Granted Patent B2

US 12,532,475 · App. 18/455,079 · Granted Jan 20, 2026

Inventors: Hiroyuki Ogawa (Nagoya, JP); Masanori Tsutsumi (Yokkaichi, JP)

Assignee: Sandisk Technologies, Inc.

H10B43/27H10B41/27H10B41/41H10B43/40

Abstract

Claims (63)

1 . A memory device, comprising:

a first-tier structure comprising a first first-tier alternating stack and a second first-tier alternating stack, wherein each of the first first-tier alternating stack and the second first-tier alternating stack comprises a respective vertically alternating sequence of first-tier insulating layers and first-tier electrically conductive layers;

a second-tier structure overlying or underlying the first-tier structure and comprising a first second-tier alternating stack and a second second-tier alternating stack that are laterally spaced apart from each other by a jumper alternating stack, wherein each of the first second-tier alternating stack, the second second-tier alternating stack, and the jumper alternating stack comprises a respective vertically alternating sequence of second-tier insulating layers and second-tier electrically conductive layers;

first memory stack structures vertically extending through the first first-tier alternating stack and the first second-tier alternating stack;

second memory stack structures vertically extending through the second first-tier alternating stack and the second second-tier alternating stack, wherein each of the first memory stack structures and the second memory stack structures comprises a respective vertical semiconductor channel and a respective set of memory elements located at levels of the first-tier electrically conductive layers and the second-tier electrically conductive layers; and

an electrically conductive path comprising a first first-tier electrically conductive layer within the first first-tier alternating stack, a first second-tier electrically conductive layer within the jumper alternating stack, a second first-tier electrically conductive layer within the second first-tier alternating stack, a first layer contact via structure contacting the first first-tier electrically conductive layer and a first portion of the first second-tier electrically conductive layer within the jumper alternating stack, and a second layer contact via structure contacting the second first-tier electrically conductive layer and a second portion of the first second-tier electrically conductive layer within the jumper alternating stack.

2 . The memory device of claim 1 , wherein the jumper alternating stack comprises a passive alternating stack that lacks the memory elements which store data.

3 . The memory device of claim 2 , wherein:

the passive alternating stack lacks the memory stack structures; and

the first first-tier alternating stack, the second first-tier alternating stack, the first second-tier alternating stack and the second second-tier alternating stack comprise active alternating stacks.

4 . The memory device of claim 2 , wherein the first layer contact via structure vertically extends from a horizontal plane including a bottommost surface of a combination of the first first-tier alternating stack and the first second-tier alternating stack to a horizontal plane including a topmost surface of the combination of the first first-tier alternating stack and the first second-tier alternating stack.

5 . The memory device of claim 2 , wherein the first layer contact via structure is electrically isolated from each of the first-tier electrically conductive layers within the first first-tier alternating stack other than the first first-tier electrically conductive layer.

6 . The memory device of claim 2 , wherein the first layer contact via structure is electrically isolated from each of the second-tier electrically conductive layers within the passive alternating stack other than the first second-tier electrically conductive layer within the passive alternating stack.

7 . The memory device of claim 2 , wherein the first layer contact via structure comprises:

a conductive pillar portion that vertically extends through a subset of layers within the first first-tier alternating stack and through a subset of layers within the passive alternating stack;

a first conductive fin portion laterally protruding from the conductive pillar portion and contacting an annular top surface segment of the first first-tier electrically conductive layer; and

a second conductive fin portion laterally protruding from the conductive pillar portion and contacting an annular top surface segment of the first portion of the first second-tier electrically conductive layer within the passive alternating stack.

8 . The memory device of claim 7 , further comprising:

first annular insulating plates laterally surrounding the conductive pillar portion and located at levels of, and laterally surrounded by, a subset of the first-tier electrically conductive layers within the first first-tier alternating stack; and

second annular insulating plates laterally surrounding the conductive pillar portion and located at levels of, and laterally surrounded by, a subset of the second-tier electrically conductive layers within the passive alternating stack.

9 . The memory device of claim 8 , further comprising:

a first layer stack of a first insulating liner and a first dielectric fill material layer overlying the first conductive fin portion and contacting a first cylindrical surface segment of the conductive fin portion; and

a second layer stack of a second insulating liner and second dielectric fill material layer overlying the second conductive fin portion and contacting a second cylindrical surface segment of the conductive fin portion.

10 . The memory device of claim 2 , wherein:

the first-tier structure and the second-tier structure overlie a substrate; and

the first first-tier alternating stack comprises first stepped surfaces such that the first-tier electrically conductive layers within the first first-tier alternating stack have first variable lateral extents that decrease with a vertical distance from the substrate.

11 . The memory device of claim 10 , wherein:

the passive alternating stack comprises second stepped surfaces such that second-tier electrically conductive layers within the passive alternating stack have second variable lateral extents that decrease with a vertical distance from the substrate; and

the layer contact via structure vertically extends through the first stepped surfaces and through the second stepped surfaces.

