Patents by Inventor Somit Talwar

Somit Talwar 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: 7879741
    Abstract: Apparatus and method for performing laser thermal annealing (LTA) of a substrate using an annealing radiation beam that is not substantially absorbed in the substrate at room temperature. The method takes advantage of the fact that the absorption of long wavelength radiation (1 micron or greater) in some substrates, such as undoped silicon substrates, is a strong function of temperature. The method includes heating the substrate to a critical temperature where the absorption of long-wavelength annealing radiation is substantial, and then irradiating the substrate with the annealing radiation to generate a temperature capable of annealing the substrate.
    Type: Grant
    Filed: June 29, 2006
    Date of Patent: February 1, 2011
    Assignee: Ultratech, Inc.
    Inventors: Somit Talwar, Michael O. Thompson, Boris Grek, David A. Markle
  • Patent number: 7763828
    Abstract: A method and apparatus for performing laser thermal processing (LTP) using a two-dimensional array of laser diodes to form a line image, which is scanned across a substrate. The apparatus includes a two-dimensional array of laser diodes, the radiation from which is collimated in one plane using a cylindrical lens array, and imaged onto the substrate as a line image using an anomorphic, telecentric optical imaging system. The apparatus also includes a scanning substrate stage for supporting a substrate to be LTP processed. The laser diode radiation beam is incident on the substrate at angles at or near the Brewster's angle for the given substrate material and the wavelength of the radiation beam, which is linearly P-polarized. The use of a two-dimensional laser diode array allows for a polarized radiation beam of relatively high energy density to be delivered to the substrate, thereby allowing for LTP processing with good uniformity, reasonably short dwell times, and thus reasonably high throughput.
    Type: Grant
    Filed: September 2, 2003
    Date of Patent: July 27, 2010
    Assignee: Ultratech, Inc.
    Inventors: Somit Talwar, David A. Markle
  • Patent number: 7731798
    Abstract: A chuck for supporting a wafer and maintaining a constant background temperature across the wafer during laser thermal processing (LTP) is disclosed. The chuck includes a heat sink and a thermal mass in the form of a heater module. The heater module is in thermal communication with the heat sink, but is physically separated therefrom by a thermal insulator layer. The thermal insulator maintains a substantially constant power loss at least equal to the maximum power delivered by the laser, less that lost by radiation and convection. A top plate is arranged atop the heater module, supports the wafer to be processed, and provides a contamination barrier. The heater module is coupled to a power supply that is adapted to provide varying amounts of power to the heater module to maintain the heater module at the constant background temperature even when the wafer experiences a spatially and temporally varying heat load from an LTP laser beam.
    Type: Grant
    Filed: December 1, 2004
    Date of Patent: June 8, 2010
    Assignee: Ultratech, Inc.
    Inventors: Iqbal A. Shareef, Igor Landau, David A. Markle, Somit Talwar, Michael O. Thompson, Ivelin A. Angelov, Senquan Zhou
  • Publication number: 20090095724
    Abstract: A method and apparatus for performing laser thermal processing (LTP) using one or more two-dimensional arrays of laser diodes and corresponding one or more LTP optical systems to form corresponding one or more line images. The line images are scanned across a substrate, e.g., by moving the substrate relative to the one or more line images. The apparatus also includes one or more recycling optical systems arranged to re-image reflected annealing radiation back onto the substrate. The use of one or more recycling optical systems greatly improves the heating efficiency and uniformity during LTP.
    Type: Application
    Filed: December 9, 2008
    Publication date: April 16, 2009
    Applicant: ULTRATECH, INC.
    Inventors: Somit Talwar, David A. Markle
  • Patent number: 7494942
    Abstract: A method for performing laser thermal annealing (LTA) of a substrate using an annealing radiation beam that is not substantially absorbed in the substrate at room temperature. The method takes advantage of the fact that the absorption of long wavelength radiation (1 micron or greater) in some substrates, such as undoped silicon substrates, is a strong function of temperature. The method includes preheating a portion of the substrate to a critical temperature where the absorption of long-wavelength annealing radiation is substantial, and then irradiating the portion of the substrate with the annealing radiation to generate a temperature capable of annealing the portion of the substrate.
    Type: Grant
    Filed: July 6, 2006
    Date of Patent: February 24, 2009
    Assignee: Ultratech, Inc.
    Inventors: Somit Talwar, David A. Markle
  • Patent number: 7399945
    Abstract: Apparatus and methods for thermally processing a substrate with scanned laser radiation are disclosed. The apparatus includes a continuous radiation source and an optical system that forms an image on a substrate. The image is scanned relative to the substrate surface so that each point in the process region receives a pulse of radiation sufficient to thermally process the region.
    Type: Grant
    Filed: November 3, 2006
    Date of Patent: July 15, 2008
    Assignee: Ultratech, Inc.
