Patents Assigned to SanDisk Technologies
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Publication number: 20240071527Abstract: A storage device comprises: a non-volatile memory including control circuitry and an array of memory cells formed using a set of word lines and a set of bit lines. A controller, coupled to the non-volatile memory, configured to: determine, based on a stage of a product lifetime of the non-volatile memory, a negative word line setting for implementing during performance of a first operation; perform the first operation, the first operation including adjusting, based on the negative word line setting, a negative word line relative parameter; determine, based on another stage of the product lifetime of the non-volatile memory, another negative word line setting for implementing during performance of a second operation; and perform the second operation, the second operation including adjusting, based on the other negative word line setting, another negative word line relative parameter.Type: ApplicationFiled: August 26, 2022Publication date: February 29, 2024Applicant: SanDisk Technologies LLCInventors: Xiaoyu Che, Yanjie Wang, Runchen Fang
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Publication number: 20240071526Abstract: A memory apparatus and operating method are provided. The apparatus includes memory cells connected to word lines and disposed in strings and configured to retain a threshold voltage corresponding to data states. A control means is configured to program and verify the memory cells during a program operation. The memory cells associated with predetermined ones of the data states are not verified until the memory cells associated with specific prior ones of the data states finish programming to define verify windows ranging between each one of the specific prior ones of the data states and each one of the predetermined ones. The control means adjusts the verify windows in response to the memory cells associated with one of the specific prior ones of the data states not finishing programming before the one of the predetermined ones of the at least one of the verify windows is verified.Type: ApplicationFiled: August 25, 2022Publication date: February 29, 2024Applicant: SanDisk Technologies LLCInventor: Kazuki Yamauchi
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Publication number: 20240071544Abstract: To reduce spikes in the current used by a NAND memory die, different ramp rates are used for the pass voltage applied to unselected word lines during a program operation depending on whether data is stored in a multi-level cell (MLC) format or in a single level cell (SLC) format. These ramp rates can be determined through device characterization and stored as parameter values on the memory die. Different ramp rate interval values can also be used for the pass voltage applied to unselected word lines during a program operation depending on whether data is stored in an MLC format or in an SLC format.Type: ApplicationFiled: August 29, 2022Publication date: February 29, 2024Applicant: SanDisk Technologies LLCInventors: Abu Naser Zainuddin, Jiahui Yuan, Dong-il Moon
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Publication number: 20240071525Abstract: A memory apparatus and operating method are provided. The apparatus includes memory cells connected to word lines and disposed in memory holes and configured to retain a threshold voltage. The memory holes are organized in rows grouped in strings and the strings comprise a plurality of blocks which comprise planes. A control means is configured to program the memory cells connected to one of the word lines and associated with one of the strings in each of the plurality of planes and acquire a smart verify programming voltage individually for each of the planes in a smart verify operation. The control means concurrently programs at least some of the memory cells connected to each of the word lines in each of the planes in a program operation using the smart verify programming voltage individually acquired for each of the planes in the smart verify operation.Type: ApplicationFiled: August 25, 2022Publication date: February 29, 2024Applicant: SanDisk Technologies LLCInventors: Ke Zhang, Liang Li
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Publication number: 20240071508Abstract: The memory device includes a plurality of memory blocks, each including a plurality of memory cells arranged in a plurality of word lines. Control circuitry is in communication with the plurality of memory blocks. In operation, the control circuitry receives a data write instruction and programs the memory cells of the memory blocks to a one bit per memory cell (SLC) format. In response to the data programmed to the memory cells of the memory blocks in the SLC format reaching an SLC limit prior to completion of the data write instruction, without erasing the memory cells programmed to the SLC format, the control circuitry programs the memory cells of at least some of the plurality of memory blocks from the SLC format to a two bits per memory cell (MLC) format.Type: ApplicationFiled: August 26, 2022Publication date: February 29, 2024Applicant: SanDisk Technologies LLCInventors: Xiang Yang, Jiacen Guo, Takayuki Inoue
