US 12,068,044 B2
Memory system including semiconductor memory and controller capable of determining necessary shifted boundary read voltages in a short period of time
Tsukasa Tokutomi, Kanagawa (JP); and Masanobu Shirakawa, Kanagawa (JP)
Assigned to KIOXIA CORPORATION, Tokyo (JP)
Filed by KIOXIA CORPORATION, Tokyo (JP)
Filed on May 5, 2023, as Appl. No. 18/312,696.
Application 18/312,696 is a continuation of application No. 17/696,339, filed on Mar. 16, 2022, granted, now 11,682,464.
Application 17/696,339 is a continuation of application No. 16/892,817, filed on Jun. 4, 2020, granted, now 11,315,643, issued on Apr. 26, 2022.
Application 16/892,817 is a continuation of application No. 16/291,281, filed on Mar. 4, 2019, granted, now 10,714,192, issued on Jul. 14, 2020.
Claims priority of application No. 2018-174175 (JP), filed on Sep. 18, 2018.
Prior Publication US 2023/0274784 A1, Aug. 31, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. G11C 16/04 (2006.01); G06F 11/10 (2006.01); G11C 11/56 (2006.01); G11C 16/10 (2006.01); G11C 16/26 (2006.01); G11C 16/34 (2006.01); G11C 29/52 (2006.01)
CPC G11C 16/34 (2013.01) [G06F 11/1068 (2013.01); G11C 11/5628 (2013.01); G11C 11/5642 (2013.01); G11C 16/10 (2013.01); G11C 16/26 (2013.01); G11C 29/52 (2013.01); G11C 16/0483 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A memory system comprising:
a semiconductor memory including memory cells and a word line coupled to the memory cells, each of the memory cells being capable of storing four-bit data, and
a controller configured to:
read a first data item from the memory cells through application of a first voltage to the word line;
repeat a first operation to read first bit data in each of the memory cells, the first operation including applying a second voltage to the word line, the first operation including applying a third voltage to the word line after applying the second voltage, the third voltage having a magnitude different from that of the second voltage, the second voltage being changed within a first range every time the first operation is repeated, the third voltage being changed within a second range every time the first operation is repeated;
read a plurality of second data items by the repeating of the first operation; and
mask part of each of the second data items using the first data item.