    Inventors: Somit Talwar, David A. Markle
  • Patent number: 7326877
    Abstract: Chuck methods and apparatus for supporting a semiconductor substrate and maintaining it at a substantially constant background temperature even when subject to a spatially and temporally varying thermal load. Chuck includes a thermal compensating heater module having a sealed chamber containing heater elements, a wick, and an alkali metal liquid/vapor. The chamber employs heat pipe principles to equalize temperature differences in the module. The spatially varying thermal load is quickly made uniform by thermal conductivity of the heater module. Heatsinking a constant amount of heat from the bottom of the heater module accommodates large temporal variations in the thermal heat load. Constant heat loss is preferably made to be at least as large as the maximum variation in the input heat load, less heat lost through radiation and convection, thus requiring a heat input through electrical heating elements. This allows for temperature control of the chuck, and hence the substrate.
    Type: Grant
    Filed: December 1, 2004
    Date of Patent: February 5, 2008
    Assignee: Ultratech, Inc.
    Inventors: Iqbal A. Shareef, Igor Landau, David A. Markle, Somit Talwar, Michael O. Thompson, Ivelin A. Angelov, Senquan Zhou
  • Publication number: 20070051708
    Abstract: Apparatus and methods for thermally processing a substrate with scanned laser radiation are disclosed. The apparatus includes a continuous radiation source and an optical system that forms an image on a substrate. The image is scanned relative to the substrate surface so that each point in the process region receives a pulse of radiation sufficient to thermally process the region.
    Type: Application
    Filed: November 3, 2006
    Publication date: March 8, 2007
    Inventors: Somit Talwar, David Markle
  • Publication number: 20070004232
    Abstract: Chuck methods and apparatus for supporting a semiconductor substrate and maintaining it at a substantially constant background temperature even when subject to a spatially and temporally varying thermal load. Chuck includes a thermal compensating heater module having a sealed chamber containing heater elements, a wick, and an alkali metal liquid/vapor. The chamber employs heat pipe principles to equalize temperature differences in the module. The spatially varying thermal load is quickly made uniform by thermal conductivity of the heater module. Heatsinking a constant amount of heat from the bottom of the heater module accommodates large temporal variations in the thermal heat load. Constant heat loss is preferably made to be at least as large as the maximum variation in the input heat load, less heat lost through radiation and convection, thus requiring a heat input through electrical heating elements. This allows for temperature control of the chuck, and hence the substrate.
    Type: Application
    Filed: December 1, 2004
    Publication date: January 4, 2007
    Inventors: Iqbal Shareef, Igor Landau, David Markle, Somit Talwar, Michael Thompson, Ivelin Angelov, Senquan Zhou
  • Patent number: 7157660
    Abstract: Apparatus and methods for thermally processing a substrate with scanned laser radiation are disclosed. The apparatus includes a continuous radiation source and an optical system that forms an image on a substrate. The image is scanned relative to the substrate surface so that each point in the process region receives a pulse of radiation sufficient to thermally process the region.
    Type: Grant
    Filed: March 22, 2004
    Date of Patent: January 2, 2007
    Assignee: Ultratech, Inc.
    Inventors: Somit Talwar, Michael O. Thompson, David A. Markle
  • Patent number: 7154066
    Abstract: Apparatus and methods for thermally processing a substrate with scanned laser radiation are disclosed. The apparatus includes a continuous radiation source and an optical system that forms an image on a substrate. The image is scanned relative to the substrate surface so that each point in the process region receives a pulse of radiation sufficient to thermally process the region.
    Type: Grant
    Filed: February 26, 2004
    Date of Patent: December 26, 2006
    Assignee: Ultratech, Inc.
    Inventors: Somit Talwar, David A. Markle
  • Patent number: 7148159
    Abstract: Apparatus and method for performing laser thermal annealing (LTA) of a substrate using an annealing radiation beam that is not substantially absorbed in the substrate at room temperature. The method takes advantage of the fact that the absorption of long wavelength radiation (1 micron or greater) in some substrates, such as undoped silicon substrates, is a strong function of temperature. The method includes heating the substrate to a critical temperature where the absorption of long-wavelength annealing radiation is substantial, and then irradiating the substrate with the annealing radiation to generate a temperature capable of annealing the substrate.
    Type: Grant
    Filed: September 29, 2003
    Date of Patent: December 12, 2006
    Assignee: Ultratech, Inc.
    Inventors: Somit Talwar, Michael O. Thompson, Boris Grek, David A. Markle
  • Patent number: 7145104
    Abstract: An apparatus and method for uniformizing the temperature distribution across a semiconductor wafer during radiation annealing of process regions formed in the wafer is disclosed. The method includes forming a silicon layer atop the upper surface of the wafer and irradiating the layer with one or more pulses of radiation having wavelengths that are substantially absorbed by the silicon layer. The silicon layer acts to uniformly absorb the one or more radiation pulses and then transfers the heat from the absorbed radiation to the process regions across the wafer.
    Type: Grant
    Filed: February 26, 2004
    Date of Patent: December 5, 2006
    Assignee: Ultratech, Inc.
