Non-phosphoric acid-based silicon nitride film etching composition and etching method using the same

Patent metadata

Field	Value
Publication number	US-11521859-B2
Application number	US-202117305034-A
Country	US
Kind code	B2
Filing date	Jun 29, 2021
Priority date	Jan 26, 2021
Publication date	Dec 6, 2022
Grant date	Dec 6, 2022

Abstract

A non-phosphoric acid-based silicon nitride film etching composition includes 5 to 50 wt % of an organic acid-based chelating agent including an organic phosphonic acid group, a carboxylic acid group, or a combination thereof, based on a total weight of the etching composition. The etching composition for pressurization suppresses etching a silicon oxide film and selectively etches a silicon nitride film in a vertically laminated structure in which both the silicon nitride film and the silicon oxide film are exposed to a surface or the silicon nitride film and the silicon oxide film are alternately laminated.

First claim

What is claimed is:

1. An etching method comprising: selectively etching a silicon nitride film rather than a silicon oxide film under a pressurization condition, using the an etching composition comprising:
an organic acid-based chelating agent including an organic phosphonic acid group, a carboxylic acid group, or a combination thereof, wherein the composition satisfies the following (A) to (C):
(A) includes 10 to 50 wt % of the organic acid-based chelating agent and a balance of water based on a total weight of the etching composition,
(B) has an etching rate of the silicon nitride film of 35 A/min or more, and
(C) has an etching selection ratio of the silicon nitride film to the silicon oxide film of 40 or more.

2. The etching method of claim 1 , wherein a subject to be etched of the etching composition is
a wafer in which both the silicon oxide film and the silicon nitride film are exposed to a surface; or
a wafer having a lamination structure having the silicon oxide film and the silicon nitride film as a unit layer.

3. The etching method of claim 1 , wherein the pressurization condition is performed at 2 to 220 atm.

4. The etching method of claim 1 , wherein the etching method is for etching at a high temperature of 100° C. or higher.

5. A method of manufacturing a semiconductor device, comprising the etching method of claim 1 .

6. The etching method of claim 1 , wherein the organic acid-based chelating agent is one or two or more selected from citric acid, tartaric acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, N-(hydroxyethyl)ethylenediaminetriacetic acid, nitrilotriacetic acid, ethylenediaminedisuccinic acid, and salts thereof.

7. The etching method of claim 1 , wherein the organic acid-based chelating agent is one or two or more selected from ethylenediaminetetra(methylenephosphonic acid), aminotris(methylenephosphonic acid), diethylenetriamine-penta(methylenephosphonic acid), etidronic acid, and salts thereof.

8. The etching method of claim 1 , wherein the organic acid-based chelating agent is one or two or more selected from phosphonobutane-3-carboxylic acid, N-(phosphonomethyl)iminodiacetic acid, 2-carboxyethylphosphonic acid, 2-hydroxyphosphonoacetic acid, and salts thereof.

9. The etching method of claim 1 , wherein the composition satisfies the following (D):
(D) having an outer thickness (T 0 ) relative to an inner thickness (T i ) of the silicon oxide film satisfying the following Equation 1, in a vertically laminated structure having the silicon oxide film and the silicon nitride film as a unit layer:
1.0≥ T o /T i ≥0.89.  [Equation 1]

10. The etching method of claim 1 , wherein the composition further comprising: a hydroxide, a fluorine-based compound, or a combination thereof.

11. The etching method of claim 10 , wherein the composition further comprising:
an inorganic acid selected from hydrochloric acid, nitric acid, sulfuric acid, and boric acid; and
a silicon-based compound represented by the following Chemical Formula 1:

wherein
R 1 to R 4 are independently of one another hydrogen, hydroxy, C1-C20 alkyl, C1-C20 aminoalkyl, C1-C20 alkoxy, C1-C20 acetyloxy, or C1-C20 haloalkylacetyloxy.

12. The etching method of claim 11 , wherein the composition satisfies the following (A′) to (D′):
(A′) including 10 to 50 wt % of the organic acid-based chelating agent and a balance of water,
(B′) having the etching rate of the silicon nitride film of 40 Å/min or more,
(C′) having the etching selection ratio of the silicon nitride film to the silicon oxide film of 400 or more, and
(D′) having the outer thickness (T′ 0 ) relative to the inner thickness (T′ i ) of the silicon oxide film satisfying the following Equation 2, in a vertically laminated structure having the silicon oxide film and the silicon nitride film as a unit layer:
1.0≥ T′o/T′i≥ 0.89.  [Equation 2]

13. The etching method of claim 1 , wherein the etching composition is non-phosphoric acid-based.

Assignees

• Univ Yonsei Iacf

Inventors

• Lim Sangwoo
• Son Changjin

Classifications

• H10P50/282

  of inorganic materials · CPC title

• H10P50/28

  of insulating materials · CPC title

• H10P14/69433

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

• H10P50/283 Primary

  by chemical means · CPC title

• C09K13/06

  with organic material · CPC title