Patents Assigned to SanDisk Technologies
  • Patent number: 11776640
    Abstract: A method for programming a non-volatile memory structure, comprises initiating a two-dimensional fractional number of bits-per-cell programming scheme of a plurality of memory cells, wherein the memory structure comprises: (1) a first memory array comprising a first population of memory cells and the associated peripheral circuitry disposed below the first population of cells, (2) a second memory array positioned above the first memory array and comprising a second population of memory cells and associated peripheral circuitry disposed above the second population of cells, and (3) a data bus tap electrically coupling the first and second memory arrays. Further, the method comprises: (1) storing input data in data latches associated with the first array and with the second array. Additionally, the method comprises converting the stored data using data conversion logic implemented by a data path circuit of the first and second arrays and rewriting the converted data to the latches.
    Type: Grant
    Filed: October 27, 2021
    Date of Patent: October 3, 2023
    Assignee: SanDisk Technologies LLC
    Inventors: Kei Kitamura, Yuki Fujita, Kyosuke Matsumoto, Masahiro Kano, Minoru Yamashita, Ryuji Yamashita, Shuzo Otsuka
  • Patent number: 11776589
    Abstract: 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: Grant
    Filed: April 28, 2022
    Date of Patent: October 3, 2023
    Assignee: SanDisk Technologies LLC
    Inventors: Hua-Ling Cynthia Hsu, YenLung Li
  • Patent number: 11776628
    Abstract: The following disclosure is directed to mitigating issues related to semi-circle drain side select gate (SC-SGD) memory holes in memory structures. When a memory hole is cut, the channel and the charge trap layer of the memory hole cut. Further, the outer dielectric layer (used to shield the channel and the charge trap layer) is cut and partially removed. When the selected SC-SGD is selected for an operation (e.g., programming), the channel and the charge trap layer are exposed to neighboring electrical field from bias voltage applied to an unselected SC-SGD. To prevent or mitigate the effects of this electrical field, a negative bias voltage is applied to the unselected SC-SGD. Additionally, this disclosure is directed to self-compensating techniques for SC-SGD. For example, the memory structure can utilize the neighboring electric field during verify, program, and read operations, whether the neighboring electric field is relatively strong or weak.
    Type: Grant
    Filed: June 17, 2021
    Date of Patent: October 3, 2023
    Assignee: SanDisk Technologies LLC
    Inventors: Xiang Yang, Kazuki Isozumi, Parth Amin
  • Publication number: 20230307071
    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: Application
    Filed: March 22, 2022
    Publication date: September 28, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Xue Bai Pitner, Yu-Chung Lien, Ravi Kumar, Jiahui Yuan, Bo Lei, Zhenni Wan
  • Publication number: 20230307072
    Abstract: The memory device includes a controller that is configured to program the memory cells of a selected word line in a plurality of program-verify iterations. During a verify portion at least one of the program-verify iterations, the controller determines a threshold voltage of at least one memory cell relative to a first verify low voltage VL1, a second verify low voltage VL2, and a verify high voltage VH associated with a data state being programmed. The controller also maintains a count of program-verify iterations since the at least one memory cell passed a verify high voltage of a previously programmed data state or discharges a sense node through a channel including the at least one memory cell and compares a discharge time to predetermined sense times associated with the first and second verify low voltages and with the verify high voltage.
    Type: Application
    Filed: March 22, 2022
    Publication date: September 28, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Muhammad Masuduzzaman, Deepanshu Dutta, Gerrit Jan Hemink
  • Publication number: 20230307070
    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: Application
    Filed: February 8, 2022
    Publication date: September 28, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Abhijith Prakash, Xiang Yang
  • Patent number: 11769560
    Abstract: A non-volatile memory device, described herein, comprises: a plurality of memory strings and at least one control circuit in communication with the non-volatile memory cell array. The at least one control circuit is configured to perform, for the plurality of memory strings, one erase-verify iteration in an erase operation including determining whether at least one memory string of the plurality of memory strings passes an erase-verify test. The at least one control circuit is configured to, if the at least one memory string passes the erase-verify test, inhibit the at least one memory string for erase including ramping up, to an erase voltage, of a voltage applied to a gate of a SGD transistor of the at least one memory string and to perform a next erase-verify iteration in the erase operation for remaining memory strings of the plurality of memory strings other than the at least one memory string.
