US 12,354,955 B2
Three-dimensional memory device with high contact via density and methods of forming the same
Tomohiro Kubo, Yokkaichi (JP); Hirofumi Tokita, Yokkaichi (JP); Shiqian Shao, Fremont, CA (US); and Fumiaki Toyama, Cupertino, CA (US)
Assigned to Sandisk Technologies, Inc., Milpitas, CA (US)
Filed by SANDISK TECHNOLOGIES LLC, Addison, TX (US)
Filed on Jun. 30, 2022, as Appl. No. 17/810,124.
Prior Publication US 2024/0006310 A1, Jan. 4, 2024
Int. Cl. H01L 23/528 (2006.01); H10B 41/27 (2023.01); H10B 43/27 (2023.01)
CPC H01L 23/5283 (2013.01) [H10B 41/27 (2023.02); H10B 43/27 (2023.02)] 20 Claims
OG exemplary drawing
 
1. A three-dimensional memory device, comprising:
an alternating stack of insulating layers and electrically conductive layers;
a first three-dimensional memory array located in a first memory array region; and
a second three-dimensional memory array located in a second memory array region that is laterally spaced from the first memory array region along a first horizontal direction by an inter-array region, wherein the electrically conductive layers comprise common word lines for the first three-dimensional memory array and for the second three-dimensional memory array,
wherein:
the alternating stack is laterally bounded by two trench fill structures that are laterally spaced apart along a second horizontal direction by an inter-trench spacing;
the electrically conductive layers continuously extend between the first memory array region and a second memory array region and comprise a respective bridge region that is located in the inter-array region;
the bridge region of the at least one of the electrically conductive layers has a variable width along the second horizontal direction;
the inter-array region comprises a stepped surface region comprising vertically-extending surface segments of the alternating stack that are perpendicular to the first horizontal direction;
the stepped surface region further comprises horizontally-extending surface segments connecting a respective neighboring pair of vertically-extending surface segments of the vertically-extending surface segments; and
the horizontally-extending surface segments have a variable lateral extent along the second horizontal direction including at least one stepwise increase as a function of a lateral distance from the first memory array region toward the second memory array region.