Patents by Inventor Naoto HOJO

Naoto HOJO 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: 11355515
    Abstract: Fabricating a three-dimensional memory device may include forming an alternating stack of insulating layers and sacrificial material layers over a substrate. Stepped surfaces are formed by patterning the alternating stack. Sacrificial pads are formed on physically exposed horizontal surfaces of the sacrificial material layers. A retro-stepped dielectric material portion is formed over the sacrificial pads. After memory stack structures extending through the alternating stack are formed, the sacrificial material layers and the sacrificial pads can be replaced with replacement material portions that include electrically conductive layers. The electrically conductive layers can be formed with thicker end portions. Contact via structures can be formed on the thicker end portions.
    Type: Grant
    Filed: May 21, 2020
    Date of Patent: June 7, 2022
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Naoto Hojo, Takahiro Tabira, Yoshitaka Otsu
  • Patent number: 10971514
    Abstract: A multi-tier three-dimensional memory array includes multiple alternating stacks of insulating layers and electrically conductive layers that are vertically stacked. Memory stack structures including memory films and semiconductor channels extend through the alternating stacks. The alternating stacks are formed as alternating stacks of insulating layers and sacrificial material layers, and are subsequently modified by replacing the sacrificial material layers with electrically conductive layers. Structural support during replacement of the sacrificial material layers with the electrically conductive layers is provided by the memory stack structures and dielectric support pillar structures. The dielectric support pillar structures may be formed only for a first-tier structure including a first-tier alternating stack of first insulating layers and first spacer material layers, or may vertically extend over multiple tiers.
    Type: Grant
    Filed: February 15, 2019
    Date of Patent: April 6, 2021
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Yoshitaka Otsu, Kei Nozawa, Yashushi Doda, Naoto Hojo, Yoshinobu Tanaka, Koichi Ito, Zhiwei Chen, Yusuke Ikawa, Takeshi Kawamura, Ryoichi Ehara
  • Patent number: 10957706
    Abstract: A multi-tier three-dimensional memory array includes multiple alternating stacks of insulating layers and electrically conductive layers that are vertically stacked. Memory stack structures including memory films and semiconductor channels extend through the alternating stacks. The alternating stacks are formed as alternating stacks of insulating layers and sacrificial material layers, and are subsequently modified by replacing the sacrificial material layers with electrically conductive layers. Structural support during replacement of the sacrificial material layers with the electrically conductive layers is provided by the memory stack structures and dielectric support pillar structures. The dielectric support pillar structures may be formed only for a first-tier structure including a first-tier alternating stack of first insulating layers and first spacer material layers, or may vertically extend over multiple tiers.
    Type: Grant
    Filed: February 15, 2019
    Date of Patent: March 23, 2021
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Yoshitaka Otsu, Kei Nozawa, Yashushi Doda, Naoto Hojo, Yoshinobu Tanaka, Koichi Ito
  • Patent number: 10879264
    Abstract: An alternating layer stack of insulating layers and sacrificial material layers is formed over a semiconductor substrate, and memory stack structures are formed through the vertically-alternating layer stack. A pair of unconnected barrier trenches or a moat trench is formed through the alternating stack concurrently with formation of backside trenches. Backside recesses are formed by isotropically etching the sacrificial material layers selective to the insulating layers while a dielectric liner covers the barrier trenches or the moat trench. A vertically alternating sequence of the insulating plates and the dielectric spacer plates is provided between the pair of barrier trenches or inside the moat trench. Electrically conductive layers are formed in the backside recesses. A first conductive via structure is formed through the vertically alternating sequence concurrently with formation of a second conductive via structure through a dielectric material portion adjacent to the alternating stack.
    Type: Grant
    Filed: June 18, 2019
    Date of Patent: December 29, 2020
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Yoshitaka Otsu, Kei Nozawa, Naoto Hojo
  • Publication number: 20200402905
    Abstract: An alternating layer stack of insulating layers and sacrificial material layers is formed over a semiconductor substrate, and memory stack structures are formed through the vertically-alternating layer stack. A pair of unconnected barrier trenches or a moat trench is formed through the alternating stack concurrently with formation of backside trenches. Backside recesses are formed by isotropically etching the sacrificial material layers selective to the insulating layers while a dielectric liner covers the barrier trenches or the moat trench. A vertically alternating sequence of the insulating plates and the dielectric spacer plates is provided between the pair of barrier trenches or inside the moat trench. Electrically conductive layers are formed in the backside recesses. A first conductive via structure is formed through the vertically alternating sequence concurrently with formation of a second conductive via structure through a dielectric material portion adjacent to the alternating stack.
    Type: Application
    Filed: June 18, 2019
    Publication date: December 24, 2020
    Inventors: Yoshitaka OTSU, Kei NOZAWA, Naoto HOJO, Hirofumi TOKITA, Eiji HAYASHI, Masanori TERAHARA
  • Publication number: 20200402992
    Abstract: An alternating layer stack of insulating layers and sacrificial material layers is formed over a semiconductor substrate, and memory stack structures are formed through the vertically-alternating layer stack. A pair of unconnected barrier trenches or a moat trench is formed through the alternating stack concurrently with formation of backside trenches. Backside recesses are formed by isotropically etching the sacrificial material layers selective to the insulating layers while a dielectric liner covers the barrier trenches or the moat trench. A vertically alternating sequence of the insulating plates and the dielectric spacer plates is provided between the pair of barrier trenches or inside the moat trench. Electrically conductive layers are formed in the backside recesses. A first conductive via structure is formed through the vertically alternating sequence concurrently with formation of a second conductive via structure through a dielectric material portion adjacent to the alternating stack.
