Patents by Inventor Naoya Tokiwa

Naoya Tokiwa 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: 10642537
    Abstract: A semiconductor memory includes a first plane that includes a first memory cell array, a second plane that includes a second memory cell array, and a control circuit that includes a first circuit configured to store a first priority for a first operation performed on the first plane and a second circuit configured to store a second priority for a second operation performed on the second plane, and is configured to control the first and second operations based on the first priority and the second priority. When a value of the second priority is higher than a value of the first priority, the control circuit controls the first operation such that a timing of a process executed in the first operation does not overlap with a timing of a process executed in the second operation.
    Type: Grant
    Filed: August 30, 2018
    Date of Patent: May 5, 2020
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventor: Naoya Tokiwa
  • Publication number: 20200126626
    Abstract: A semiconductor memory device includes a memory block, a plurality of bit lines, a plurality of select gate lines, a plurality of word lines, and a controller. The memory block includes a plurality of memory strings, each memory string including a selection transistor and a plurality of memory cells. The plurality of bit lines are arranged in the first direction and connected to the respective memory strings. The plurality of select gate lines are arranged in the second direction and connected to gates of the respective selection transistors of the memory strings. The plurality of word lines are arranged in the third direction and connected to gates of the respective memory cells of the memory strings. The controller is configured to perform an erase operation in a unit of the memory block, and perform a sequence of erase verify operations.
    Type: Application
    Filed: December 18, 2019
    Publication date: April 23, 2020
    Inventor: Naoya TOKIWA
  • Patent number: 10553287
    Abstract: A semiconductor memory device includes a memory block, a plurality of bit lines, a plurality of select gate lines, a plurality of word lines, and a controller. The memory block includes a plurality of memory strings, each memory string including a selection transistor and a plurality of memory cells. The plurality of bit lines are arranged in the first direction and connected to the respective memory strings. The plurality of select gate lines are arranged in the second direction and connected to gates of the respective selection transistors of the memory strings. The plurality of word lines are arranged in the third direction and connected to gates of the respective memory cells of the memory strings. The controller is configured to perform an erase operation in a unit of the memory block, and perform a sequence of erase verify operations.
    Type: Grant
    Filed: August 29, 2019
    Date of Patent: February 4, 2020
    Assignee: Toshiba Memory Corporation
    Inventor: Naoya Tokiwa
  • Publication number: 20190385682
    Abstract: A semiconductor memory device includes a memory block, a plurality of bit lines, a plurality of select gate lines, a plurality of word lines, and a controller. The memory block includes a plurality of memory strings, each memory string including a selection transistor and a plurality of memory cells. The plurality of bit lines are arranged in the first direction and connected to the respective memory strings. The plurality of select gate lines are arranged in the second direction and connected to gates of the respective selection transistors of the memory strings. The plurality of word lines are arranged in the third direction and connected to gates of the respective memory cells of the memory strings. The controller is configured to perform an erase operation in a unit of the memory block, and perform a sequence of erase verify operations.
    Type: Application
    Filed: August 29, 2019
    Publication date: December 19, 2019
    Inventor: Naoya TOKIWA
  • Patent number: 10403370
    Abstract: A semiconductor memory device includes a memory block, a plurality of bit lines, a plurality of select gate lines, a plurality of word lines, and a controller. The memory block includes a plurality of memory strings, each memory string including a selection transistor and a plurality of memory cells. The plurality of bit lines are arranged in the first direction and connected to the respective memory strings. The plurality of select gate lines are arranged in the second direction and connected to gates of the respective selection transistors of the memory strings. The plurality of word lines are arranged in the third direction and connected to gates of the respective memory cells of the memory strings. The controller is configured to perform an erase operation in a unit of the memory block, and perform a sequence of erase verify operations.
    Type: Grant
    Filed: January 2, 2019
    Date of Patent: September 3, 2019
    Assignee: Toshiba Memory Corporation
    Inventor: Naoya Tokiwa
  • Publication number: 20190163398
    Abstract: A semiconductor memory includes a first plane that includes a first memory cell array, a second plane that includes a second memory cell array, and a control circuit that includes a first circuit configured to store a first priority for a first operation performed on the first plane and a second circuit configured to store a second priority for a second operation performed on the second plane, and is configured to control the first and second operations based on the first priority and the second priority. When a value of the second priority is higher than a value of the first priority, the control circuit controls the first operation such that a timing of a process executed in the first operation does not overlap with a timing of a process executed in the second operation.
    Type: Application
    Filed: August 30, 2018
    Publication date: May 30, 2019
    Inventor: Naoya TOKIWA
  • Publication number: 20190139611
    Abstract: A semiconductor memory device includes a memory block, a plurality of bit lines, a plurality of select gate lines, a plurality of word lines, and a controller. The memory block includes a plurality of memory strings, each memory string including a selection transistor and a plurality of memory cells. The plurality of bit lines are arranged in the first direction and connected to the respective memory strings. The plurality of select gate lines are arranged in the second direction and connected to gates of the respective selection transistors of the memory strings. The plurality of word lines are arranged in the third direction and connected to gates of the respective memory cells of the memory strings. The controller is configured to perform an erase operation in a unit of the memory block, and perform a sequence of erase verify operations.