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Publication number: 20240071493Abstract: To reduce spikes in the current used by a NAND memory die, different ramp rates for different regions, or zones, of word lines are used for the pass voltage applied to unselected word lines during a program operation. The properties of the word lines, such as their resistance and capacitance (RC) values, vary across the NAND memory array. By determining the RC values of the word lines across the array, the word lines can be broken into multiple zones based on these properties. The zones can then be individually assigned different ramp rates for applying a pass voltage to the unselected word lines, where a parameter for the ramp rates can be stored as a register value on the memory die.Type: ApplicationFiled: August 29, 2022Publication date: February 29, 2024Applicant: SanDisk Technologies LLCInventors: Abu Naser Zainuddin, Jiahui Yuan, Towhidur Razzak
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Publication number: 20240071524Abstract: Technology is disclosed herein for smart verify in a memory system that has a four bit per cell program mode (or X4 mode) and also a three bit per cell program mode (or X3 mode). The X3 mode uses a three-bit gray code that is based on a four-bit gray code of the X4 mode. The memory system skips verify of states in the X3 mode, while using a considerable portion of the programming logic from the X4 mode. In one X3 mode the memory system skips B-state verify while the number of memory cells having a Vt above an A-state verify voltage is below a threshold. In one X3 mode the memory system determines whether to skip verify for a first set of data states based on a first test and determines whether to skip verify for a second set of data states based on a second test.Type: ApplicationFiled: August 25, 2022Publication date: February 29, 2024Applicant: SanDisk Technologies LLCInventors: Xiang Yang, Henry Chin, Erika Penzo, Muhammad Masuduzzaman
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Publication number: 20240069803Abstract: The memory device has a plurality of memory blocks including a plurality of memory cells arranged in a plurality of word lines. The memory device also includes control circuitry that is in communication with the plurality of memory blocks. The control circuitry is configured to receive a data write instruction. The control circuitry is further configured to program the memory cells of the memory blocks to an SLC format. In response to the data programmed to the memory cells of the memory blocks in the SLC format reaching an SLC limit prior to completion of the data write instruction, without erasing the memory cells programmed to the SLC format, the control circuitry is configured to program the memory cells of at least some of the plurality of memory blocks from the SLC format to a TLC format.Type: ApplicationFiled: August 30, 2022Publication date: February 29, 2024Applicant: SanDisk Technologies LLCInventors: Xiang Yang, Wei Cao
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Publication number: 20240071433Abstract: An apparatus includes a control circuit that is configured to connect to an array of non-volatile memory cells. The control circuit includes a first plurality of data latches configured to connect to non-volatile memory cells of a first plane and a second plurality of data latches configured to connect to non-volatile memory cells of a second plane. The control circuit also includes a shared data transfer data latch configured for transfer of data with the first plurality of data latches and the second plurality of data latches.Type: ApplicationFiled: August 31, 2022Publication date: February 29, 2024Applicant: SanDisk Technologies LLCInventors: Hua-Ling Cynthia Hsu, YenLung Li, Siddarth Naga Murty Bassa, Jeongduk Sohn
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Publication number: 20240071529Abstract: Memory cells are arranged as NAND strings to form a block divided into sub-blocks, and each NAND string includes a dummy memory cell connected to a dummy word line. Memory cells are programmed by applying programming pulses to a selected word line in a selected sub-block with program-verify performed between pulses. Unselected NAND strings are inhibited from programming by boosting channels of the unselected NAND strings in the selected sub-block from a positive pre-charge voltage to a boosted voltage. The pre-charging of the channels of unselected NAND strings is performed while lowering voltages at the end of program-verify by applying overdrive voltages to data word lines in a sub-block closer to the source line than the selected sub-block and lowering to a resting voltage a dummy word line between the sub-blocks prior to lowering to a resting voltage the data word lines in the sub-block closer to the source line.Type: ApplicationFiled: August 30, 2022Publication date: February 29, 2024Applicant: SanDisk Technologies LLCInventors: Jiacen Guo, Dengtao Zhao, Xiang Yang
