Patents by Inventor Sudhakar Subrahmanyam

Sudhakar Subrahmanyam 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: 6291028
    Abstract: A method and apparatus for depositing a layer having improved film quality at an interface. The method includes the steps of introducing an inert gas into a processing chamber and forming a plasma from the inert gas by applying RF power to the chamber at a selected rate of increase. After RF power has reached full power, a process gas including a reactant gas is introduced to deposit the layer. In a preferred embodiment, the reactant gas is tetraethoxysilane. In another preferred embodiment, the process gas further includes fluorine.
    Type: Grant
    Filed: June 30, 2000
    Date of Patent: September 18, 2001
    Assignee: Applied Materials, Inc.
    Inventors: Anand Gupta, Virendra V. S. Rana, Amrita Verma, Mohan K. Bhan, Sudhakar Subrahmanyam
  • Patent number: 6289843
    Abstract: A method and apparatus for depositing a layer having improved film quality at an interface. The method includes the steps of introducing an inert gas into a processing chamber and forming a plasma from the inert gas by applying RF power to the chamber at a selected rate of increase. After RF power has reached full power, a process gas including a reactant gas is introduced to deposit the layer. In a preferred embodiment, the reactant gas is tetraethoxysilane. In another preferred embodiment, the process gas further includes fluorine.
    Type: Grant
    Filed: August 21, 2000
    Date of Patent: September 18, 2001
    Assignee: Applied Materials, Inc.
    Inventors: Anand Gupta, Virendra V. S. Rana, Amrita Verma, Mohan K. Bhan, Sudhakar Subrahmanyam
  • Patent number: 6223685
    Abstract: An improved method of reducing the level of contaminants (e.g., fluorine) absorbed in films deposited within a substrate processing chamber. A seasoning layer is deposited within the substrate processing chamber to cover contaminants that may be absorbed within walls or insulation areas of the chamber interior. The deposited seasoning layer is more stable than prior art seasoning layers and is thus less likely to release the absorbed contaminants into the substrate processing chamber during the subsequent deposition of films. In a preferred embodiment, the seasoning layer is formed from a mixed frequency PECVD process in which the low frequency RF signal is supplied at a high power level to increase ion bombardment and enhance film stability. The increased bombardment favors the formation of stable SiF bonds between silicon and fluorine atoms in the lattice structure of the film rather than unstable SiF2 or other bonds. When residual fluorine atoms (e.g.
    Type: Grant
    Filed: December 1, 1999
    Date of Patent: May 1, 2001
    Assignee: Applied Materials, Inc.
    Inventors: Anand Gupta, Mohan Bhan, Sudhakar Subrahmanyam
  • Patent number: 6121163
    Abstract: A method and apparatus for depositing a layer having improved film quality at an interface. The method includes the steps of introducing an inert gas into a processing chamber and forming a plasma from the inert gas by applying RF power to the chamber at a selected rate of increase. After RF power has reached full power, a process gas including a reactant gas is introduced to deposit the layer. In a preferred embodiment, the reactant gas is tetraethoxysilane. In another preferred embodiment, the process gas further includes fluorine.
    Type: Grant
    Filed: February 9, 1996
    Date of Patent: September 19, 2000
    Assignee: Applied Materials, Inc.
    Inventors: Anand Gupta, Virendra V. S. Rana, Amrita Verma, Mohan K. Bhan, Sudhakar Subrahmanyam
  • Patent number: 6090167
    Abstract: A method and apparatus for improving film stability of a halogen-doped silicon oxide layer. The method includes the step of introducing helium along with the process gas that includes silicon, oxygen and a halogen element. Helium is introduced at an increased rate to stabilize the deposited layer. In a preferred embodiment, the halogen-doped film is a fluorosilicate glass film and TEOS is employed as a source of silicon in the process gas. In still another preferred embodiment, SiF.sub.4 is employed as the fluorine source for the FSG film.
    Type: Grant
    Filed: October 6, 1999
    Date of Patent: July 18, 2000
    Assignee: Applied Materials, Inc.
