Three-dimensional memory device with wiggled drain-select-level isolation structure and methods of manufacturing the same

Patent metadata

Field	Value
Publication number	US-11805649-B2
Application number	US-202117385728-A
Country	US
Kind code	B2
Filing date	Jul 26, 2021
Priority date	Mar 13, 2019
Publication date	Oct 31, 2023
Grant date	Oct 31, 2023

Abstract

A three-dimensional memory device includes an alternating stack of insulating layers and electrically conductive layers located over a substrate, memory openings vertically extending through the alternating stack, memory opening fill structures located within a respective one of the memory openings, and at least one drain-select-level isolation structure vertically extending through at least a topmost electrically conductive layer among the electrically conductive layers. The at least one drain-select-level isolation structure may include wiggles and cut through upper portions of at least some of the memory opening fill structures, or may include a vertically-extending dielectric material portion and laterally-protruding dielectric material portions adjoined to the vertically-extending dielectric material portion and laterally protruding into lateral recesses located adjacent to the at least the topmost electrically conductive layer.

First claim

What is claimed is:

1. A three-dimensional memory device, comprising:
an alternating stack of insulating layers and electrically conductive layers;
memory openings vertically extending through the alternating stack;
memory opening fill structures located within a respective one of the memory openings, wherein each of the memory opening fill structures comprises a memory film and a vertical semiconductor channel; and
at least one drain-select-level isolation structure vertically extending through at least a topmost electrically conductive layer of the electrically conductive layers and laterally extending generally along a first horizontal direction and having a periodic repetition of lateral wiggles along a second horizontal direction that is perpendicular to the first horizontal direction, wherein the at least one drain-select-level isolation structure cuts through drain-select-level portions of at least some of the memory opening fill structures.

2. The three-dimensional memory device of claim 1 , wherein:
the memory opening fill structures comprise multiple rows of memory opening fill structures that are arranged along the first horizontal direction with a first pitch; and
the periodic repetition of lateral wiggles has a periodicity of the first pitch along the first horizontal direction.

3. The three-dimensional memory device of claim 2 , wherein:
the at least one drain-select-level isolation structure cuts through the drain-select-level portions of the memory opening fill structures in first rows located adjacent to the at least one drain-select-level isolation structure; and
the at least one drain-select-level isolation structure does not cut through the drain-select-level portions of the memory opening fill structures in second rows that are spaced from the at least one drain-select-level isolation structure by the first row of memory opening fill structures.

4. The three-dimensional memory device of claim 3 , wherein:
the drain-select-level portions of the memory opening fill structures located in the first rows have a horizontal cross-sectional shape of a segment of a circle having two planar sidewalls corresponding to two chords extending between end points of a major arc; and
the drain-select-level portions of the memory opening fill structures located in the second rows have a horizontal cross-sectional shape of a circle.

5. The three-dimensional memory device of claim 3 , wherein:
the memory opening fill structures located in the first rows comprise a stepped sidewall including a first sidewall segment underlying a horizontal plane including each bottom surface of the at least one drain-select-level isolation structure, a second sidewall segment overlying the horizontal plane, and a connecting segment that connects the first sidewall segment to the second sidewall segment within the horizontal plane; and
the at least one drain-select-level isolation structure does not contact, and is laterally spaced from, the memory opening fill structures located in the second rows.

6. The three-dimensional memory device of claim 1 , wherein the at least one drain-select-level isolation structure comprises:
a vertically-extending dielectric material portion located between the adjacent first rows of the memory opening fill structures; and
laterally-protruding dielectric material portions adjoined to the vertically-extending dielectric material portion and laterally protruding into lateral recesses located adjacent to the at least the topmost electrically conductive layer.

7. A three-dimensional memory device, comprising:
an alternating stack of insulating layers and electrically conductive layers;
memory openings vertically extending through the alternating stack;
memory opening fill structures located within a respective one of the memory openings, wherein each of the memory opening fill structures comprises a memory film and a vertical semiconductor channel; and
at least one drain-select-level isolation structure vertically extending through at least a topmost electrically conductive layer of the electrically conductive layers,
wherein the at least one drain-select-level isolation structure comprises a vertically-extending dielectric material portion and laterally-protruding dielectric material portions adjoined to the vertically-extending dielectric material portion and laterally protruding into lateral recesses located adjacent to the at least the topmost electrically conductive layer.

8. The three-dimensional memory device of claim 7 , wherein:
the vertically-extending dielectric material portion has a lateral extent that is bounded by a pair of vertical planes that generally extend along a first horizontal direction and located between a neighboring pair of rows of the memory opening fill structures; and
the laterally-protruding dielectric material portions laterally protrude along a second horizontal direction that is perpendicular to the first horizontal direction from a respective one of the pair of vertical planes.

9. The three-dimensional memory device of claim 7 , wherein:
the at least one drain-select-level isolation structure cuts through drain-select-level portions of at least some of the memory opening fill structures; and
the memory opening fill structures comprise multiple rows of memory opening fill structures that are arranged along the first horizontal direction with a first pitch.

10. The three-dimensional memory device of claim 9 , wherein:
the at least one drain-select-level isolation structure cuts through the drain-select-level portions of the memory opening fill structures in first rows located adjacent to the at least one drain-select-level isolation structures; and
the at least one drain-select-level isolation structure does not cut through the drain-select-level portions of the memory opening fill structures in second rows that are spaced from the at least one drain-select-level isolation structure by the first row of memory opening fill structures.

11. The three-dimensional memory device of claim 10 , wherein the at least one drain-select-level isolation structure comprises a periodic repetition of lateral wiggles along the second horizontal direction, and the periodic repetition of lateral wiggles has a periodicity of the first pitch along the first horizontal direction.

12. The three-dimensional memory device of claim 11 , wherein:
the drain-select-level portions of the memory opening fill structures located in the first rows have a horizontal cross-sectional shape of a segment of a circle having two planar sidewalls corresponding to two chords extending between end points of a major arc; and
the drain-select-level portions of the memory opening fill structures located in the second rows have a horizontal cross-sectional shape of a circle.

13. The three-dimensional memory device of claim 10 , wherein the pair of lengthwise sidewalls of the vertically-extending dielectric material portion comprises a pair of straight lengthwise sidewall segments that are parallel to the first horizontal direction.

14. The three-dimensional memory device of claim 10 , wherein:
the memory opening fill structures located in the first rows comprise a stepped sidewall including a first sidewall segment underlying a horizontal plane including each bottom surface of the at least one drain-select-level isolation structure, a second sidewall segment overlying the horizontal plane, and a connecting segment that connects the first sidewall segment to the second sidewall segment within the horizontal plane; and
the at least one drain-select-level isolation structure does not contact, and is laterally

Assignees

• Sandisk Technologies Llc

Inventors

• Pulugurtha Srinivas
• Alsmeier Johann
• Zhang Yanli
• Kai James

Classifications

• H10P50/691

  for Group V materials or Group III-V materials · CPC title

• H10P50/667

  by liquid etching only · CPC title

• H10P50/73

  using masks for insulating materials · CPC title

• H10W10/17

  formed using trench refilling with dielectric materials, e.g. shallow trench isolations · CPC title

• H10W10/014

  using trench refilling with dielectric materials, e.g. shallow trench isolations · CPC title