Patents by Inventor Anand Gupta

Anand Gupta 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: 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
  • Patent number: 5824375
    Abstract: A method and apparatus for reducing fluorine and other sorbable contaminants in plasma reactor used in chemical vapor deposition process such as the deposition of silicon oxide layer by the reaction of TEOS and oxygen. According to the method of the present invention, plasma of an inert gas is maintained in plasma reactor following chamber clean to remove sorbable contaminants such as fluorine. The plasma clean is typically followed by seasoning of the reactor to block or retard remaining contaminants. According to one embodiment of the invention, the combination of chamber clean, plasma clean, and season film is conducted before PECVD oxide layer is deposited on wafer positioned in the plasma reactor.
    Type: Grant
    Filed: October 24, 1996
    Date of Patent: October 20, 1998
    Assignee: Applied Materials, Inc.
    Inventor: Anand Gupta
  • Patent number: 5810937
    Abstract: A method and apparatus for protecting a susceptor during a cleaning operation by loading a ceramic wafer onto the susceptor before introducing the cleaning agent into the chamber is provided. In particular, the ceramic wafer is chosen to have a dielectric value sufficient to alter the electromagnetic field of a plasma to spread the plasma away from the susceptor during a cleaning operation, directing more of the plasma towards the walls of the chamber.
    Type: Grant
    Filed: March 13, 1996
    Date of Patent: September 22, 1998
    Assignee: Applied Materials, Inc.
    Inventors: Anand Gupta, Srihari Ponnekanti, Gana A. Rimple, Laxman Murugesh
  • Patent number: 5779807
    Abstract: An electrostatic technique for removing particulate matter from a semiconductor wafer in a plasma processing chamber, such as a plasma-enhanced chemical vapor deposition (PECVD) chamber. During a particulate removal phase of operation, a normally grounded electrode that supports the wafer is temporarily isolated from ground and a bias voltage generator is simultaneously connected to the electrode, supplying sufficient bias voltage to electrostatically launch particulates from the surface of the wafer. A plasma formed above the normally grounded electrode is maintained during the particulate removal phase, and particulates launched from the wafer become suspended in a sheath region surrounding the plasma, from where they can be later removed by a purging flow of gas. Preferably, the bias voltage generator provides a bias voltage that alternates in polarity, to ensure removal of both positively-charged and negatively charged particles from the wafer surface.
    Type: Grant
    Filed: October 29, 1996
    Date of Patent: July 14, 1998
    Assignee: Applied Materials, Inc.
    Inventors: Charles Dornfest, Anand Gupta, Gerald Girard
  • Patent number: 5628870
    Abstract: An apparatus suitable for marking a substrate comprises a holder for holding a substrate and a ground for electrically grounding the substrate. At least one needle electrode has a tip located proximate to the substrate so that there is a gap between the substrate and the tip. A high voltage source provides a current to the electrode tip to ionize the gas in the gap so that the ionized gas can impinge upon and mark the substrate.
    Type: Grant
    Filed: June 5, 1995
    Date of Patent: May 13, 1997
    Assignee: Applied Materials, Inc.
    Inventors: Yan Ye, Anand Gupta, Yuri S. Uritsky
  • Patent number: 5622565
    Abstract: The present invention provides an apparatus for semiconductor processing in which the reactor chamber and the vacuum conduit means connected to the chamber are coated with a film of halogenated polymer material having a low vapor pressure and a low sticking coefficient. Preferred materials include low molecular weight polyfluoroethylene polymers such as polytetrafluoroethylene and polychlorotrifluoro-ethylene. A method is provided to prevent contaminant buildup on coated surfaces of semiconductor processing chambers and vacuum conduit means connected thereto during processing of a workpiece.
    Type: Grant
    Filed: January 16, 1996
    Date of Patent: April 22, 1997
    Assignee: Applied Materials, Inc.
