Patents by Inventor Hiroshi Maejima

Hiroshi Maejima 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).

  • Publication number: 20190392905
    Abstract: According to one embodiment, a semiconductor memory device includes first and second memory cells; a first word line connected to the first and second memory cells; a first bit line connected to the first memory cell; a second bit line connected to the second memory cell; a first sense amplifier connected to the first bit line; a second sense amplifier connected to the second bit line; a voltage generation circuit; and a first row decoder which supplies a voltage to the first word line.
    Type: Application
    Filed: June 3, 2019
    Publication date: December 26, 2019
    Applicant: Toshiba Memory Corporation
    Inventors: Takeshi Hioka, Tsukasa Kobayashi, Koji Kato, Yuki Shimizu, Hiroshi Maejima
  • Publication number: 20190371403
    Abstract: A semiconductor memory device includes a memory cell array having memory strings that include memory cells and first and second selection transistors. During a read operation, a controller applies a first voltage higher than ground to a source line, and a second voltage to a first and second selection gate lines that are connected to a selected memory string. The second voltage is also applied to the first selection gate lines connected to non-selected memory strings during a first period of the read operation. A third voltage higher than ground and lower than the second voltage is applied to the first selection gate lines connected to non-selected memory strings during a second period of the read operation subsequent to the first period.
    Type: Application
    Filed: August 14, 2019
    Publication date: December 5, 2019
    Inventor: Hiroshi MAEJIMA
  • Publication number: 20190325973
    Abstract: A semiconductor memory device includes first and second memory cells, each of which includes a charge storage layer, a first bit line that is connected to the first memory cell, and a second bit line that is connected to the second memory cell. A writing operation includes multiple loops of a programming operation and a verification operation, and first data is written in the first memory cell, and second data different from the first data is written in the second memory cell through the writing operation. In a first loop of the writing operation, a first voltage is applied to the first bit line and the second bit line is maintained in an electrically floating state during the programming operation, and a verification operation relating to the second data is not performed and a verification operation relating to the first data is performed.
    Type: Application
    Filed: July 1, 2019
    Publication date: October 24, 2019
    Inventors: Hiroshi MAEJIMA, Koji HOSONO, Tadashi YASUFUKU, Noboru SHIBATA
  • Publication number: 20190295657
    Abstract: A memory device includes a memory cell array with memory strings including a first and second select transistor and memory cells between the first and second select transistors. Each memory string has a bit line connected thereto. A different word line is connected to each of the memory cells of a memory strings. A control circuit is configured to execute a first read operation in which data is read at the same time from memory cells connected to all the bit lines and a second read operation in which data is read from memory cells connected to a first subset of bit lines and a shield voltage is applied to a second subset of bit lines in the plurality of bit lines. The controller selects the first or second read operation for execution according to the number of read voltage levels required for determining data in the memory cells.
    Type: Application
    Filed: August 24, 2018
    Publication date: September 26, 2019
    Inventor: Hiroshi MAEJIMA
  • Patent number: 10418104
    Abstract: A semiconductor memory device includes a memory cell array having memory strings that include memory cells and first and second selection transistors. During a read operation, a controller applies a first voltage higher than ground to a source line, and a second voltage to a first and second selection gate lines that are connected to a selected memory string. The second voltage is also applied to the first selection gate lines connected to non-selected memory strings during a first period of the read operation. A third voltage higher than ground and lower than the second voltage is applied to the first selection gate lines connected to non-selected memory strings during a second period of the read operation subsequent to the first period.
    Type: Grant
    Filed: May 11, 2018
    Date of Patent: September 17, 2019
    Assignee: Toshiba Memory Corporation
    Inventor: Hiroshi Maejima
  • Publication number: 20190267108
    Abstract: A semiconductor memory device includes a first memory cell which is capable of being set to any one of at least eight threshold voltages, a first bit line connected to the first memory cell, a word line connected to a gate of the first memory cell, a sense amplifier connected to the first bit line, wherein the sense amplifier has at least four data latch circuits, and an extra data latch circuit connected to the sense amplifier through a data bus. A verification operation for verifying the threshold voltage of the first memory cell is performed after a programming operation is performed on the first memory cell, and the verification operation includes seven verification operations during which the four data latch circuits, but not the extra data latch circuit, are accessed.
    Type: Application
    Filed: May 13, 2019
    Publication date: August 29, 2019
    Inventors: Hiroshi MAEJIMA, Noboru SHIBATA
  • Publication number: 20190252021
    Abstract: A semiconductor storage device includes word lines extending in first and second directions, and separated from each other in a third direction, sense amplifier circuits that partially overlap the word lines in the third direction, memory strings intersecting the word lines and extending in the third direction, memory-side bit lines extending in the first direction, separated from each other in the second direction, and including first and second adjacent memory-side bit lines, circuit-side bit lines between the word lines and the sense amplifier circuits and partially overlapping the respective memory-side bit lines in the third direction, and contact plugs extending in the third direction and respectively connecting the memory-side bit lines and the circuit-side bit lines. The contact plugs include first and second contract plugs that are electrically connected to the first and second memory-side bit lines, respectively, and are not aligned along the first or second direction.
