# US 12,765,292 B2 · Etching method and plasma processing system

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- Number: US 12,765,292 B2
- Document ID: US12765292B2
- Status: Granted
- Kind: B2
- Application number: 18/198,736
- Filed: 2023-05-17
- Published: 2023-11-23
- Granted: 2026-10-13
- Earliest claimed: 2022-05-19
- Assignees: Tokyo Electron Limited
- Applicants: Tokyo Electron Limited
- Inventors: Satoshi Ohuchida; Masahito Yamaguchi; Takatoshi Orui; Maju Tomura
- Web page: https://patentgrep.com/patent/US12765292B2

## CPC

- H10P 50/268: {of silicon-containing layers}
- H10P 50/242: {of Group IV materials}
- H10P 50/267: {using plasmas}
- H10P 50/283: {by chemical means}
- H10P 72/72: using electrostatic chucks
- H01J 37/32449: {Gas control, e.g. control of the gas flow}
- H01J 2237/3341: Reactive etching
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)

## Abstract

The purpose of this disclosure is to provide an etching method. This method includes: (a) providing a substrate on a substrate support in a chamber, the substrate including a silicon-containing film and a mask on the silicon-containing film, the silicon-containing film including silicon and nitrogen; (b) supplying a process gas to the chamber, the process gas containing a hydrogen fluoride gas and a chlorine-containing gas, where a flow rate of the chlorine-containing gas is 1.5 volume % or more of a total flow of the process gas excluding an inert gas; and (c) generating a plasma from the process gas to etch the silicon-containing film.

## Claims

### Claim 1

An etching method comprising:
(a) providing a substrate on a substrate support in a chamber, the substrate including a silicon-containing film and a mask on the silicon-containing film, the silicon-containing film including silicon and nitrogen;
(b) supplying a process gas to the chamber, the process gas containing a hydrogen fluoride gas and a chlorine-containing gas that contains carbon and hydrogen, where a flow rate of the chlorine-containing gas is 1.5 volume % or more and 5 volume % or less of a total flow of the process gas excluding an inert gas; and
(c) generating a plasma from the process gas to etch the silicon-containing film.

### Claim 2 (depends on 1)

The etching method according to claim 1, wherein the process gas further contains a phosphorus fluoride gas.

### Claim 3 (depends on 2)

The etching method according to claim 2, wherein the phosphorus fluoride gas is at least either one of PF3 gas and PF5 gas.

### Claim 4 (depends on 1)

The etching method according to claim 1, wherein the chlorine-containing gas contains a CxHyFzClw gas (where x and w are integers of 1 or larger, and y and z are integers of 0 or larger).

### Claim 5 (depends on 1)

The etching method according to claim 1, wherein the process gas further contains a phosphorus-containing gas.

### Claim 6 (depends on 1)

The etching method according to claim 1, wherein the flow rate of the hydrogen fluoride gas is higher than a flow rate of any other gas in the process gas excluding the inert gas.

### Claim 7 (depends on 1)

The etching method according to claim 1, wherein the process gas further contains a carbon-containing gas.

### Claim 8 (depends on 7)

The etching method according to claim 7, wherein the carbon-containing gas is either a fluorocarbon gas or a hydrofluorocarbon gas.

### Claim 9 (depends on 7)

The etching method according to claim 7, wherein the process gas further contains at least either one of an oxygen-containing gas and a metal-containing gas.

### Claim 10 (depends on 1)

The etching method according to claim 1, wherein the silicon-containing film further contains at least any one of a silicon nitride film, a silicon oxide film, and a polysilicon film.

### Claim 11 (depends on 1)

The etching method according to claim 1, wherein the mask is a carbon-containing film or a metal-containing film.

### Claim 12 (depends on 1)

The etching method according to claim 1, wherein a temperature of the substrate support is set to 0° C. or less in (c).

### Claim 13 (depends on 1)

The etching method according to claim 1, wherein the chlorine-containing gas is CHCl3 gas or CH2Cl2 gas.

### Claim 14

An etching method comprising:
(a) providing a substrate on a substrate support in a chamber, the substrate including a silicon-containing film and a mask on the silicon-containing film, the silicon-containing film including silicon and nitrogen;
(b) supplying a process gas to the chamber, the process gas containing a single or mixed gas and a chlorine-containing gas that contains carbon and hydrogen, the single or mixed gas containing fluorine and hydrogen, where a flow rate of the chlorine-containing gas is 1.5 volume % or more and 5 volume % or less of a total flow of the process gas excluding an inert gas; and
(c) generating a plasma from the process gas to etch the silicon-containing film, where the plasma contains active species of hydrogen fluoride.

### Claim 15 (depends on 14)

The etching method according to claim 14, wherein the single or mixed gas is at least one selected from the group consisting of a hydrogen fluoride gas, a hydrofluorocarbon gas, and a mixed gas containing a fluorine-containing gas and a hydrogen-containing gas.