    Inventors: Mohan Krishan Bhan, Sudhakar Subrahmanyam, Anand Gupta, Viren V. S. Rana
  • Patent number: 6079426
    Abstract: Apparatus and methods are disclosed for utilizing a plasma cleaning operation of a CVD system incorporating cleaning process endpoint detection. In one embodiment, the cleaning process is performed at a constant exhaust capacity and the endpoint detection is in response to a specified rate of change of chamber pressure. In another embodiment, a servo-controlled exhaust system maintains a controlled chamber pressure and the endpoint detection is in response to a specified control signal. In a preferred embodiment, nitrogen trifluoride is converted into a plasma containing free fluorine radicals in a magnetron-powered remote microwave plasma generator. The remotely produced free fluorine radicals are used to remove silicon nitride deposits from a substrate processing chamber. The use of such a remote plasma system provides an efficient cleaning process that takes as little as half the time compared to similar in situ plasma cleaning processes.
    Type: Grant
    Filed: July 2, 1997
    Date of Patent: June 27, 2000
    Assignee: Applied Materials, Inc.
    Inventors: Sudhakar Subrahmanyam, Tsutomu Tanaka, Mukul Kelkar
  • Patent number: 6020035
    Abstract: An improved method of reducing the level of contaminants (e.g., fluorine) absorbed in films deposited within a substrate processing chamber. A seasoning layer is deposited within the substrate processing chamber to cover contaminants that may be absorbed within walls or insulation areas of the chamber interior. The deposited seasoning layer is more stable than prior art seasoning layers and is thus less likely to release the absorbed contaminants into the substrate processing chamber during the subsequent deposition of films. In a preferred embodiment, the seasoning layer is formed from a mixed frequency PECVD process in which the low frequency RF signal is supplied at a high power level to increase ion bombardment and enhance film stability. The increased bombardment favors the formation of stable SiF bonds between silicon and fluorine atoms in the lattice structure of the film rather than unstable SiF.sub.2 or other bonds. When residual fluorine atoms (e.g.
    Type: Grant
    Filed: October 29, 1996
    Date of Patent: February 1, 2000
    Assignee: Applied Materials, Inc.
    Inventors: Anand Gupta, Mohan Bhan, Sudhakar Subrahmanyam
  • Patent number: 6001728
    Abstract: A method and apparatus for improving film stability of a halogen-doped silicon oxide layer. The method includes the step of introducing helium along with the process gas that includes silicon, oxygen and a halogen element. Helium is introduced at an increased rate to stabilize the deposited layer. In a preferred embodiment, the halogen-doped film is a fluorosilicate glass film and TEOS is employed as a source of silicon in the process gas. In still another preferred embodiment, SiF.sub.4 is employed as the fluorine source for the FSG film.
    Type: Grant
    Filed: March 15, 1996
    Date of Patent: December 14, 1999
    Assignee: Applied Materials, Inc.
    Inventors: Mohan Krishan Bhan, Sudhakar Subrahmanyam, Anand Gupta, Viren V. S. Rana
  • Patent number: 5827785
    Abstract: A method and apparatus for improving film stability of a halogen-doped silicon oxide layer. The method includes the step of introducing a process gas including a first halogen source and a second halogen source, different from the first halogen source, into a deposition chamber along with silicon and oxygen sources. A plasma is then formed from the process gas to deposit a halogen-doped layer over a substrate disposed in the chamber. It is believed that the introduction of the additional halogen source enhances the etching effect of the film. The enhanced etching component of the film deposition improves the film's gap-fill capabilities and helps stabilizes the film. In a preferred embodiment, the halogen-doped film is a fluorosilicate glass film, SiF.sub.4 is employed as the first halogen source, TEOS is employed as a source of silicon and the second halogen source is either F.sub.2 or NF.sub.3.
    Type: Grant
    Filed: October 24, 1996
    Date of Patent: October 27, 1998
    Assignee: Applied Materials, Inc.
    Inventors: Mohan Krishan Bhan, Sudhakar Subrahmanyam, Anand Gupta, Virendra V. S. Rana