Patents by Inventor Ajit Balakrishna

Ajit Balakrishna 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: 7569463
    Abstract: The present invention generally describes one or more apparatuses and various methods that are used to perform an annealing process on desired regions of a substrate. In one embodiment, an amount of energy is delivered to the surface of the substrate to preferentially melt certain desired regions of the substrate to remove unwanted damage created from prior processing steps (e.g., crystal damage from implant processes), more evenly distribute dopants in various regions of the substrate, and/or activate various regions of the substrate. The preferential melting processes will allow more uniform distribution of the dopants in the melted region, due to the increased diffusion rate and solubility of the dopant atoms in the molten region of the substrate. The creation of a melted region thus allows: 1) the dopant atoms to redistribute more uniformly, 2) defects created in prior processing steps to be removed, and 3) regions that have hyper-abrupt dopant concentrations to be formed.
    Type: Grant
    Filed: July 25, 2006
    Date of Patent: August 4, 2009
    Assignee: Applied Materials, Inc.
    Inventors: Ajit Balakrishna, Paul Carey, Dean Jennings, Abhilash Mayur, Stephen Moffatt, William Schaffer, Mark Yam
  • Publication number: 20090188624
    Abstract: Methods and apparatus for processing substrates are provided herein. In some embodiments, an apparatus for processing a substrate may include a process chamber having an inner volume and an exhaust system coupled thereto, wherein the exhaust system includes a plurality of first conduits, each first conduit having an inlet adapted to receive exhaust from the inner volume of the process chamber. A pumping plenum is coupled to each of the plurality of first conduits. The pumping plenum has a pumping port adapted to pump the exhaust from the chamber. The conductance between each inlet of the plurality of first conduits and the pumping port is substantially equivalent.
    Type: Application
    Filed: January 25, 2008
    Publication date: July 30, 2009
    Applicant: APPLIED MATERIALS, INC.
    Inventors: KALLOL BERA, James D. Carducci, Ajit Balakrishna, Shahid Rauf, Kenneth S. Collins, Andrew Nguyen, Hamid Noorbakhsh
  • Patent number: 7552736
    Abstract: A process is provided for removing polymer from a backside of a workpiece. The process includes supporting the workpiece on the backside in a vacuum chamber while leaving at least a peripheral annular portion of the backside exposed. The process further includes confining gas flow at the edge of the workpiece within a gap at the edge of the workpiece on the order of about 1% of the diameter of the chamber, the gap defining a boundary between an upper process zone containing the wafer front side and a lower process zone containing the wafer backside. The process also includes providing a polymer etch precursor gas underneath the backside edge of the workpiece and applying RF power to a region underlying the backside edge of the workpiece to generate a first plasma of polymer etch species concentrated in an annular ring concentric with and underneath the backside edge of the workpiece.
    Type: Grant
    Filed: March 14, 2007
    Date of Patent: June 30, 2009
    Assignee: Applied Materials, Inc.
    Inventors: Kenneth S. Collins, Hiroji Hanawa, Andrew Nguyen, Ajit Balakrishna, David Palagashvili, James P. Cruse, Jennifer Y. Sun, Valentin N. Todorov, Shahid Rauf, Kartik Ramaswamy, Gerhard M. Schneider, Imad Yousif, Martin Jeffrey Salinas
  • Publication number: 20090156013
    Abstract: Polymer is removed from the backside of a wafer held on a support pedestal in a reactor using an arcuate side gas injection nozzle extending through the reactor side wall with a curvature matched to the wafer edge and supplied with plasma by-products from a remote plasma source.
    Type: Application
    Filed: December 12, 2007
    Publication date: June 18, 2009
    Inventors: Imad Yousif, Anchel Sheyner, Ajit Balakrishna, Nancy Fung, Ying Rui, Martin Jeffrey Salinas, Walter R. Merry, Shahid Rauf
  • Publication number: 20080179287
    Abstract: A process is provided for removing polymer from a backside of a workpiece. The process includes supporting the workpiece on the backside in a vacuum chamber while leaving a peripheral annular portion of the backside exposed. Gas flow is confined at the edge of the workpiece within a gap at the edge of the workpiece, the gap configured to be on the order of about 1% of the diameter of the chamber, the gap defining a boundary between an upper process zone containing the front side and a lower process zone containing the backside. The process further includes evacuating the lower process zone, generating a plasma in an external chamber from a polymer etch precursor gas, and introducing a by-product from the plasma into the lower process zone. The process further includes pumping a purge gas into the upper process zone to remove polymer etch species from the upper process zone.
