Patents Assigned to SanDisk Technologies
  • Patent number: 11971829
    Abstract: For a non-volatile memory that uses hard bit and a soft bit data in error correction operations, an on-the-fly compression scheme is used for the soft bit data. As soft bit data is transferred to a memory's input-output interface, the soft bit data is compressed prior to transmission to the an ECC engine memory controller, while hard bit data is transferred in un-compressed form.
    Type: Grant
    Filed: December 21, 2021
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies LLC
    Inventors: Hua-Ling Cynthia Hsu, A. Harihara Sravan, YenLung Li
  • Patent number: 11972808
    Abstract: A memory apparatus and method of operation are provided. The apparatus includes memory cells connected to word lines and disposed in memory holes organized in rows grouped in strings and configured to retain a threshold voltage. The memory cells are connected in series between a drain-side select gate transistor on a drain-side of each of the memory holes and a source-side select gate transistor on a source-side of each of the memory holes. A control means determines whether a downshift recovery trigger event has occurred in memory operations. In response to determining the downshift recovery trigger event has occurred, the control means inserts at least one of a predetermined idle time in the memory operations and a recovery pulse of a negative voltage to the drain-side select gate transistor of the memory holes of the strings for a predetermined pulse period of time during one of the memory operations.
    Type: Grant
    Filed: February 8, 2022
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies, LLC
    Inventors: Abhijith Prakash, Xiang Yang
  • Patent number: 11972809
    Abstract: A non-volatile semiconductor memory device includes non-volatile storage elements and one or more control circuits in communication with the non-volatile storage elements. The one or more control circuits are configured to determine for a program iteration of a program operation on a word line whether a condition is met and in response to determining that the condition is met, identify one or more memory cells of the word line that are in an erased state that have a threshold voltage higher than an erase threshold voltage and perform the program iteration of the program operation. The program iteration includes applying a first bitline inhibit voltage to bitlines connected to the identified one or more memory cells and a second bitline inhibit voltage to bitlines connected to one or more memory cells that are in the erased state that do not have a threshold voltage higher than the erase threshold voltage.
    Type: Grant
    Filed: February 28, 2022
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies, LLC
    Inventors: Sujjatul Islam, Yu-Chung Lien, Ravi Kumar, Xue Pitner
  • Patent number: 11972822
    Abstract: Technology is disclosed for a fast ECC engine for a mixed read of MRAM cells. A codeword read from MRAM cells using a referenced read is decoded using a first ECC mode. If decoding passes, results are provided to a host. If decoding fails, a self-referenced read (SRR) is performed. The data read using the SRR is decoded with a second ECC mode that is capable of correcting a greater number of bits than the first ECC mode. The second ECC mode may have a higher mis-correction rate than the first ECC mode (for a given raw bit error rate (RBER)). However, the RBER may be lower when using the second ECC mode. Therefore, the first and second ECC modes may result in about the same probability of an undetectable error (or mis-correction).
    Type: Grant
    Filed: December 15, 2021
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies LLC
    Inventors: Martin Hassner, Michael Nicolas Albert Tran, Ward Parkinson, Michael Grobis, Nathan Franklin, Raj Ramanujan
  • Patent number: 11972787
    Abstract: Technology is disclosed herein for refreshing threshold switching selectors in programmable resistance memory cells in cross-point memory arrays. The Vt of the threshold switching selector may drift over time. The memory system resets the Vt of the threshold switching selectors with a selector refresh operation and uses a separate data refresh operation to refresh data in programmable resistance memory elements. The data refresh operation itself may also refresh the selector. However, the threshold switching selector refresh operation is faster than the data refresh operation. Moreover, the selector refresh operation consumes much less power and/or current then the data refresh operation. The selector refresh operation may thus be performed at a higher rate than the data refresh operation.
    Type: Grant
    Filed: May 25, 2022
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies LLC
    Inventors: Michael Nicolas Albert Tran, Michael K. Grobis, Ward Parkinson, Nathan Franklin
  • Patent number: 11972807
    Abstract: Technology is disclosed herein for a memory system that regulates charge pump current during a ramp up of the output voltage. The memory systems operates the charge pump in a current regulation mode while the charge pump output voltage ramps up. After the output voltage crosses a threshold voltage, the charge pump is operated in a voltage regulation mode in which the output voltage is regulated to a target output voltage. In one aspect, the memory system generates a random duty cycle clock in the current regulation mode. The memory system determines a target duty cycle for the random duty cycle clock that will regulate the input current of the charge pump to a target current, given the present output voltage. A clock based on the random duty cycle clock is provided to a clock input of the charge pump to regulate the charge pump current.
