Selective deposition of abarrier layer on a metal film

• US 20030181035A1
• Filed: 12/18/2002
• Published: 09/25/2003
• Est. Priority Date: 12/21/2001
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Zhang, Hui, Xi, Ming, Yoon, Hyungsuk Alexander, Yang, Michael X., Hong, Soonil
• Granted Patent: US 6,809,026 B2
• Time in Patent Office: Days
• US Class Current: 438/653
• CPC Class Codes: C23C 16/45525 Atomic layer deposition [ALD]
• CPC Class Codes: H01L 21/28562 Selective deposition
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76849 the layer being positioned on top of the main fill metal

Abstract

A method to selectively deposit a barrier layer on a metal film formed on a substrate is disclosed. The barrier layer is selectively deposited on the metal film using a cyclical deposition process including a predetermined number of deposition cycles followed by a purge step. Each deposition cycle comprises alternately adsorbing a refractory metal-containing precursor and a reducing gas on the metal film formed on the substrate in a process chamber.

Claims

1. A method of selectively forming a barrier layer on a metal feature, comprising:

providing a substrate having exposed metal features surrounded by a dielectric material to a process environment;

forming a barrier layer on the exposed metal features using a cyclical deposition process wherein the cyclical deposition process includes a predetermined number of deposition cycles followed by a purge step, and wherein each deposition cycle comprises alternately providing a refractory metal-containing precursor and a reducing gas to the process environment; and

repeating the cyclical deposition process until a desired thickness for the barrier layer is formed.

2. The method of claim 1 wherein the predetermined number of deposition cycles is selected to start forming the barrier layer on the exposed metal features but be less than the number of deposition cycles needed to start forming the barrier layer on the dielectric material.

3. The method of claim 1 wherein the refractory metal-containing precursor is a tungsten-containing precursor.

4. The method of claim 3 wherein the tungsten-containing precursor is selected from the group consisting of tungsten hexafluoride (WF₆) and tungsten hexacarbonyl (W(CO)₆)

5. The method of claim 4 wherein the tungsten-containing precursor is tungsten hexafluoride (WF₆).

6. The method of claim 3 wherein the tungsten-containing precursor is provided at about 10 sccm (standard cubic centimeters per minute) to about 100 sccm.

7. The method of claim 6 wherein the tungsten-containing precursor is provided at about 30 sccm.

8. The method of claim 3 wherein the tungsten-containing precursor is provided for a duration of about 100 milliseconds to about 1000 milliseconds.

9. The method of claim 8 wherein the tungsten-containing precursor is provided for a duration of about 500 milliseconds.

10. The method of claim 1 wherein the reducing gas is selected from the group consisting of silane (SiH₄), disilane (Si₂H₆), dichlorosilane (SiCI₂H₂), borane (BH₃), diborane (B₂H₆), triborane (B₃H₉), tetraborane (B₄H₁₂), pentaborane (B₅H₁₅), hexaborane (B₆H₁₈), heptaborane (B₇H₂₁), octaborane (B₈H₂₄), nanoborane (B₉H₂₇) and decaborane (B₁₀H₃₀).

11. The method of claim 10 wherein the reducing gas is silane (SiH₄).

12. The method of claim 1 wherein the reducing gas is provided at about 10 sccm (standard cubic centimeters per minute) to about 200 sccm.

13. The method of claim 12 wherein the reducing gas is provided at about 20 sccm.

14. The method of claim 1 wherein the reducing gas is provided for a duration of about 100 milliseconds to about 1000 milliseconds.

15. The method of claim 14 wherein the reducing gas is provided for a duration of about 500 milliseconds.

16. The method of claim 1 wherein the purge step comprises providing a purge gas to the process environment.

17. The method of claim 16 wherein the purge gas is selected from the group consisting of helium (He), argon (Ar), nitrogen (N₂), hydrogen (H₂), and combinations thereof.

18. The method of claim 16 wherein the purge gas is provided at about 300 sccm to about 1000 sccm.

19. The method of claim 1 wherein the process environment comprises a temperature of about 250°

C. to about 375°

C.

20. The method of claim 19 wherein the process environment comprises a temperature of about 300°

C.

21. The method of claim 1 wherein the process environment comprises a pressure of about 1 torr to about 40 torr.

22. The method of claim 21 wherein the process environment comprises a pressure of about 5 torr.

23. A method of selectively forming a tungsten barrier layer on a metal feature, comprising:

providing a substrate having exposed metal features surrounded by a dielectric material to a process environment;

forming a tungsten barrier layer on the exposed metal features using a cyclical deposition process wherein the cyclical deposition process includes a predetermined number of deposition cycles followed by a purge step, and wherein each deposition cycle comprises alternately providing a tungsten-containing precursor and a reducing gas to the process environment; and

repeating the cyclical deposition process until a desired thickness for the tungsten barrier layer is formed.

24. The method of claim 23 wherein the predetermined number of deposition cycles is selected to start forming the tungsten barrier layer on the exposed metal features but be less than the number of deposition cycles needed to start forming the tungsten barrier layer on the dielectric material.

25. The method of claim 23 wherein the tungsten-containing precursor is selected from the group consisting of tungsten hexafluoride (WF₆) and tungsten hexacarbonyl (W(CO)₆).

26. The method of claim 25 wherein the tungsten-containing precursor is tungsten hexafluoride (WF₆).

27. The method of claim 23 wherein the tungsten-containing precursor is provided at about 10 sccm (standard cubic centimeters per minute) to about 100 sccm.

28. The method of claim 27 wherein the tungsten-containing precursor is provided at about 30 sccm.

29. The method of claim 23 wherein the tungsten-containing precursor is provided for a duration of about 100 milliseconds to about 1000 milliseconds.

30. The method of claim 29 wherein the tungsten-containing precursor is provided for a duration of about 500 milliseconds.

31. The method of claim 23 wherein the reducing gas is selected from the group consisting of silane (SiH₄), disilane (Si₂H₆), dichlorosilane (SiCl₂H₂), borane (BH₃), diborane (B₂H₆), triborane (B₃H₉), tetraborane (B₄H₁₂), pentaborane (B₅H₁₅), hexaborane (B₆H₁₈), heptaborane (B₇H₂₁), octaborane (B₈H₂₄), nanoborane (B₉H₂₇) and decaborane (B₁₀H₃₀).

32. The method of claim 31 wherein the reducing gas is silane (SiH₄).

33. The method of claim 23 wherein the reducing gas is provided at about 10 sccm (standard cubic centimeters per minute) to about 200 sccm.

34. The method of claim 33 wherein the reducing gas is provided at about 20 sccm.

35. The method of claim 23 wherein the reducing gas is provided for a duration of about 100 milliseconds to about 1000 milliseconds.

36. The method of claim 35 wherein the reducing gas is provided for a duration of about 500 milliseconds.

37. The method of claim 23 wherein the purge step comprises providing a purge gas to the process environment.

38. The method of claim 37 wherein the purge gas is selected from the group consisting of helium (He), argon (Ar), nitrogen (N₂), hydrogen (H₂), and combinations thereof.

39. The method of claim 37 wherein the purge gas is provided at about 300 sccm to about 1000 sccm.

40. The method of claim 23 wherein the process environment comprises a temperature of about 250°

C. to about 375°

C.

41. The method of claim 40 wherein the process environment comprises a temperature of about 300°

C.

42. The method of claim 23 wherein the process environment comprises a pressure of about 1 torr to about 40 torr.

43. The method of claim 42 wherein the process environment comprises a pressure of about 5 torr.