    Type: Application
    Filed: March 14, 2007
    Publication date: July 31, 2008
    Inventors: Kenneth S. Collins, Hirojii Hanawa, Andrew Nguyen, Ajit Balakrishna, David Palagashvili, James P. Cruse, Jennifer Y. Sun, Valentin N. Todorow, Shahid Rauf, Kartik Ramaswamy, Gerhard M. Schneider, Imad Yousif, Martin Jeffrey Salinas
  • Publication number: 20080179291
    Abstract: A process is provided for removing polymer from a backside of a workpiece and/or photoresist from a front side of the workpiece. For backside polymer removal, the wafer is positioned near the ceiling to above a localized or remote plasma source having a side outlet through the sidewall of the chamber, and backside polymer is removed by rotating the workpiece while flowing plasma by-products from the side outlet to the wafer backside. For front side photoresist removal, the wafer is positioned away from the ceiling and below the side outlet of the localized plasma source, and front side photoresist is remove by rotating the workpiece while flowing plasma by-products from the side outlet to the wafer front side.
    Type: Application
    Filed: May 8, 2007
    Publication date: July 31, 2008
    Inventors: Kenneth S. Collins, Hiroji Hanawa, Andrew Nguyen, Shahid Rauf, Ajit Balakrishna, Valentin N. Todorow, Kartik Ramaswamy, Martin Jeffrey Salinas, Imad Yousif, Walter R. Merry, Ying Rui, Michael R. Rice
  • Publication number: 20080179009
    Abstract: A reactor is provided for removing polymer from a backside of a workpiece. The reactor includes a vacuum chamber having a ceiling, a floor and a cylindrical side wall. A workpiece support apparatus within the chamber is configured to support a workpiece thereon so that the workpiece has its front side facing the ceiling. The support apparatus leaves at least an annular periphery of the backside of the workpiece exposed. A confinement member defines a narrow gap with the outer edge of the workpiece, the narrow gap being on the order of about 1% of the workpiece diameter, the narrow gap corresponding to a boundary dividing the chamber between an upper process zone and a lower process zone. A vacuum pump is coupled to the lower process zone.
    Type: Application
    Filed: March 14, 2007
    Publication date: July 31, 2008
    Inventors: KENNETH S. COLLINS, Hiroji Hanawa, Andrew Nguyen, Ajit Balakrishna, David Palagashvili, James P. Cruse, Jennifer Y. Sun, Valentin N. Todorow, Shahid Rauf, Kartik Ramaswamy, Gerhard M. Schneider, Imad Yousif, Martin Jeffrey Salinas
  • Publication number: 20080179008
    Abstract: A reactor is provided for removing polymer from a backside of a workpiece. The reactor includes a vacuum chamber having a ceiling, a floor and a cylindrical side wall. A workpiece support apparatus within the chamber is configured to support a workpiece thereon, so that the workpiece has its front side facing the ceiling. The support apparatus leaves at least an annular periphery of the backside of the workpiece exposed. A confinement member defines a narrow gap with the outer edge of the workpiece, the narrow gap being on the order of about 1% of workpiece diameter, the narrow gap corresponding to a boundary dividing the chamber between an upper process zone and a lower process zone. A vacuum pump is coupled to the lower process zone. A lower external plasma-generating chamber introduces a plasma by-product into the lower process zone and a supply of a polymer etch precursor gas coupled to the lower external plasma-generating chamber.
    Type: Application
    Filed: March 14, 2007
    Publication date: July 31, 2008
    Inventors: Kenneth S. Collins, Hiroji Hanawa, Andrew Nguyen, Ajit Balakrishna, David Palagashvili, James P. Cruse, Jennifer Y. Sun, Valentin N. Todorov, Shahid Rauf, Kartik Ramaswamy, Gerhard M. Schneider, Imad Yousif, Martin Jeffrey Salinas
  • Publication number: 20080179289
    Abstract: A process is provided for removing polymer from a backside of a workpiece. The process includes supporting the workpiece on the backside in a vacuum chamber while leaving a peripheral annular portion of the backside exposed. The process further includes confining gas flow at an edge of the workpiece within a gap at the edge of the workpiece on the order of about 1% of the diameter of the chamber, the gap defining a boundary between an upper process zone containing the front side and a lower process zone containing the backside. A first plasma is generated in a local plasma chamber from a polymer etch precursor gas. The process includes directing a localized stream of an etchant by-product from the first plasma onto a target portion of the backside of the workpiece, the target portion having a diameter corresponding to a diameter of the stream, while rotating the workpiece.
