Etching method and etching apparatus

Patent metadata

Field	Value
Publication number	US-9865471-B2
Application number	US-201615133314-A
Country	US
Kind code	B2
Filing date	Apr 20, 2016
Priority date	Apr 30, 2015
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

A method for etching a silicon film formed on a substrate includes supplying HBr gas, NF 3 gas, and O 2 gas into a chamber and performing a plurality of etching processes on the silicon film with a plasma generated by the supplied HBr gas, NF 3 gas, and O 2 gas, gradually reducing a flow rate of the HBr gas during the plurality of etching processes, and adjusting a flow rate of the O 2 gas according to the reduction of the HBr gas.

First claim

What is claimed is:

1. A method for etching a silicon film formed on a substrate, the method comprising:
a first process of supplying HBr gas, NF 3 gas, and O 2 gas into a chamber and performing a first etching process on a silicon film with a plasma generated by the supplied HBr gas, NF 3 gas, and O 2 gas,
a second process of continuously supplying the HBr gas, the NF 3 gas, and the O 2 gas into the chamber and performing a second etching process on a base film with the plasma generated by the supplied HBr gas, NF 3 gas, and O 2 gas,
gradually reducing a flow rate of the HBr gas during the first and second etching processes, and
adjusting a flow rate of the O 2 gas according to the reduction of the HBr gas so as to gradually increase a flow rate ratio of the O 2 gas relative to the HBr gas.

2. The method as claimed in claim 1 , wherein the flow rate of the HBr is gradually reduced during the etching processes including the last etching process of the etching processes.

3. The method as claimed in claim 1 , wherein the flow rate of the O 2 gas is gradually increased.

4. The method as claimed in claim 1 , further comprising:
controlling the NF 3 gas to a constant flow rate or increasing the flow rate of the NF 3 gas;
wherein when the flow rate of the NF 3 gas is increased, the flow rate of the O 2 gas is increased according to the increase of the NF 3 gas.

5. The method as claimed in claim 1 , wherein a temperature of the substrate is adjusted to range from 100° C. to 200° C.

6. The method as claimed in claim 1 , wherein the plurality of etching processes includes applying a pulse wave of a high-frequency electric power LF for biasing, the pulse wave having a power greater than or equal to 4000 W.

7. The method as claimed in claim 6 , wherein a frequency of the pulse wave of the high-frequency electric power LF for biasing ranges from 0.1 kHz to 50 kHz and has a duty ratio from 5% to 30%.

8. An etching apparatus for etching a silicon film formed on a substrate, the etching apparatus comprising:
a control part configured to perform the steps of:
a first process of supplying HBr gas, NF 3 gas, and O 2 gas into a chamber and performing a first etching process on a silicon film with a plasma generated by the supplied HBr gas, NF 3 gas, and O 2 gas,

a second process of continuously supplying the HBr gas, the NF 3 gas, and the O 2 gas into the chamber and performing a second etching process on a base film with the plasma generated by the supplied HBr gas, NF 3 gas, and O 2 gas,
gradually reducing a flow rate of the HBr gas during the first and second etching processes, and
adjusting a flow rate of the O 2 gas according to the reduction of the HBr gas so as to gradually increase a flow rate ratio of the O 2 gas relative to the HBr gas.

9. The etching apparatus as claimed in claim 8 , wherein the control part is further configured to apply a pulse wave of a high-frequency electric power LF for biasing, the pulse wave having a power greater than or equal to 4000 W.

10. The method as claimed in claim 1 , wherein the adjusting the flow rate of the O 2 gas includes gradually increasing the flow rate of the O 2 gas when the flow rate of the HBr is gradually reduced.

11. The method as claimed in claim 1 , wherein the base film includes at least one of a silicon oxide film and a silicon nitride film.

Assignees

• Tokyo Electron Ltd

Inventors

• SHIMODA Gaku
• Maruyama Hotaka
• Sato Takanori
• Urakawa Masafumi
• Ogasawara Masahiro

Classifications

• H10P72/0434

  mainly by convection · CPC title

• H10P50/242 Primary

  of Group IV materials · CPC title

• H01J2237/334

  Etching · CPC title

• H01J37/32724

  Temperature · CPC title

• H01L21/67109

  Electricity · mapped topic