# US 10,504,740 B2 · Method of removing silicon oxide film

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- Number: US 10,504,740 B2
- Document ID: US10504740B2
- Status: Granted
- Kind: B2
- Application number: 16/038,863
- Filed: 2018-07-18
- Published: 2019-01-24
- Granted: 2019-12-10
- Earliest claimed: 2017-07-24
- Assignees: Tokyo Electron Limited
- Applicants: Tokyo Electron Limited
- Inventors: Hideaki Yamasaki; Takamichi Kikuchi; Seishi Murakami
- Web page: https://patentgrep.com/patent/US10504740B2

## CPC

- H01L 21/31111
- H01J 37/00: Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof (H01J33/00, H01J40/00, H01J41/00, H01J47/00, H01J49/00 take precedence)
- H01L 21/02063
- H01L 21/02118
- H01L 21/02205
- H01L 21/02271
- H01L 21/67017
- H01L 21/6719
- H01L 21/67207
- H01L 21/6831
- H01L 21/76802
- H01L 21/67069
- H01L 21/67103
- H01L 21/67167
- H01L 21/6833
- H01L
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

Provided is a method of removing a silicon oxide film of a workpiece having an insulating film and the silicon oxide film exposed at a bottom portion of an opening formed in the insulating film, including: forming a protective film containing carbon on a surface of the workpiece, wherein the protective film has a first region extending along a side wall surface of the insulating film that defines the opening and a second region extending on the silicon oxide film: removing the second region of the protective film and the silicon oxide film by sputter etching with ions from plasma of a first inert gas; and removing a residue of the silicon oxide film by chemical etching. The step of forming the protective film includes executing a plurality of cycles.

## Claims

### Claim 1

A method of removing a silicon oxide film of a workpiece having an insulating film and the silicon oxide film exposed at a bottom portion of an opening formed in the insulating film, comprising:
forming a protective film containing carbon on a surface of the workpiece, wherein the protective film has a first region extending along a side wall surface of the insulating film that defines the opening and a second region extending on the silicon oxide film;
removing the second region of the protective film and the silicon oxide film by sputter etching with ions from plasma of a first inert gas; and
removing a residue of the silicon oxide film by chemical etching,
wherein forming a protective film is executed in a state where the workpiece is disposed in a chamber, and
wherein forming a protective film includes:
executing a plurality of cycles, each of the cycles including:
forming a precursor layer containing carbon on the surface of the workpiece by supplying a carbon-containing gas into the chamber;
purging the chamber;
reducing the amount of impurities contained in the precursor layer by generating plasma of a second inert gas in the chamber; and
purging the chamber.

### Claim 2 (depends on 1)

The method of claim 1, wherein the carbon-containing gas is a hydrofluorocarbon gas.

### Claim 3 (depends on 2)

The method of claim 2, wherein the carbon-containing gas is a CH3F gas.

### Claim 4 (depends on 1)

The method of claim 1, wherein the carbon-containing gas is a hydrocarbon gas.

### Claim 5 (depends on 1)

The method of claim 1, wherein forming a precursor layer includes further supplying at least one of a chlorine gas and a hydrogen gas into the chamber.

### Claim 6 (depends on 1)

The method of claim 1, wherein the second inert gas used in reducing the amount of impurities is a rare gas.

### Claim 7 (depends on 1)

The method of claim 1, wherein the first inert gas used in removing the second region of the protective film and the silicon oxide film is a rare gas.

### Claim 8 (depends on 1)

The method of claim 1, wherein removing a residue of the silicon oxide film includes:
forming an altered region from the residue of the silicon oxide film by supplying a process gas to the residue of the silicon oxide film, wherein the altered region contains ammonium silicofluoride; and
removing the altered region by heating the workpiece having the altered region.

### Claim 9 (depends on 8)

The method of claim 8, wherein the process gas contains a HF gas and a NH3 gas.