Methods to fill high aspect ratio features on semiconductor substrates with MOCVD cobalt film

Patent metadata

Field	Value
Publication number	US-10600685-B2
Application number	US-201715823422-A
Country	US
Kind code	B2
Filing date	Nov 27, 2017
Priority date	Nov 27, 2016
Publication date	Mar 24, 2020
Grant date	Mar 24, 2020

Abstract

In some embodiments, a method of forming a cobalt layer on a substrate disposed in a process chamber, includes: (a) exposing the substrate to a first process gas comprising a cobalt precursor and a hydrogen containing gas to grow a smooth cobalt layer on a first surface of the substrate and on sidewalls and a bottom surface of a feature formed in the first surface of the substrate; (b) purging the first process gas from the process chamber; and (c) annealing the substrate in a hydrogen atmosphere to fill in voids within the cobalt layer to form a void-free cobalt layer. In some embodiments, plasma treating the substrate in gas under low pressure and/or thermally baking the substrate in gas in an atmosphere under a low pressure, may be performed prior to anneal.

First claim

The invention claimed is:

1. A method of forming a cobalt layer on a substrate disposed in a process chamber, comprising:
(a) exposing the substrate to a first process gas comprising a cobalt precursor and a hydrogen containing gas to grow a smooth cobalt layer on a first surface of the substrate and on sidewalls and a bottom surface of a feature formed in the first surface of the substrate, wherein the feature has an aspect ratio of about 6:1 to about 20:1 and wherein the smooth cobalt layer has a roughness root mean square value over a layer thickness ratio of about 5% to below about 10%;
(b) purging the first process gas from the process chamber; and
(c) annealing the substrate in a hydrogen atmosphere to fill in voids within the cobalt layer to form a void-free cobalt layer.

2. The method of claim 1 , further comprising exposing the substrate to a ruthenium precursor prior to exposing the substrate to the first process gas to form a ruthenium layer on the first surface of the substrate and on sidewalls and the bottom surface of the feature formed in the first surface of the substrate.

3. The method of claim 1 , further comprising plasma treating the substrate in hydrogen gas under low pressure and/or thermally baking the substrate in hydrogen containing gas in an atmosphere under a pressure of less than one ATM.

4. The method of claim 1 , wherein the cobalt precursor is one or more of cobalt carbonyl complexes, cobalt amidinate compounds, cobaltocene compounds, cobalt dienyl complexes, cobalt nitrosyl complexes, dicobalt hexacarbonyl acetyl compounds, cyclopentadienyl cobalt bis(carbonyl) (CpCo(CO) 2 ), tricarbonyl allyl cobalt ((CO) 3 Co(CH 2 CH═CH 2 )), or derivatives thereof, complexes thereof, or combinations thereof.

5. The method of claim 1 , wherein the hydrogen containing gas is ammonia (NH 3 ) gas or hydrogen (H 2 ) gas.

6. The method of claim 1 , further comprising exposing the substrate to a plasma generated from a second process gas comprising hydrogen, nitrogen, argon, helium, or mixtures thereof.

7. The method of claim 1 , further comprising repeating (a)-(c) to fill the feature with a cobalt layer.

8. The method of claim 1 , wherein a ratio of cobalt precursor to hydrogen containing gas is about 0.1% to about 1%.

9. The method of claim 1 , wherein the cobalt precursor is provided at a flow rate of about 20 mgm to about 200 mgm.

10. A method of forming a cobalt layer on a substrate disposed in a process chamber, comprising:
(a) exposing the substrate to a ruthenium precursor to form a ruthenium layer on a first surface of the substrate and on sidewalls and a bottom surface of a feature formed in the first surface of the substrate, wherein the feature has an aspect ratio of about 6:1 to about 20:1;
(b) purging the process chamber of the ruthenium precursor;
(c) exposing the substrate to a first process gas comprising a cobalt precursor and an ammonia (NH 3 ) gas to grow a smooth cobalt layer on the ruthenium layer formed on the first surface of the substrate and on the sidewalls and the bottom surface of the feature formed in the first surface of the substrate;
(d) purging the first process gas from the process chamber;
(e) exposing the substrate to a plasma generated from a second process gas comprising hydrogen, nitrogen, argon, helium, or mixtures thereof and/or thermally baking the substrate in hydrogen containing gas in an atmosphere under a pressure of less than one ATM;
(f) repeating (c)-(e) to fill the feature with a cobalt layer; and
(g) annealing the substrate in a hydrogen atmosphere to fill in voids within the cobalt layer to form a void-free cobalt layer.

