Metal doped carbon based hard mask removal in semiconductor fabrication

Patent metadata

Field	Value
Publication number	US-11062897-B2
Application number	US-201715640345-A
Country	US
Kind code	B2
Filing date	Jun 30, 2017
Priority date	Jun 9, 2017
Publication date	Jul 13, 2021
Grant date	Jul 13, 2021

Abstract

Methods and apparatuses for etching metal-doped carbon-containing materials are provided herein. Etching methods include using a mixture of an etching gas suitable for etching the carbon component of the metal-doped carbon-containing material and an additive gas suitable for etching the metal component of the metal-doped carbon-containing material and igniting a plasma to selectively remove metal-doped carbon-containing materials relative to underlayers such as silicon oxide, silicon nitride, and silicon, at high temperatures. Apparatuses suitable for etching metal-doped carbon-containing materials are equipped with a high temperature movable pedestal, a plasma source, and a showerhead between a plasma generating region and the substrate.

First claim

What is claimed is:

1. A method of processing a substrate having a metal-doped carbon-containing material thereon, the method comprising:
(a) providing the substrate to a process chamber,
wherein the substrate is a semiconductor substrate and comprises the metal-doped carbon-containing material and an underlying material positioned below the metal-doped carbon-containing material, and
wherein the metal-doped carbon-containing material and the underlying material each comprise negative features formed therein; and

(b) after (a), simultaneously (i) heating the substrate to a temperature between about 200° C. and about 500° C., and (ii) exposing the metal-doped carbon-containing material to a plasma generated from a gas mixture comprising a first etching gas and a second etching gas to etch the metal-doped carbon-containing material,
wherein the first etching gas forms a first volatile by product with the carbon of the metal-doped carbon-containing material,
wherein the second etching gas forms a second volatile by product with the metal of the metal-doped carbon-containing material, and
wherein the metal of the metal-doped carbon-containing material is selected from the group consisting of tungsten, titanium, tantalum, nitrides thereof, silicides thereof, and combinations thereof.

2. The method of claim 1 , wherein the second etching gas comprises a halogen-containing gas selected from the group consisting of nitrogen trifluoride (NF 3 ), chlorine (Cl 2 ), fluorine (F 2 ), bromine (Br 2 ), iodine (I 2 ), sulfur hexafluoride (SF 6 ), and combinations thereof.

3. The method of claim 1 , further comprising exposing the substrate to a pre oxidation gas comprising oxygen (O 2 ) and igniting an oxygen-based plasma to oxidize and thereby protect exposed silicon surfaces on the substrate, wherein the substrate is exposed to the pre oxidation gas while the negative features are present in the metal-doped carbon-containing material and in the underlying material, and before (b).

4. The method of claim 3 , wherein the pre oxidation gas is a mixture of oxygen (O 2 ) and nitrogen (N 2 ).

5. The method of claim 1 , wherein the metal-doped carbon-containing material comprises a metal dopant and density of the metal dopant in the metal-doped carbon-containing material in atomic percentage is between about 33% and about 66%.

6. The method of claim 1 , wherein the plasma is ignited at a power per station of between about 500 W and about 10000 W.

7. The method of claim 1 , wherein the metal-doped carbon-containing material is etched without applying a bias to a pedestal upon which the substrate is placed.

8. The method of claim 1 , wherein the process chamber is set to a chamber pressure between about 100 mTorr and about 4000 mTorr.

9. The method of claim 8 , wherein the process chamber is set to a chamber pressure between about 200 mTorr and about 4000 mTorr.

10. The method of claim 1 , wherein percentage of metal in the metal-doped carbon-containing material is between about 5% and about 95%.

11. The method of claim 1 , wherein the metal-doped carbon-containing material is a patterned hard mask used for forming the negative features in the underlying material, wherein the underlying material comprises a material selected from the group consisting of silicon oxide, silicon nitride, doped silicon oxide, doped silicon nitride, tungsten, and combinations thereof, wherein an etch selectivity of the metal-doped carbon-containing material relative to the underlying material is at least about 1000:1 during (b).

