Sandisk Technologies Inc.

Alexander Kwok-Tung Mak

Gautam Ashok Dusija

Yingda Dong

Man Lung Mui

Chris Nga Yee Avila

Jian Feng Chen

Chris Avila

Seungpil Lee

Pao-Ling Koh

Deepak Raghu

Jonathan Hsu

Yan Li

Steven Theodore Sprouse

Grishma Shah

Xiying Costa

Bo Liu

Kwang-Ho Kim

Chi-Ming Wang

Eugene Jinglun Tam

Sergey Anatolievich Gorobets

Jianmin Huang

Robert W Ellis

Jun Wan

Tien-Chien Kuo

James M Higgins

Mrinal Kochar

Farookh Moogat

Steven S Cheng

Yee Lih Koh

Dennis S Ea

Jian Chen

An array of non-volatile memory cells includes a first plurality of nonvolatile memory cells and a second plurality of non-volatile memory cells. The first plurality of memory cells, which have first diameters of memory holes, are assigned to store portions of data that are not frequently read. The second plurality of memory cells, which have second diameters of memory holes, are assigned to store portions of data that are frequently read. The first diameters are smaller than the second diameters.

Weighted read scrub for nonvolatile memory including memory holes

A 3D NAND stacked non-volatile memory device, comprising: a string comprising a plurality of non-volatile storage elements, the string comprises a channel and extends vertically through layers of the 3D stacked non-volatile memory device, and the plurality of storage elements are subdivided into different groups based on group assignments, each group of the different groups comprises multiple adjacent storage elements of the plurality of storage elements; and a control circuit in communication with the string, the control circuit, to perform a Pseudo Block Operation Mode.

Pseudo block operation mode in 3D NAND

In a nonvolatile memory array in which a NAND string includes a back gate that has a charge storage element, the threshold voltage of the back gate is monitored, and if the threshold voltage deviates from a desired threshold voltage range, charge is added to, or removed from the charge storage element to return the threshold voltage to the desired threshold voltage range.

System for maintaining back gate threshold voltage in three dimensional NAND memory

When data from a portion of a three dimensional NAND memory array is determined to be uncorrectable by Error Correction Code (ECC), a determination is made as to whether data is uncorrectable by ECC throughout some unit that is larger than the portion. If modified read conditions provide ECC correctable data, the modified read conditions are recorded for subsequent reads of the larger unit.

Adaptive operation of three dimensional memory

Portions of data stored in a three dimensional memory array are selected based on their locations for calculation of redundancy data. Locations are selected so that no two portions in a set of portions for a given calculation are likely to become uncorrectable at the same time. Selected portions may be separated by at least one word line and separated by at least one string in a block.

Selection of data for redundancy calculation in three dimensional nonvolatile memory

In a nonvolatile memory array, such as a three-dimensional array of charge-storage memory cells, data is scrubbed according to a scheme which weights particular data that is exposed to potentially damaging voltages. Data that may cause damage to other data is moved to a location where such potential damage is reduced.

Weighted read scrub for nonvolatile memory

A method of operation in a non-volatile memory device, including executing a memory operation with respect to a portion of a non-volatile memory device, and measuring a current corresponding to current drawn by at least the portion of the non-volatile memory device during the memory operation. An age metric is determined for at least the portion of the non-volatile memory device based on age criteria including a characteristic of the measured current. In accordance with a determination that the age metric satisfies one or more predefined threshold criteria, one or more configuration parameters associated with the non-volatile memory device are adjusted. After the adjusting, data is read from and data to the portion of the non-volatile memory device according to the one or more adjusted configuration parameters.

Internal current measurement for age measurements

Data that is stored in a higher error rate format in a nonvolatile memory is backed up in a lower error rate format. Data to be stored may be transferred once to on-chip data latches where it is maintained while it is programmed in both the high error rate format and the low error rate format without being resent to the nonvolatile memory. High error rate format may be MLC format and programming in the high error rate format may program both lower page and upper page data together in a full sequence programming scheme that is suitable for handling high data volume.

Write operations with full sequence programming for defect management in nonvolatile memory

Multiple bits of data are programmed together to each cell of a segment of a word line while other segments of the same word line are unprogrammed. Subsequently, additional segments are similarly programmed. Data is read from a partially programmed word line (with a mix of programmed and unprogrammed segments) using a single reading scheme.

Systems and methods for partial page programming of multi level cells

A method and system for phasing power-intensive operations is disclosed. A non-volatile storage device controller detects a power reset. The controller is in communication with non-volatile memories in the non-volatile storage device. In response to detecting a power reset, the controller determines a current consumption necessary to reset the non-volatile memories in the non-volatile storage device. The controller simultaneously resets all of the non-volatile memories when the determined current consumption is less than a current consumption threshold. If the determined current consumption is greater than the current consumption threshold, the controller resets a first subset of the plurality of non-volatile memories, and after a predetermined delay, resets a second subset of the non-volatile memories. Therefore, a power-intensive operation may be performed without exceeding a current consumption threshold by dividing the operation into a sequence of steps that do not exceed the threshold.

Phased NAND power-on reset

Memory hole diameter in a three dimensional memory array may be calculated from characteristics that are observed during programming. Suitable operating parameters may be selected for operating a block based on memory hole diameters. Hot counts of blocks may be adjusted according to memory hole size so that blocks that are expected to fail earlier because of small memory holes are more lightly used than blocks with larger memory holes.

Block structure profiling in three dimensional memory

A memory device cooperating with a memory controller scrambles each unit of data using a selected scrambling key before storing it in an array of nonvolatile memory cells. This helps to reduce program disturbs, user read disturbs, and floating gate to floating gate coupling that result from repeated and long term storage of specific data patterns. For a given page of data having a logical address and for storing at a physical address, the key is selected from a finite sequence thereof as a function of both the logical address and the physical address. In a block management scheme the memory array is organized into erase blocks, the physical address is the relative page number in each block. When logical address are grouped into logical groups and manipulated as a group and each group is storable into a sub-block, the physical address is the relative page number in the sub-block.

Non-volatile memory and method with improved data scrambling

In a nonvolatile memory array, data is stored in multi-level cells (MLC) as upper-page data and lower-page data. Safe copies of both upper-page and lower-page data are stored in on-chip cache during programming. If a write fail occurs, data is recovered from on-chip cache. The controller does not have to maintain safe copies of data.

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Los Altos Hills, CA, United States of America

Alexander Kwok-Tung Mak