    Type: Grant
    Filed: August 13, 2021
    Date of Patent: September 26, 2023
    Assignee: SanDisk Technologies LLC
    Inventor: Hideto Tomiie
  • Publication number: 20230298667
    Abstract: An apparatus is provided that includes a word line coupled to a word line driver circuit, bit lines, a plurality of non-volatile memory cells each coupled to the word line and a corresponding one of the bit lines, and a control circuit coupled to the word line and the bit lines. The control circuit is configured to program the memory cells by causing the word line driver to apply a program pulse to the word line, and biasing each bit line to a corresponding bit line voltage that has a value that varies based on a distance between the word line driver and the corresponding bit line.
    Type: Application
    Filed: March 17, 2022
    Publication date: September 21, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Jiacen Guo, Xiang Yang, Xiaochen Zhu
  • Patent number: 11763907
    Abstract: Systems and methods for improving the reliability of non-volatile memory by reducing the number of memory cell transistors that experience excessive hole injection are described. The excessive hole injection may occur when the threshold voltage for a memory cell transistor is being set below a particular negative threshold voltage. To reduce the number of memory cell transistors with threshold voltages less than the particular negative threshold voltage, the programmed data states of the memory cell transistors may be reversed such that the erased state comprises the highest data state corresponding with the highest threshold voltage distribution. To facilitate programming of the memory cell transistors with reversed programmed data states, a non-volatile memory device structure may be used in which the bit line connections to NAND strings comprise direct poly-channel contact to P+ silicon and the source line connections to the NAND strings comprise direct poly-channel contact to N+ silicon.
    Type: Grant
    Filed: August 23, 2022
    Date of Patent: September 19, 2023
    Assignee: SanDisk Technologies LLC
    Inventor: Kiyohiko Sakakibara
  • Publication number: 20230290419
    Abstract: The memory device includes a plurality of memory cells which are arranged in an array. The memory device further includes a plurality of bit lines that are coupled with the memory cells and a controller. The controller is configured to program the memory cells from an erased data state to three programmed data states in a programming operation that includes three programming pulses and zero verify operations using different patterns to dictate the application of inhibit voltages to the bit lines during each of the three programming pulses. The patterns include two pre-established patterns and additional patterns that are derived from the pre-established patterns using logic operations.
    Type: Application
    Filed: March 9, 2022
    Publication date: September 14, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Xiang Yang, Takayuki Inoue, Jiacen Guo
  • Publication number: 20230290403
    Abstract: An apparatus disclosed herein comprises: a plurality of memory cells and a control circuit coupled to the plurality of memory cells. The control circuit is configured to: determine whether the apparatus is in low power mode; in response to determining that the apparatus is in low power mode, perform a normal order read operation on a set of memory cells of the plurality of memory cells; and in response to determining that the apparatus is not in low power mode, perform a reverse order read operation on the set of memory cells of the plurality of memory cells.
    Type: Application
    Filed: March 9, 2022
    Publication date: September 14, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Jiahui Yuan, Kai Kirk, Yu-Chung Lien
  • Publication number: 20230282295
    Abstract: A method for programming a target memory cell of a memory array of a non-volatile memory system, the method comprises determining a total number of erase/programming (EP) cycles that were applied previously to the memory cell and, (1) if the determined total number of cycles does not exceed a threshold value, applying an asymmetric programming scheme, and, (2) if the determined total number of cycles exceeds the threshold value, applying a symmetric programming scheme. Further, a magnitude of a boosting voltage bias (VPASS) that is to be applied to an unselected word line may be determined according to the determined total number of erase/programming (EP) cycles.
    Type: Application
    Filed: March 2, 2022
    Publication date: September 7, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Yu-Chung Lien, Xue Bai Pitner, Ken Oowada
  • Publication number: 20230282288
    Abstract: The memory device includes a chip with circuitry, a plurality of memory blocks, and a plurality of bit lines. The memory blocks include an array of memory cells, and the circuitry either overlies or underlies the array of memory cells. The bit lines are divided into two portions that are electrically connected with one another via at least one transistor so that at least one portion of each bit line can be charged independently of the other portion of the same bit line. During some read operations, this allows the memory device to operate with lower power requirements.
    Type: Application
    Filed: March 3, 2022
    Publication date: September 7, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Xiang Yang, Deepanshu Dutta, Ohwon Kwon, James Kai, Yuki Mizutani
  • Publication number: 20230274785
    Abstract: A non-volatile semiconductor memory device comprises 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: Application
    Filed: February 28, 2022
    Publication date: August 31, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Sujjatul Islam, Yu-Chung Lien, Ravi Kumar, Xue Pitner
  • Publication number: 20230268015
    Abstract: 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. A control means is coupled to the word lines and the memory holes and programs the memory cells associated with a first one of the strings in a program operation and acquire a smart verify programming voltage in a smart verify operation including smart verify loops. The control means discards the smart verify programming voltage and determines another smart verify programming voltage in another smart verify operation on the memory cells associated with a second one of the strings in response to a quantity of the smart verify loops needed to complete programming of the memory cells associated with the first one of the strings being outside a predetermined threshold criteria.