    Type: Grant
    Filed: May 11, 2022
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies LLC
    Inventor: Hiroki Yabe
  • Patent number: 11972810
    Abstract: A memory apparatus and method of operation are provided. The apparatus includes memory cells connected word lines. The memory cells are disposed in strings and configured to retain a threshold voltage. A control means is configured to apply a program voltage to selected ones of the word lines while applying pass voltages to unselected ones of the word lines and ramp down both the selected ones of the plurality of word lines and the unselected ones of the word lines to a recovery voltage at a start of a verify phase of each of a plurality of program loops and apply a targeted word line bias to each of the word lines during the verify phase. The control means is also configured to adjust the recovery voltage based on the targeted word line bias applied to each of the plurality of word lines during the verify phase.
    Type: Grant
    Filed: June 21, 2022
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies, LLC
    Inventors: Han-Ping Chen, Wei Zhao, Henry Chin
  • Patent number: 11972813
    Abstract: A memory device with adaptive sense time tables is disclosed. In order to maintain a desired (initial or preset) threshold voltage distribution, the sense time is adjusted as the program-erase cycle count increases. The program-erase cycle process tends to wear down memory cells, causing the QPW window to expand and the threshold voltage to widen. However, by adjusting (i.e., reducing) the sense time for increased program-erase cycles, the QPW window and the threshold voltage can be at least substantially maintained. Additionally, systems and methods for adjusting sense time based on die-to-die variations are also disclosed.
    Type: Grant
    Filed: December 20, 2021
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies, LLC
    Inventors: Jiacen Guo, Xiang Yang, Swaroop Kaza, Laidong Wang
  • Patent number: 11971826
    Abstract: For a non-volatile memory that uses hard bit and a soft bit data in error correction operations, architectures are introduced for the compression of the soft bit data to reduce the amount of data transferred over the memory's input-output interface. For a memory device with multiple planes of memory cells, the internal global data bus is segmented and a data compression circuit associated with each segment. This allows soft bit data from a cache buffer of a plane using one segment to transfer data between the cache buffer and the associated compression circuit concurrently with transferring data from a cache buffer of another plane using another segment, either for compression or transfer to the input-output interface.
    Type: Grant
    Filed: December 21, 2021
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies LLC
    Inventors: Hua-Ling Cynthia Hsu, A. Harihara Sravan, YenLung Li
  • Patent number: 11972814
    Abstract: The memory device includes a plurality of memory cells, which include a first set of memory cells and a second set of memory cells. A controller is in communication with the memory cells. The controller is configured to, in a first programming pass and then a second programming pass, program the memory cells of the first and second sets to respective final threshold voltages associated with a plurality of programmed data states. The controller is further configured to, in the first programming pass, verify the first set of memory cells at a first set of checkpoint data states and verify the second set of memory cells at a second set of checkpoint data states that is different than the first set of checkpoint data states.
    Type: Grant
    Filed: March 22, 2022
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies, LLC
    Inventors: Xue Bai Pitner, Yu-Chung Lien, Ravi Kumar, Jiahui Yuan, Bo Lei, Zhenni Wan
  • Patent number: 11972815
    Abstract: The memory device includes a controller that is configured to program a plurality of memory cells of a selected word line in a plurality of programming loops and count the number of programming loops to complete programming. The controller is also configured to compare the number of programming loops to complete programming of the memory cells of the selected word line to at least one of a predetermined upper limit and a predetermined lower limit to determine if a plane containing the selected word line is at an elevated risk for read failure. In response to the controller making a determination that the plane containing the selected word line is at an elevated risk for read failure, the controller is configured to conduct a post write read operation at least one word line of the plurality of word lines.
    Type: Grant
    Filed: May 10, 2022
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies, LLC
    Inventors: Ke Zhang, Minna Li, Li Liang
  • Patent number: 11972806
    Abstract: The memory device includes a memory block with a plurality of memory cells, which are programmed to multiple bits per memory cell, arranged in a plurality of word lines. Control circuitry is provided and is configured to read the memory cells of a selected word line. The control circuitry separates the memory cells of the selected word line into a first group of memory cells, which are located on a side of the word line are near a voltage driver, and a second group of memory cells, which are located on an opposite side of the word line from the voltage driver. The control circuitry reads the memory cells of the first group using a first read mode and reads the memory cells of the second group using a second read mode that is different than the first read mode to reduce a fail bit count during read.
    Type: Grant
    Filed: June 10, 2022
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies, LLC
    Inventors: Jiacen Guo, Xiang Yang
  • Patent number: 11972803
    Abstract: A memory device that uses different programming parameters base on the word line(s) to be programmed is described. The programming parameter PROGSRC_PCH provides a pre-charge voltage to physical word lines. In some instances, the PROGSRC_PCH voltage is decoupled, and a new PROGSRC_PCH represents an adjusted (e.g., increased) pre-charge voltage for a certain physical word line or word line zone (i.e., predetermined group of word lines). Using different PROGSRC_PCH voltages can limit or prevent Vt distribution window degradation, particularly for relatively low physical word lines. Additionally, the overall programming time and average current consumed can also be reduced.
