Selective anisotropic metal etch

Patent metadata

Field	Value
Publication number	US-11658043-B2
Application number	US-202117389119-A
Country	US
Kind code	B2
Filing date	Jul 29, 2021
Priority date	Sep 3, 2020
Publication date	May 23, 2023
Grant date	May 23, 2023

Abstract

A method of patterning a substrate is provided. The method includes modifying a surface of a metal-containing layer formed over a substrate positioned in a processing region of a processing chamber by exposing the surface of the metal-containing layer to plasma effluents of a chlorine-containing gas precursor and an oxygen-containing gas precursor to form a modified surface of the metal-containing layer. The method further includes directing plasma effluents of an inert gas precursor towards the modified surface of the metal-containing layer. The plasma effluents of the inert gas precursor are directed by applying a bias voltage to a substrate support holding the substrate. The method further includes anisotropically etching the modified surface of the metal-containing layer with the plasma effluents of the inert gas precursor to form a first recess having a first sidewall in the metal-containing layer.

First claim

The invention claimed is:

1. A method of patterning a substrate, comprising:
exposing an initial surface of a metal-containing layer to an ion doping implantation by a plasma doping (PLAD) technique to produce a surface of the metal-containing layer during a pre-amorphization treatment process; then
modifying the surface of the metal-containing layer formed over a substrate positioned in a processing region of a processing chamber by exposing the surface of the metal-containing layer to a chlorine-containing gas precursor and an oxygen-containing gas precursor to form a modified surface of the metal-containing layer;
directing plasma effluents of an inert gas precursor towards the modified surface of the metal-containing layer, wherein the plasma effluents of the inert gas precursor are directed by applying a bias voltage to a substrate support holding the substrate;
anisotropically etching the modified surface of the metal-containing layer with the plasma effluents of the inert gas precursor to form a first recess having a first sidewall in the metal-containing layer, wherein the plasma effluents of the inert gas precursor selectively etch the modified surface of the metal-containing layer relative to unmodified portions; and
exposing the first recess to an etchant gas mixture including a passivation gas and an etchant gas to remove additional metal from the metal-containing layer.

2. The method of claim 1 , wherein the inert gas precursor is argon.

3. The method of claim 1 , wherein the metal-containing layer comprises ruthenium.

4. The method of claim 1 , wherein anisotropically etching the modified surface of the metal-containing layer forms a feature comprising a bit-line metal-containing layer.

5. The method of claim 1 , wherein the chlorine-containing gas precursor flows into the processing region at a flow rate of from about 10 sccm to about 50 sccm and the oxygen-containing gas precursor flows into the processing region at a flow rate from about 100 sccm to about 150 sccm.

6. The method of claim 1 , wherein a pressure within the processing region while modifying the surface of the metal-containing layer and anisotropically etching the modified surface of the metal-containing layer is maintained at about 20 mTorr or less.

7. The method of claim 1 , wherein the bias voltage directing the plasma effluents of the inert gas precursor towards the modified surface of the metal-containing layer is at about 150 watts or less.

8. The method of claim 1 , further comprising repeating the method in at least one additional cycle.

9. The method of claim 1 , wherein a temperature of the processing chamber is maintained at about 50 degrees Celsius or less.

10. The method of claim 1 , wherein modifying the surface of the metal-containing layer is performed without etching the surface of the metal-containing layer.

11. The method of claim 1 , further comprising:
forming a plasma of the etchant gas mixture;
passivating, with plasma effluents of the passivation gas, the first sidewall of the first recess; and
anisotropically etching the first recess with plasma effluents of the etchant gas to deepen the first recess with a second sidewall in the metal-containing layer aligned with the first sidewall.

12. The method of claim 11 , wherein the passivation gas is selected from nitrogen (N 2 ), sulfur dioxide (SO 2 ), or a combination thereof.

13. The method of claim 12 , wherein the etchant gas comprises oxygen (O 2 ) and chlorine (Cl 2 ).

14. A method of patterning a substrate, comprising:
exposing an initial surface of a ruthenium-containing layer to an ion doping implantation by a plasma doping (PLAD) technique to produce a surface of the ruthenium-containing layer during a pre-amorphization treatment process; then
exposing the surface of the ruthenium-containing layer formed over a substrate positioned in a processing region of a processing chamber to an etchant gas mixture including a passivation gas selected from N 2 and SO 2 and an etchant gas comprising O 2 and Cl 2 ; and
anisotropically etching the ruthenium-containing layer with a plasma of the etchant gas mixture.

15. The method of claim 14 , further comprising:
modifying a surface of the ruthenium-containing layer by exposing the surface of the ruthenium-containing layer to plasma effluents of a chlorine-containing gas precursor and an oxygen-containing gas precursor to form a modified surface of the ruthenium-containing layer prior to exposing the surface of the ruthenium-containing layer to the etchant gas mixture.

16. The method of claim 15 , wherein anisotropically etching the ruthenium-containing layer with a plasma of the etchant gas mixture removes the modified surface of the ruthenium-containing layer.

17. A method of patterning a substrate, comprising:
exposing an initial surface of a ruthenium-containing layer to an ion doping implantation by a plasma doping (PLAD) technique to produce a surface of the ruthenium-containing layer during a pre-amorphization treatment process; then
exposing the surface of the ruthenium-containing layer formed over a substrate positioned in a processing region of a processing chamber to an etchant gas mixture, comprising:
O 2 having a flow rate from about 50 sccm to about 200 sccm;
Cl 2 having a flow rate from about 10 sccm to about 100 sccm;
argon having a flow rate from about 100 sccm to about 300 sccm; and
N 2 having a flow rate from about 5 sccm to about 100 sccm or SO 2 having a flow rate from about 10 sccm to about 30 sccm;

anisotropically etching the ruthenium-containing layer with a plasma of the etchant gas mixture to form a recess having a first sidewall in the ruthenium-containing layer, comprising:
maintaining the substrate at a temperature from about 20 degrees Celsius to about 40 degrees Celsius; and
maintaining the plasma of the etchant gas mixture at a pressure from about 10 mTorr to about 20 MTorr; and

exposing the recess to an etchant gas mixture including a passivation gas and an etchant gas to remove additional metal from the ruthenium-containing layer.

18. The method of claim 17 , wherein anisotropically etching the ruthenium-containing layer forms a feature comprising a bit-line ruthenium-containing layer.

19. The method of claim 17 , further comprising:
forming a plasma of the etchant gas mixture;
passivating, with plasma effluents of the passivation gas the first sidewall of the first recess; and
anisotropically etching the recess with plasma effluents of the etchant gas to deepen the recess with a second sidewall in the metal-containing layer aligned with the first sidewall.

20. The method of claim 17 , wherein the passivation gas is selected from nitrogen (N 2 ), sulfur dioxide (SO 2 ), or a combination thereof, and wherein the etchant gas comprises oxygen (O 2 ) and chlorine (Cl 2 ).

Assignees

• Applied Materials Inc

Inventors

• Shaw Jonathan
• Panda Priyadarshi
• Fung Nancy
• Dong Yongchang
• Rasouli Somaye
• Lee Gene

Classifications

• H10P50/267 Primary

  using plasmas · CPC title

• H10B12/482

  Bit lines · CPC title

• H01L21/32136 Primary

  Electricity · mapped topic

• H10P50/71

  using masks for conductive or resistive materials · CPC title