# US 12,110,435 B2 · Etching composition and method for selectively removing silicon nitride during manufacture of a semiconductor device

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- Number: US 12,110,435 B2
- Document ID: US12110435B2
- Status: Granted
- Kind: B2
- Application number: 17/656,828
- Filed: 2022-03-28
- Published: 2022-07-21
- Granted: 2024-10-08
- Earliest claimed: 2019-09-30
- Assignees: Versum Materials US, LLC
- Applicants: Versum Materials US, LLC
- Inventors: Jhih Kuei Ge; Yi-Chia Lee; Wen Dar Liu; Aiping Wu; Laisheng Sun
- Web page: https://patentgrep.com/patent/US12110435B2

## CPC

- C09K 13/06: with organic material
- C07F 7/0838: {Compounds with one or more Si-O-Si sequences (compounds with a ring containing only alternating Si and O atoms, i.e. cyclosilanes C07F7/21)}
- C07F 9/06: without P—C bonds
- H10P 14/69433: {the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz}
- H10P 50/283: {by chemical means}
- H10P 14/69215: {the material being a silicon oxide, e.g. SiO2}
- H10P 70/23: {during, before or after processing of insulating materials}
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C07F: ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM (metal-containing porphyrins C07D487/22)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

The disclosed and claimed subject matter is directed to an etching composition that includes (A) phosphoric acid and (B) a mixture that includes (i) a silicon-containing compound and (ii) an aqueous solvent. In some embodiments, the etching compositions include additional ingredients. The etching compositions are useful for the selective removal of silicon nitride over silicon oxide from a microelectronic device having such material(s) thereon during its manufacture.

## Claims

### Claim 1

A composition comprising:
A. greater than approximately 70% by weight of neat phosphoric acid; and
B. a mixture comprising at least one of:
I. a compound of Formula I:
wherein:
(i) m=0-20,
(ii) each of R1, R2, R3, R4 and R5 is independently selected from the group of hydrogen, a C1 to C10 linear alkyl group, a C1 to C10 linear alkyl group substituted with fluorine, a nitrogen-containing group, an oxygen-containing group, a C3 to C10 branched alkyl group, a C3 to C10 cyclic alkyl group, a C5 to C12 aryl group, a C2 to C10 linear or branched alkenyl group and a C2 to C10 linear or branched alkynyl group,
and
(iii) each of Ra and Rb is independently selected from a C1 to C10 linear alkyl group, a C3 to C10 branched alkyl group, a C3 to C10 cyclic alkyl group, a C5 to C12 aryl group, a C2 to C10 linear or branched alkenyl group and a C2 to C10 linear or branched alkynyl group,
a C1-C10 alkyl substituted with
or
II. a compound of Formula II:
wherein:
(i) m=0-20,
(ii) n=0-20,
(iii) R3 is selected from the group of hydrogen, a C1 to C10 linear alkyl group, a C1 to C10 linear alkyl group substituted with fluorine, a nitrogen-containing group, an oxygen-containing group, a C3 to C10 branched alkyl group, a C3 to C10 cyclic alkyl group, a C5 to C12 aryl group, a C2 to C10 linear or branched alkenyl group and a C2 to C10 linear or branched alkynyl group,
Z1 and Z2, and
(iv) each of Ra and Rb is independently selected from a C1 to C10 linear alkyl group, a C3 to C10 branched alkyl group, a C3 to C10 cyclic alkyl group, a C5 to C12 aryl group, a C2 to C10 linear or branched alkenyl group and a C2 to C10 linear or branched alkynyl group,
a C1-C10 alkyl substituted with
(v) Z1 and Z2 are each independently selected from:
and
III. an aqueous solvent,
wherein the composition is free of ammonium ions.

### Claim 2 (depends on 1)

The composition of claim 1, wherein the mixture further comprises at least one additional acid other than neat phosphoric acid selected from HNO3, H2SO4, HCl and methane sulfuric acid.

### Claim 3 (depends on 1)

The composition of claim 1, wherein (i) the composition comprises greater than approximately 75% by weight of neat phosphoric acid and (ii) less than approximately 25% by weight of the mixture.

### Claim 4 (depends on 1)

The composition of claim 1, wherein the mixture further comprises one or more additional silicon-containing compound selected from alkylsilsesquioxanes, vinylsilsesquioxane, carboxylic acid alkylsilsesquioxane and alkyleneglycol alkylsilsesquioxane.

### Claim 5 (depends on 1)

The composition of claim 1, wherein the mixture comprises a compound of Formula I.

### Claim 6 (depends on 1)

The composition of claim 1, wherein the mixture comprises a compound of Formula II.

### Claim 7 (depends on 1)

The composition of claim 1, wherein m in one or both of Formula I and Formula II is 0.

### Claim 8 (depends on 1)

The composition of claim 1, wherein a content of the compound of Formula I is approximately 5% or less by weight.

### Claim 9 (depends on 1)

The composition of claim 1, wherein a content of the compound of Formula II is approximately 5% or less by weight.

### Claim 10 (depends on 1)

The composition of claim 1 comprising a compound of Formula I, wherein
(i) the compound of Formula I comprises:

### Claim 11 (depends on 1)

The composition of claim 1 comprising a compound of Formula I, wherein
(i) the compound of Formula I comprises:
and
(ii) a content of the neat phosphoric is greater than approximately 75% by weight of the composition.

### Claim 12 (depends on 1)

The composition of claim 1 comprising a compound of Formula I, wherein
(i) the compound of Formula I comprises:

### Claim 13 (depends on 1)

The composition of claim 1 comprising a compound of Formula I, wherein
(i) the compound of Formula I comprises:
and
(ii) a content of the neat phosphoric is greater than approximately 75% by weight of the composition.

### Claim 14 (depends on 1)

The composition of claim 1 comprising a compound of Formula II, wherein
(i) the compound of Formula II comprises:

### Claim 15 (depends on 1)

The composition of claim 1 comprising a compound of Formula II, wherein
(i) the compound of Formula II comprises:
and
(ii) a content of the neat phosphoric is greater than approximately 75% by weight of the composition.

### Claim 16 (depends on 1)

The composition of claim 1 comprising a compound of Formula II, wherein
(i) the compound of Formula II comprises:

### Claim 17 (depends on 1)

The composition of claim 1 comprising a compound of Formula II, wherein
(i) the compound of Formula II comprises:
and
(ii) a content of the neat phosphoric is greater than approximately 75% by weight of the composition.

### Claim 18 (depends on 1)

A method of selectively enhancing the etch rate of silicon nitride relative to silicon dioxide on a semiconductor substrate comprising silicon nitride and silicon dioxide, the method comprising the steps of:
a. contacting the semiconductor substrate comprising silicon nitride and silicon dioxide with the composition of claim 1; and
b. rinsing the semiconductor device after the silicon nitride is at least partially removed.