Patents Assigned to SanDisk Technologies
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Publication number: 20230260589Abstract: 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: ApplicationFiled: February 16, 2022Publication date: August 17, 2023Applicant: SanDisk Technologies LLCInventors: Hua-Ling Cynthia Hsu, YenLung Li
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Publication number: 20230260582Abstract: When erasing multiple sub-blocks of a block, erase verify is performed for memory cells connected to even word lines to generate even results and for memory cells connected to odd word lines to generate odd results. The even results and the odd results are used to determine that the erase verify process successfully completed. For each NAND string of a first sub-block, a last even result for the NAND string is compared to a last odd result for the NAND string. Despite the determination that the first sub-block successfully completed erase verify, the erasing failed for the first sub-block because the number of NAND strings that have the last even result different than the last odd result is greater than a limit. The system determines that one or more additional sub-blocks also failed erasing based on and in response to determining that the first sub-block failed erasing.Type: ApplicationFiled: February 16, 2022Publication date: August 17, 2023Applicant: SanDisk Technologies LLCInventors: Jayavel Pachamuthu, Dana Lee
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Publication number: 20230253048Abstract: The memory device includes an array of memory cells, which are configured to retain multiple bits per memory cell, arranged in a plurality of word lines. A controller is configured to program the memory cells of a selected word line in a first programming pass. The first programming pass includes a plurality of programming pulses, each including the application of a programming voltage Vpgm by the controller to a control gate of the selected word line for a first duration. The controller is also configured to further program the memory cells of the selected word line in a second programming pass. The second programming pass includes a plurality of programming pulses, each of which includes the application of a programming voltage Vpgm by the controller to the control gate of the selected word line for a second duration that is different than the first duration.Type: ApplicationFiled: February 8, 2022Publication date: August 10, 2023Applicant: SanDisk Technologies LLCInventors: Sujjatul Islam, Ravi Kumar
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Publication number: 20230253049Abstract: A non-volatile semiconductor memory device, described herein, comprises a bit line, a source line, a memory string comprising a plurality of memory cells connected in series between the source line and the bit line, and control circuitry coupled to the plurality of memory cells, the source line, and the bit line. The control circuitry is configured to: determine if a program operation is a single-bit program operation or multi-bit program operation; in response to the determination, identify a voltage level to set the source line to during performance of the program operation; and perform the program operation on the memory string, the program operation including setting the source line to the voltage level.Type: ApplicationFiled: February 8, 2022Publication date: August 10, 2023Applicant: SanDisk Technologies LLCInventors: Yu-Chung Lien, Deepanshu Dutta, Sarath Puthenthermadam, Jiahui Yuan
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Publication number: 20230253046Abstract: The memory device includes a plurality of dies, and each die includes a plurality of blocks with a plurality of word lines. Some of the word lines are arranged in a plurality of exclusive OR (XOR) sets with each XOR set containing word lines in the same positions across the plurality of dies. The memory device further includes a controller that is configured to program the word lines of the blocks of at least one of the dies in a first programming direction. The controller is further configured to program the word lines of the blocks of at least one other die in a second programming direction that is opposite of the first programming direction.Type: ApplicationFiled: February 4, 2022Publication date: August 10, 2023Applicant: SanDisk Technologies LLCInventors: Qing Li, Henry Chin, Xiaoyu Yang
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Publication number: 20230253047Abstract: A non-volatile semiconductor memory device, described herein, 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, during a program iteration of a program operation, determine whether a program voltage level of the program iteration exceeds a threshold program voltage level and in response to the determination, identify a set of voltage levels to apply to a source line connected to a set of the non-volatile storage elements. The one or more control circuits are further configured to perform the program iteration of the program operation on the set of non-volatile storage elements, where the program iteration includes applying the set of voltage levels to the source line.Type: ApplicationFiled: February 7, 2022Publication date: August 10, 2023Applicant: SanDisk Technologies LLCInventors: Xue Pitner, Yu-Chung Lien, Sarath Puthenthermadam, Sujjatul Islam
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Publication number: 20230253053Abstract: A memory apparatus and method of operation are provided. The memory apparatus includes memory cells connected to word lines and disposed in memory holes organized in rows grouped in strings. The memory cells are configured to retain a threshold voltage. The rows include full circle rows and semi-circle rows in which the memory holes are partially cut by a slit half etch. The memory holes of the semi-circle rows are coupled semi-circle bit lines and the memory holes of the full circle rows are coupled to full circle bit lines. A control means is configured to erase the memory cells in an erase operation. During the erase operation, the control means creates a capacitive coupling between each of the semi-circle bit lines and at least one neighboring one of the full circle bit lines to increase a semi-circle erase voltage applied to each of the semi-circle bit lines.Type: ApplicationFiled: February 8, 2022Publication date: August 10, 2023Applicant: SanDisk Technologies LLCInventors: Xiang Yang, Kou Tei, Ohwon Kwon