    Type: Application
    Filed: April 22, 2019
    Publication date: August 15, 2019
    Inventor: Hiroshi MAEJIMA
  • Patent number: 10381096
    Abstract: A semiconductor memory device includes first and second memory cells, each of which includes a charge storage layer, a first bit line that is connected to the first memory cell, and a second bit line that is connected to the second memory cell. A writing operation includes multiple loops of a programming operation and a verification operation, and first data is written in the first memory cell, and second data different from the first data is written in the second memory cell through the writing operation. In a first loop of the writing operation, a first voltage is applied to the first bit line and the second bit line is maintained in an electrically floating state during the programming operation, and a verification operation relating to the second data is not performed and a verification operation relating to the first data is performed.
    Type: Grant
    Filed: May 23, 2018
    Date of Patent: August 13, 2019
    Assignee: Toshiba Memory Corporation
    Inventors: Hiroshi Maejima, Koji Hosono, Tadashi Yasufuku, Noboru Shibata
  • Patent number: 10319450
    Abstract: A semiconductor memory device includes a first memory cell which is capable of being set to any one of at least eight threshold voltages, a first bit line, a word line, and a sense amplifier which is connected to the first bit line. A verification operation for verifying the threshold voltage of the first memory cell is performed after a programming operation is performed on the first memory cell, and the verification operation includes seven verification operations. The sense amplifier applies a charging voltage to the first bit line during two of the seven verification operations, and does not apply the charging voltage to the first bit line during the remaining five of the seven verification operations.
    Type: Grant
    Filed: June 27, 2018
    Date of Patent: June 11, 2019
    Assignee: Toshiba Memory Corporation
    Inventors: Hiroshi Maejima, Noboru Shibata
  • Publication number: 20190172540
    Abstract: A three dimensional stacked nonvolatile semiconductor memory according to an example of the present invention includes a memory cell array comprised of first and second blocks. The first block has a first cell unit which includes a memory cell to be programmed and a second cell unit which does not include a memory cell to be programmed, and programming is executed by applying a program potential or a transfer potential to word lines in the first block after the initial potential of channels of the memory cells in the first and second cell units is set to a plus potential. In the programming, the program potential and the transfer potential are not applied to word lines in the second block.
    Type: Application
    Filed: January 18, 2019
    Publication date: June 6, 2019
    Applicant: Toshiba Memory Corporation
    Inventor: Hiroshi MAEJIMA
  • Publication number: 20190146685
    Abstract: A semiconductor storage device includes memory cells, select transistors, memory strings, first and second blocks, word lines, and select gate lines. In the memory string, the current paths of plural memory cells are connected in series. When data are written in a first block, after a select gate line connected to the gate of a select transistor of one of the memory strings in the first block is selected, the data are sequentially written in the memory cells in the memory string connected to the selected select gate line. When data are written in the second block, after a word line connected to the control gates of memory cells of different memory strings in the second block is selected, the data are sequentially written in the memory cells of the different memory strings in the second block which have their control gates connected to the selected word line.
    Type: Application
    Filed: October 11, 2018
    Publication date: May 16, 2019
    Inventor: Hiroshi MAEJIMA
  • Patent number: 10276241
    Abstract: According to one embodiment, a semiconductor storage device of an embodiment of the present disclosure is provided with peripheral circuits, a memory cell array, upper bit lines, and first and second connecting parts. The memory cell array is disposed above the peripheral circuit, and includes at least first and second regions. The upper bit lines extend in a first direction and are above the memory cell array. The first and second connecting parts are respectively provided with contact plugs, and one of these connecting parts is formed between first and second regions. The upper bit lines includes a first group of upper bit lines which are connected to the peripheral circuits via the first connecting part, and a second group of upper bit lines which are connected to the peripheral circuits via the second connecting part.
    Type: Grant
    Filed: June 28, 2018
    Date of Patent: April 30, 2019
    Assignee: Toshiba Memory Corporation
    Inventor: Hiroshi Maejima
  • Publication number: 20190115089
    Abstract: A memory device includes first and second memory strings, first and second word lines and a controller. The first memory string includes first and second memory cells, a first select transistor, a second select transistor, and a third select transistor between the first and second memory cells. The second memory string includes third and fourth memory cells, a fourth select transistor above the third memory cell, a fifth select transistor below the fourth memory cell, and a sixth select transistor between the third and fourth memory cells. The first word line is electrically connected to gates of the first and third memory cells. The second word line is electrically connected to gates of the second and fourth memory cells. The controller is configured to execute a read operation on one of the memory cells, the read operation including a first phase and a second phase after the first phase.