    Type: Grant
    Filed: January 7, 2022
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies, LLC
    Inventors: Yu-Chung Lien, Fanqi Wu, Jiahui Yuan
  • Patent number: 11972818
    Abstract: A memory apparatus and method of operation are provided. The apparatus includes memory cells each connected to word lines. The memory cells are disposed in strings and configured to retain a threshold voltage corresponding to data states. A control means is configured to apply verification pulses of program verify voltages each associated with one of the data states to selected ones of the word lines to determine whether the memory cells connected thereto have the threshold voltage above each of the program verify voltages targeted for each of the memory cells during a program-verify portion of a program operation. The control means is also configured to trim the program verify voltages for each of the data states for a grouping of the memory cells based on quantities of the memory cells having the threshold voltage crossing over between the data states in crossovers in a verify level trimming process.
    Type: Grant
    Filed: June 15, 2022
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies, LLC
    Inventors: Abhijith Prakash, Xiang Yang
  • Patent number: 11972805
    Abstract: 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: Grant
    Filed: August 5, 2022
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies LLC
    Inventors: Yi Song, Yanjie Wang, Jiahui Yuan
  • Patent number: 11972804
    Abstract: The memory device includes a memory block with an array of memory cells. The memory device also includes control circuitry that is in communication with the memory cells. The control circuitry is configured to program a group of the memory cells in a programming operation that does not include verify to obtain a natural threshold voltage (nVt) distribution, calculate an nVt width of the nVt distribution, compare the nVt width to a threshold, and identify the memory block as being vulnerable to cross-temperature read errors in response to the nVt width exceeding the threshold.
    Type: Grant
    Filed: June 22, 2022
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies, LLC
    Inventors: Xuan Tian, Henry Chin, Liang Li, Vincent Yin, Wei Zhao, Tony Zou
  • Patent number: 11973044
    Abstract: An integrated memory assembly comprises a control die bonded to a memory die. The memory die includes multiple non-volatile memory structures (e.g., planes, arrays, groups of blocks, etc.), each comprising a stack of alternating conductive and dielectric layers forming staircases at one or more edges of the non-volatile memory structures. The non-volatile memory structures are positioned with gaps between the non-volatile memory structures such that the gaps separate the staircases of adjacent non-volatile memory structures. Metal interlayer segments positioned in the gaps are connected to a top metal layer positioned above non-volatile memory structures and to one or more electrical circuits on the control die via zero, one or more other metal layers/segments.
    Type: Grant
    Filed: December 23, 2021
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies LLC
    Inventors: Shiqian Shao, Fumiaki Toyama, Tuan Pham
  • Patent number: 11972819
    Abstract: In a non-volatile memory system that performs programming of selected memory cells (in coordination with pre-charging and boosting of channels for unselected memory cells) and program-verify to determine whether the programming was successful, the system transitions from program-verify to the next dose of programming by concurrently lowering a voltage applied to a selected word line and voltages applied to word lines on a first side of the selected word line at the conclusion of program-verify. Subsequent to lowering the voltage applied to the selected word line, the system successively lowers voltages applied to groups of one or more word lines on a second side of the selected word line at the conclusion of program-verify beginning with a group of one or more word lines immediately adjacent the selected word line and progressing to other groups of one or more word lines disposed increasingly remote from the selected word line.
    Type: Grant
    Filed: July 25, 2022
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies LLC
    Inventors: Jiacen Guo, Peng Zhang, Xiang Yang, Yanli Zhang
  • Patent number: 11972812
    Abstract: A memory system identifies memory cells connected to a common word line that have had their threshold voltage unintentionally drift lower than programmed by determining whether memory cells meet two criteria: (1) the memory cells have threshold voltages within an offset of a read compare voltage of a data state; and (2) adjacent memory cells (connected to word lines that are adjacent to the common word line) are in one or more low data states. For those memory cells meeting the two criteria, the memory system performs some amount of programming on the memory cells to refresh the data stored in those memory cells to be as originally intended.
    Type: Grant
    Filed: December 13, 2021
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies LLC
    Inventors: Yi Song, Jiahui Yuan, Jun Wan, Deepanshu Dutta
  • Patent number: 11972817
    Abstract: A memory apparatus and method of operation are provided. The apparatus includes memory cells connected to word lines. The memory cells are disposed in strings and are configured to retain a threshold voltage corresponding to data states. A control means is configured to apply verification pulses of program verify voltages each associated with one of the data states to selected ones of the word lines to determine whether the memory cells connected thereto have the threshold voltage above each of the program verify voltages associated with the data states targeted for each of the memory cells being programmed during verify loops of a program-verify operation. The control means slows the memory cells targeted for a selected one of the data states identified as being faster to program than other ones of the memory cells during one of verify loops associated with an earlier one of data states.
    Type: Grant
    Filed: June 10, 2022
    Date of Patent: April 30, 2024
    Assignee: SanDisk Technologies, LLC
    Inventors: Ke Zhang, Ming Wang, Liang Li