    Inventors: Yan Ye, Anand Gupta, Shamouil Shamouliam
  • Patent number: 5622595
    Abstract: Contaminant particles in a vacuum plasma processing chamber can be removed from the surface of a substrate in the chamber by first reducing the pressure in the chamber so as to elevate the particles above any obstruction about the substrate, including a clamping ring and the like, maintaining a plasma from a gas fed to the chamber so that the particles are in the plasma, and then increasing the gas flow to the chamber so as to sweep the particles out of the chamber through the exhaust system of the processing chamber while maintaining a plasma in the chamber.
    Type: Grant
    Filed: November 20, 1995
    Date of Patent: April 22, 1997
    Assignee: Applied Materials, Inc
    Inventors: Anand Gupta, Joseph Lanucha
  • Patent number: 5608155
    Abstract: The apparent size of sub-micron contaminant particles on a wafer surface is enlarged by selective condensation of a vapor on the particles. The substrate is located proximate to and spaced apart from a liquid vapor source which is heated. The vaporized liquid adheres to the particles, and after a predetermined period of time, condensation of vapor on the substrate is stopped, and the substrate is scanned for detecting the particles.
    Type: Grant
    Filed: June 30, 1995
    Date of Patent: March 4, 1997
    Assignee: Applied Materials, Inc.
    Inventors: Yan Ye, Anand Gupta
  • Patent number: 5578131
    Abstract: The present invention provides an apparatus for semiconductor processing in which the reactor chamber and the vacuum conduit means connected to the chamber are coated with a film of halogenated polymer material having a low vapor pressure and a low sticking coefficient. Preferred materials include low molecular weight polyfluoroethylene polymers such as polytetrafluoroethylene and polychlorotrifluoro-ethylene. A method is provided to prevent contaminant buildup on coated surfaces of semiconductor processing chambers and vacuum conduit means connected thereto during processing of a workpiece.
    Type: Grant
    Filed: June 2, 1995
    Date of Patent: November 26, 1996
    Inventors: Yan Ye, Anand Gupta, Shamouil Shamouliam
  • Patent number: 5494523
    Abstract: A plasma processing apparatus including a wafer supporting pedestal which is designed to reduce particle trapping phenomena. In a region of the pedestal surface which surrounds or abuts the wafer, the pedestal has a permittivity which is substantially equal to or greater than that of the wafer surface. As a result, the sheath boundary is reshaped to reduce particle trapping.
    Type: Grant
    Filed: February 23, 1995
    Date of Patent: February 27, 1996
    Assignee: Applied Materials, Inc.
    Inventors: Robert J. Steger, Charles S. Rhoades, Anand Gupta
  • Patent number: 5474640
    Abstract: An apparatus suitable for marking a substrate comprises a holder for holding a substrate and a ground for electrically grounding the substrate. At least one needle electrode has a tip located proximate to the substrate so that there is a gap between the substrate and the tip. A high voltage source provides a current to the electrode tip to ionize the gas in the gap so that the ionized gas can impinge upon and mark the substrate.
    Type: Grant
    Filed: July 19, 1993
    Date of Patent: December 12, 1995
    Assignee: Applied Materials, Inc.
    Inventors: Yan Ye, Anand Gupta, Yuri Uritsky
  • Patent number: 5456796
    Abstract: An RF signal is rapidly brought to a high power level prior to the introduction of a wafer into the reaction chamber to initiate a plasma that agitates and circulates any particles within the reaction chamber, thereby allowing effective reaction chamber cleaning; and an RF signal is slowly brought to a high power level to initiate a plasma prior to or during wafer processing to avoid disturbing and circulating such particles during wafer processing, thereby preventing particle induced contamination. A magnetic field may be applied to the reaction chamber to move particles from a plasma sheath/glow region interface to a reaction chamber exhaust line, and thereby prevent such particles from falling onto a processed wafer.
    Type: Grant
    Filed: June 2, 1993
    Date of Patent: October 10, 1995
    Assignee: Applied Materials, Inc.