    Type: Application
    Filed: March 14, 2007
    Publication date: July 31, 2008
    Inventors: KENNETH S. COLLINS, Hiroji Hanawa, Andrew Nguyen, Ajit Balakrishna, David Palagashvili, James P. Cruse, Jennifer Y. Sun, Valentin N. Todorov, Shahid Rauf, Kartik Ramaswamy, Gerhard M. Schneider, Imad Yousif, Martin Jeffrey Salinas
  • Publication number: 20080179007
    Abstract: A reactor is provided for removing polymer from a backside of a workpiece. The reactor includes a vacuum chamber having a ceiling, a floor and a cylindrical side wall. The reactor further includes workpiece support apparatus within the chamber configured for a workpiece to be placed thereon with its front side facing the ceiling. The support apparatus is configured to leave at least an annular periphery of the backside of the workpiece exposed. A confinement member defines a narrow gap with an outer edge of the workpiece, the narrow gap being on the order of about 1% of the workpiece diameter, the narrow gap corresponding to a boundary dividing the chamber between an upper process zone and a lower process zone, the reactor further comprising a vacuum pump coupled to the lower process zone.
    Type: Application
    Filed: March 14, 2007
    Publication date: July 31, 2008
    Inventors: KENNETH S. COLLINS, Hiroji Hanawa, Andrew Nguyen, Ajit Balakrishna, David Palagashvili, James P. Cruse, Jennifer Y. Sun, Valentin N. Todorow, Shahid Rauf, Kartik Ramaswamy, Gerhard M. Schneider, Imad Yousif, Martin Jeffrey Salinas
  • Publication number: 20080179290
    Abstract: A workpiece is supported on the backside in a vacuum chamber while leaving at least a peripheral annular portion of a backside of the workpiece exposed. The process first increases the temperature of the workpiece starting at a temperature below about 200 degrees C. The edge of the workpiece is confined so as to establish a gap at the edge on the order of about 1% of the diameter of the chamber, the gap corresponding to a boundary between an upper process zone containing the front side and a lower process zone containing the backside. Before the workpiece temperature exceeds about 200 degrees C., backside polymer is removed using a first plasma containing polymer etch species in the lower process zone. After the workpiece temperature reaches about 300 degrees C., photoresist is stripped from the workpiece front side using by-products of a second plasma containing a photoresist strip species in the upper process zone.
    Type: Application
    Filed: March 14, 2007
    Publication date: July 31, 2008
    Inventors: Kenneth S. Collins, Hiroji Hanawa, Andrew Nguyen, Ajit Balakrishna, David Palagashvili, James P. Cruse, Jennifer Y. Sun, Valentin N. Todorow, Shahid Rauf, Kartik Ramaswamy, Gerhard M. Schneider, Imad Yousif, Martin Jeffrey Salinas
  • Publication number: 20080179288
    Abstract: A process is provided for removing polymer from a backside of a workpiece. The process includes supporting the workpiece on the backside in a vacuum chamber while leaving a peripheral annular portion of the backside exposed. The process further includes confining gas flow at the edge of the workpiece within a gap at the edge of the workpiece on the order of about 1% of the diameter of the chamber, the gap defining a boundary between an upper process zone containing the front side and a lower process zone containing the backside. A first plasma is generated in a lower external chamber from a polymer etch precursor gas, and an etchant by-product is introduced from the first plasma into the lower process zone. A second plasma is generated in an upper external plasma chamber from a precursor gas of a scavenger of the etchant by-product, and scavenger species are introduced from the second plasma into the upper process zone.
    Type: Application
    Filed: March 14, 2007
    Publication date: July 31, 2008
    Inventors: KENNETH S. COLLINS, Hiroji Hanawa, Andrew Nguyen, Ajit Balakrishna, David Palagashvili, James P. Cruse, Jennifer Y. Sun, Valentin N. Todorow, Shahid Rauf, Kartik Ramaswamy, Gerhard M. Schneider, Imad Yousif, Martin Jeffrey Salinas
  • Publication number: 20080178913
    Abstract: A process is provided for removing polymer from a backside of a workpiece. The process includes supporting the workpiece on the backside in a vacuum chamber while leaving at least a peripheral annular portion of the backside exposed. The process further includes confining gas flow at the edge of the workpiece within a gap at the edge of the workpiece on the order of about 1% of the diameter of the chamber, the gap defining a boundary between an upper process zone containing the wafer front side and a lower process zone containing the wafer backside. The process also includes providing a polymer etch precursor gas underneath the backside edge of the workpiece and applying RF power to a region underlying the backside edge of the workpiece to generate a first plasma of polymer etch species concentrated in an annular ring concentric with and underneath the backside edge of the workpiece.
