Patents Assigned to SanDisk Technologies LLC
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Patent number: 11037631Abstract: Strings of non-volatile memory cells include one or more joint regions adjacent to dummy non-volatile memory cells. During erase operations, different voltage levels are used for different dummy word lines coupled to respective dummy non-volatile memory cells. For example, a selection circuit may set a voltage level of a particular dummy word line to a voltage level greater than a different dummy word line. In another example, the selection circuit may determine a voltage level for a given dummy word line based on a distance between a non-volatile memory cell coupled to the given dummy word line and a selection device included in a string of non-volatile memory cells. Electron holes generated using the dummy word lines during erase operations may neutralize undesired trapped charges in a non-volatile memory string, thereby reducing disparity in erase times for different strings in the non-volatile memory circuit.Type: GrantFiled: January 18, 2019Date of Patent: June 15, 2021Assignee: Sandisk Technologies LLCInventors: Jayavel Pachamuthu, Amul Dhirajbhai Desai, Ankitkumar Babariya
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Patent number: 11037640Abstract: Techniques are provided to reduce neighbor word line interference and charge loss in a multi-pass program operation. In one implementation, the first pass of a multi-pass program operation uses one or more program pulses without performing associated verify tests. The memory cells may be programmed to different intermediate threshold voltage (Vth) distributions in the first program pass. Different bit line voltages can be used to obtain the different intermediate Vth distributions when the single program pulse is applied. In other cases, multiple program pulses are applied without performing verify tests. The intermediate Vth distributions can be provided for the memory cells assigned to the higher data states but not the lower data states, or for memory cells assigned to both the higher and lower data states.Type: GrantFiled: June 12, 2020Date of Patent: June 15, 2021Assignee: SanDisk Technologies LLCInventors: Ashish Baraskar, Ching-Huang Lu, Vinh Diep, Yingda Dong
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Patent number: 11037641Abstract: Apparatuses and techniques are described for periodically refreshing word line voltages in a memory device. A decision to perform a refresh operation is made based on the temperature and number of program-erase (P-E) cycles. In one approach, the refresh operation is not performed if the number of P-E cycles is below a threshold number and/or the temperature is below a threshold temperature. When the temperature and number of P-E cycles indicate that a refresh operation should be performed, a timer counts an elapsed time until the elapsed time reaches an allowed discharge time. The allowed discharge time can be based on the temperature, number of P-E cycles, and other factors which affect an expected number of fail bits. The allowed discharge time can also change as the temperature changes during the counting of the elapsed time.Type: GrantFiled: December 5, 2019Date of Patent: June 15, 2021Assignee: SanDisk Technologies LLCInventors: Abhijith Prakash, Vishwanath Basavaegowda Shanthakumar, Jiahui Yuan
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Patent number: 11037635Abstract: Apparatuses and techniques are described for managing power consumption in a memory device. When a multi-plane read command is received, a control circuit determines whether the blocks identified by the read command are fully or partially programmed. If they are fully programmed, the read command is executed while applying a common read pass voltage to the unprogrammed word lines of the respective blocks. If the blocks are not all fully programmed, the control circuit determines a last-programmed word line. If the last-programmed word lines are not equal in each block, the read command is executed while applying a base read pass voltage to the unprogrammed word lines of one or more higher-programmed blocks and a lower read pass voltage to the unprogrammed word lines of one or more lower-programmed blocks.Type: GrantFiled: February 6, 2020Date of Patent: June 15, 2021Assignee: SanDisk Technologies LLCInventors: Yu-Chung Lien, Tomer Eliash, Huai-Yuan Tseng