    Type: Application
    Filed: December 5, 2018
    Publication date: April 18, 2019
    Inventor: Hiroshi MAEJIMA
  • Patent number: 10224106
    Abstract: A three dimensional stacked nonvolatile semiconductor memory according to an example of the present invention includes a memory cell array comprised of first and second blocks. The first block has a first cell unit which includes a memory cell to be programmed and a second cell unit which does not include a memory cell to be programmed, and programming is executed by applying a program potential or a transfer potential to word lines in the first block after the initial potential of channels of the memory cells in the first and second cell units is set to a plus potential. In the programming, the program potential and the transfer potential are not applied to word lines in the second block.
    Type: Grant
    Filed: March 9, 2018
    Date of Patent: March 5, 2019
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventor: Hiroshi Maejima
  • Patent number: 10186323
    Abstract: A memory device includes first and second memory strings, first and second word lines and a controller. The first memory string includes first and second memory cells, a first select transistor, a second select transistor, and a third select transistor between the first and second memory cells. The second memory string includes third and fourth memory cells, a fourth select transistor above the third memory cell, a fifth select transistor below the fourth memory cell, and a sixth select transistor between the third and fourth memory cells. The first word line is electrically connected to gates of the first and third memory cells. The second word line is electrically connected to gates of the second and fourth memory cells. The controller is configured to execute a read operation on one of the memory cells, the read operation including a first phase and a second phase after the first phase.
    Type: Grant
    Filed: February 22, 2018
    Date of Patent: January 22, 2019
    Assignee: TOSHIBA MEMORY CORPORATION
    Inventor: Hiroshi Maejima
  • Patent number: 10126957
    Abstract: A semiconductor storage device includes memory cells, select transistors, memory strings, first and second blocks, word lines, and select gate lines. In the memory string, the current paths of plural memory cells are connected in series. When data are written in a first block, after a select gate line connected to the gate of a select transistor of one of the memory strings in the first block is selected, the data are sequentially written in the memory cells in the memory string connected to the selected select gate line. When data are written in the second block, after a word line connected to the control gates of memory cells of different memory strings in the second block is selected, the data are sequentially written in the memory cells of the different memory strings in the second block which have their control gates connected to the selected word line.
    Type: Grant
    Filed: October 3, 2017
    Date of Patent: November 13, 2018
    Assignee: Toshiba Memory Corporation
    Inventor: Hiroshi Maejima
  • Publication number: 20180315486
    Abstract: A semiconductor memory device includes a first memory cell which is capable of being set to any one of at least eight threshold voltages, a first bit line, a word line, and a sense amplifier which is connected to the first bit line. A verification operation for verifying the threshold voltage of the first memory cell is performed after a programming operation is performed on the first memory cell, and the verification operation includes seven verification operations. The sense amplifier applies a charging voltage to the first bit line during two of the seven verification operations, and does not apply the charging voltage to the first bit line during the remaining five of the seven verification operations.
    Type: Application
    Filed: June 27, 2018
    Publication date: November 1, 2018
    Inventors: Hiroshi MAEJIMA, Noboru SHIBATA
  • Publication number: 20180308549
    Abstract: According to one embodiment, a semiconductor storage device of an embodiment of the present disclosure is provided with peripheral circuits, a memory cell array, upper bit lines, and first and second connecting parts. The memory cell array is disposed above the peripheral circuit, and includes at least first and second regions. The upper bit lines extend in a first direction and are above the memory cell array. The first and second connecting parts are respectively provided with contact plugs, and one of these connecting parts is formed between first and second regions. The upper bit lines includes a first group of upper bit lines which are connected to the peripheral circuits via the first connecting part, and a second group of upper bit lines which are connected to the peripheral circuits via the second connecting part.
    Type: Application
    Filed: June 28, 2018
    Publication date: October 25, 2018
    Inventor: Hiroshi MAEJIMA
  • Publication number: 20180301197
    Abstract: A semiconductor memory device includes first and second memory cells, each of which includes a charge storage layer, a first bit line that is connected to the first memory cell, and a second bit line that is connected to the second memory cell. A writing operation includes multiple loops of a programming operation and a verification operation, and first data is written in the first memory cell, and second data different from the first data is written in the second memory cell through the writing operation. In a first loop of the writing operation, a first voltage is applied to the first bit line and the second bit line is maintained in an electrically floating state during the programming operation, and a verification operation relating to the second data is not performed and a verification operation relating to the first data is performed.
    Type: Application
    Filed: May 23, 2018
    Publication date: October 18, 2018
    Inventors: Hiroshi MAEJIMA, Koji HOSONO, Tadashi YASUFUKU, Noboru SHIBATA
  • Publication number: 20180261289
    Abstract: A semiconductor memory device includes a memory cell array having memory strings that include memory cells and first and second selection transistors. During a read operation, a controller applies a first voltage higher than ground to a source line, and a second voltage to a first and second selection gate lines that are connected to a selected memory string. The second voltage is also applied to the first selection gate lines connected to non-selected memory strings during a first period of the read operation. A third voltage higher than ground and lower than the second voltage is applied to the first selection gate lines connected to non-selected memory strings during a second period of the read operation subsequent to the first period.
    Type: Application
    Filed: May 11, 2018
    Publication date: September 13, 2018
    Inventor: Hiroshi MAEJIMA