Storing highly read data at low impact read disturb pages of a memory device

Patent metadata

Field	Value
Publication number	US-11762767-B2
Application number	US-202117302064-A
Country	US
Kind code	B2
Filing date	Apr 22, 2021
Priority date	Apr 22, 2021
Publication date	Sep 19, 2023
Grant date	Sep 19, 2023

Abstract

A highly read data manager of a memory device receives a request to perform receives a request to perform a data relocation operation on a first wordline of a plurality of wordlines for a memory device, the memory device comprising a plurality of multi-level memory cells, wherein each multi-level memory cell comprises a plurality of pages; determines at the first wordline comprises data stored at one or more high read disturb pages of the plurality of pages; determines whether the data comprises a characteristic that satisfies a threshold criterion in relation to additional data stored on additional wordlines of the plurality of wordlines; responsive to determining that the data comprises the characteristic that satisfies the threshold criterion, identifies one or more low read disturb pages of the plurality of pages of a target wordline for relocating the data; and responsive to identifying the one or more low read disturb pages of the target wordline, stores at least a portion of the data at the one or more low read disturb pages of the target wordline.

First claim

What is claimed is:

1. A method comprising:
receiving, by a processing device, a request to perform a data relocation operation on a first wordline of a plurality of wordlines for a memory device, the memory device comprising a plurality of multi-level memory cells, wherein each multi-level memory cell comprises a plurality of pages;
determining that the first wordline comprises data stored at one or more high read disturb pages of the plurality of pages;
determining whether the data comprises a characteristic that satisfies a threshold criterion in relation to additional data stored on additional wordlines of the plurality of wordlines;
responsive to determining that the data comprises the characteristic that satisfies the threshold criterion, identifying a target wordline in a non-empty target data block for relocating the data;
determining whether any wordline adjacent to the target wordline has a bit error rate that exceeds a corresponding threshold; and
responsive to determining that there are no wordlines adjacent to the target wordline having a bit error rate that exceeds the corresponding threshold, storing at least a portion of the data at one or more low read disturb pages of the target wordline.

2. The method of claim 1 , wherein the data relocation operation comprises at least one of a garbage collection operation or a folding operation.

3. The method of claim 1 , wherein the one or more high read disturb pages have suffered more read disturb than the one or more low read disturb pages.

4. The method of claim 1 , wherein determining whether the data comprises the first characteristic that satisfies the threshold criterion comprises:
identifying a second wordline of the plurality of wordlines, wherein the second wordline is adjacent to the first wordline; and
identifying a third wordline of the plurality of wordlines, wherein the third wordline is adjacent to the first wordline, and wherein the first wordline is between the second wordline and the third wordline.

5. The method of claim 4 , further comprising:
determining a first bit error rate associated with at least a portion of the memory cells of the first wordline;
determining a second bit error rate associated with at least a portion of the memory cells of the second wordline;
determining a third bit error rate associated with at least a portion of the memory cells of the third wordline;
determining whether the second bit error rate and the third bit error rate satisfy a threshold criterion associated with a high read disturb condition;
responsive to determining that the second bit error rate and the third bit error rate satisfy the threshold criterion, determining whether the first bit error rate satisfies the threshold criterion; and
responsive to determining that the first bit error rate does not satisfy the threshold criterion, determining that the first wordline comprises data with the characteristic.

6. The method of claim 1 , whether the data comprises the characteristic that satisfies the threshold criterion comprises:
determining a read count associated with the first wordline, wherein the read count comprises an indication of a number of host read operations performed on the memory cells of the first wordline;
determining whether the read count satisfies a read threshold criterion associated with a highly read data condition; and
responsive to determining that the read count satisfies the read threshold criterion, determining that the first wordline comprises data with the characteristic.

7. The method of claim 1 , further comprising:
identifying one or more additional low read disturb pages of an additional target wordline; and
storing an additional portion of the data at the one or more additional low read disturb pages of the additional target wordline.

8. The method of claim 1 , further comprising:
identifying a second target wordline, wherein the second target wordline is adjacent to the target wordline;
determining a bit error rate associated with at least a portion of the memory cells of the second target wordline;
determining whether the bit error rate satisfies a threshold criterion associated with a high error rate condition; and
responsive to determining that the bit error rate satisfies the threshold criterion, identifying one or more additional low read disturb pages of an additional target wordline for relocating the data, wherein the additional target wordline is not adjacent to the second target wordline.

9. A method comprising:
receiving, by a processing device, a request to write data to a memory device, wherein the request comprises an indication that the data has a characteristic, wherein the memory device comprises a plurality of multi-level memory cells, and wherein each multi-level memory cell comprises a plurality of pages;
identifying, by the processing device, a target wordline of a plurality of wordlines in a non-empty target data block of the memory device in view of the characteristic;
determining, whether any wordline adjacent to the target wordline has a bit error rate that exceeds a corresponding threshold;
responsive to determining that there are no wordlines adjacent to the target wordline having a bit error rate that exceeds the corresponding threshold, selecting one or more low read disturb pages of the plurality of pages of the target wordline; and
storing at least a portion of the data at the one or more low read disturb pages of the target wordline.

10. The method of claim 9 , wherein the one or more low read disturb pages have suffered less read disturb than one or more high read disturb pages of the plurality of pages.

11. The method of claim 9 , wherein identifying the target wordline comprises:
identifying a first wordline of the plurality of wordlines;
determining a first bit error rate associated with at least a portion of the memory cells of the first wordline;
determining whether the first bit error rate satisfies a threshold criterion associated with a high error rate condition; and
responsive to determining that the bit error rate does not satisfy the threshold criterion, selecting the first wordline as the target wordline for storing the data.

12. The method of claim 11 , further comprising:
identifying a second wordline of the plurality of wordlines, wherein the second wordline is adjacent to the first wordline;
determining a second bit error rate associated with at least a portion of the memory cells of the second wordline;
determining whether the second bit error rate satisfies the threshold criterion; and
responsive to determining that the second bit error rate satisfies the threshold criterion, identifying an additional target wordline for storing the data, wherein the additional wordline is not adjacent to the second wordline.

13. The method of claim 9 , further comprising:
identifying one or more additional low read disturb pages of an additional target wordline; and
storing an additional portion of the data at the one or more additional low read disturb pages of the additional target wordline.

14. A system comprising:
a memory device; and
a processing device, operatively coupled with the memory device to perform operations comprising:
receiving, by a processing device, a request to perform a data relocation operation on a first wordline of a plurality of wordlines for a memory device, the memory device comprising a plurality of multi-level memory cells, wherein each multi-level memory cell comprises a plurality of pages;
determining that the first wordline comprises data stored at one or more high read disturb pages of the plurality of pages;

Assignees

• Micron Technology Inc

Inventors

• Muchherla Kishore Kumar
• Puzzilli Giuseppina
• Rayaprolu Vamsi Pavan
• Malshe Ashutosh
• Fitzpatrick James
• Raghunathan Shyam Sunder
• Moschiano Violante
• Ghilardi Tecla

Classifications

• G11C16/26 Primary

  Sensing or reading circuits; Data output circuits · CPC title

• G11C16/3422 Primary

  Circuits or methods to evaluate read or write disturbance in nonvolatile memory, without steps to mitigate the problem · CPC title

• G06F12/0269 Primary

  Incremental or concurrent garbage collection, e.g. in real-time systems (G06F12/0261 takes precedence) · CPC title

• G11C16/3427

  Circuits or methods to prevent or reduce disturbance of the state of a memory cell when neighbouring cells are read or written · CPC title

• G11C16/0483

  comprising cells having several storage transistors connected in series · CPC title