Etching method and etching apparatus

Patent metadata

Field	Value
Publication number	US-11594418-B2
Application number	US-202117179502-A
Country	US
Kind code	B2
Filing date	Feb 19, 2021
Priority date	Feb 21, 2020
Publication date	Feb 28, 2023
Grant date	Feb 28, 2023

Abstract

An etching method includes: (a) etching a substrate including an etching target film and a mask formed on the etching target film to form a recess that reaches the etching target film; (b) forming a protective film having a thickness corresponding to one molecular layer on a surface of the recess using a first gas; (c) etching the etching target film with plasma generated from a second gas while leaving the protective film on a side wall of the recess; and (d) repeating (b) and (c).

First claim

What is claimed is:

1. An etching method comprising:
(a) etching a substrate including an etching target film and a mask formed on the etching target film to form a recess that reaches the etching target film;
(b) forming a protective film having a thickness corresponding to one molecular layer on a surface of the recess using a first gas, wherein the first gas is an aminosilane-based gas or a silicon alkoxide-based gas;
(c) etching the etching target film with plasma generated from a second gas while leaving the protective film on a side wall of the recess; and
(d) repeating (b) and (c).

2. The etching method according to claim 1 , wherein, in (b), the protective film is formed by adsorbing molecules of the first gas on the surface of the recess.

3. The etching method according to claim 2 , wherein, in (b), the protective film is formed by causing a substitution reaction between hydroxyl groups on the surface of the recess and the molecules of the first gas.

4. The etching method according to claim 3 , wherein (c) ends before the protective film disappears on the side wall of the recess.

5. The etching method according to claim 4 , wherein, in (c), the etching target film is etched under a condition that an etching rate of the side wall of the recess is smaller than an etching rate of other portions of the recess.

6. The etching method according to claim 5 , wherein, in (c), the protective film is modified at the same time as the etching of the etching target film, by causing an oxidation reaction with respect to the protective film by oxygen radicals contained in the plasma generated from the second gas.

7. The etching method according to claim 6 , wherein, in (a), the substrate in which a plurality of plate-shaped members is embedded in the etching target film is etched toward a top portion of the plate-shaped members to form the recess having a width larger than a gap between the plate-shaped members,
in (b), after a plate-shaped member is exposed at a bottom portion of the recess by repeating (d), the protective film is formed on the surface of the recess and a surface of the exposed plate-shaped member,
in (c), the etching target film positioned between adjacent plate-shaped members is etched while leaving the protective film on the side wall of the recess and a side wall of the exposed plate-shaped member, and
in (d), (b) and (c) are repeated until the etching target film positioned between adjacent plate-shaped members is removed.

8. The etching method according to claim 1 , wherein (c) ends before the protective film disappears on the side wall of the recess.

9. The etching method according to claim 1 , wherein, in (c), the etching target film is etched under a condition that an etching rate of the side wall of the recess is smaller than an etching rate of other portions of the recess.

10. The etching method according to claim 1 , wherein, in (c), the protective film is modified at the same time as the etching of the etching target film, by causing an oxidation reaction with respect to the protective film by oxygen radicals contained in the plasma generated from the second gas.

11. The etching method according to claim 1 , wherein, in (a), the substrate in which a plurality of plate-shaped members is embedded in the etching target film is etched toward a top portion of the plate-shaped members to form the recess having a width larger than a gap between the plate-shaped members,
in (b), after a plate-shaped member is exposed at a bottom portion of the recess by repeating (d), the protective film is formed on the surface of the recess and a surface of the exposed plate-shaped member,
in (c), the etching target film positioned between adjacent plate-shaped members is etched while leaving the protective film on the side wall of the recess and a side wall of the exposed plate-shaped member, and
in (d), (b) and (c) are repeated until the etching target film positioned between adjacent plate-shaped members is removed.

12. An etching method comprising:
(a) providing a substrate including an etching target film and a mask formed on the etching target film, the etching target film having a recess;
(b) forming a protective film having a thickness corresponding to one molecular layer on a surface of the recess using a first gas, wherein the first gas is an aminosilane-based gas or a silicon alkoxide-based gas;
(c) etching the etching target film with plasma generated from a second gas while leaving the protective film on a side wall of the recess; and
(d) repeating (b) and (c).

13. The etching method according to claim 12 , wherein, in (b), the protective film is formed on the surface of the recess and the mask using the first gas.

14. The etching method according to claim 12 , wherein the etching target film is made of carbon (C), silicon (Si), or silicon nitride (SiN).

15. The etching method according to claim 12 , wherein the mask is an anti-reflection film.

Assignees

• Tokyo Electron Ltd

Inventors

• Yamaguchi Kentaro
• Takino Yusuke

Classifications

• H10P72/0604

  Process monitoring, e.g. flow or thickness monitoring · CPC title

• H10P72/0421

  for drying etching · CPC title

• H10P50/242 Primary

  of Group IV materials · CPC title

• H10P72/72

  using electrostatic chucks · CPC title

• H10P72/0434

  mainly by convection · CPC title