12 . The memory device of claim 2 , wherein:

the first first-tier alternating stack and the second first-tier alternating stack are laterally spaced apart from each other along a first horizontal direction by a first lateral spacing;

the first second-tier alternating stack and the second second-tier alternating stack are laterally spaced apart from each other along the first horizontal direction by a second lateral spacing that is greater than the first lateral spacing;

the passive alternating stack has a lateral extent along the first horizontal direction that is less than the second lateral spacing;

the passive alternating stack comprises a first set of stepped surfaces and a second set of stepped surfaces that are laterally spaced apart from each other;

the first set of stepped surfaces has an areal overlap with the first first-tier alternating stack in a plan view; and

the second set of stepped surfaces has an areal overlap with the second first-tier alternating stack in the plan view.

13 . The memory device of claim 2 , further comprising a word line driver circuit configured to apply a word line bias voltage to the first first-tier electrically conductive layer within the first first-tier alternating stack and to the second first-tier electrically conductive layer within the second first-tier alternating stack through a combination of the first layer contact via structure, the second layer contact via structure, and the first second-tier electrically conductive layer within the passive alternating stack.

14 . The memory device of claim 13 , wherein:

the first layer contact via structure is electrically connected to the word line driver circuit through a first word line switching transistor; and

the second layer contact via structure is electrically connected to the word line driver circuit through the first word line switching transistor, the first second-tier electrically conductive layer within the passive alternating stack and the first first-tier electrically conductive layer.

15 . A method of forming a memory device, comprising:

forming a first-tier structure comprising a first first-tier alternating stack and a second first-tier alternating stack over a substrate, wherein each of the first first-tier alternating stack and the second first-tier alternating stack comprises a respective vertically alternating sequence of first-tier insulating layers and first-tier electrically conductive layers;

forming a second-tier structure comprising a first second-tier alternating stack and a second second-tier alternating stack that are laterally spaced apart from each other by a jumper alternating stack over the substrate, wherein each of the first second-tier alternating stack, the second second-tier alternating stack, and the jumper alternating stack comprises a respective vertically alternating sequence of second-tier insulating layers and second-tier electrically conductive layers, wherein the second-tier structure is formed above, or below, the first-tier structure;

forming first memory stack structures vertically extending through the first first-tier alternating stack and the first second-tier alternating stack;

forming second memory stack structures vertically extending through the second first-tier alternating stack and the second second-tier alternating stack, wherein each of the first memory stack structures and the second memory stack structures comprises a respective vertical semiconductor channel and a respective set of memory elements located at levels of the first-tier electrically conductive layers and the second-tier electrically conductive layers;

forming a first layer contact via structure and a second layer contact via structure, whereby an electrically conductive path is provided which comprises a first first-tier electrically conductive layer within the first first-tier alternating stack, a first second-tier electrically conductive layer within the jumper alternating stack, a second first-tier electrically conductive layer within the second first-tier alternating stack, the first layer contact via structure, and the second layer contact via structure, wherein:

the first layer contact via structure contacts the first first-tier electrically conductive layer and a first portion of the first second-tier electrically conductive layer within the jumper alternating stack; and

the second layer contact via structure contacts the second first-tier electrically conductive layer and a second portion of the first second-tier electrically conductive layer within the jumper alternating stack.

16 . The method of claim 15 , wherein

the jumper alternating stack comprises a passive alternating stack that lacks the memory elements which store data; and

the first layer contact via structure is formed on an annular top surface segment of the first first-tier electrically conductive layer and on an annular top surface segment of the first portion of the first second-tier electrically conductive layer within the passive alternating stack.

17 . The method of claim 16 , wherein:

the first first-tier alternating stack comprises first stepped surfaces such that lateral extents of the first-tier electrically conductive layers in the first first-tier alternating stack decrease with a vertical distance from the substrate;

the passive alternating stack comprises second stepped surfaces such that lateral extents of the second-tier electrically conductive layers in the passive alternating stack decrease with the vertical distance from the substrate; and

the first layer contact via structure is formed directly on a horizontally-extending surface of the first stepped surfaces and directly on a horizontally-extending surface of the second stepped surfaces.

18 . The method of claim 16 , further comprising:

forming a sacrificial finned cavity fill material structure through the first-tier structure and the second-tier structure, wherein the sacrificial finned cavity fill material structure is laterally surrounded by first annular insulating plates at levels of a subset of the first-tier electrically conductive layers within the first first-tier alternating stack, and is laterally surrounded by second annular insulating plates at levels of a subset of the second-tier electrically conductive layers within the passive alternating stack; and

replacing the sacrificial finned cavity fill material structure with the first layer contact via structure.

19 . The method of claim 16 , wherein:

the first first-tier alternating stack and the second first-tier alternating stack are laterally spaced apart from each other along a first horizontal direction by a first lateral spacing;

the first second-tier alternating stack and the second second-tier alternating stack are laterally spaced apart from each other along the first horizontal direction by a second lateral spacing that is greater than the first lateral spacing; and

the passive alternating stack has a lateral extent along the first horizontal direction that is less than the second lateral spacing.

20 . The method of claim 16 , further comprising electrically connecting a word line driver circuit to one of the first layer contact via structure and the second layer contact via structure, wherein the word line driver circuit is configured to apply a word line bias voltage to the first first-tier electrically conductive layer within the first first-tier alternating stack and to the second first-tier electrically conductive layer within the second first-tier alternating stack through a combination of a first word line switching transistor electrically connected to the first layer contact via structure, the second layer contact via structure, and the first second-tier electrically conductive layer within the passive alternating stack.

Assignments (4)

Continuity (1)

References Cited (57)