11. The method of claim 10 , wherein the ruthenium precursor is one or more of methyl-cyclohexadine ruthenium tricarbonylcyclohexadine, ruthenium tricarbonyl, butadiene ruthenium tricarbonyl, dimethyl butadiene ruthenium tricarbonyl, or modified dines with Ru(CO) 3 .

12. The method of claim 10 , wherein the cobalt precursor is one or more of cobalt carbonyl complexes, cobalt amidinate compounds, cobaltocene compounds, cobalt dienyl complexes, cobalt nitrosyl complexes, dicobalt hexacarbonyl acetyl compounds, cyclopentadienyl cobalt bis(carbonyl) (CpCo(CO) 2 ), tricarbonyl allyl cobalt ((CO) 3 Co(CH 2 CH═CH 2 )), or derivatives thereof, complexes thereof, or combinations thereof.

13. The method of claim 10 , wherein (e) comprises only one of exposing the substrate to a plasma generated from a second process gas comprising hydrogen, nitrogen, argon, helium, or mixtures thereof, and thermally baking the substrate in hydrogen containing gas in an atmosphere under a pressure of less than one ATM.

14. A method of forming a cobalt layer on a substrate disposed in a process chamber, comprising:
(a) exposing the substrate to a ruthenium precursor to form a ruthenium layer on a first surface of the substrate and on sidewalls and a bottom surface of a feature formed in the first surface of the substrate, wherein the feature has an aspect ratio of about 6:1 to about 20:1;
(b) purging the process chamber of the ruthenium precursor;
(c) exposing the substrate to a first process gas comprising a cobalt precursor and a hydrogen containing gas to grow a smooth cobalt layer on the ruthenium layer formed on the first surface of the substrate and on the sidewalls and the bottom surface of the feature formed in the first surface of the substrate;
(d) purging the first process gas from the process chamber; and
(e) annealing the substrate in a hydrogen atmosphere to fill in voids within the cobalt layer to form a void-free cobalt layer.

15. The method of claim 14 , wherein the ruthenium precursor is one or more of methyl-cyclohexadine ruthenium tricarbonylcyclohexadine, ruthenium tricarbonyl, butadiene ruthenium tricarbonyl, dimethyl butadiene ruthenium tricarbonyl, or modified dines with Ru(CO) 3 .

16. The method of claim 14 , wherein the substrate is exposed to the hydrogen containing gas at a flow rate of about 100 sccm to about 2,000 sccm.

17. The method of claim 14 , wherein the cobalt precursor is one or more of cobalt carbonyl complexes, cobalt amidinate compounds, cobaltocene compounds, cobalt dienyl complexes, cobalt nitrosyl complexes, dicobalt hexacarbonyl acetyl compounds, cyclopentadienyl cobalt bis(carbonyl) (CpCo(CO) 2 ), tricarbonyl allyl cobalt ((CO) 3 Co(CH 2 CH═CH 2 )), or derivatives thereof, complexes thereof, or combinations thereof.

18. The method of claim 14 , further comprising exposing the substrate to a plasma generated from a second process gas comprising hydrogen, nitrogen, argon, helium, or mixtures thereof to remove contaminants from the cobalt layer.

19. The method of claim 14 , further comprising repeating (c)-(d) to fill the feature with a cobalt layer.

20. The method of claim 14 , wherein the hydrogen containing gas comprises ammonia, a hydrogen (H 2 ) gas, or a combination thereof.

Assignees

• Applied Materials Inc

Inventors

• Yao Daping
• Lu Jiang
• Xu Can
• Ma Paul F
• Chang Mei

Classifications

• H10W20/4437

  the principal metal being a transition metal · CPC title

• H01L21/76883

  Electricity · mapped topic

• H01L21/76856

  Electricity · mapped topic

• H01L23/53209

  Electricity · mapped topic

• H01L21/76877

  Electricity · mapped topic