US 11,889,683 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); Darwin A. Clampitt, Wilder, ID (US); Michael J. Puett, Boise, ID (US); and Christopher R. Ritchie, Boise, ID (US)
Assigned to Micron Technology, Inc., Boise, ID (US)
Filed by Micron Technology, Inc., Boise, ID (US)
Filed on Jul. 1, 2020, as Appl. No. 16/918,129.
Prior Publication US 2022/0005817 A1, Jan. 6, 2022
Int. Cl. H10B 41/27 (2023.01); H01L 23/522 (2006.01); H10B 43/27 (2023.01); H10B 43/10 (2023.01); H10B 41/10 (2023.01); H10B 43/35 (2023.01)
CPC H10B 41/27 (2023.02) [H01L 23/5226 (2013.01); H10B 41/10 (2023.02); H10B 43/10 (2023.02); H10B 43/27 (2023.02); H10B 43/35 (2023.02)] 14 Claims
OG exemplary drawing
 
1. A method used in forming a memory array comprising strings of memory cells, comprising:
forming a stack comprising vertically-alternating first tiers and second tiers, the first tiers being conductive and the second tiers being insulative in a finished construction, a channel-material string being in individual channel openings in the vertically-alternating first tiers and second tiers, the channel-material strings individually comprising a cylindrical shell of the channel material, insulator material being radially inside the cylindrical shell of the channel material, storage material being radially outside the cylindrical shell of the channel material;
vertically recessing the insulator material in the individual channel openings relative to the storage material and relative to the channel material;
forming a conductor-material contact in the individual channel openings radially inside of and directly against radially-inner sides of the cylindrical shell of the channel material of individual of the channel-material strings and atop the vertically-recessed insulator material, the conductor-material contact having a bottom that is below a bottom of an uppermost of the first tiers;
etching the conductor material of the conductor-material contact vertically-downward to vertically recess the conductor material relative to the storage material in the individual channel openings and etching the channel material of the cylindrical shell of the individual channel-material strings vertically-downward to vertically recess the cylindrical shell relative to the storage material in the individual channel openings, the conductor material after said etching thereof having a planar uppermost surface; and
forming a conductive via in the individual channel openings directly against a top of the channel material of the vertically-recessed cylindrical shell of the channel-material string and directly against all of the planar uppermost surface of the vertically-recessed conductor-material contact that are in that individual channel opening.
 
4. A method used in forming a memory array comprising strings of memory cells, comprising:
forming a stack comprising vertically-alternating first tiers and second tiers, a channel-material string being in individual channel openings in the vertically-alternating first tiers and second tiers, the channel-material strings individually comprising a cylindrical shell of the channel material, insulator material being radially inside the cylindrical shell of the channel material, storage material being radially outside the cylindrical shell of the channel material;
vertically recessing the insulator material in the individual channel openings relative to the storage material and relative to the channel material;
forming a conductor-material contact in the individual channel openings radially inside of and directly against radially-inner sides of the cylindrical shell of the channel material of individual of the channel-material strings and atop the vertically-recessed insulator material;
etching the conductor material of the conductor-material contact vertically-downward to vertically recess the conductor material relative to the storage material in the individual channel openings and etching the channel material of the cylindrical shell of the individual channel-material strings vertically-downward to vertically recess the cylindrical shell relative to the storage material in the individual channel openings, the conductor material after said etching thereof having a planar uppermost surface;
forming a conductive via in the individual channel openings directly against a top of the channel material of the vertically-recessed cylindrical shell of the channel-material string and directly against all of the planar uppermost surface of the vertically-recessed conductor-material contact that are in that individual channel opening; and
the etching of the conductor material of the conductor-material contact and the etching of the channel material of the cylindrical shell occurring at the same time.
 
11. A method used in forming a memory array comprising strings of memory cells, comprising:
forming a stack comprising vertically-alternating first tiers and second tiers, the first tiers being conductive and the second tiers being insulative in a finished construction, a channel-material string being in individual channel openings in the vertically-alternating first tiers and second tiers, the channel-material strings individually comprising a cylindrical shell, insulator material being radially inside the cylindrical shell, storage material being radially outside the cylindrical shell;
vertically recessing the insulator material in the individual channel openings relative to the storage material and relative to the channel material;
forming a conductor-material contact in the individual channel openings radially inside of and directly against radially-inner sides of the cylindrical shell of the channel material of individual of the channel-material strings and atop the vertically-recessed insulator material, the conductor-material contact having a bottom that is below a bottom of an uppermost of the first tiers;
vertically recessing the conductor-material contacts and the cylindrical shell of the individual channel-material strings relative to the storage material in the individual channel openings; and
forming a conductive via in the individual channel openings directly against a top of the vertically-recessed cylindrical shell of the channel-material string and directly against a top of the vertically-recessed conductor-material contact that are in that individual channel opening.