# US 12,014,932 B2 · Memory, substrate structure of the memory, and method for preparing the substrate structure of the memory

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- Number: US 12,014,932 B2
- Document ID: US12014932B2
- Status: Granted
- Kind: B2
- Application number: 17/396,690
- Filed: 2021-08-07
- Published: 2021-11-25
- Granted: 2024-06-18
- Earliest claimed: 2019-11-26
- Assignees: Changxin Memory Technologies, Inc.
- Applicants: Changxin Memory Technologies, Inc.
- Inventors: Zhen Zhou
- Web page: https://patentgrep.com/patent/US12014932B2

## CPC

- H10P 50/695: {characterised by the process involved to create the mask, e.g. lift-off masks or sidewalls or to modify the mask}
- H10P 50/73: {using masks for insulating materials}
- H10P 14/69215: {the material being a silicon oxide, e.g. SiO2}
- H10P 14/69433: {the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz}
- H10P 50/283: {by chemical means}
- H10B 12/01: {Manufacture or treatment}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10B: ELECTRONIC MEMORY DEVICES

## Abstract

A substrate structure of the memory, and a method for preparing the substrate structure of the memory are provided. The method includes: providing a substrate; forming a first mask layer on the substrate, the first mask layer including a plurality of strip patterns extending in a direction and spaced apart from each other; forming a first dielectric layer covering the first mask layer; forming a plurality of sacrificial portions spaced apart from each other in the first dielectric layer and covering a portion of the plurality of strip patterns; filling gaps between the sacrificial portions with a second dielectric material; forming a second mask layer by removing the sacrificial portions while retaining the second dielectric material in the gaps; and performing layer-by-layer etching into the substrate to form a plurality of active areas arranged in an array.

## Claims

### Claim 1

A method for preparing a substrate structure of a memory, comprising:
providing a substrate;
forming a first mask layer on a surface of the substrate, the first mask layer comprising a plurality of strip patterns extending in a direction and spaced apart from each other;
forming a first dielectric layer on and covering the plurality of strip patterns of the first mask layer;
patterning the first dielectric layer to form a plurality of sacrificial portions spaced apart from each other, the sacrificial portions covering a first portion of the plurality of strip patterns and exposing a second portion of the plurality of strip patterns;
filling gaps between the sacrificial portions with a second dielectric material;
forming, by removing the sacrificial portions while retaining the second dielectric material in the gaps, a second mask layer, with through-hole patterns exposing the first portion of the plurality of strip patterns formed in areas that correspond to the sacrificial portions in the second mask layer; and
performing layer-by-layer etching using the first mask layer and the second mask layer as masks to transfer the strip patterns and the through-hole patterns to the substrate to form a plurality of active areas arranged in an array.

### Claim 2 (depends on 1)

The method of claim 1, wherein patterning the first dielectric layer to form the plurality of sacrificial portions spaced apart from each other comprises:
forming a plurality of first through-holes distributed in an array in the first dielectric layer; and
forming a plurality of second through-holes distributed in an array in the first dielectric layer, the first through-holes and the second through-holes are alternately arranged in both a first direction and a second direction perpendicular to the first direction, and an orthographic projection of any first through-hole on the substrate is in contact or overlaps with an orthographic projection of a neighboring second through-hole on the substrate in the first direction and the second direction,
wherein a portion of the first dielectric layer between any two neighboring first through-holes in a third direction forms a sacrificial portion, and a deviation angle of the third direction relative to the first direction is π/4.

### Claim 3 (depends on 2)

The method of claim 2, wherein the first through-holes and the second through-holes have a same cross-sectional shape.

### Claim 4 (depends on 3)

The method of claim 3, wherein the first through-holes and the second through-holes are circular holes.

### Claim 5 (depends on 4)

The method of claim 4, wherein the first through-holes and the second through-holes have a same diameter.

### Claim 6 (depends on 1)

The method of claim 1, wherein removing the sacrificial portions while retaining the second dielectric material in the gaps comprises:
etching the sacrificial portions to form the second mask layer, wherein the through-hole patterns exposing the first portion of the plurality of strip patterns are formed in the areas that correspond to the sacrificial portions in the second mask layer.