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Publication number: 20230253056Abstract: A memory apparatus and method of operation are provided. The apparatus includes memory cells connected to word lines including a dummy word line and other data word lines. The memory cells are disposed in memory holes and configured to retain a threshold voltage. A control means is coupled to the word lines and the memory holes and is configured to determine whether one of the word lines being programmed in a program operation is a particular one of the word lines adjacent the dummy word line needing a dummy positioning operation. The control means is also configured to program the memory cells connected to the dummy word line to adjust the threshold voltage to a predetermined position threshold voltage in the dummy positioning operation in response to determining the one of the plurality of word lines being programmed in the program operation is the particular one of the word lines.Type: ApplicationFiled: February 4, 2022Publication date: August 10, 2023Applicant: SanDisk Technologies LLCInventors: Xiang Yang, Abhijith Prakash
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Patent number: 11721397Abstract: A memory apparatus and method of operation are provided. The apparatus includes a page of memory cells connected to a plurality of word lines and arranged in strings and configured to retain a threshold voltage. A control circuit couples to the word lines and strings and identifies the memory cells having the threshold voltage less than a primary demarcation threshold voltage of a series for demarcating between memory states in a page read. The control circuit also identifies the memory cells having the threshold voltage less than a secondary demarcation threshold voltage of the series. The control circuit supplies a near zero voltage to the strings of the memory cells identified as having the threshold voltages less than at least one of the primary and secondary demarcation threshold voltages to inhibit conduction currents while identifying the memory cells having the threshold voltage less than a tertiary demarcation threshold voltage.Type: GrantFiled: December 28, 2020Date of Patent: August 8, 2023Assignee: SanDisk Technologies LLCInventors: Jianzhi Wu, Jia Li, Yanjie Wang
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Publication number: 20230238062Abstract: The memory device includes a block with a plurality of memory cells arranged in a plurality of data word lines, which are arranged in sub-blocks that are not separated from one another by physical joints or by dummy word lines. A controller is configured to erase the memory cells of a selected sub-block of the plurality of sub-blocks without erasing the memory cells of the unselected sub-blocks. The controller reads data of the edge one word lines of the unselected sub-blocks adjacent the selected sub-block and stores this data in a temporary location external of the block before erasing the memory cells of the selected sub-block. The controller then re-programs the data that is being temporarily stored back into the memory cells of the edge word lines of the unselected sub-blocks after erase of the selected sub-block is completed.Type: ApplicationFiled: January 25, 2022Publication date: July 27, 2023Applicant: SanDisk Technologies LLCInventor: Xiang Yang
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Patent number: 11705206Abstract: Apparatuses and techniques are described for modifying program and erase parameters in a memory device in which memory cells can be operated in a single bit per cell (SLC) mode or a multiple bits per cell mode. In one approach, the stress on a set of memory cells in an SLC mode is reduced during programming and erasing when the number of program-erase cycles for the block in the SLC mode is below a threshold. For example, during programming, the program-verify voltage and program voltages can be reduced to provide a shallower than normal programming. During erasing, the erase-verify voltage can be increased while the erase voltages can be reduced to provide a shallower than normal erase. When the number of program-erase cycles for the block in the SLC mode is above the threshold, the program and erase parameters revert to a default levels.Type: GrantFiled: August 17, 2021Date of Patent: July 18, 2023Assignee: SanDisk Technologies LLCInventors: Abu Naser Zainuddin, Jia Li, Jiahui Yuan, Bo Lei
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Patent number: 11705203Abstract: Techniques disclosed herein cope with temperature effects in non-volatile memory systems. A control circuit is configured to sense a current temperature of the memory system and read, verify, program, and erase data in non-volatile memory cells by modifying one or more read/verify/program/erase parameters based on a temperature compensation value. The control circuit is further configured to read, verify, program, and erase data by accessing a historical temperature value stored in the memory system, the historical temperature value comprising a temperature at which a previous read, verify, program or erase occurred and measuring a current temperature value. The control circuit determines the temperature compensation value by applying a smoothing function.Type: GrantFiled: June 18, 2021Date of Patent: July 18, 2023Assignee: SanDisk Technologies LLCInventors: Henry Chin, Hua-Ling Cynthia Hsu, Wei Zhao, Fanglin Zhang
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Publication number: 20230223087Abstract: The memory device includes a plurality of memory cells arranged in a plurality of blocks, which are arranged in at least one plane. A controller is in electrical communication with the plurality of memory cells. The controller is configured to define a multi-block group that includes at least two blocks to be erased. The controller is further configured to simultaneously apply at least one erase pulse to the multi-block group. The controller is further configured to individually and sequentially apply a verify pulse to the blocks. In response to all blocks passing verify, the controller is configured to complete the erase operation. In response to at least one of the blocks not passing verify, the controller is configured to individually and sequentially apply an erase pulse and then a verify pulse to the at least one block that did not pass verify.Type: ApplicationFiled: January 12, 2022Publication date: July 13, 2023Applicant: SanDisk Technologies LLCInventors: Ke Zhang, Liang Li