    Type: Application
    Filed: January 2, 2019
    Publication date: May 9, 2019
    Inventor: Naoya TOKIWA
  • Patent number: 10186319
    Abstract: A semiconductor memory device includes a memory block, a plurality of bit lines, a plurality of select gate lines, a plurality of word lines, and a controller. The memory block includes a plurality of memory strings, each memory string including a selection transistor and a plurality of memory cells. The plurality of bit lines are arranged in the first direction and connected to the respective memory strings. The plurality of select gate lines are arranged in the second direction and connected to gates of the respective selection transistors of the memory strings. The plurality of word lines are arranged in the third direction and connected to gates of the respective memory cells of the memory strings. The controller is configured to perform an erase operation in a unit of the memory block, and perform a sequence of erase verify operations.
    Type: Grant
    Filed: March 26, 2018
    Date of Patent: January 22, 2019
    Assignee: Toshiba Memory Corporation
    Inventor: Naoya Tokiwa
  • Patent number: 10140059
    Abstract: A memory system includes a semiconductor memory device including a plurality of memory cells, and a memory controller. The semiconductor memory device includes first, second, and third caches for storing data before the data are written into the memory cells. The memory controller is configured to issue commands to the semiconductor memory device, the commands including a first command issued with write data to store the write data in the first cache and a second command issued with write data to store the write data in the first cache and then transfer the write data in the first cache to one of the second and third caches.
    Type: Grant
    Filed: June 13, 2016
    Date of Patent: November 27, 2018
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventor: Naoya Tokiwa
  • Publication number: 20180211712
    Abstract: A semiconductor memory device includes a memory block, a plurality of bit lines, a plurality of select gate lines, a plurality of word lines, and a controller. The memory block includes a plurality of memory strings, each memory string including a selection transistor and a plurality of memory cells. The plurality of bit lines are arranged in the first direction and connected to the respective memory strings. The plurality of select gate lines are arranged in the second direction and connected to gates of the respective selection transistors of the memory strings. The plurality of word lines are arranged in the third direction and connected to gates of the respective memory cells of the memory strings. The controller is configured to perform an erase operation in a unit of the memory block, and perform a sequence of erase verify operations.
    Type: Application
    Filed: March 26, 2018
    Publication date: July 26, 2018
    Inventor: Naoya TOKIWA
  • Patent number: 9928916
    Abstract: A semiconductor memory device includes a memory block, a plurality of bit lines, a plurality of select gate lines, a plurality of word lines, and a controller. The memory block includes a plurality of memory strings, each memory string including a selection transistor and a plurality of memory cells. The plurality of bit lines are arranged in the first direction and connected to the respective memory strings. The plurality of select gate lines are arranged in the second direction and connected to gates of the respective selection transistors of the memory strings. The plurality of word lines are arranged in the third direction and connected to gates of the respective memory cells of the memory strings. The controller is configured to perform an erase operation in a unit of the memory block, and perform a sequence of erase verify operations.
    Type: Grant
    Filed: October 23, 2017
    Date of Patent: March 27, 2018
    Assignee: Toshiba Memory Corporation
    Inventor: Naoya Tokiwa
  • Patent number: 9928920
    Abstract: According to one embodiment, a temperature of a non-volatile memory or an ambient temperature of the non-volatile memory is acquired. A distribution of a threshold voltage, which is corrected according to the acquired temperature, is acquired from the non-volatile memory. Read voltages related to the reading of data are detected from the distribution. Error correction is performed for data read from the non-volatile memory, using the read voltages. The detected read voltages are separately corrected on the basis of the acquired temperature when the error correction has failed.
    Type: Grant
    Filed: December 21, 2015
    Date of Patent: March 27, 2018
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventors: Yasuhiko Kurosawa, Tsuyoshi Atsumi, Masanobu Shirakawa, Tokumasa Hara, Naoya Tokiwa
  • Publication number: 20180047451
    Abstract: A semiconductor memory device includes a memory block, a plurality of bit lines, a plurality of select gate lines, a plurality of word lines, and a controller. The memory block includes a plurality of memory strings, each memory string including a selection transistor and a plurality of memory cells. The plurality of bit lines are arranged in the first direction and connected to the respective memory strings. The plurality of select gate lines are arranged in the second direction and connected to gates of the respective selection transistors of the memory strings. The plurality of word lines are arranged in the third direction and connected to gates of the respective memory cells of the memory strings. The controller is configured to perform an erase operation in a unit of the memory block, and perform a sequence of erase verify operations.
    Type: Application
    Filed: October 23, 2017
    Publication date: February 15, 2018
    Inventor: Naoya TOKIWA
  • Patent number: 9875804
    Abstract: A nonvolatile semiconductor memory device includes a memory cell array. The memory cells of the memory cell array can be programmed to have different threshold voltages. A word line is connected to the memory cells. A controller is configured to receive a first command and perform a first read sequence and a second read sequence to read data from the memory cell array. In the first read sequence, a series of different voltage levels are applied to the word line and data is read from the array at each voltage level. In the second read sequence, a read voltage level is set based on the data obtained during the first read sequence. The read voltage level is applied to the word line to read the data to be output from the memory cell array.
