US 12,394,718 B2
Three-dimensional memory device containing etch-stop structures and self-aligned insulating spacers and method of making the same
Koichi Matsuno, Fremont, CA (US); and Kota Funayama, Yokkaichi (JP)
Assigned to Sandisk Technologies, Inc., Milpitas, CA (US)
Filed by SANDISK TECHNOLOGIES LLC, Addison, TX (US)
Filed on Feb. 28, 2022, as Appl. No. 17/682,515.
Prior Publication US 2023/0275026 A1, Aug. 31, 2023
Int. Cl. H01L 23/535 (2006.01); H01L 23/528 (2006.01); H10B 41/27 (2023.01); H10B 43/27 (2023.01)
CPC H01L 23/535 (2013.01) [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 located over a substrate, wherein the alternating stack comprises a staircase region in which lateral extents of the electrically conductive layers decrease with a vertical distance from the substrate;
a retro-stepped dielectric material portion overlying the staircase region of the alternating stack;
memory stack structures vertically extending through the alternating stack, wherein each of the memory stack structures comprises a respective vertical semiconductor channel and a respective memory film;
an electrically conductive or semiconductor perforated etch stop plate interposed between the alternating stack and a stepped bottom surface of the retro-stepped dielectric material portion; and
laterally-insulated contact structures vertically extending through the retro-stepped dielectric material portion and through a respective one of perforation openings in the perforated etch stop plate, wherein each of the laterally-insulated contact structures comprises an assembly of a contact via structure contacting a top surface of a respective one of the electrically conductive layers and an insulating spacer laterally surrounding the contact via structure and contacting the perforated etch stop plate,
wherein the insulating spacer of each of the laterally-insulated contact structures comprises:
a tubular insulating portion including a vertically-extending outer sidewall segment in contact with the retro-stepped dielectric material portion; and
a laterally-bulging insulating portion adjoined to a bottom of the tubular insulating portion and laterally protruding outward from a vertical plane including the vertically-extending outer sidewall segment,
wherein a surface segment of the laterally-bulging insulating portion contacts a surface segment of a horizontal portion of the perforated etch stop plate for at least one of the laterally-insulated contact structures.