Patents by Inventor Toshiya Yokota

Toshiya Yokota 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).

  • Floating gate separation in NAND flash memory
    Patent number: 9595444
    Abstract: A method of forming a NAND flash memory includes anisotropically etching trenches of a gate stack down to an intermediate level in a floating gate polysilicon layer, leaving remaining portions of the floating gate polysilicon over the gate dielectric layer. Subsequently, forming a protective layer along exposed sides of the trenches. Then, electrically separating individual floating gates by a selective process that is directed to the remaining portions of the floating gate polysilicon layer exposed by trenches.
    Type: Grant
    Filed: May 14, 2015
    Date of Patent: March 14, 2017
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Toshiya Yokota, Atsushi Shimoda, Takuya Sakurai
  • Floating Gate Separation in NAND Flash Memory
    Publication number: 20160336182
    Abstract: A method of forming a NAND flash memory includes anisotropically etching trenches of a gate stack down to an intermediate level in a floating gate polysilicon layer, leaving remaining portions of the floating gate polysilicon over the gate dielectric layer. Subsequently, forming a protective layer along exposed sides of the trenches. Then, electrically separating individual floating gates by a selective process that is directed to the remaining portions of the floating gate polysilicon layer exposed by trenches.
    Type: Application
    Filed: May 14, 2015
    Publication date: November 17, 2016
    Inventors: Toshiya Yokota, Atsushi Shimoda, Takuya Sakurai
  • Wide and narrow patterning using common process
    Patent number: 9224744
    Abstract: A NAND flash memory chip includes narrow word lines that are directly patterned from sidewall spacers and larger structures that are patterned from sidewall spacers with covering material. Sidewall spacers with covering material define wider features than sidewalls alone. Closely spaced sidewalls with covering material define large structures such as contact pads and select lines.
    Type: Grant
    Filed: September 3, 2014
    Date of Patent: December 29, 2015
    Assignee: SanDisk Technologies Inc.
    Inventors: Toshiya Yokota, Chia-Lin Hsiung, Fumiaki Toyama