    Type: Grant
    Filed: October 21, 2016
    Date of Patent: January 23, 2018
    Assignee: Toshiba Memory Corporation
    Inventor: Naoya Tokiwa
  • Patent number: 9818487
    Abstract: A semiconductor memory device has a memory block including memory strings with first and second selection transistors at opposite ends of the memory strings. A bit line is connected to the first selection transistor of each memory string and a sense amplifier is connected to the bit line. The memory block includes word lines connected to each memory cell transistor in the memory strings. The memory device also includes a controller to control an erase operation that includes applying an erase voltage to the word lines, addressing a first memory string by applying a selection voltage to a gate electrode of first and second selection transistors of the first memory string, then applying an erase verify voltage to the word lines and using the sense amplifier to read data of memory cell transistors in the first memory string, then addressing a second memory string without first discharging the word lines.
    Type: Grant
    Filed: February 27, 2017
    Date of Patent: November 14, 2017
    Assignee: Toshiba Memory Corporation
    Inventor: Naoya Tokiwa
  • Publication number: 20170255385
    Abstract: A nonvolatile semiconductor memory device includes a memory cell array. The memory cells of the memory cell array can be programmed to have different threshold voltages. A word line is connected to the memory cells. A controller is configured to receive a first command and perform a first read sequence and a second read sequence to read data from the memory cell array. In the first read sequence, a series of different voltage levels are applied to the word line and data is read from the array at each voltage level. In the second read sequence, a read voltage level is set based on the data obtained during the first read sequence. The read voltage level is applied to the word line to read the data to be output from the memory cell array.
    Type: Application
    Filed: October 21, 2016
    Publication date: September 7, 2017
    Inventor: Naoya TOKIWA
  • Publication number: 20170169889
    Abstract: A semiconductor memory device has a memory block including memory strings with first and second selection transistors at opposite ends of the memory strings. A bit line is connected to the first selection transistor of each memory string and a sense amplifier is connected to the bit line. The memory block includes word lines connected to each memory cell transistor in the memory strings. The memory device also includes a controller to control an erase operation that includes applying an erase voltage to the word lines, addressing a first memory string by applying a selection voltage to a gate electrode of first and second selection transistors of the first memory string, then applying an erase verify voltage to the word lines and using the sense amplifier to read data of memory cell transistors in the first memory string, then addressing a second memory string without first discharging the word lines.
    Type: Application
    Filed: February 27, 2017
    Publication date: June 15, 2017
    Inventor: Naoya TOKIWA
  • Patent number: 9627080
    Abstract: A semiconductor memory device has a memory block including memory strings with first and second selection transistors at opposite ends of the memory strings. A bit line is connected to the first selection transistor of each memory string and a sense amplifier is connected to the bit line. The memory block includes word lines connected to each memory cell transistor in the memory strings. The memory device also includes a controller to control an erase operation that includes applying an erase voltage to the word lines, addressing a first memory string by applying a selection voltage to a gate electrode of first and second selection transistors of the first memory string, then applying an erase verify voltage to the word lines and using the sense amplifier to read data of memory cell transistors in the first memory string, then addressing a second memory string without first discharging the word lines.
    Type: Grant
    Filed: July 1, 2016
    Date of Patent: April 18, 2017
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Naoya Tokiwa
  • Publication number: 20170076810
    Abstract: According to one embodiment, a temperature of a non-volatile memory or an ambient temperature of the non-volatile memory is acquired. A distribution of a threshold voltage, which is corrected according to the acquired temperature, is acquired from the non-volatile memory. Read voltages related to the reading of data are detected from the distribution. Error correction is performed for data read from the non-volatile memory, using the read voltages. The detected read voltages are separately corrected on the basis of the acquired temperature when the error correction has failed.
    Type: Application
    Filed: December 21, 2015
    Publication date: March 16, 2017
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Yasuhiko KUROSAWA, Tsuyoshi ATSUMI, Masanobu SHIRAKAWA, Tokumasa HARA, Naoya TOKIWA
  • Patent number: RE47866
    Abstract: A three-dimensionally stacked nonvolatile semiconductor memory of an aspect of the present invention including conductive layers stacked on a semiconductor substrate in such a manner as to be insulated from one another, a bit line which is disposed on the stacked conductive layers, a semiconductor column which extends through the stacked conductive layers, word lines for which the stacked conductive layers except for the uppermost and lowermost conductive layers are used and which have a plate-like planar shape, memory cells provided at intersections of the word lines and the semiconductor column, a register circuit which has information to supply a potential suitable for each of the word lines, and a potential control circuit which reads the information retained in the register circuit in accordance with an input address signal of a word line and which supplies a potential suitable for the word line corresponding to the address signal.
    Type: Grant
    Filed: February 4, 2016
    Date of Patent: February 18, 2020
    Assignee: Toshiba Memory Corporation
    Inventors: Naoya Tokiwa, Hideo Mukai