Patents Assigned to SanDisk Technologies LLC
  • Publication number: 20220310161
    Abstract: Technology is disclosed for detecting latent defects in non-volatile storage systems. Prior to writing data, a stress voltage is applied to SGS transistors in a 3D memory structure. After applying the stress voltage, the Vt of the SGS transistors are tested to determine whether they meet a criterion. The criterion may be whether a Vt distribution of the SGS transistors falls within an allowed range. If the criterion is not met, then a sub-block mode may be enabled. In the sub-block mode, data is not written to memory cells in a sub-block that contains SGS transistors whose Vt does not meet the criterion. Hence, the possibility of data loss due to defective SGS transistors is avoided. However, in the sub-block mode, data is written to memory cells in a sub-block that does not contain SGS transistors whose Vt does not meet the criterion. Hence, data capacity is preserved.
    Type: Application
    Filed: March 26, 2021
    Publication date: September 29, 2022
    Applicant: SanDisk Technologies LLC
    Inventors: Jayavel Pachamuthu, Siddharth Bhatt
  • Publication number: 20220310179
    Abstract: A method of performing an erase operation on non-volatile storage is disclosed. The method comprises: applying, in a first erase loop of a plurality of erase loops of the erase operation, a first erase pulse to a first grouping of non-volatile storage elements; after applying the first erase pulse, determining an upper tail of a threshold voltage distribution of the first grouping of non-volatile storage elements; determining a difference between the upper tail of the first grouping of non-volatile storage elements and an upper tail of a threshold voltage distribution of a second grouping of non-volatile storage elements; and disabling, in a second erase loop of the plurality of erase loops, the erase operation on the first grouping of non-volatile storage elements if the difference is greater than or equal to the threshold amount.
    Type: Application
    Filed: March 25, 2021
    Publication date: September 29, 2022
    Applicant: SanDisk Technologies LLC
    Inventors: Fanqi Wu, Deepanshu Dutta, Huai-Yuan Tseng
  • Patent number: 11456044
    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: March 11, 2021
    Date of Patent: September 27, 2022
    Assignee: SanDisk Technologies LLC
    Inventor: Kiyohiko Sakakibara
  • Patent number: 11456042
    Abstract: Apparatuses and techniques are described for reducing damage to memory cells during single bit per cell programming. An initial program pulse in a single bit per cell program operation has a lower, first program level followed by a higher, second program level. As a result of the lower, first program level, the electric field across the memory cells is reduced. The step up time from the first program level to the second program level can be reduced by concurrently stepping up pass voltages of the adjacent unselected word lines. If an additional program pulse is applied, the step up in the program pulse can be omitted. The magnitude of the first program level can be adjusted based on factors such as temperature, number of program-erase cycles, selected sub-block position and selected word line position.
    Type: Grant
    Filed: April 13, 2021
    Date of Patent: September 27, 2022
    Assignee: SanDisk Technologies LLC
    Inventors: Xiang Yang, Jiahui Yuan, Abhijith Prakash
  • Patent number: 11450393
    Abstract: A non-volatile memory apparatus and method of operation are provided. The apparatus includes storage elements connected to a word line. Each of the storage elements is configured to be programmed to a respective target data state. The apparatus also includes a respective bit line associated with each of the storage elements and a control circuit configured to apply a plurality of program pulses to the word line that progressively increase by a program step voltage. The control circuit counts an over programming number of the storage elements having a threshold voltage exceeding an over programming verify level of the respective target data state that is less than a default verify level and based on the program step voltage. The control circuit adjusts a voltage of the respective bit line to one or more adjusted levels in response to the over programming number being greater than a predetermined over programming number.