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Publication number: 20230223084Abstract: 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: ApplicationFiled: January 7, 2022Publication date: July 13, 2023Applicant: SanDisk Technologies LLCInventors: Yu-Chung Lien, Fanqi Wu, Jiahui Yuan
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Publication number: 20230223086Abstract: The memory device includes a plurality of memory cell that arranged in an array, which includes a plurality of channels that are in electrical communication with a source line. The memory device also includes a controller that is configured to erase the memory cells in at least one erase pulse. During the at least one erase pulse, the controller is configured to drive the source line to an elevated voltage that is equal to an erase voltage Vera plus a kick voltage V_kick for a duration t_kick. The controller is then configured to reduce the voltage of the source line to the erase voltage Vera such that a voltage of the channel remains elevated during the entire erase pulse, including after the voltage of the source line has been reduced to the erase voltage Vera.Type: ApplicationFiled: January 10, 2022Publication date: July 13, 2023Applicant: SanDisk Technologies LLCInventors: Xuan Tian, Liang Li
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Patent number: 11698750Abstract: Technology is disclosed herein for efficient use of volatile memory that is used for accumulating parity data of user data being written to non-volatile memory cells. A memory controller may replace primary parity in a first portion of a parity buffer with data other than primary parity while a second portion of the buffer is still being used to store the primary parity. Therefore, the memory controller smartly re-uses the parity buffer, which makes efficient use of the volatile memory. In one aspect, a memory controller accumulates secondary parity for the user data in a first portion of the parity buffer while a second portion of the parity buffer is still being used to store the primary parity. The memory controller may compute the secondary parity from present content of the first portion of the parity buffer and primary parity presently stored in the second portion of the buffer.Type: GrantFiled: October 4, 2021Date of Patent: July 11, 2023Assignee: SanDisk Technologies LLCInventors: Bhanushankar Doni, Pratik Bhatt
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Patent number: 11699502Abstract: Technology is disclosed herein for testing circuitry that controls memory operations in a memory structure having non-volatile memory cells. The testing of the circuitry can be performed without the memory structure. The memory structure may reside on one semiconductor die, with sense blocks and a control circuit on another semiconductor die. The control circuit is able to perform die level control of memory operations in the memory structure. The control circuit may control the sense blocks to simulate sensing of non-volatile memory cells in the memory structure even though the sense blocks are not connected to the memory structure. The control circuit verifies correct operation of the semiconductor die based on the simulated sensing. For example, the control circuit may verify correct operation of a state machine that controls sense operations at a die level. Thus, the operation of the semiconductor die may be tested without the memory structure.Type: GrantFiled: December 14, 2021Date of Patent: July 11, 2023Assignee: SanDisk Technologies LLCInventors: Iris Lu, Yan Li, Ohwon Kwon
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Patent number: 11699495Abstract: A method for programming a memory block of a non-volatile memory structure, comprising determining whether a number of programming/erase cycles previously applied to the block exceeds a first programming/erase cycle threshold and, if the first threshold is exceeded, determining whether the number of programming/erase cycles previously applied to the block exceeds an extended programming/erase cycle threshold. Further, if the determination is made that the extended threshold is not exceeded, the method comprises applying a two-pulse per programming loop scheme to each of the outermost strings of the block and applying a single-pulse per programming loop scheme to all other strings of the block. Alternatively, or in addition thereto, relative to a programming/erase cycle threshold, one or more outermost strings of the block may be unpermitted to be further programmed, and a “sub-block” comprised of all valid strings of the block may be defined and permitted for further programming.Type: GrantFiled: June 16, 2021Date of Patent: July 11, 2023Assignee: SanDisk Technologies LLCInventor: Xiang Yang
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Patent number: 11694755Abstract: An apparatus includes control circuits configured to connect to a plurality of non-volatile memory cells. The control circuits are configured to abort fine programming of the plurality of non-volatile memory cells at an intermediate stage and read the plurality of non-volatile memory cells at the intermediate stage to obtain first partial data of at least one logical page. The control circuits are configured obtain the at least one logical page of data by combining the first partial data with second partial data of the at least one logical page stored in data latches.Type: GrantFiled: June 2, 2021Date of Patent: July 4, 2023Assignee: SanDisk Technologies LLCInventors: Hiroyuki Mizukoshi, Heguang Li, Althaf Rahamathulla, Qihan Li
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Publication number: 20230207021Abstract: A memory apparatus and method of operation are provided. The memory apparatus includes memory cells connected to word lines and disposed in memory holes. The memory cells are connected in series between a drain-side select gate transistor on a drain-side and connected to one of a plurality of bit lines and a source line on a source-side. A control means is configured to apply a first and a second select gate voltage to the drain-side select gate transistor while applying a predetermined source line voltage to the source line of selected ones of the memory holes in a predetermined grouping and a read level voltage to at least one of the word lines associated with the predetermined grouping. The control means counts the memory cells conducting during each of a first and a second read operation and adjusts the predetermined source line voltage accordingly.Type: ApplicationFiled: December 23, 2021Publication date: June 29, 2023Applicant: SanDisk Technologies LLCInventors: Jiacen Guo, Xiang Yang