Sandisk Technologies Inc.

Western Digital Technologies, Inc.

Lanlan Gu

Yongke Sun

Nima Mokhlesi

Eran Sharon

Idan Alrod

Nian Niles Yang

Jiahui Yuan

Ming Jin

Xinde Hu

Grishma Shah

James M Higgins

Bo Lei

Deepak Raghu

Guirong Liang

Wenzhou Chen

Gen Pei

Lisha Wang

Itshak Afriat

Bin Wu

Ashish Pal Singh Ghai

Scott Kayser

A slow programming audit is performed on one or more memory blocks and/or associated word lines of one or more memory dies. The slow programming audit is used to determine whether identified or known weak word lines of one or more memory dies are causing performance issues. If it is determined that the weak word lines are causing data read, data write and/or data retention issues, the weak word lines of the one or more memory dies are marked for slow programming in subsequent programming operations.

Slow programming on weak word lines of a memory device

Aspects of the disclosure are directed to a storage device including a memory and a controller. In some examples, the controller is configured to measure an error rate of one or more blocks of the memory. In some examples, the controller is further configured to estimate, based at least in part on the error rate, a time shift indicative of a duration of time for which the storage device was powered off. In some examples, the controller is further configured to set a read level for multiple blocks of the memory, wherein the read level is determined based at least in part on the time shift.

Data retention management after power off

This disclosure includes back pattern counter measures for solid state drives. Embodiments described herein include setting and applying read threshold offsets according to flags set based on an amount of data stored within a memory block (e.g., an 'openness' of the block). The flag is implemented during read commands to account for shifts in voltage distribution of open blocks. A value of the flag may be chosen based on a number of word lines included in the block that store data. The read threshold offsets may further be based on at least one of the set flag or an age of a respective NAND cell.

Back pattern counter measure for solid state drives

A non-volatile memory system includes a plurality of non-volatile data memory cells arranged into groups of data memory cells, a plurality of select devices connected to the groups of data memory cells, a selection line connected to the select devices, a plurality of data word lines connected to the data memory cells, and one or more control circuits connected to the selection line and the data word lines. The one or more control circuits are configured to determine whether the select devices are corrupted. If the select devices are corrupted, then the one or more control circuits repurpose one of the word lines (e.g., the first data word line closet to the select devices) to be another selection line, thus operating the memory cells connected to the repurposed word line as select devices.

Non-volatile memory with dynamic repurpose of word line

Data, normally read using a page-by page read process, can be recovered from memory cells connected to a broken word line by performing a sequential read process. To determine whether a word line is broken, both a page-by page read process and a sequential read process are performed. The results of both read processes are compared. If the number of mismatches between the two read processes is greater than a threshold, it is concluded that there is a broken word line.

Non-volatile storage with broken word line screen and data recovery

Methods and devices for operating non-volatile storage are disclosed. One or more programming conditions depend on the word line that is selected for programming. Applying a selected word line dependent program condition may reduce or eliminate program disturb. The duration of a programming pulse may depend on the word line that is selected for programming. This could be a physical characteristic of the word line or its location on a NAND string. As one example, a shorter pulse width may be used for the programming signal when programming edge word lines.

Selected word line dependent programming voltage

The non-volatile storage system predicts which blocks (or other units of storage) will become bad based on performance data. User data in those blocks predicted to become bad can be re-programmed to other blocks, and the blocks predicted to become bad can be removed from further use.

Identifying at-risk data in non-volatile storage

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San Jose, CA, United States of America

Lanlan Gu