    Type: Application
    Filed: February 23, 2022
    Publication date: August 24, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Ke Zhang, Minna Li, Liang Li
  • Publication number: 20230268013
    Abstract: A non-volatile storage apparatus that comprises a plurality of planes of non-volatile memory cells is capable of concurrently programming memory cells in multiple planes. In order to screen for failure of the programming process in a subset of planes, the completion of programming of a fastest plane to a particular data state is used as a trigger to test for program failure of other planes to a different data state. In one embodiment, the test for program failure of other planes to the different data state comprises determining if the memory cells of the other planes that are targeted for programming to the different data state have successfully completed verification of programming for the different data state. The programming process is stopped for those planes that fail the test.
    Type: Application
    Filed: February 22, 2022
    Publication date: August 24, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Shota Murai, Hideto Tomiie
  • Publication number: 20230267981
    Abstract: Technology is disclosed for improving read margin in a cross-point memory array. Drive transistors pass a read and write currents to the cross-point memory array. The read current charges a selected word line to turn on a threshold switching selector of a selected memory cell. While the threshold switching selector is on, the current (read or write) passes through the selected memory cell. The memory system applies a smaller overdrive voltage to the drive transistor when the drive transistor is passing the read current than when the drive transistor is passing the write current. A smaller overdrive voltage increases the resistance of the drive transistor which improves read margin. Increasing the resistance of the drive transistor increases the resistance seen by the threshold switching selector in the selected memory cell, which reduces the Ihold of the threshold switching selector. Reducing Ihold of the threshold switching selector improves read margin.
    Type: Application
    Filed: February 22, 2022
    Publication date: August 24, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Ward Parkinson, James O'Toole, Thomas Trent, Nathan Franklin, Michael Grobis, James W. Reiner, Hans Jurgen Richter, Michael Nicolas Albert Tran
  • Patent number: 11735288
    Abstract: Technology is disclosed herein for loading redundancy information during a memory system power on read (POR). A memory structure has primary regions (e.g., primary columns) and a number of redundant regions (e.g., redundant columns). The status of the regions is stored in isolation latches during the POR. Initially, simultaneously all latches for primary regions are reset to used and all latches for redundant regions are reset to unused. Then, isolation latches for defective primary regions are set to unused while isolation latches for corresponding redundant regions are set to used. There is no need to individually set isolation latches for redundant regions to unused, which saves time during POR. Moreover, whenever the isolation latch for a defective primary region is set from used to unused, in parallel the isolation latch for the replacement redundant column may be set from unused to used, thereby not incurring a time penalty.
    Type: Grant
    Filed: February 16, 2022
    Date of Patent: August 22, 2023
    Assignee: SanDisk Technologies LLC
    Inventors: Hua-Ling Cynthia Hsu, YenLung Li
  • Publication number: 20230259149
    Abstract: A circuit is provided that includes a first transistor having a first terminal, a second terminal and a third terminal, and a second transistor comprising a first terminal, a second terminal and a third terminal. The first terminal of the first transistor comprises an input terminal of the circuit, the second terminal of the first transistor is coupled to a power supply bus, and the first transistor conducts a first current. The first terminal of the first transistor comprises an output terminal of the circuit, the second terminal of the second transistor is coupled to the power supply bus, and the third terminal of the second transistor is coupled to the third terminal of the first transistor. The second transistor conducts a second current proportional to the first current substantially independent of distance between the first transistor and the second transistor.
    Type: Application
    Filed: February 16, 2022
    Publication date: August 17, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: James O'Toole, Ward Parkinson, Thomas Trent
  • Publication number: 20230259300
    Abstract: Technology is disclosed for a non-volatile memory system that decouples dataload from program execution. A memory controller transfers data for a program operation and issues a first type of program execution command. When in a coupled mode, the die programs the data in response to the first type of program execution command. When in a decoupled mode, rather than program the data into non-volatile memory cells the die enters a wait state. Optionally, the memory controller can instruct another die to execute a memory operation while the first die is in the wait state. In response to receiving a second type of program execution command from the memory controller when in the wait state, the first die will program the data into non-volatile memory cells. The memory controller may issue the second type of program execution command in response to determining that sufficient power resources (or thermal budget) exist.
    Type: Application
    Filed: February 17, 2022
    Publication date: August 17, 2023
    Applicant: SanDisk Technologies LLC
    Inventors: Hua-Ling Cynthia Hsu, Aaron Lee