    Type: Grant
    Filed: March 9, 2021
    Date of Patent: September 20, 2022
    Assignee: SanDisk Technologies LLC
    Inventors: Abhijith Prakash, Anubhav Khandelwal
  • Publication number: 20220293197
    Abstract: A non-volatile memory apparatus and method of operation are provided. The apparatus includes storage elements connected to a word line. Each of the storage elements is configured to be programmed to a respective target data state. The apparatus also includes a respective bit line associated with each of the storage elements and a control circuit configured to apply a plurality of program pulses to the word line that progressively increase by a program step voltage. The control circuit counts an over programming number of the storage elements having a threshold voltage exceeding an over programming verify level of the respective target data state that is less than a default verify level and based on the program step voltage. The control circuit adjusts a voltage of the respective bit line to one or more adjusted levels in response to the over programming number being greater than a predetermined over programming number.
    Type: Application
    Filed: March 9, 2021
    Publication date: September 15, 2022
    Applicant: SanDisk Technologies LLC
    Inventors: Abhijith Prakash, Anubhav Khandelwal
  • Publication number: 20220293156
    Abstract: A control circuit is configured to connect to a cross-point memory array in which each conductive line, such as a bit line or word line, is connected to a transistor pair comprising a pMOSFET in parallel with an nMOSFET. When selecting a memory cell to be read, a voltage of a first conductive line may be pulled up using the pMOSFET in a conductive state while the nMOSFET is in a non-conductive state. Further, when reading the selected memory cell, the parallel nMOSFET of the first conductive line may be in a conductive state.
    Type: Application
    Filed: May 31, 2022
    Publication date: September 15, 2022
    Applicant: SanDisk Technologies LLC
    Inventors: Ward Parkinson, James O'Toole, Nathan Franklin, Thomas Trent
  • Patent number: 11444062
    Abstract: A semiconductor device is disclosed including a memory module formed from a pair of semiconductor dies mounted face to face to each other at the wafer level. These die pairs are formed using wafer-to-wafer bonding technology, where the wafers may be bonded to each other when they are of full thickness. Once bonded, respective inactive surfaces of the wafers may be thinned and then the die pairs diced from the wafers to form a completed memory module. When the wafers are bonded face to face, they compensate each other, mechanically resulting in the die pair having a minimum warpage.
    Type: Grant
    Filed: April 29, 2021
    Date of Patent: September 13, 2022
    Assignee: SanDisk Technologies LLC
    Inventor: Nagesh Vodrahalli
  • Patent number: 11444016
    Abstract: A non-volatile storage apparatus comprises a non-volatile memory structure and a plurality of I/O pads in communication with the non-volatile memory structure. The I/O pads include a power I/O pad, a ground I/O pad and data/control I/O pads. The non-volatile storage apparatus further comprises one or more capacitors connected to the power I/O pad and the ground I/O pad. The one or more capacitors are positioned in one or more metal interconnect layers below the signal lines and/or above device capacitors on the top surface of the substrate.
    Type: Grant
    Filed: May 28, 2020
    Date of Patent: September 13, 2022
    Assignee: SanDisk Technologes LLC
    Inventors: Luisa Lin, Mohan Dunga, Venkatesh P. Ramachandra, Peter Rabkin, Masaaki Higashitani
  • Publication number: 20220284961
    Abstract: The nonvolatile memory includes a plurality of nonvolatile memory cells configured to store multiple data states; a word line connected to a control gate of at least one of the plurality of non-volatile memory cells; a control gate line to supply a control gate signal; a word line switch connected between the word line and the control gate line to control the potential applied to the word line from the control gate line; and a memory controller circuit. The memory controller circuit is configured to control a word line potential on the word line and a control gate potential on the control gate line and to control a state of the control gate. The memory controller circuit, when the nonvolatile memory transitions to a not-on state, is further configured to turn off the word line switch and to charge the control gate line to a charged potential.
    Type: Application
    Filed: March 3, 2021
    Publication date: September 8, 2022
    Applicant: SanDisk Technologies LLC
    Inventors: Abhijith Prakash, Anubhav Khandelwal
  • Publication number: 20220284964
    Abstract: An apparatus includes a plurality of solid-state storage elements, a plurality of control lines coupled to the plurality of solid-state storage elements, and control circuitry in communication with the plurality of control lines. The control circuitry is configured to during a first phase of a control line pre-charging stage, charge one or more unselected control lines of the plurality of control lines using a regulated charging current for a period of time based at least in part on a predicted parasitic capacitance associated with the programming state of the control lines, and during a second phase of the control line pre-charging stage, charge the one or more unselected bit lines to an inhibit voltage level using an unregulated charging current.
