Selective deposition of a barrier layer on a metal film

• US 6,809,026 B2
• Filed: 12/18/2002
• Issued: 10/26/2004
• Est. Priority Date: 12/21/2001
• Status: Expired due to Term

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Zhang, Hui, Yoon, Hyungsuk Alexander, Hong, Soonil, Xi, Ming, Yang, Michael X.
• Primary Examiner(s): Zarneke, David A.
• Assistant Examiner(s): SARKAR, ASOK K
• Application Number:
  US10/322,345
• Publication Number:
  US 20030181035A1
• Time in Patent Office: 678 Days
• Field of Search: 438/618, 438/620, 438/622-629, 438/632, 438/633, 438/643, 438/655
• US Class Current: 438/627
• 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 the 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, 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, 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 refractory metal-containing precursor is a tungsten-containing precursor.

3. The method of claim 2, wherein the tungsten-containing precursor is selected from the group consisting of tungsten hexafluoride and tungsten hexacarbonyl.

4. The method of claim 3, wherein the tungsten-containing precursor is tungsten hexafluoride.

5. The method of claim 2, wherein the tungsten-containing precursor is provided at a flow rate from about 10 sccm to about 100 sccm.

6. The method of claim 5, wherein the flow rate is about 30 sccm.

7. The method of claim 5, wherein the tungsten-containing precursor is provided for a duration from about 100 milliseconds to about 1,000 milliseconds.

8. The method of claim 7, wherein the duration is about 500 milliseconds.

9. The method of claim 1, wherein the reducing gas is selected from the group consisting of silane, disilane, dichlorosilane, borane, diborane, triborane, tetraborane, pentaborane, hexaborane, heptaborane, octaborane, nanoborane and decaborane.

10. The method of claim 9, wherein the reducing gas is silane or diborane.

11. The method of claim 1, wherein the reducing gas is provided at a flow rate from about 10 sccm to about 200 sccm.

12. The method of claim 11, wherein the flow rate is about 20 sccm.

13. The method of claim 1, wherein the reducing gas is provided for a duration from about 100 milliseconds to about 1,000 milliseconds.

14. The method of claim 13, wherein the duration is about 500 milliseconds.

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

16. The method of claim 15, wherein the purge gas is selected from the group consisting of helium, argon, nitrogen, hydrogen, and combinations thereof.

17. The method of claim 15, wherein the purge gas is provided at a flow rate from about 300 sccm to about 1,000 sccm.

18. The method of claim 1, wherein the process environment comprises a temperature in a range from about 250°

C. to about 375°

C.

19. The method of claim 18, wherein the temperature is about 300°

C.

20. The method of claim 1, wherein the process environment comprises a pressure in a range from about 1 Torr to about 40 Torr.

21. The method of claim 20, wherein the pressure is about 5 Torr.

22. 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 the 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, 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, and wherein each desposition 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.

23. The method of claim 22, wherein the tungsten-containing precursor is selected from the group consisting of tungsten hexafluoride and tungsten hexacarbonyl.

24. The method of claim 23, wherein the tungsten-containing precursor is tungsten hexafluoride.

25. The method of claim 22, wherein the tungsten-containing precursor is provided at a flow rate from about 10 sccm to about 100 sccm.

26. The method of claim 25, wherein the flow rate is about 30 sccm.

27. The method of claim 22, wherein the tungsten-containing precursor is provided for a duration from about 100 milliseconds to about 1,000 milliseconds.

28. The method of claim 27, wherein the duration is about 500 milliseconds.

29. The method of claim 22, wherein the reducing gas is selected from the group consisting of silane, disilane, dichlorosilane, borane, diborane, triborane, tetraborane, pentaborane, hexaborane, heptaborane, octaborane, nanoborane and decaborane.

30. The method of claim 29, wherein the reducing gas is silane or diborane.

31. The method of claim 22, wherein the reducing gas is provided at a flow rate from about 10 sccm to about 200 sccm.

32. The method of claim 31, wherein the flow rate is about 20 sccm.

33. The method of claim 22, wherein the reducing gas is provided for a duration from about 100 milliseconds to about 1,000 milliseconds.

34. The method of claim 33, wherein the duration is about 500 milliseconds.

35. The method of claim 22 wherein the purge comprises providing a purge gas to the process environment.

36. The method of claim 35, wherein the purge gas is selected from the group consisting of helium, argon, nitrogen, hydrogen, and combinations thereof.

37. The method of claim 35, wherein the purge gas is provided at a flow rate from about 300 sccm to about 1,000 sccm.

38. The method of claim 22, wherein the process environment comprises a temperature in a range from about 250°

C. to about 375°

C.

39. The method of claim 38, wherein the temperature is about 300°

C.

40. The method of claim 22, wherein the process environment comprises a pressure in a range from about 1 Torr to about 40 Torr.

41. The method of claim 40, wherein the pressure is about 5 Torr.

42. 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;

exposing the substrate including the dielectric material to a cyclical deposition process comprising a metal-containing precursor and a reducing gas;

forming the barrier layer on the exposed metal features while not forming the barrier layer on the dielectric material; and

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

43. The method of claim 42, wherein the barrier layer comprises tungsten.