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Publication number: 20240071533Abstract: An apparatus is provided that includes a block of memory cells having a NAND string that includes a first select transistor, and a control circuit coupled to the block of memory cells. The control circuit is configured to perform an erase operation on the block of memory cells by determining a first count of a number of times that the block of memory cells previously has been programmed and erased, determining based on the first count a first drain-to-gate voltage of the first select transistor, wherein the first drain-to-gate voltage is configured to cause the first select transistor to generate a first gate-induced drain leakage current, and applying a first erase pulse to the first select transistor based on the determined first drain-to-gate voltage.Type: ApplicationFiled: August 31, 2022Publication date: February 29, 2024Applicant: SanDisk Technologies LLCInventors: Yihang Liu, Xiaochen Zhu, Lito De La Rama, Feng Gao
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Publication number: 20240071509Abstract: The techniques include a memory device receiving a data write instruction. The memory device programs the memory cells of the memory blocks to a one bit per memory cell (SLC) format with a first and second SLC data states. In response to the data programmed to the memory cells of the memory blocks reaching an SLC limit prior to completion of the data write instruction, without erasing the memory cells, the memory device programs at least some of the memory cells from the SLC format to a two bits per memory cell (MLC) format. When programming from the SLC format to the MLC format, the memory device inhibits programming of some of the memory cells in the first and second SLC data states to form a first MLC data state and programs other memory cells of the SLC data states to form second, third, and fourth MLC data states.Type: ApplicationFiled: August 29, 2022Publication date: February 29, 2024Applicant: SanDisk Technologies LLCInventors: Xiang Yang, Jiacen Guo, Shubhajit Mukherjee
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Patent number: 11915769Abstract: A non-volatile memory device includes a control circuit configured to connect to a bit line that is connected to one or more non-volatile memory cells. The control circuit includes a first plurality of data latches connected to a first local data bus to store first program-verify pass/fail bits and a second plurality of data latches connected to a second local data bus to store second program-verify pass/fail bits for second non-volatile memory cells. The non-volatile memory device further includes a shared isolation latch and one or more interface circuits connected to the first local data bus and the second local data bus. The one or more interface circuits are configured to selectively block the first program-verify pass/fail bits from the first plurality of latches and the second program-verify pass/fail bits from the second plurality of latches according to an indicator bit stored in the shared isolation latch.Type: GrantFiled: May 16, 2022Date of Patent: February 27, 2024Assignee: SanDisk Technologies LLCInventors: Kei Kitamura, Iris Lu, Tai-Yuan Tseng
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Patent number: 11907545Abstract: For a non-volatile memory that uses hard bit and soft bit data in error correction operations, to reduce the amount of soft bit data that needs to be transferred from a memory to the controller and improve memory system performance, the soft bit data can be compressed before transfer. After the soft bit data is read and stored into the internal data latches associated with the sense amplifiers, it is compressed within these internal data latches. The compressed soft bit data can then be transferred to the transfer data latches of a cache buffer, where the compressed soft bit data can be consolidated and transferred out over an input-output interface. Within the input-output interface, the compressed data can be reshuffled to put into logical user data order if needed.Type: GrantFiled: April 28, 2022Date of Patent: February 20, 2024Assignee: SanDisk Technologies LLCInventors: YenLung Li, Siddarth Naga Murty Bassa, Chen Chen, Hua-Ling Cynthia Hsu
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Publication number: 20240055051Abstract: Technology is disclosed herein reconfiguring word lines as either data word lines or dummy word lines. In a sub-block mode reconfigurable word lines are used as dummy word lines that provide electrical isolation between data word lines in a block. The block may be divided into an upper tier, a middle tier, and a lower tier, with the reconfigurable word lines within the middle tier. In a full-block mode the reconfigurable group of the word lines are used as data word lines. Because the reconfigurable word lines are used as data word lines in the full-block mode storage capacity is greater in the full-block mode than in the sub-block mode. Moreover, because the sub-blocks are smaller in size but greater in number than the full-blocks, the memory system may be provisioned with fewer blocks and still meet user storage requirements in both the full-block mode and the sub-block mode.Type: ApplicationFiled: August 15, 2022Publication date: February 15, 2024Applicant: SanDisk Technologies LLCInventors: Xiang Yang, YenLung Li, James Kai
