Patents by Inventor Michael W. Keevan

Michael W. Keevan 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).

  • Primary distillation boron reduction
    Patent number: 10294109
    Abstract: The present invention relates to an apparatus and a method for producing polycrystalline silicon having a reduced amount of boron compound impurities. Especially, the boron compounds are removed from the process for producing polycrystalline silicon, while the trichlorosilane is purified by distillation. The invention feeds condensed liquid trichlorosilane into a primary distillation tower below the liquid level inside the primary distillation tower thereby scrubbing the boron impurities upon contact inside the primary distillation tower. There result is trichlorosilane leaving the primary distillation tower with total amount of boron at least 10 times less.
    Type: Grant
    Filed: January 16, 2018
    Date of Patent: May 21, 2019
    Assignees: MITSUBISHI POLYCRYSTALLINE SILICON AMERICA CORPORATION (MIPSA), MITSUBISHI MATERIALS CORPORATION
    Inventors: April Ashworth, Michael W. Keevan
  • PRIMARY DISTILLATION BORON REDUCTION
    Publication number: 20180141819
    Abstract: The present invention relates to an apparatus and a method for producing polycrystalline silicon having a reduced amount of boron compound impurities. Especially, the boron compounds are removed from the process for producing polycrystalline silicon, while the trichlorosilane is purified by distillation. The invention feeds condensed liquid trichlorosilane into a primary distillation tower below the liquid level inside the primary distillation tower thereby scrubbing the boron impurities upon contact inside the primary distillation tower. There result is trichlorosilane leaving the primary distillation tower with total amount of boron at least 10 times less.
    Type: Application
    Filed: January 16, 2018
    Publication date: May 24, 2018
    Inventors: April Ashworth, Michael W. Keevan
  • PRIMARY DISTILLATION BORON REDUCTION
    Publication number: 20160152481
    Abstract: The present invention relates to an apparatus and a method for producing polycrystalline silicon having a reduced amount of boron compound impurities. Especially, the boron compounds are removed from the process for producing polycrystalline silicon, while the trichlorosilane is purified by distillation. The invention feeds condensed liquid trichlorosilane into a primary distillation tower below the liquid level inside the primary distillation tower thereby scrubbing the boron impurities upon contact inside the primary distillation tower. There result is trichlorosilane leaving the primary distillation tower with total amount of boron at least 10 times less.
    Type: Application
    Filed: December 1, 2014
    Publication date: June 2, 2016
    Inventors: April Ashworth, Michael W. Keevan
  • Apparatus and method for producing polycrystalline silicon having a reduced amount of boron compounds by forming phosphorus-boron compounds
    Patent number: 8404205
    Abstract: The invention concerns an apparatus and a method for manufacturing polycrystalline silicon having a reduced amount of boron compounds. The invention provides an apparatus and a method which mix an unpurified trichlorosilane with purified hydrogen gas from an activated carbon tower. The mixture is sent to a distillation apparatus for purifying trichlorosilane.
    Type: Grant
    Filed: January 7, 2011
    Date of Patent: March 26, 2013
    Assignees: Mitsubishi Polycrystalline Silicon America Corporation (MIPSA), Mitsubishi Materials Corporation (MMC)
    Inventors: Laura Prine, Richard M. Halstead, Michael W. Keevan
  • APPARATUS AND METHOD FOR PRODUCING POLYCRYSTALLINE SILICON HAVING A REDUCED AMOUNT OF BORON COMPOUNDS BY FORMING PHOSPHORUS-BORON COMPOUNDS
    Publication number: 20120177559
    Abstract: The invention concerns an apparatus and a method for manufacturing polycrystalline silicon having a reduced amount of boron compounds. The invention provides an apparatus and a method which mix an unpurified trichlorosilane with purified hydrogen gas from an activated carbon tower. The mixture is sent to a distillation apparatus for purifying trichlorosilane.
    Type: Application
    Filed: January 7, 2011
    Publication date: July 12, 2012
    Applicants: Mitsubishi Materials Corporation, Mitsubishi Polycrystalline Silicon America Corporation (MIPSA)
    Inventors: Laura Prine, Richard M. Halstead, Michael W. Keevan