### Claim 7 (depends on 6)

The method of claim 6, wherein an etching rate of the second dielectric material is less than an etching rate of the sacrificial portion, and etching the sacrificial portions to form the second mask layer comprises:
etching the sacrificial portions and the second dielectric material to form the second mask layer, wherein the through-hole patterns exposing the first portion of the plurality of strip patterns are formed in the areas that correspond to the sacrificial portions in the second mask layer.

### Claim 8 (depends on 7)

The method of claim 7, wherein the second dielectric material is silicon oxide, and the sacrificial portion is made of silicon nitride.

### Claim 9 (depends on 8)

The method of claim 8, wherein etching the sacrificial portions and the second dielectric material to form the second mask layer comprises:
etching, by using phosphoric acid, the sacrificial portions and the second dielectric material to form the second mask layer, wherein the through-hole patterns exposing the first portion of the plurality of strip patterns are formed in the areas that correspond to the sacrificial portions in the second mask layer.

### Claim 10 (depends on 7)

The method of claim 7, wherein the second dielectric material is silicon nitride, and the sacrificial portion is made of silicon oxide.

### Claim 11 (depends on 10)

The method of claim 10, wherein etching the sacrificial portions and the second dielectric material to form the second mask layer comprises:
etching, by using hydrofluoric acid, the sacrificial portions and the second dielectric material to form the second mask layer, wherein the through-hole patterns exposing the first portion of the plurality of strip patterns are formed in the areas that correspond to the sacrificial portions in the second mask layer.

### Claim 12 (depends on 1)

The method of claim 1, wherein performing layer-by-layer etching, using the first mask layer and the second mask layer as masks to transfer the strip patterns and the through-hole patterns to the substrate to form a plurality of active areas arranged in an array comprises:
etching, using the second mask layer as a mask, the first mask layer, to transfer the through-hole patterns to the first mask layer to sever the strip patterns; and
etching, using the first mask layer with severed strip patterns as a mask, the substrate, to transfer the strip patterns and the through-hole patterns to the substrate to form the plurality of active areas arranged in the array.

### Claim 13 (depends on 1)

The method of claim 1, wherein a distance between any two adjacent sacrificial portions is greater than a maximum size of any sacrificial portion in a direction parallel to the substrate.

### Claim 14 (depends on 1)

The method of claim 1, wherein filling the gaps between the sacrificial portions with the second dielectric material comprises:
forming a second dielectric layer covering the sacrificial portions and the gaps between the sacrificial portions; and
removing portions of the second dielectric layer outside the gaps.

### Claim 15 (depends on 14)

The method of claim 14, wherein removing the portions of the second dielectric layer outside the gaps comprises:
removing, by using a chemical mechanical grinding process, the portions of the second dielectric layer outside the gaps.

### Claim 16

A substrate structure of a memory, wherein the substrate structure is prepared by a method, the method comprising:
providing a substrate;
forming a first mask layer on a surface of the substrate, the first mask layer comprising a plurality of strip patterns extending in a direction and spaced apart from each other;
forming a first dielectric layer on and covering the plurality of strip patterns of the first mask layer;
patterning the first dielectric layer to form a plurality of sacrificial portions spaced apart from each other, the sacrificial portions covering a first portion of the plurality of strip patterns and exposing a second portion of the plurality of strip patterns;
filling gaps between the sacrificial portions with a second dielectric material;
forming, by removing the sacrificial portions while retaining the second dielectric material in the gaps, a second mask layer, with through-hole patterns exposing the first portion of the plurality of strip patterns formed in areas that correspond to the sacrificial portions in the second mask layer; and
performing layer-by-layer etching using the first mask layer and the second mask layer as masks to transfer the strip patterns and the through-hole patterns to the substrate to form a plurality of active areas arranged in an array.

### Claim 17 (depends on 16)

A memory, comprising the substrate structure of claim 16.