaraj, Brian Lue, Ramkishan Rao Lingampalli, Shun Jackson Wu
  • Patent number: 6143078
    Abstract: The present invention provides an apparatus for depositing a film on a substrate comprising a processing chamber, a substrate support member disposed within the chamber, a first gas inlet, a second gas inlet, a plasma generator and a gas exhaust. The first gas inlet provides a first gas at a first distance from an interior surface of the chamber, and the second gas inlet provides a second gas at a second distance that is closer than the first distance from the interior surface of the chamber. Thus, the second gas creates a higher partial pressure adjacent the interior surface of the chamber to significantly reduce deposition from the first gas onto the interior surface.
    Type: Grant
    Filed: November 13, 1998
    Date of Patent: November 7, 2000
    Assignee: Applied Materials, Inc.
    Inventors: Tetsuya Ishikawa, Padmanabhan Krishnaraj, Feng Gao, Alan W. Collins, Lily Pang