# US 9,039,909 B2 · Plasma etching method, semiconductor device manufacturing method and computer-readable storage medium

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- Number: US 9,039,909 B2
- Document ID: US9039909B2
- Status: Granted
- Kind: B2
- Application number: 13/405,539
- Filed: 2012-02-27
- Published: 2012-08-30
- Granted: 2015-05-26
- Earliest claimed: 2011-02-28
- Assignees: Tokyo Electron Limited
- Applicants: Akira Nakagawa; Yuji Otsuka
- Inventors: Akira Nakagawa; Yuji Otsuka
- Web page: https://patentgrep.com/patent/US9039909B2

## CPC

- H10P 50/283: {by chemical means}
- H10P 50/73: {using masks for insulating materials}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

There is provided a plasma etching method for forming a hole in a silicon oxide film formed on an etching stopper layer. The plasma etching method includes a main etching process for etching the silicon oxide film; and an etching process that is performed when at least a part of the etching stopper layer is exposed after the main etching process. The etching process includes a first etching process using a gaseous mixture of a C4F6 gas, an Ar gas and an O2 gas as the processing gas; and a second etching process using a gaseous mixture of a C4F8 gas, an Ar gas and an O2 gas or a gaseous mixture of a C3F8 gas, an Ar gas and an O2 gas as the processing gas. The first etching process and the second etching process are alternately performed plural times.

## Claims

### Claim 1

A plasma etching method for forming, via a mask layer, a hole in a silicon dioxide film formed on an etching stopper layer of a processing target substrate accommodated in a processing chamber by using plasma generated from a processing gas introduced into the processing chamber, the method comprising:
a main etching process for etching the silicon dioxide film using, as the processing gas, a gaseous mixture including C4F6 gas, C4F8 gas, Ar gas, O2 gas and CO gas, wherein the main etching process is stopped upon exposing at least a part of the etching stopper layer; and
a cyclic etching process that is started after at least the part of the etching stopper layer is exposed and after the main etching process is stopped,
wherein the cyclic etching process that is started after at least the part of the etching stopper layer is exposed includes:
a first etching process using a gaseous mixture of a C4F6 gas, an Ar gas and an O2 gas as the processing gas; and
a second etching process using a gaseous mixture of a C4F8 gas, an Ar gas and an O2 gas as the processing gas, and
the first etching process and the second etching process are alternately performed plural times.

### Claim 2 (depends on 1)

The plasma etching method of claim 1, wherein a time during which each of the first etching process and the second etching process is performed one time is in a range from about 3 seconds to about 15 seconds.

### Claim 3 (depends on 1)

The plasma etching method of claim 1, wherein the etching stopper layer is made of silicon nitride.

### Claim 4 (depends on 1)

The plasma etching method of claim 1, wherein the mask layer is made of polysilicon.

### Claim 5

A semiconductor device manufacturing method comprising:
a plasma etching process for forming, via a mask layer, a hole in a silicon dioxide film formed on an etching stopper layer of a processing target substrate accommodated in a processing chamber by using plasma generated from a processing gas introduced into the processing chamber,
wherein the plasma etching process includes:
a main etching process for etching the silicon dioxide film using, as the processing gas, a gaseous mixture including C4F6 gas, C4F8 gas, Ar gas, O2 gas and CO gas, wherein the main etching process is stopped upon exposing at least a part of the etching stopper layer; and
a cyclic etching process that is started after at least the part of the etching stopper layer is exposed and after the main etching process is stopped,
wherein the cyclic etching process that is started after at least the part of the etching stopper layer is exposed includes:
a first etching process using a gaseous mixture of a C4F6 gas, an Ar gas and an O2 gas as the processing gas; and
a second etching process using a gaseous mixture of a C4F8 gas, an Ar gas and an O2 gas as the processing gas, and
the first etching process and the second etching process are alternately performed plural times.

### Claim 6 (depends on 5)

The semiconductor device manufacturing method of claim 5, wherein a time during which each of the first etching process and the second etching process is performed one time in a range from about 3 seconds to about 15 seconds.

### Claim 7 (depends on 5)

The semiconductor device manufacturing method of claim 5, wherein the etching stopper layer is made of silicon nitride.

### Claim 8 (depends on 5)

The semiconductor device manufacturing method of claim 5, wherein the mask layer is made of polysilicon.