US 11,889,696 B2
Memory arrays comprising strings of memory cells and methods used in forming a memory array comprising strings of memory cells
John D. Hopkins, Meridian, ID (US); and Nancy M. Lomeli, Boise, ID (US)
Assigned to Micron Technology, Inc., Boise, ID (US)
Filed by Micron Technology, Inc., Boise, ID (US)
Filed on Jan. 3, 2022, as Appl. No. 17/567,297.
Application 17/567,297 is a continuation of application No. 15/930,836, filed on May 13, 2020, granted, now 11,251,190.
Prior Publication US 2022/0130858 A1, Apr. 28, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. H10B 43/27 (2023.01); H10B 41/10 (2023.01); H10B 41/27 (2023.01); H10B 43/10 (2023.01)
CPC H10B 43/27 (2023.02) [H10B 41/10 (2023.02); H10B 41/27 (2023.02); H10B 43/10 (2023.02)] 22 Claims
OG exemplary drawing
 
1. A method used in forming a memory array comprising strings of memory cells, comprising:
forming a lower portion of a stack that will comprise vertically-alternating first tiers and second tiers, the stack comprising laterally-spaced memory-block regions, material of the first tiers being of different composition from material of the second tiers, a lowest of the first tiers comprising first sacrificial material;
forming horizontally-elongated lines in a next-lowest first tier that are individually between immediately-laterally-adjacent of the memory-block regions; the lines comprising second sacrificial material;
forming the vertically-alternating first tiers and second tiers of an upper portion of the stack above the lower portion and the lines,
forming channel-material-string structures that extend through first tiers and the second tiers in the upper portion to the lowest first tier in the lower portion;
forming horizontally-elongated trenches into the stack that are individually between the immediately-laterally-adjacent memory-block regions and extend to the line there-between;
removing the second sacrificial material of the lines through the trenches; and
forming intervening material in the trenches and void-spaces left as a result of the removing of the second sacrificial material of the lines.