Two-stage etching process

• US 6,787,054 B2
• Filed: 02/03/2003
• Issued: 09/07/2004
• Est. Priority Date: 03/27/2000
• Status: Expired due to Fees

• Current Assignee: Scott Williams, Shaoher X. Pan, Xikun Wang
• Original Assignee: Scott Williams, Shaoher X. Pan, Xikun Wang
• Inventors: Wang, Xikun, Williams, Scott, Pan, Shaoher X.
• Primary Examiner(s): Kornakov, M.
• Application Number:
  US10/358,086
• Publication Number:
  US 20030173333A1
• Time in Patent Office: 582 Days
• Field of Search: 216/63, 216/64, 216/67, 216/68, 216/72, 216/74, 216/79, 216/69, 216/70, 216/58, 438/706, 438/707, 438/710, 438/711, 438/714, 438/716, 438/719, 438/723, 438/724, 438/726, 438/727, 438/734, 438/766, 438/906, 134/1.1, 134/1.2, 134/1.3, 134/22.1, 134/22.18, 134/26, 134/30, 134/902
• US Class Current: 216/72
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H01L 21/3065 Plasma etching; Reactive-ion etching
• CPC Class Codes: H01L 21/3081 characterised by their composition, e.g. multilayer masks, materials
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/32137 of silicon-containing layers
• CPC Class Codes: Y10S 134/902 Semiconductor wafer
• CPC Class Codes: Y10S 438/905 Cleaning of reaction chamber
• CPC Class Codes: Y10S 438/906 Cleaning of wafer as interim step

Abstract

A process for etching a substrate and removing etch residue deposited on the surfaces in the etching chamber has two stages. In the first stage, an energized first process gas is provided in the chamber, and in the second stage, an energized second process gas is provided in the chamber. The energized first process gas comprises SF₆ and Ar, the volumetric flow ratio of SF₆ to other components of the first process gas being from about 5:1 to about 1:10. The energized second process gas comprises CF₄ and Ar, the volumetric flow ratio of CF₄ to other components of the second process gas being from about 1:0 to about 1:10.

Claims

1. A substrate etching method comprising:

placing a substrate in the chamber, the substrate comprising a first silicon-containing layer overlying a second silicon-containing layer;

in a first stage, etching the first silicon-containing layer by providing in the chamber, an energized first process gas comprising (i) SF₆ and (ii) one or more other components, the other components comprising HBr and Ar, the volumetrie flow ratio of SF₆ to the other components of the first procoss gas being from about 5;

1 to about 1;

10; and

in a second stage, etching the second sllicon-containing layer by providing in the chamber, an energizod second process gas comprising (i) CF₄ and (ii) one or more other components, the other components comprising Ar.

2. A method according to claim 1 wherein the other components of the first process gas comprise CF₄ and CHF₃.

3. A method according to claim 1 wherein the first silicon-containing layer comprises silicon nitride or metal silicide.

4. A method according to claim 3 wherein the second silicon containing layer comprises silicon oxide.

5. A method according to claim 1 comprising energizing at least one of the first and second processes gases in the chamber with an inductive source power from about 600 to about 1200 watts and a bias power from about 70 to about 100 watts, and comprising maintaining the chamber at a pressure from about 5 to about 70 m Torr.

6. A substrate etching method comprising:

placing a substrate in the chamber, the substrate comprising a first silicon-containing layer overlying a second silicon-containing layer;

in a first stage, etching the first silicon-containing layer by providing in the chamber, an energized first process gas comprising SF₆, HBr and CHF₃; and

in a second stage, etching the second siiicon-containing layer by providing in the chamber, an energized second process gas comprising (i) CF₄ and (ii) one or more other components, the other components comprising Ar process gas.

7. A method according to claim 6 wherein the first silicon-containing layer comprises silicon nitride or metal silicide.

8. A method according to claim 6 wherein the second process gas comprises HBr.

9. A method according to claim 6 wherein the second silicon-containing layer comprises silicon oxide.

10. A method according to claim 6 comprising energizing at least one of the first and second processes gases in the chamber with an inductive source power from about 600 to about 1200 watts and a bias power from about 70 to about 100 watts, and comprising maintaining the chamber at a pressure from about 5 to about 70 mTorr.

11. A substrate etching method comprising:

placing a substrate in the chamber, the substrate comprising a first silicon-containing layer overlying a second silicon-containing layer;

in a first stage, etching the first silicon-containing layer by providing in the chamber, an energized first process gas comprising SF₆, CF₄, CHF₃, HBr and Ar; and

in a second stage, etching the second silicon-containing layer by providing in the chamber, an energized second process gas comprising (i) CF₄ and (ii) one or more other oomponents, the other components comprising Ar.

12. A method according to claim 11 wherein the volumetric flow ratio of SF₆ to the other components of the first process gas is from about 5:

1 to about 1;

1.

13. A method according to claim 11 whereln the first silicon-containing layer comprises silicon nitride or metal silicide.

14. A method according to claim 11 wherein the second silicon-containing layer comprises silicon oxide.