Carbon containing hardmask removal process using sulfur containing process gas

Patent metadata

Field	Value
Publication number	US-11264249-B2
Application number	US-201916713281-A
Country	US
Kind code	B2
Filing date	Dec 13, 2019
Priority date	Dec 18, 2018
Publication date	Mar 1, 2022
Grant date	Mar 1, 2022

Abstract

Apparatus, systems, and methods for conducting a hardmask (e.g., carbon containing hardmask) removal process on a workpiece are provided. In one example implementation, a process can include admitting a process gas into a plasma chamber, generating a plasma in the plasma chamber from the process gas using an inductively coupled plasma source, and exposing the carbon containing hardmask to the plasma to remove at least a portion of the carbon containing hardmask. The process gas can include a sulfur containing gas. The process gas does not include a halogen containing gas. The inductively coupled plasma source can be separated from the plasma chamber by a grounded electrostatic shield to reduce capacitive coupling between the inductively coupled plasma source and the plasma.

First claim

What is claimed is:

1. A process for etching a carbon containing hardmask on a workpiece, the process comprising:
admitting a process gas into a plasma chamber, the process gas comprising a sulfur containing gas and a passivation gas, wherein the process gas does not include a halogen containing gas;
generating a plasma in the plasma chamber from the process gas using an inductively coupled plasma source, the inductively coupled plasma source separated from the plasma chamber by a grounded electrostatic shield; and
exposing the carbon containing hardmask to the plasma to remove at least a portion of the carbon containing hardmask;
wherein the passivation gas is one or more of methane (CH 4 ), ethylene (C 2 H 4 ), ethane (C 2 H 6 ), propene (C 3 H 6 ), or propane (C 3 H 8 ).

2. The process of claim 1 , wherein the sulfur containing gas comprises carbonyl sulfide (COS), sulfur dioxide (SO 2 ), hydrogen sulfide (H 2 S), or sulfur trioxide (SO 3 ).

3. The process of claim 1 , wherein the process gas further comprises an etching gas.

4. The process of claim 3 , wherein the etching gas comprises carbon monoxide (CO), nitrogen (N 2 ), carbon dioxide (CO 2 ), oxygen (O 2 ), ozone (O 3 ), water vapor (H 2 O), hydrogen peroxide (H 2 O 2 ), nitrogen trihydride (NH 3 ), dinitrogen tetrahydride (N 2 H 4 ), hydrogen (H 2 ), or nitrogen monoxide (NO).

5. The process of claim 1 , wherein the process gas further comprises an inert gas.

6. The process of claim 5 , wherein the inert gas comprises helium (He), argon (Ar), neon (Ne), or xenon (Xe).

7. The process of claim 1 , wherein exposing the carbon containing hardmask to the plasma to remove at least the portion of the carbon containing hardmask forms a trench feature with a vertical profile.

8. The process of claim 1 , wherein exposing the carbon containing hardmask to the plasma to remove at least the portion of the carbon containing hardmask forms a trench feature with a sloped profile.

9. The process of claim 8 , wherein exposing the carbon containing hardmask to the plasma to remove at least the portion of the carbon containing hardmask forms a trench feature with a sloped profile such that a bottom critical dimension of the carbon containing hardmask is less than half of a top critical dimension of the carbon containing hardmask.

10. The process of claim 1 , wherein the grounded electrostatic shield is located between the inductively coupled plasma source and a dielectric window forming at least a portion of the plasma chamber.

11. The process of claim 1 , wherein when the inductively coupled plasma source is energized with a radio frequency (RF) source to generate the plasma, the process further comprises energizing an RF bias source.

12. The process of claim 11 , wherein a ratio between an RF source power of the RF source and a bias power of the RF bias source is in a range of about 2:1 to about 20:1.

13. The process of claim 11 , wherein the RF bias source is coupled to a workpiece support configured to support the workpiece in a processing chamber.

14. The process of claim 1 , wherein a pressure of the plasma chamber is less than about 20 mT.

15. The process of claim 1 , wherein the inductively coupled plasma source comprises a first inductive coupling element and a second inductive coupling element, the first inductive coupling element and the second inductive coupling element energized with RF energy at different RF frequencies.

16. The process of claim 1 , wherein the carbon containing hardmask is located below a dielectric hardmask on the workpiece.

17. The process of claim 16 , wherein exposing the carbon containing hardmask to the plasma to remove at least the portion of the carbon containing hardmask is performed after a dielectric hardmask etch process.

18. The process of claim 17 , further comprising conducting a strip process for removal of photoresist subsequent to the dielectric hardmask etch process.

Assignees

• Mattson Tech Inc
• Beijing E Town Semiconductor Tech Co Ltd

Inventors

• Dai Fen
• Wang Tinghao
• Jan Oliver D
• Kim Moo-Hyun
• Ma Shawming
• Liu Zhongming

Classifications

• H10P76/4085

  characterised by the processes involved to create the masks · CPC title

• H10P76/405

  characterised by their composition, e.g. multilayer masks · CPC title

• H10P50/73

  using masks for insulating materials · CPC title

• H10P50/285 Primary

  of materials not containing Si, e.g. PZT or Al2O3 · CPC title

• H10P50/283

  by chemical means · CPC title