    Inventors: Anand Gupta, Yan Ye, Joseph Lanucha
  • Patent number: 5427621
    Abstract: A novel and improved method of in-situ cleaning unwanted films and particles of a material from a surface situated inside a vacuum chamber by equipping such chamber with a means of generating a magnetic field having a magnetic flux density of at least 25 gauss, flowing at least one gas into the chamber and igniting a plasma and thus producing plasma ions of at least one gas, switching on the magnetic field generating means to a magnetic flux density of no less than 25 gauss and, reducing the magnetic field by a flux density of at least 10 gauss such that the unwanted films and particles of the material are dislodged from the surface by the sudden change in the magnetic flux density at the magnetic field.
    Type: Grant
    Filed: October 29, 1993
    Date of Patent: June 27, 1995
    Assignee: Applied Materials, Inc.
    Inventor: Anand Gupta
  • Patent number: 5423918
    Abstract: A technique for removing particles from above a semiconductor wafer, particularly particles that are trapped in a plasma chamber during processing of the wafer. Trapped particles are usually not all drawn out with gases exhausted from the chamber, in part because a peripheral focus ring and clamping mechanism impede their flow. In the method of the invention, the focus ring and clamping mechanism are raised on completion of processing, but before radio-frequency (rf) power is disconnected from the process chamber. Trapped particles are then easily flowed from the chamber with an introduced inert gas, and the level of particulate contamination of the wafer is significantly reduced.
    Type: Grant
    Filed: September 21, 1993
    Date of Patent: June 13, 1995
    Assignee: Applied Materials, Inc.
    Inventors: Anand Gupta, Charles S. Rhoades, Yan Ye, Joseph Lanucha
  • Patent number: 5410122
    Abstract: Particles are repelled from the upper face of a wafer in a plasma chamber by inducing positive or negative charges on the substrate without generating a gas plasma above the substrate. The charges are induced in the substrate by bringing a conductive sheet carrying a DC voltage close to the underside of the substrate. The particle repelling effect may be enhanced by inducing alternating positive and negative charges in the substrate. This can be done by switching the polarity of the DC voltage applied to the conductive sheet, or alternatively by moving an actuator to repetitively ground and isolate the substrate from the chamber.
    Type: Grant
    Filed: March 15, 1993
    Date of Patent: April 25, 1995
    Assignee: Applied Materials, Inc.
    Inventors: Yuh-Jia Su, Anand Gupta, Graham W. Hills, Joseph Lanucha
  • Patent number: 5328555
    Abstract: A process of removing particles from the surface of a substrate to be processed in a vacuum chamber comprising forming a plasma from an inert plasma precursor gas in said chamber, thereby lifting loosely adhered particles from the surface of the substrate, and increasing the flow of said inert gas without increasing the pressure in the vacuum chamber, thereby sweeping the particles beyond the surface of the substrate, where they can be removed by the vacuum chamber exhaust system. Particles having a particle size of about 0.1 micron or larger can be removed in this fashion.
    Type: Grant
    Filed: November 24, 1992
    Date of Patent: July 12, 1994
    Assignee: Applied Materials, Inc.
    Inventor: Anand Gupta
  • Patent number: 5083865
    Abstract: A particle monitor for a processing chamber exhaust line is disclosed which incorporates exhaust line heating, purge gas flow over surfaces such as optical windows in the exhaust gas line, and a thermally and electrically insulating particle monitor mounting arrangement. The features collectively protect the particle monitor from electrical disturbance and from the heated inlet and maintain the optical surfaces clean and free of depositions from the exhaust gas flow for an extended period. The arrangement also suppresses etching of the optical surfaces.
    Type: Grant
    Filed: May 11, 1990
    Date of Patent: January 28, 1992
    Assignee: Applied Materials, Inc.
    Inventors: Patrick Kinney, Boris Fishkin, Jun Zhao, Anand Gupta, Robert Bendler