Pulsed nucleation deposition of tungsten layers

• US 20030127043A1
• Filed: 07/12/2002
• Published: 07/10/2003
• Est. Priority Date: 07/13/2001
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Yoo, John Hyun, Lu, Xinliang, Xi, Ming, Mak, Alfred W., Jackson, Robert L., Lai, Ken Kaung, Jian, Ping
• Granted Patent: US 7,211,144 B2
• Time in Patent Office: Days
• US Class Current: 117/95
• CPC Class Codes: C23C 16/14 Deposition of only one other metal element
• CPC Class Codes: C23C 16/45523 Pulsed gas flow or change of composition over time
• CPC Class Codes: C23C 16/45525 Atomic layer deposition [ALD]
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 29/02 Elements
• CPC Class Codes: H01L 21/28562 Selective deposition

Abstract

A method of forming a tungsten nucleation layer using a sequential deposition process. The tungsten nucleation layer is formed by reacting pulses of a tungsten-containing precursor and a reducing gas in a process chamber to deposit tungsten on the substrate. Thereafter, reaction by-products generated from the tungsten deposition are removed from the process chamber. After the reaction by-products are removed from the process chamber, a flow of the reducing gas is provided to the process chamber to react with residual tungsten-containing precursor remaining therein. Such a deposition process forms tungsten nucleation layers having good step coverage. The sequential deposition process of reacting pulses of the tungsten-containing precursor and the reducing gas, removing reaction by-products, and than providing a flow of the reducing gas to the process chamber may be repeated until a desired thickness for the tungsten nucleation layer is formed.

Claims

1. A method of depositing a tungsten nucleation layer on a substrate in a process chamber, comprising:

(a) providing a flow of a gas mixture comprising a tungsten-containing precursor and a reducing gas to a process chamber to deposit tungsten on a substrate;

(b) removing reaction by-products generated during step (a) from the process chamber;

(c) providing a flow of the reducing gas to the process chamber to react with residual tungsten-containing precursor in the process chamber and deposit tungsten on the substrate; and

(d) removing reaction by-products generated during step (c) from the process chamber.

2. The method of claim 1 further comprising repeating steps (a)-(d) until a tungsten nucleation layer thickness of up to about 500 Å

is deposited.

3. The method of claim 1 wherein the tungsten-containing precursor comprises tungsten hexafluoride (WF₆).

4. The method of claim 1 wherein the reducing gas in steps (a) and (c) is selected from the group consisting of silane (SiH₄), disilane (Si₂H₆), borane (BH₃), diborane (B₂H₆), and combinations thereof.

5. The method of claim 1 wherein the gas mixture of step (a) is provided for a time period of about 0.1 seconds to about 10 seconds.

6. The method of claim 1 wherein the tungsten-containing precursor and the reducing gas are provided in a tungsten-containing precursor:

reducing gas ratio of about 1;

1 to about 5;

1.

7. The method of claim 1 wherein the reaction by-products in steps (b) and (d) are removed from the process chamber by providing a purge gas thereto and evacuating both the purge gas and the reaction by-products therefrom.

8. The method of claim 7 wherein the purge gas comprises on or more gases selected from the group consisting of nitrogen (N₂), helium (He), argon (Ar), xenon (Xe) and neon (Ne).

9. The method of claim 7 wherein the purge gas is provided to the process chamber for up to about 10 seconds.

10. The method of claim 1 wherein the reducing gas of step (c) is provided to the process chamber for up to about 10 seconds.

11. The method of claim 1 wherein time periods for steps (b) and (c) overlap.

12. A method of depositing a tungsten nucleation layer on a substrate in a process chamber, comprising:

(a) providing a flow of a gas mixture comprising a tungsten-containing precursor and a reducing gas to a process chamber for about 0.1 seconds to about 10 seconds to deposit tungsten on a substrate;

(b) removing reaction by-products generated during step (a) by providing a purge gas to the process chamber and evacuating both the purge gas and the reaction by-products therefrom;

(c) providing a flow of the reducing gas to the process chamber for up to about 10 seconds to react with residual tungsten-containing precursor in the process chamber and deposit tungsten on the substrate;

(d) removing reaction by-products generated during step (c) by providing a purge gas to the process chamber and evacuating both the purge gas and the reaction by-products therefrom; and

(e) repeating steps (a)-(d) until a tungsten nucleation layer thickness of up to about 500 Å

is deposited.

13. The method of claim 12 wherein the tungsten-containing precursor comprises tungsten hexafluoride (WF₆).

14. The method of claim 12 wherein the reducing gas in steps (a) and (c) is selected from the group consisting of silane (SiH₄), disilane (Si₂H₆), borane (BH₃), diborane (B₂H₆), and combinations thereof.

15. The method of claim 12 wherein the tungsten-containing precursor and the reducing gas are provided in a tungsten-containing precursor:

reducing gas ratio of about 1;

1 to about 5;

1.

16. The method of claim 12 wherein the purge gas of steps (b) and (d) comprises one or more gases selected from the group consisting of nitrogen (N₂), helium (He), argon (Ar), xenon (Xe) and neon (Ne).

17. The method of claim 12 wherein the purge gas of steps (b) and (d) is provided to the process chamber for up to about 10 seconds.

18. The method of claim 12 wherein time periods for steps (b) and (c) overlap.

19. A method of depositing a tungsten nucleation layer on a substrate in a process chamber, comprising:

(a) providing a flow of a gas mixture comprising tungsten hexafluoride (WF₆) and silane (SiH₄) to a process chamber for about 0.1 seconds to about 10 seconds to deposit tungsten on a substrate;

(b) removing reaction by-products generated during step (a) by providing a purge gas to the process chamber and evacuating both the purge gas and the reaction by-products therefrom;

(c) providing a flow of silane (SiH₄) to the process chamber for up to about 10 seconds to react with residual tungsten hexafluoride (WF₆) in the process chamber and deposit tungsten on the substrate;

(d) removing reaction by-products generated during step (c) by providing a purge gas to the process chamber and evacuating both the purge gas and the reaction by-products therefrom; and

(e) repeating steps (a)-(d) until a tungsten nucleation layer thickness of up to about 500 Å

is deposited.

20. The method of claim 19 wherein the tungsten hexafluoride (WF₆) and the silane (SiH₄) are provided in a tungsten hexafluoride (WF₆):

silane (SiH₄) ratio of about 1;

1 to about 5;

1.

21. The method of claim 19 wherein the purge gas of steps (b) and (d) comprises one or more gases selected from the group consisting of nitrogen (N₂), helium (He), argon (Ar), xenon (Xe) and neon (Ne).

22. The method of claim 19 wherein the purge gas of steps (b) and (d) is provided to the process chamber for up to about 10 seconds.

23. The method of claim 19 wherein time periods for steps (b) and (c) overlap.