    Inventors: Somit Talwar, Michael O. Thompson
  • Publication number: 20060252282
    Abstract: Apparatus and method for performing laser thermal annealing (LTA) of a substrate using an annealing radiation beam that is not substantially absorbed in the substrate at room temperature. The method takes advantage of the fact that the absorption of long wavelength radiation (1 micron or greater) in some substrates, such as undoped silicon substrates, is a strong function of temperature. The method includes heating the substrate to a critical temperature where the absorption of long-wavelength annealing radiation is substantial, and then irradiating the substrate with the annealing radiation to generate a temperature capable of annealing the substrate.
    Type: Application
    Filed: July 6, 2006
    Publication date: November 9, 2006
    Inventors: Somit Talwar, David Markle
  • Publication number: 20060246694
    Abstract: Apparatus and method for performing laser thermal annealing (LTA) of a substrate using an annealing radiation beam that is not substantially absorbed in the substrate at room temperature. The method takes advantage of the fact that the absorption of long wavelength radiation (1 micron or greater) in some substrates, such as undoped silicon substrates, is a strong function of temperature. The method includes heating the substrate to a critical temperature where the absorption of long-wavelength annealing radiation is substantial, and then irradiating the substrate with the annealing radiation to generate a temperature capable of annealing the substrate.
    Type: Application
    Filed: June 29, 2006
    Publication date: November 2, 2006
    Inventors: Somit Talwar, Michael Thompson, Boris Grek, David Markle
  • Patent number: 7098155
    Abstract: Apparatus and method for performing laser thermal annealing (LTA) of a substrate using an annealing radiation beam that is not substantially absorbed in the substrate at room temperature. The method takes advantage of the fact that the absorption of long wavelength radiation (1 micron or greater) in some substrates, such as undoped silicon substrates, is a strong function of temperature. The method includes heating the substrate to a critical temperature where the absorption of long-wavelength annealing radiation is substantial, and then irradiating the substrate with the annealing radiation to generate a temperature capable of annealing the substrate.
    Type: Grant
    Filed: January 22, 2004
    Date of Patent: August 29, 2006
    Assignee: Ultratech, Inc.
    Inventors: Somit Talwar, David A. Markle
  • Publication number: 20060113290
    Abstract: A chuck for supporting a wafer and maintaining a constant background temperature across the wafer during laser thermal processing (LTP) is disclosed. The chuck includes a heat sink and a thermal mass in the form of a heater module. The heater module is in thermal communication with the heat sink, but is physically separated therefrom by a thermal insulator layer. The thermal insulator maintains a substantially constant power loss at least equal to the maximum power delivered by the laser, less that lost by radiation and convection. A top plate is arranged atop the heater module, supports the wafer to be processed, and provides a contamination barrier. The heater module is coupled to a power supply that is adapted to provide varying amounts of power to the heater module to maintain the heater module at the constant background temperature even when the wafer experiences a spatially and temporally varying heat load from an LTP laser beam.
    Type: Application
    Filed: December 1, 2004
    Publication date: June 1, 2006
    Inventors: Iqbal Shareef, Igor Landau, David Markle, Somit Talwar, Michael Thompson, Ivelin Angelov, Senquan Zhou
  • Publication number: 20050189340
    Abstract: An apparatus and method for uniformizing the temperature distribution across a semiconductor wafer during radiation annealing of process regions formed in the wafer is disclosed. The method includes forming a silicon layer atop the upper surface of the wafer and irradiating the layer with one or more pulses of radiation having wavelengths that are substantially absorbed by the silicon layer. The silicon layer acts to uniformly absorb the one or more radiation pulses and then transfers the heat from the absorbed radiation to the process regions across the wafer.
    Type: Application
    Filed: February 26, 2004
    Publication date: September 1, 2005
    Inventors: Somit Talwar, Michael Thompson
  • Publication number: 20050189329
    Abstract: A method and apparatus for performing laser thermal processing (LTP) using one or more two-dimensional arrays of laser diodes and corresponding one or more LTP optical systems to form corresponding one or more line images. The line images are scanned across a substrate, e.g., by moving the substrate relative to the one or more line images. The apparatus also includes one or more recycling optical systems arranged to re-image reflected annealing radiation back onto the substrate. The use of one or more recycling optical systems greatly improves the heating efficiency and uniformity during LTP.
    Type: Application
    Filed: May 3, 2004
    Publication date: September 1, 2005
    Inventors: Somit Talwar, David Markle
  • Publication number: 20050103998
    Abstract: Apparatus and method for performing laser thermal annealing (LTA) of a substrate using an annealing radiation beam that is not substantially absorbed in the substrate at room temperature. The method takes advantage of the fact that the absorption of long wavelength radiation (1 micron or greater) in some substrates, such as undoped silicon substrates, is a strong function of temperature. The method includes heating the substrate to a critical temperature where the absorption of long-wavelength annealing radiation is substantial, and then irradiating the substrate with the annealing radiation to generate a temperature capable of annealing the substrate.
    Type: Application
    Filed: January 22, 2004
    Publication date: May 19, 2005
    Inventors: Somit Talwar, David Markle