US 11,894,080 B2
Time-tagging read levels of multiple wordlines for open block data retention
Erika Penzo, San Jose, CA (US); Henry Chin, Fremont, CA (US); Jie Liu, Milpitas, CA (US); and Dong-Il Moon, San Jose, CA (US)
Assigned to SANDISK TECHNOLOGIES LLC, Addison, TX (US)
Filed by SanDisk Technologies LLC, Addison, TX (US)
Filed on Apr. 29, 2022, as Appl. No. 17/733,042.
Prior Publication US 2023/0352108 A1, Nov. 2, 2023
Int. Cl. G11C 16/06 (2006.01); G11C 16/34 (2006.01); G11C 16/26 (2006.01); G11C 16/24 (2006.01); G11C 16/04 (2006.01)
CPC G11C 16/349 (2013.01) [G11C 16/0483 (2013.01); G11C 16/24 (2013.01); G11C 16/26 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An apparatus, comprising:
a plurality of memory cells;
a control circuit coupled to the plurality of memory cells and configured to:
acquire a first set of read levels on a wordline of a first block of pages of a first set of memory cells of the plurality of memory cells;
perform, using the first set of read levels, a first read operation on a page of a second block of pages of a second set of memory cells of the plurality of memory cells;
determine whether a fail bit count of the page after the first read operation is above a threshold amount;
in response to determining that the fail bit count of the page after the first read operation is above the threshold amount, acquire a second set of read levels on a first wordline of the second block;
perform, using the second set of read levels, a second read operation on the page;
determine whether a fail bit count of the page after the second read operation is above the threshold amount;
in response to determining that the fail bit count of the page after the second read operation is above the threshold amount, acquire a third set of read levels on a second wordline of the second block; and
perform, using the third set of read levels, a third read operation on the page.