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Publication number: 20210173734Abstract: For a non-volatile memory die formed of multiple blocks of memory cells, the memory die has a multi-bit bad block flag for each block stored on the memory die, such as in a fuse ROM. For each block, the multi-bit flag indicates if the block has few defects and is of the highest reliability category, is too defective to be used, or is in of one of multiple recoverability categories. The multi-bit bad blocks values can be determined as part a test process on fresh devices, where the test of a block can be fail stop for critical category errors, but, for recoverable categories, the test continues and tracks the test results to determine a recoverability category for the block and write this onto the die as a bad block flag for each block. These recoverability categories can be incorporated into wear leveling operations.Type: ApplicationFiled: December 9, 2019Publication date: June 10, 2021Applicant: SanDisk Technologies LLCInventors: Shih-Chung Lee, Takashi Murai, Ken Oowada
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Publication number: 20210173559Abstract: A method for memory block management includes identifying a first group of bit lines corresponding to memory blocks of a 3-dimensional memory array. The method also includes biasing the first group of bit lines to a first voltage using respective bit line biasing transistors. The method also includes identifying, for each memory block, respective sub-memory blocks corresponding to word lines of each memory block that intersect the first group of bit lines. The method also includes logically grouping memory addresses of memory cells for each respective sub-memory block associated with the first group of bit lines.Type: ApplicationFiled: December 5, 2019Publication date: June 10, 2021Applicant: SanDisk Technologies LLCInventors: Masatoshi Nishikawa, Hardwell Chibvongodze
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Publication number: 20210174886Abstract: Apparatuses and techniques are described for periodically refreshing word line voltages in a memory device. A decision to perform a refresh operation is made based on the temperature and number of program-erase (P-E) cycles. In one approach, the refresh operation is not performed if the number of P-E cycles is below a threshold number and/or the temperature is below a threshold temperature. When the temperature and number of P-E cycles indicate that a refresh operation should be performed, a timer counts an elapsed time until the elapsed time reaches an allowed discharge time. The allowed discharge time can be based on the temperature, number of P-E cycles, and other factors which affect an expected number of fail bits. The allowed discharge time can also change as the temperature changes during the counting of the elapsed time.Type: ApplicationFiled: December 5, 2019Publication date: June 10, 2021Applicant: SanDisk Technologies LLCInventors: Abhijith Prakash, Vishwanath Basavaegowda Shanthakumar, Jiahui Yuan
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Patent number: 11031059Abstract: Magnetic random-access memory (MRAM) circuits are provided herein. In one example implementation, an MRAM circuit includes control circuitry coupled to a magnetic tunnel junction (MTJ) element in series with a selector element. This control circuitry is configured to adjust current through the selector element when the selector element is in a conductive state. The circuit also includes a compensation circuitry configured to compensate for a offset voltage across the selector element in the conductive state based on adjustments to the current through the selector element. An output circuit is also configured to report a magnetization state of the MTJ element.Type: GrantFiled: February 21, 2019Date of Patent: June 8, 2021Assignee: Sandisk Technologies LLCInventors: Christopher J. Petti, Tz-Yi Liu, Ali Al-Shamma, Yoocharn Jeon
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Patent number: 11031308Abstract: A first workpiece includes first active pads, a first test pad, and a second test pad on a primary surface of the first workpiece, the first test pad electrically connected to the second test pad. A second workpiece includes second active pads, a third test pad, and a fourth test pad on a primary surface of the second workpiece. The first and second workpieces are bonded along an interface between the primary surface of the first workpiece and the primary surface of the second workpiece to bond the first active pads with the second active pads, bond the first test pad with the third test pad, and bond the second test pad with the fourth test pad. Connectivity detection circuits test electrical connectivity between the third test pad and the fourth test pad.Type: GrantFiled: May 30, 2019Date of Patent: June 8, 2021Assignee: SanDisk Technologies LLCInventors: Seungpil Lee, Kwang-Ho Kim