    Type: Application
    Filed: March 14, 2007
    Publication date: July 31, 2008
    Inventors: KENNETH S. COLLINS, Hiroji Hanawa, Andrew Nguyen, Ajit Balakrishna, David Palagashvili, James P. Cruse, Jennifer Y. Sun, Valentin N. Todorow, Shahid Rauf, Kartik Ramaswamy, Gerhard M. Schneider, Imad Yousif, Martin Jeffrey Salinas
  • Publication number: 20070218644
    Abstract: The present invention generally describes one or more apparatuses and various methods that are used to perform an annealing process on desired regions of a substrate. In one embodiment, an amount of energy is delivered to the surface of the substrate to preferentially melt certain desired regions of the substrate to remove unwanted damage created from prior processing steps (e.g., crystal damage from implant processes), more evenly distribute dopants in various regions of the substrate, and/or activate various regions of the substrate. The preferential melting processes will allow more uniform distribution of the dopants in the melted region, due to the increased diffusion rate and solubility of the dopant atoms in the molten region of the substrate. The creation of a melted region thus allows: 1) the dopant atoms to redistribute more uniformly, 2) defects created in prior processing steps to be removed, and 3) regions that have hyper-abrupt dopant concentrations to be formed.
    Type: Application
    Filed: July 25, 2006
    Publication date: September 20, 2007
    Inventors: Ajit Balakrishna, Paul Carey, Dean Jennings, Abhilash J. Mayur, Stephen Moffatt, William Schaffer, Mark Yam
  • Patent number: 7041931
    Abstract: In a system for thermal processing of a semiconductor substrate, a reflector plate has a stepped surface facing the substrate during heating and cooling of the substrate. The raised surface of the reflector plate has reduced reflectivity, providing advantages during, among other things, cooling of the substrate. The reflector plate also includes a number of recesses to which one or more pyrometers are coupled. These recesses have a highly reflective surface, providing advantages in the performance of the pyrometers.
    Type: Grant
    Filed: October 24, 2002
    Date of Patent: May 9, 2006
    Assignee: Applied Materials, Inc.
    Inventors: Dean Jennings, Joseph M. Ranish, Brian Haas, Ajit Balakrishna, Sundar Ramamurthy, Aaron Hunter, Mark Yam
  • Patent number: 6803546
    Abstract: A thermal processing method is described in which a temperature response of a substrate may be controlled during a heat-up phase or a cool-down phase, or during both phases. This reduces the thermal budget of the substrate and improves the quality and performance of devices formed on the substrate. In particular, by controlling the rate of heat transfer between the substrate and a thermal reservoir (e.g., a water-cooled reflector plate assembly), the temperature response of the substrate may be controlled during the thermal process. The rate of heat transfer may be changed by changing the thermal conductivity between the substrate and the thermal reservoir, by changing the emissivity of a surface of the thermal reservoir, or by changing the distance between the substrate and the thermal reservoir.
    Type: Grant
    Filed: July 6, 2000
    Date of Patent: October 12, 2004
    Assignee: Applied Materials, Inc.
    Inventors: Ryan C Boas, Ajit Balakrishna, Benjamin Bierman, Brian L Haas, Dean Jennings, Wolfgang Aderhold, Sundar Ramamurthy, Abhilash Mayur
  • Publication number: 20040079746
    Abstract: In a system for thermal processing of a semiconductor substrate, a reflector plate has a stepped surface facing the substrate during heating and cooling of the substrate. The raised surface of the reflector plate has reduced reflectivity, providing advantages during, among other things, cooling of the substrate. The reflector plate also includes a number of recesses to which one or more pyrometers are coupled. These recesses have a highly reflective surface, providing advantages in the performance of the pyrometers.
    Type: Application
    Filed: October 24, 2002
    Publication date: April 29, 2004
    Applicant: Applied Materials, Inc.
    Inventors: Dean Jennings, Joseph M. Ranish, Brian Haas, Ajit Balakrishna, Sundar Ramamurthy, Aaron Hunter, Mark Yam
  • Patent number: 6215106
    Abstract: A thermal processing method is described in which a temperature response of a substrate may be controlled during a heat-up phase or a cool-down phase, or during both phases. This reduces the thermal budget of the substrate and improves the quality and performance of devices formed on the substrate. In particular, by controlling the rate of heat transfer between the substrate and a thermal reservoir (e.g., a watercooled reflector plate assembly), the temperature response of the substrate may be controlled during the thermal process. The rate of heat transfer may changed by changing the thermal conductivity between the substrate and the thermal reservoir, by changing the emissivity of a surface of the thermal reservoir, or by changing the distance between the substrate and the thermal reservoir. The thermal conductivity may be changed by changing the characteristics of a thermal transport medium (e.g., a purge gas) located between the substrate and the thermal reservoir.
    Type: Grant
    Filed: July 8, 1999
    Date of Patent: April 10, 2001
    Assignee: Applied Materials, Inc.
    Inventors: Ryan C. Boas, Ajit Balakrishna, Benjamin B. Bierman, Brian L. Haas, Dean Jennings, Wolfgang R. Aderhold