12. The method of claim 1 , wherein the metal-doped carbon-containing material is a patterned hard mask used for forming the negative features in the underlying material, wherein the underlying material comprises a material selected from the group consisting of silicon oxide, silicon nitride, silicon, doped derivatives thereof, and combinations thereof, wherein an etch selectivity of the metal-doped carbon-containing material relative to the underlying material is at least about 1000:1 during (b).

13. The method of claim 1 , wherein the metal-doped carbon-containing material is a patterned hard mask used for forming the negative features in the underlying material, wherein the underlying material comprises a material selected from the group consisting of silicon oxide, silicon nitride, silicon, germanium, doped derivatives thereof, and combinations thereof, wherein an etch selectivity of the metal-doped carbon-containing material relative to the underlying material is between about 10:1 and about 30:1 during (b).

14. The method of claim 1 , wherein the metal-doped carbon-containing material is a patterned hard mask used for forming the negative features in the underlying material, wherein the underlying material comprises a material selected from the group consisting of silicon oxide, cobalt, tantalum nitride, copper, and low k dielectric, and combinations thereof, and wherein an etch selectivity of the metal-doped carbon-containing material relative to the underlying material is between about 10:1 and about 30:1.

15. The method of claim 1 , wherein the plasma is ignited upstream of a showerhead for delivering the gas mixture.

16. The method of claim 1 , wherein the metal-doped carbon-containing material is etched at an etch rate between about 30 nm/min and about 1000 nm/min.

17. The method of claim 1 , wherein the metal-doped carbon-containing material has a ratio of metal to carbon, and a ratio of second etching gas volume to first etching gas volume is about equal to the ratio of metal to carbon in the metal-doped carbon-containing material.

18. The method of claim 1 , wherein the second etching gas further comprises nitrogen gas (N 2 ).

19. The method of claim 1 , wherein the second etching gas comprises a halogen-containing gas selected from the group consisting of nitrogen trifluoride (NF 3 ), fluorine (F 2 ), bromine (Br 2 ), iodine (I 2 ), sulfur hexafluoride (SF 6 ), and combinations thereof.

20. The method of claim 1 , wherein the first etching gas comprises nitrogen (N 2 ); hydrogen (H 2 ); nitrous oxide (N 2 O); oxygen (O 2 ) and nitrogen (N 2 ); oxygen (O 2 ) and nitrous oxide (N 2 O); oxygen (O 2 ) and water vapor (H 2 O); oxygen (O 2 ), water vapor (H 2 O), and nitrous oxide (N 2 O); or nitrogen (N 2 ) and hydrogen (H 2 ).

21. The method of claim 1 , wherein the first etching gas comprises a gas selected from the group consisting of nitrogen (N 2 ), hydrogen (H 2 ), nitrous oxide (N 2 O), and water vapor (H 2 O).

22. A method of etching a tungsten doped carbon hard mask on a substrate, the method comprising:
(a) providing the substrate to a process chamber, wherein the substrate comprises the tungsten doped carbon hard mask positioned over an underlying material, and wherein the tungsten doped carbon hard mask and the underlying material each comprise negative features formed therein; and
(b) after (a), simultaneously (i) heating the substrate to a temperature between about 200° C. and about 500° C., and (ii) exposing the tungsten doped carbon hard mask to a plasma generated from a gas mixture of oxygen and chlorine to etch the tungsten doped carbon hard mask by forming tungsten chlorides or tungsten oxychlorides.

23. The method of claim 22 , wherein the plasma is ignited using a power per station of between about 500 W and about 10000 W.

24. The method of claim 22 , wherein a composition of a total flow of gases flowed to the process chamber whe

Assignees

• Lam Res Corp

Inventors

• Yu Yongsik
• Cheung David Wingto
• Ostrowski Kirk J
• Ghosh Nikkon
• Colinjivadi Karthik S
• Tan Samantha
• MUSSELWHITE Nathan
• Kawaguchi Mark Naoshi

Classifications

• H10P76/405

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

• H10P72/3306

  Horizontal transfer of a single workpiece · CPC title

• H10P72/0606

  Position monitoring, e.g. misposition detection or presence detection · CPC title

• H10P72/0468

  comprising a chamber adapted to a particular process · CPC title

• H10P72/0454

  surrounding a central transfer chamber · CPC title