Method of making high aspect ratio openings in a semiconductor device using ion implanted regrown cladding mask

Patent metadata

Field	Value
Publication number	US-12512366-B2
Application number	US-202418613834-A
Country	US
Kind code	B2
Filing date	Mar 22, 2024
Priority date	May 8, 2023
Publication date	Dec 30, 2025
Grant date	Dec 30, 2025

Abstract

A method of patterning a structure includes forming an alternating stack of first material layers and second material layers over a substrate, forming an etch mask material layer over the alternating stack, forming openings in an upper portion of the alternating stack by performing a first anisotropic etch process that transfers a pattern in the etch mask material layer through a first subset of layers within the alternating stack, anisotropically depositing a cladding material on the etch mask material layer to form a cladding material layer, ion implanting dopant atoms into the cladding material layer, and vertically extending the openings downward in the alternating stack by performing a second anisotropic etch process. The dopant atoms decrease an etch rate of the cladding material layer during the second anisotropic etch process.

First claim

What is claimed is:

1 . A method of patterning a structure, comprising:
forming an alternating stack of first material layers and second material layers over a substrate; forming an etch mask material layer over the alternating stack; forming openings in an upper portion of the alternating stack by performing a first anisotropic etch process that transfers a pattern in the etch mask material layer through a first subset of layers within the alternating stack; anisotropically depositing a cladding material on the etch mask material layer to form a cladding material layer; ion implanting dopant atoms into the cladding material layer; and vertically extending the openings downward in the alternating stack by performing a second anisotropic etch process, wherein the dopant atoms decrease an etch rate of the cladding material layer during the second anisotropic etch process.

2 . The method of claim 1 , wherein the dopants atoms comprise carbon atoms.

3 . The method of claim 1 , wherein the dopants atoms comprise Si, Ge, N, P or As atoms.

4 . The method of claim 1 , wherein the dopant atoms comprise Ne, Ar or Kr atoms.

5 . The method of claim 1 , wherein the dopant atoms comprise metal atoms.

6 . The method of claim 1 , wherein the step of ion implanting the dopant atoms comprises a tilted ion implantation process.

7 . The method of claim 6 , further comprising rotating the substrate during the tilted ion implantation process.

8 . The method of claim 6 , wherein the tilted ion implantation process comprises multiple tilted ion implantation steps in which a respective ion beam direction is tilted relative to a vertical direction by a same tilt angle along different azimuthal tilt directions.

9 . The method of claim 6 , wherein an ion beam direction is tilted relative to a vertical direction perpendicular to a top surface of the substrate by a tilt angle is greater than an arctangent of a ratio of a maximum lateral dimension of openings after formation of the cladding material layer to 0.9 times a maximum height of a combination of the etch mask material layer and the cladding material layer as measured above a horizontal plane including a topmost surface of the alternating stack.

10 . The method of claim 9 , wherein the tilt angle is in a range from 10 degrees to 45 degrees.

11 . The method of claim 1 , wherein the cladding material is anisotropically deposited by an non-conformal physical vapor deposition process.

12 . The method of claim 1 , wherein the cladding material is anisotropically deposited by a chemical vapor deposition or atomic layer deposition process.

13 . The method of claim 1 , wherein the cladding material layer comprises carbon.

14 . The method of claim 13 , wherein the etch mask material layer comprises a carbon-based material comprising carbon atoms at an atomic concentration greater than 50%.

15 . The method of claim 1 , wherein sidewalls of the etch mask material layer have a first taper angle relative to a vertical direction perpendicular to a top surface of the substrate after performing the first anisotropic etch process.

16 . The method of claim 15 , further comprising performing a profile-shaping process that increases a tilt angle of the sidewalls of the etch mask material layer to a second taper angle that is greater than the first taper angle prior to the step of anisotropically depositing the cladding material layer.

17 . The method of claim 16 , wherein a difference between the second taper angle and the first taper angle is in a range from 0.1 degree to 6 degrees.

18 . The method of claim 1 , wherein:
the first material layers comprise silicon oxide layers; and the second material layers comprise silicon nitride layers.

19 . The method of claim 1 , wherein the openings are vertically extended to a top surface of the substrate during the second anisotropic etch process or during a subsequent anisotropic etch process that is performed after the second anisotropic etch process.

20 . The method of claim 1 , further comprising:
removing remaining portions of the etch mask material layer and the cladding material layer; and forming memory opening fill structures in the openings, wherein each of the memory opening fill structures comprises a respective memory film, a respective vertical semiconductor channel, a respective dielectric core, and a respective drain region.

Assignees

• Western Digital Tech Inc
• Sandisk Technologies Inc

Inventors

• Zhou Bing
• Sondhi Kartik
• Kanakamedala Senaka

Classifications

• H10P50/644

  Anisotropic liquid etching (H10P50/61 takes precedence) · CPC title

• H10W20/435 Primary

  Cross-sectional shapes or dispositions of interconnections · CPC title

• H10W20/051

  by ion implantation · CPC title

• H10W20/045

  for deposition from the gaseous phase, e.g. for chemical vapour deposition [CVD] · CPC title

• H10W20/42

  Vias, e.g. via plugs · CPC title