    Type: Application
    Filed: March 3, 2021
    Publication date: September 8, 2022
    Applicant: SanDisk Technologies LLC
    Inventors: Yanjie Wang, Henry Chin, Guirong Liang, Jianzhi Wu
  • Publication number: 20220284965
    Abstract: A method of operating a memory system includes a first programming loop, which includes applying a first programming voltage to a control gate of a selected word line and applying a first bitline voltage to a bitline coupled to a first memory cell that is being programmed to a first data state and to a different bitline coupled to a second memory cell that is being programmed to a second data state. In a second programming loop, a second bitline voltage is applied to the bitline coupled to the first memory cell, and a third bitline voltage is applied to the bitline coupled to the second memory cell. The second bitline voltage is greater than the first bitline voltage to reduce a programming speed of the first bitline voltage to increase a programming speed of the second memory cell.
    Type: Application
    Filed: March 4, 2021
    Publication date: September 8, 2022
    Applicant: SanDisk Technologies LLC
    Inventors: Yu-Chung Lien, Huai-yuan Tseng, Swaroop Kaza, Tomer Eliash
  • Publication number: 20220284971
    Abstract: A memory apparatus and method of operation are provided. The apparatus includes a plurality of memory cells. Each of the plurality of memory cells is connected to one of a plurality of word lines and is arranged in one of a plurality of blocks. Each of the plurality of memory cells is configured to retain a threshold voltage corresponding to one of a plurality of data states. A control circuit is coupled to the plurality of word lines and is configured to detect at least one use characteristic of the memory apparatus. The control circuit adjusts a verify voltage level by one of a plurality of verify level offsets based on the at least one use characteristic that is detected. The verify voltage level is applied to the one of the plurality of word lines selected for programming following an application of a program voltage during a program operation.
    Type: Application
    Filed: March 4, 2021
    Publication date: September 8, 2022
    Applicant: SanDisk Technologies LLC
    Inventors: Abhijith Prakash, Anubhav Khandelwal
  • Patent number: 11437110
    Abstract: A method of performing an erase operation on non-volatile storage is disclosed. The method comprises: applying, in a first erase loop of a plurality of erase loops of the erase operation, a first erase pulse to a first grouping of non-volatile storage elements; after applying the first erase pulse, determining an upper tail of a threshold voltage distribution of the first grouping of non-volatile storage elements; determining a difference between the upper tail of the first grouping of non-volatile storage elements and an upper tail of a threshold voltage distribution of a second grouping of non-volatile storage elements; and disabling, in a second erase loop of the plurality of erase loops, the erase operation on the first grouping of non-volatile storage elements if the difference is greater than or equal to the threshold amount.
    Type: Grant
    Filed: March 25, 2021
    Date of Patent: September 6, 2022
    Assignee: SanDisk Technologies LLC
    Inventors: Fanqi Wu, Deepanshu Dutta, Huai-Yuan Tseng
  • Patent number: 11424207
    Abstract: To overcome a shortage of area for horizontal metal lines to connect word line switch transistors to corresponding word lines and for pass through signal lines, it is proposed to implement multiple architectures for the word line hook up regions. For example, some areas of a die will be designed to provide extra horizontal metal lines to connect word line switch transistors to word lines and other areas of the die will be designed to provide extra pass through signal lines.
    Type: Grant
    Filed: April 30, 2021
    Date of Patent: August 23, 2022
    Assignee: SanDisk Technologies LLC
    Inventors: Shiqian Shao, Fumiaki Toyama
  • Patent number: 11423996
    Abstract: A memory apparatus and method of operation is provided. The apparatus includes a block of memory cells. Each of the memory cells is connected to one of a plurality of word lines and arranged in strings. Each of the memory cells is also configured to retain a threshold voltage corresponding to one of a plurality of data states and be erased in an erase operation. A control circuit is coupled to the word lines and the strings and is configured to identify ones of the strings having a faster relative erase speed compared to others of the strings. During the erase operation, the control circuit raises the threshold voltage of the memory cells associated with the ones of the strings having the faster relative erase speed while not raising the threshold voltage of the memory cells associated with the others of the strings.