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Publication number: 20240055059Abstract: Non-volatile memory cells are programmed by pre-charging channels of unselected non-volatile memory cells connected to a selected data word line, boosting the channels of unselected non-volatile memory cells connected to the selected data word line after the pre-charging and applying a program voltage pulse to selected non-volatile memory cells connected to the selected data word line while boosting. The pre-charging includes applying pre-charge voltages to one set of data word lines and dummy word line(s) as well as applying overdrive voltages to another set of data word lines connected to already programmed memory cells. At the end of the pre-charging, the dummy word lines are ramped down to a resting voltage prior to lowering the data word lines to one or more resting voltages.Type: ApplicationFiled: August 10, 2022Publication date: February 15, 2024Applicant: SanDisk Technologies LLCInventors: Jiacen Guo, Dengtao Zhao, Xiang Yang
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Patent number: 11901019Abstract: For a non-volatile memory that uses hard bit and soft bit data in error correction operations, to reduce the amount of soft bit data that needs to be transferred from a memory to the controller and improve memory system performance, the soft bit data can be compressed before transfer. After the soft bit data is read and stored into the internal data latches associated with the sense amplifiers, it is compressed within these internal data latches. The compressed soft bit data can then be transferred to the transfer data latches of a cache buffer, where the compressed soft bit data can be consolidated and transferred out over an input-output interface. Within the input-output interface, the compressed data can be reshuffled to put into logical user data order if needed.Type: GrantFiled: February 8, 2022Date of Patent: February 13, 2024Assignee: SanDisk Technologies LLCInventors: Hua-Ling Cynthia Hsu, Masaaki Higashitani, YenLung Li, Chen Chen
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Patent number: 11901018Abstract: A local data bus of a sense amplifier associated with one bit line is used to perform logical operations for a sensing operation performed by another sense amplifier associated with a different bit line. Each sense amplifier circuit includes a sensing node that is pre-charged, then discharged through a selected memory cell and a local data bus with a number of data latches connected. Target program data can be stored in the latches and combined in logical combinations with the sensed value of the memory cell to determine whether it has verified. By including a transfer circuit between the local data buses of a pair of sense amplifiers, the logical operations of a first sense amplifier can be performed using the local data bus of the paired sense amplifier, freeing the first sense amplifier's sense node to be concurrently pre-charged for a subsequent sensing operation, thereby improving performance.Type: GrantFiled: December 27, 2021Date of Patent: February 13, 2024Assignee: SanDisk Technologies LLCInventors: Iris Lu, Tai-Yuan Tseng, Chia-Kai Chou
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Patent number: 11901007Abstract: Technology for applying a positive temperature coefficient (Tco) voltage to a control terminal of a dummy select transistor. The dummy select transistor resides on a NAND string having non-volatile memory cells and a regular select transistor. The dummy select transistor is typically ON (or conductive) during memory operations such as selected string program, read, and verify. In an aspect, the positive Tco voltage is applied to the control terminal of a dummy select transistor during a program operation. Applying the positive Tco voltage during program operations reduces or eliminates program disturb to the dummy select transistor. In some aspects, the dummy select transistor is used to generate a gate induced drain leakage (GIDL) current during an erase operation. In some aspects, the dummy select transistor is a depletion mode transistor.Type: GrantFiled: October 21, 2021Date of Patent: February 13, 2024Assignee: SanDisk Technologies LLCInventors: Ken Oowada, Natsu Honda
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Publication number: 20240046996Abstract: In a non-volatile memory, to achieve a shallow and tight erased threshold voltage distribution, a process is performed that includes erasing a group of non-volatile memory cells, identifying a first set of the bit lines that are connected to non-volatile memory cells of the group that are erased past a lower limit for erased non-volatile memory cells and identifying a second set of the bit lines that are connected to non-volatile memory cells of the group that are not erased past the lower limit for erased non-volatile memory cells, and applying programming to non-volatile memory cells connected to the first set of bit lines while inhibiting programming for non-volatile memory cells connected to the second set of bit lines.Type: ApplicationFiled: August 5, 2022Publication date: February 8, 2024Applicant: SanDisk Technologies LLCInventors: Yi Song, Yanjie Wang, Jiahui Yuan