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Patent number: 11031085Abstract: A non-volatile memory system comprises a memory structure and a control circuit connected to the memory structure. The memory structure includes one or more planes of non-volatile memory cells. Each plane is divided into a plurality of partial planes. The control circuit is configured to write to and read from the memory cells by writing a partial page into a particular partial plane and reading the partial page from the particular partial plane using a set of parameters optimized for the particular partial plane.Type: GrantFiled: June 9, 2020Date of Patent: June 8, 2021Assignee: SanDisk Technologies LLCInventors: Mohan V Dunga, Pitamber Shukla
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Patent number: 11024385Abstract: A semiconductor device is disclosed including an integrated memory module. The integrated memory module includes a first semiconductor die comprising first non-volatile memory cells, a second semiconductor die comprising second non-volatile memory cells, and a third semiconductor die comprising control circuitry. The first, the second and the third semiconductor die are bonded together. The control circuitry is configured to control memory operations in the first memory cells in parallel with the second memory cells.Type: GrantFiled: May 17, 2019Date of Patent: June 1, 2021Assignee: SanDisk Technologies LLCInventors: Hardwell Chibvongodze, Masatoshi Nishikawa
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Patent number: 11024392Abstract: A sense amplifier for a memory circuit is presented that can sense a selected memory cell in either a first sensing mode, in which current from the selected memory cell flows from the memory cells into the sense amplifier, or a second sensing mode, in which current is discharged from the sense amplifier through the selected memory cell. In the first sensing mode, current from a selected memory cell is conducted through cascaded PMOS transistors to charge a sensing node, with the resultant voltage level on the sensing node used to determine the result of the sensing operation.Type: GrantFiled: December 23, 2019Date of Patent: June 1, 2021Assignee: SanDisk Technologies LLCInventors: Yingchang Chen, Seungpil Lee, Ali Al-Shamma
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Patent number: 11024393Abstract: An apparatus comprises a driver circuit, sense circuit, and die controller. The driver circuit supplies a pass voltage to a selected word line and unselected word lines, a sense voltage to an adjacent word line, and a bit line voltage to bit lines coupled to selected and unselected word lines. The sense circuit determines nonconducting and conducting memory cells on the adjacent word line. The die controller then directs the driver circuit to ramp the sense voltage on the adjacent word line to the pass voltage and ramp the pass voltage on the selected word line to ground. The die controller then directs the driver circuit to ramp the bit line voltage for bit lines coupled to nonconducting memory cells to a bit line compensation voltage and directs the sense circuit to read memory cells of the selected word line based on the bit line compensation voltage.Type: GrantFiled: January 9, 2020Date of Patent: June 1, 2021Assignee: SanDisk Technologies LLCInventors: Zhiping Zhang, Huai-Yuan Tseng, Ken Oowada, Deepanshu Dutta
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Patent number: 11024387Abstract: Techniques are provided for optimizing a program operation in a memory device to compensate for program speed variations due to block oxide thinning. In one approach, during a program operation, a program voltage which indicates program speed is acquired from sub-blocks with the highest and lowest program speeds. An initial program voltage for intermediate sub-blocks can be determined based on the acquired program voltages and the positions of the intermediate sub-blocks. The technique can accommodate a loss of one or both acquired program voltages if the programming is interrupted. In another approach, a program voltage which indicates program speed is acquired from one sub-block, and for a later-programmed sub-block, an appropriate offset is located from a table and summed with the acquired program voltage to determine an optimum initial program voltage.Type: GrantFiled: November 24, 2020Date of Patent: June 1, 2021Assignee: SanDisk Technologies LLCInventors: Ching-Huang Lu, Ashish Baraskar, Vinh Diep