    Type: Grant
    Filed: May 18, 2021
    Date of Patent: August 23, 2022
    Assignee: SanDisk Technologies LLC
    Inventors: Xiang Yang, Yi Song, Fanqi Wu
  • Patent number: 11423993
    Abstract: A method reading memory using bi-directional sensing, including programming first memory cells coupled to a first word-line using a normal programming order; programming second memory cells coupled to a second word-line using a normal programming order; reading data from the first memory cells by applying a normal sensing operation to the first word-line; and reading data from the second memory cells by applying a reverse sensing operation to the second word-line. Methods also include receiving an error associated with reading data from the first memory cells; and then reading the data from the first memory cells by applying a reverse sensing operation to the first word-line. Method also include receiving an error associated with reading the data from the second memory cells; and then reading the data from the second memory cells by applying a normal sensing operation to the second word-line.
    Type: Grant
    Filed: November 6, 2019
    Date of Patent: August 23, 2022
    Assignee: SanDisk Technologies LLC
    Inventors: Zhiping Zhang, Muhammad Masuduzzaman, Huai-Yuan Tseng, Peng Zhang, Dengtao Zhao, Deepanshu Dutta
  • Patent number: 11417400
    Abstract: Techniques are described for optimizing the peak current during a program operation by controlling a timing and ramp rate of a program-inhibit voltage signal as a function of a program loop number and/or program progress. A transition voltage between a regulated ramp up rate and an unregulated ramp up rate can also be adjusted. For initial and final sets of program loops in a program operation, the ramp up of the program-inhibit voltage signal can occur early so that it overlaps with operations of sense circuits in updating their latches based on results from a verify test in a previous program loop. For an intermediate set of program loops, the overlap is avoided. The ramp up rate can be larger and the transition voltage smaller for the initial and final sets of program loops compared to the intermediate set of program loops.
    Type: Grant
    Filed: January 31, 2020
    Date of Patent: August 16, 2022
    Assignee: SanDisk Technologies LLC
    Inventors: Yu-Chung Lien, Huai-Yuan Tseng, Deepanshu Dutta
  • Publication number: 20220254382
    Abstract: A non-volatile memory device is provided that includes an alternating stack of conducting layers and dielectric layers, a charge trap layer, a layer of polysilicon, and a tunneling dielectric layer arranged between the charge trap layer and the layer of polysilicon. The charge trap layer extends through the alternating stack of conducting layers and dielectric layers. The layer of polysilicon includes a first portion having a first thickness and a second portion having a second thickness that is greater than the first thickness. The second portion is arranged below the alternating stack of conducting layers and dielectric layers.
    Type: Application
    Filed: April 28, 2022
    Publication date: August 11, 2022
    Applicant: SanDisk Technologies LLC
    Inventors: Kiyohiko Sakakibara, Ken Oowada
  • Publication number: 20220254416
    Abstract: A memory apparatus and method of operation are provided. The apparatus includes memory cells each connected to a word line and arranged in one of a plurality of blocks and configured to retain a threshold voltage corresponding to a data state. The memory cells are operable in one of a first read condition in which a word line voltage is discharged and a second read condition in which the word line voltage is coupled up to a residual voltage level. A control circuit determines a power on event and periodically apply a predetermined refresh read voltage to the word line for a predetermined period of time for each of the plurality of blocks at a specified interval based on at least one data retention factor to maintain the memory cells of the plurality of blocks in the second read condition in response to determining the power on event.
    Type: Application
    Filed: February 11, 2021
    Publication date: August 11, 2022
    Applicant: SanDisk Technologies LLC
    Inventors: Ravi Kumar, Deepanshu Dutta, Vishwanath Basavaegowda Shanthakumar