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).
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Patent number: 10642537Abstract: 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: GrantFiled: August 30, 2018Date of Patent: May 5, 2020Assignee: TOSHIBA MEMORY CORPORATIONInventor: Naoya Tokiwa
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Publication number: 20200126626Abstract: 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: ApplicationFiled: December 18, 2019Publication date: April 23, 2020Inventor: Naoya TOKIWA
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Patent number: 10553287Abstract: 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: GrantFiled: August 29, 2019Date of Patent: February 4, 2020Assignee: Toshiba Memory CorporationInventor: Naoya Tokiwa
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Publication number: 20190385682Abstract: 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: ApplicationFiled: August 29, 2019Publication date: December 19, 2019Inventor: Naoya TOKIWA
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Patent number: 10403370Abstract: 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: GrantFiled: January 2, 2019Date of Patent: September 3, 2019Assignee: Toshiba Memory CorporationInventor: Naoya Tokiwa
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Publication number: 20190163398Abstract: 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: ApplicationFiled: August 30, 2018Publication date: May 30, 2019Inventor: Naoya TOKIWA
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Publication number: 20190139611Abstract: 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: ApplicationFiled: January 2, 2019Publication date: May 9, 2019Inventor: Naoya TOKIWA
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Patent number: 10186319Abstract: 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: GrantFiled: March 26, 2018Date of Patent: January 22, 2019Assignee: Toshiba Memory CorporationInventor: Naoya Tokiwa
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Patent number: 10140059Abstract: 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: GrantFiled: June 13, 2016Date of Patent: November 27, 2018Assignee: TOSHIBA MEMORY CORPORATIONInventor: Naoya Tokiwa
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Publication number: 20180211712Abstract: 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: ApplicationFiled: March 26, 2018Publication date: July 26, 2018Inventor: Naoya TOKIWA
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Patent number: 9928916Abstract: 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: GrantFiled: October 23, 2017Date of Patent: March 27, 2018Assignee: Toshiba Memory CorporationInventor: Naoya Tokiwa
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Patent number: 9928920Abstract: 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: GrantFiled: December 21, 2015Date of Patent: March 27, 2018Assignee: TOSHIBA MEMORY CORPORATIONInventors: Yasuhiko Kurosawa, Tsuyoshi Atsumi, Masanobu Shirakawa, Tokumasa Hara, Naoya Tokiwa
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Publication number: 20180047451Abstract: 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: ApplicationFiled: October 23, 2017Publication date: February 15, 2018Inventor: Naoya TOKIWA
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Patent number: 9875804Abstract: 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: GrantFiled: October 21, 2016Date of Patent: January 23, 2018Assignee: Toshiba Memory CorporationInventor: Naoya Tokiwa
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Patent number: 9818487Abstract: 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: GrantFiled: February 27, 2017Date of Patent: November 14, 2017Assignee: Toshiba Memory CorporationInventor: Naoya Tokiwa
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Publication number: 20170255385Abstract: 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: ApplicationFiled: October 21, 2016Publication date: September 7, 2017Inventor: Naoya TOKIWA
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Publication number: 20170169889Abstract: 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: ApplicationFiled: February 27, 2017Publication date: June 15, 2017Inventor: Naoya TOKIWA
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Patent number: 9627080Abstract: 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: GrantFiled: July 1, 2016Date of Patent: April 18, 2017Assignee: Kabushiki Kaisha ToshibaInventor: Naoya Tokiwa
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Publication number: 20170076810Abstract: 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: ApplicationFiled: December 21, 2015Publication date: March 16, 2017Applicant: Kabushiki Kaisha ToshibaInventors: Yasuhiko KUROSAWA, Tsuyoshi ATSUMI, Masanobu SHIRAKAWA, Tokumasa HARA, Naoya TOKIWA
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Patent number: RE47866Abstract: 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: GrantFiled: February 4, 2016Date of Patent: February 18, 2020Assignee: Toshiba Memory CorporationInventors: Naoya Tokiwa, Hideo Mukai