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Publication number: 20210157607Abstract: A non-volatile memory apparatus and corresponding method of operation are provided. The apparatus includes non-volatile memory cells in an integrated circuit device along with a microcontroller in communication with the non-volatile memory cells. The microcontroller is configured to receive a memory operation command and in response, determine a condition value of one of a plurality of conditions associated with the memory operation command and whether the one of the plurality of conditions is dynamic. In parallel, the microcontroller determines and outputs an output value using the condition value. The microcontroller then determines whether the one the plurality of conditions has changed. If the one of the plurality of conditions is dynamic and has changed, the microcontroller determines an updated condition value and in parallel, compares the condition value and the updated condition value and determines and outputs an updated output value using the updated condition value and the comparison.Type: ApplicationFiled: November 26, 2019Publication date: May 27, 2021Applicant: SanDisk Technologies LLCInventors: Vijay Chinchole, Nisha Padattil Kuliyampattil, Sonam Agarwal, Akash Agarwal, Pavithra Devaraj, Yan Li
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Patent number: 11017869Abstract: Techniques are provided to adaptively determine when to begin verify tests for memory cells during a program operation. The memory cells are programmed using a normal programming speed until their threshold voltage exceeds an initial verify voltage. The memory cells are then programmed further using a reduced programming speed until their threshold voltage exceeds a final verify voltage. In one aspect, a count of memory cells which exceeds the initial verify voltage is used to determine when to begin verify tests for a higher data state. In another aspect, a count of the higher state memory cells which exceeds the initial or final verify voltage is used to determine when to begin verify tests for the higher data state. The counted memory cells are not subject to the reduced programming speed.Type: GrantFiled: June 5, 2020Date of Patent: May 25, 2021Assignee: SanDisk Technologies LLCInventors: Xiang Yang, Huai-Yuan Tseng, Deepanshu Dutta
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Patent number: 11011242Abstract: An apparatus includes a programming circuit configured to supply a program pulse to increase a threshold voltage of a memory cell. The apparatus also includes a sensing circuit configured to determine that the threshold voltage of the memory cell satisfies a trigger threshold voltage in response to the program pulse. The apparatus further includes a damping circuit configured to increase a voltage of a bit line connected to the memory cell after initiation of and during a second program pulse in response to the threshold voltage of the memory cell satisfying the trigger threshold voltage, the second program pulse being sent by the programming circuit.Type: GrantFiled: March 25, 2020Date of Patent: May 18, 2021Assignee: SanDisk Technologies LLCInventors: Xiang Yang, Deepanshu Dutta, Gerrit Jan Hemink, Tai-Yuan Tseng, Yan Li
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Patent number: 11011500Abstract: 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. The semiconductor device may further include a CMOS logic circuit as part of the pair of semiconductor dies or in its own semiconductor die mounted to the pair of semiconductor dies.Type: GrantFiled: March 12, 2020Date of Patent: May 18, 2021Assignee: SanDisk Technologies LLCInventors: Nagesh Vodrahalli, Shrikar Bhagath, Chih Yang Li, Srinivasan Sivaram, Rama Shukla
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Publication number: 20210142841Abstract: A three-dimensional (3D) memory is provided, including a memory array chip and a complementary metal-oxide semiconductor (CMOS) chip disposed on the memory array chip. The memory chip provides double write/read throughput and includes a lower region with a lower array of memory cells, lower word lines, and a lower bit line, while an upper region includes an upper array of memory cells, upper word lines, and an upper bit line. A source line is disposed between the lower and upper regions and is connected to both the lower array of memory cells and the upper array of memory cells.Type: ApplicationFiled: November 13, 2019Publication date: May 13, 2021Applicant: SanDisk Technologies LLCInventors: Masatoshi Nishikawa, Hardwell Chibvongodze, Ken Oowada
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Publication number: 20210142858Abstract: A random access memory is provided including a plane structure comprising a plurality of sense amplifiers, each including a local data latch, a pair of local busses connected to each of the data latches, a differential data bus, and a pair of redrivers connected between the pair of local busses and the differential data bus.Type: ApplicationFiled: November 13, 2019Publication date: May 13, 2021Applicant: SanDisk Technologies LLCInventors: Hiroki Yabe, Koichiro Hayashi, Takuya Ariki, Naoki Ookuma, Toru Miwa