Vertical memory cell with mechanical structural reinforcement

Patent metadata

Field	Value
Publication number	US-10886364-B2
Application number	US-201815889514-A
Country	US
Kind code	B2
Filing date	Feb 6, 2018
Priority date	Feb 6, 2018
Publication date	Jan 5, 2021
Grant date	Jan 5, 2021

Abstract

A reinforced vertical-NAND structure is provided. The reinforced vertical-NAND structure includes a first set of interleaved oxide and nitride layers formed into first and second vertical structures. The first vertical structure rises from a first section of a substrate and the second vertical structure rises from a second section of the substrate. The reinforced vertical-NAND structure also includes a reinforcing layer and a second set of interleaved oxide and nitride layers formed into third and fourth vertical structures. The reinforcing layer includes sheets, which are distinct and laid across respective tops of the first and second vertical structures, and bridges connecting the sheets. The third vertical structure rises from the sheet corresponding to the first vertical structure and the fourth vertical structure rises from the sheet corresponding to the second vertical structure.

First claim

What is claimed is:

1. A method of assembling a reinforced-NAND structure, the method comprising:
disposing a first set of interleaved oxide and nitride layers on a substrate with first and second sections;
laying a reinforcing layer over the first set of the interleaved oxide and nitride layers;
disposing a second set of interleaved oxide and nitride layers on the reinforcing layer;
forming the second set of the interleaved oxide and nitride layers into third and fourth vertical structures rising from the reinforcing layer and corresponding to the first and second sections, respectively;
forming the reinforcing layer into first and second sheets, which are distinct in boundary from one another
forming bridges connecting the first and second sheets in and only in a plane of the first and second sheets;
and forming the first set of the interleaved oxide and nitride layers into first and second vertical structures rising from the substrate and corresponding to the first and second sections, respectively,
wherein the first sheet is interposed between the third and first vertical structures and the second sheet is interposed between the fourth and second vertical structures.

2. The method according to claim 1 , wherein:
the disposing of the first and second sets of the interleaved oxide and nitride layers comprises alternately depositing nitride and oxide,
the forming of the first and second set of the interleaved oxide and nitride layers into the first and second and third and fourth vertical structures comprises etching portions of the oxide and nitride between the first and second sections of the substrate, and
the forming of the reinforcing layer comprises depositing one or more of silicon oxide, silicon nitride, hafnium oxide and aluminum oxide and etch-forming the bridges.

3. The method according to claim 2 , wherein the forming of the first and second sets comprises supporting the first, second, third, and fourth vertical structures with an oxide post lined with poly-silicon.

4. The method according to claim 1 , further comprising:
laying an additional reinforcing layer over the second set of the interleaved oxide and nitride layers;
disposing an additional set of interleaved oxide and nitride layers on the additional reinforcing layer;
forming the additional set of the interleaved oxide and nitride layers into additional third and fourth vertical structures rising from the additional reinforcing layer and corresponding to the first and second sections, respectively;
forming the additional reinforcing layer into additional first and second sheets, which are distinct in boundary from one another; and
forming additional bridges connecting the additional first and second sheets in and only in respective planes of the first and second sheets,
wherein the additional first sheet is interposed between the third and the additional third vertical structures and the second sheet is interposed between the fourth and the additional fourth vertical structures.

5. A method of assembling a reinforced-NAND structure, the method comprising:
building, on first and second sections of a substrate, a structure comprising a reinforcing layer interposed between first and second sets of interleaved oxide and nitride layers;
etching portions of the second set of interleaved oxide and nitride layers between the first and second sections of the substrate using an etchant that is selective to materials of the second set of the interleaved oxide and nitride layers such that the reinforcing layer is unaffected by the etching;
etching the reinforcing layer to form distinct sheets, which are distinct in boundary from one another, using an etchant that is selective to materials of the reinforcing layer such that the first set and remainders of the second set of the interleaved oxide and nitride layers are unaffected by the etching;
etch-forming bridges between the distinct sheets to connect the distinct sheets in and only in a respective plane of the distinct sheets; and
etching portions of the first set of interleaved oxide and nitride layers between the first and second sections of the substrate.

6. The method according to claim 5 , wherein the building further comprises forming oxide posts lined with poly-silicon in the oxide, nitride and reinforcing layers.

7. The method according to claim 5 , wherein the building comprises forming sixty-four layers below the reinforcing layer.

8. The method according to claim 5 , wherein a material of the reinforcing layer comprises one or more of silicon oxide, silicon nitride, hafnium oxide and aluminum oxide.

9. The method according to claim 5 , further comprising:
building additional reinforcing layers for interposition between additional sets of interleaved oxide and nitride layers; and
repeating the etching for the additional reinforcing layers and the additional sets of interleaved oxide and nitride layers.

10. The method according to claim 5 , further comprising:
removing the nitride layers;
lining exposed surfaces of the oxide layers;
depositing metallic material around the lining; and
etching the metallic material.

Assignees

• IBM

Inventors

• Yang adam
• Lee Choong Ho
• Mataev Elnatan
• Fry Jonathan
• Lin Cheng-Yi
• Biyani Bharat
• Sim Jang

Classifications

• H10P50/283

  by chemical means · CPC title

• H10P14/69433

  the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz · CPC title

• H10P14/69392

  the material containing hafnium, e.g. HfO2 · CPC title

• H10P14/69391

  the material containing aluminium, e.g. Al2O3 · CPC title

• H10P14/69215

  the material being a silicon oxide, e.g. SiO2 · CPC title