    Type: Application
    Filed: June 18, 2019
    Publication date: December 24, 2020
    Inventors: Yoshitaka OTSU, Kei NOZAWA, Naoto HOJO
  • Patent number: 10872857
    Abstract: An alternating layer stack of insulating layers and sacrificial material layers is formed over a semiconductor substrate, and memory stack structures are formed through the vertically-alternating layer stack. A pair of unconnected barrier trenches or a moat trench is formed through the alternating stack concurrently with formation of backside trenches. Backside recesses are formed by isotropically etching the sacrificial material layers selective to the insulating layers while a dielectric liner covers the barrier trenches or the moat trench. A vertically alternating sequence of the insulating plates and the dielectric spacer plates is provided between the pair of barrier trenches or inside the moat trench. Electrically conductive layers are formed in the backside recesses. A first conductive via structure is formed through the vertically alternating sequence concurrently with formation of a second conductive via structure through a dielectric material portion adjacent to the alternating stack.
    Type: Grant
    Filed: June 18, 2019
    Date of Patent: December 22, 2020
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Yoshitaka Otsu, Kei Nozawa, Naoto Hojo, Hirofumi Tokita, Eiji Hayashi, Masanori Terahara
  • Publication number: 20200286916
    Abstract: Fabricating a three-dimensional memory device may include forming an alternating stack of insulating layers and sacrificial material layers over a substrate. Stepped surfaces are formed by patterning the alternating stack. Sacrificial pads are formed on physically exposed horizontal surfaces of the sacrificial material layers. A retro-stepped dielectric material portion is formed over the sacrificial pads. After memory stack structures extending through the alternating stack are formed, the sacrificial material layers and the sacrificial pads can be replaced with replacement material portions that include electrically conductive layers. The electrically conductive layers can be formed with thicker end portions. Contact via structures can be formed on the thicker end portions.
    Type: Application
    Filed: May 21, 2020
    Publication date: September 10, 2020
    Inventors: Naoto Hojo, Takahiro Tabira, Yoshitaka Otsu
  • Patent number: 10700089
    Abstract: Fabricating a three-dimensional memory device may include forming an alternating stack of insulating layers and sacrificial material layers over a substrate. Stepped surfaces are formed by patterning the alternating stack. Sacrificial pads are formed on physically exposed horizontal surfaces of the sacrificial material layers. A retro-stepped dielectric material portion is formed over the sacrificial pads. After memory stack structures extending through the alternating stack are formed, the sacrificial material layers and the sacrificial pads can be replaced with replacement material portions that include electrically conductive layers. The electrically conductive layers can be formed with thicker end portions. Contact via structures can be formed on the thicker end portions.
    Type: Grant
    Filed: February 12, 2019
    Date of Patent: June 30, 2020
    Assignee: SANDISK TECHNOLOGIES LLC
    Inventors: Naoto Hojo, Takahiro Tabira, Yoshitaka Otsu
  • Publication number: 20200127005
    Abstract: A multi-tier three-dimensional memory array includes multiple alternating stacks of insulating layers and electrically conductive layers that are vertically stacked. Memory stack structures including memory films and semiconductor channels extend through the alternating stacks. The alternating stacks are formed as alternating stacks of insulating layers and sacrificial material layers, and are subsequently modified by replacing the sacrificial material layers with electrically conductive layers. Structural support during replacement of the sacrificial material layers with the electrically conductive layers is provided by the memory stack structures and dielectric support pillar structures. The dielectric support pillar structures may be formed only for a first-tier structure including a first-tier alternating stack of first insulating layers and first spacer material layers, or may vertically extend over multiple tiers.
    Type: Application
    Filed: February 15, 2019
    Publication date: April 23, 2020
    Inventors: Yoshitaka OTSU, Kei NOZAWA, Yashushi DODA, Naoto HOJO, Yoshinobu TANAKA, Koichi ITO
  • Publication number: 20200127006
    Abstract: A multi-tier three-dimensional memory array includes multiple alternating stacks of insulating layers and electrically conductive layers that are vertically stacked. Memory stack structures including memory films and semiconductor channels extend through the alternating stacks. The alternating stacks are formed as alternating stacks of insulating layers and sacrificial material layers, and are subsequently modified by replacing the sacrificial material layers with electrically conductive layers. Structural support during replacement of the sacrificial material layers with the electrically conductive layers is provided by the memory stack structures and dielectric support pillar structures. The dielectric support pillar structures may be formed only for a first-tier structure including a first-tier alternating stack of first insulating layers and first spacer material layers, or may vertically extend over multiple tiers.
    Type: Application
    Filed: February 15, 2019
    Publication date: April 23, 2020
    Inventors: Yoshitaka OTSU, Kei NOZAWA, Yashushi DODA, Naoto HOJO, Yoshinobu TANAKA, Koichi ITO, Zhiwei CHEN, Yusuke IKAWA, Takeshi KAWAMURA, Ryoichi EHARA