Deposition of tungsten films

• US 20030153181A1
• Filed: 02/11/2002
• Published: 08/14/2003
• Est. Priority Date: 02/11/2002
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Fang, Hongbin, Yang, Michael X., Yoon, Hyungsuk A.
• Granted Patent: US 6,827,978 B2
• Time in Patent Office: Days
• US Class Current: 438/685
• CPC Class Codes: C23C 16/0281 of metallic sub-layers C23C16/029 takes precedence
• CPC Class Codes: C23C 16/14 Deposition of only one other metal element
• CPC Class Codes: C23C 16/45525 Atomic layer deposition [ALD]
• CPC Class Codes: H01L 21/28562 Selective deposition
• CPC Class Codes: H01L 21/28568 the conductive layers comprising transition metals H01L21/28518 takes precedence
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material

Abstract

A method of forming a composite tungsten film on a substrate is described. The composite tungsten film comprises sequentially deposited tungsten nucleation layers and tungsten bulk layers. Each of the tungsten nucleation layers and the tungsten bulk layers have a thickness less than about 300 Å. The tungsten nucleation layers and the tungsten bulk layers are formed one over the other until a desired thickness for the composite tungsten film is achieved. The resulting composite tungsten film exhibits good film morphology. The tungsten nucleation layers may be formed using a cyclical deposition process by alternately adsorbing a tungsten-containing precursor and a reducing gas on the substrate. The tungsten bulk layers may be formed using a chemical vapor deposition (CVD) process by thermally decomposing a tungsten-containing precursor.

Claims

1. A method of forming a composite tungsten film, comprising:

sequentially depositing tungsten nucleation layers and tungsten bulk layers on a substrate to form a composite tungsten layer, wherein each of the tungsten nucleation layers and the tungsten bulk layers have a thickness less than about 300 Å

.

2. The method of claim 1 wherein each of the tungsten bulk layers has a thickness within a range of about 150 Å

to about 250 Å

.

3. The method of claim 1 wherein each of the tungsten nucleation layers has a thickness within a range of about 15 Å

to about 50 Å

.

4. The method of claim 1 wherein the composite tungsten film has a thickness within a range of about 500 Å

to about 3000 Å

.

5. The method of claim 1 wherein each of the tungsten nucleation layers is deposited by alternately adsorbing a tungsten-containing precursor and a reducing gas on the substrate.

6. The method of claim 5 wherein the tungsten-containing precursor is selected from the group consisting of tungsten hexafluoride (WF₆) and tungsten carbonyl (W(CO)₆).

7. The method of claim 5 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).

8. The method of claim 5 wherein the tungsten nucleation layer is deposited at a temperature within a range of about 200°

C. to about 400°

C.

9. The method of claim 5 wherein the tungsten nucleation layer is deposited at a pressure within a range of about 1 torr to about 10 torr.

10. The method of claim 1 wherein each of the tungsten bulk layers is deposited by thermally decomposing a gas mixture comprising a tungsten-containing precursor.

11. The method of claim 10 wherein the tungsten-containing precursor is selected from the group consisting of tungsten hexafluoride (WF₆) and tungsten carbonyl (W(CO)₆).

12. The method of claim 10 wherein the tungsten bulk layer is deposited at a temperature within a range of about 450°

C. to about 650°

C.

13. The method of claim 10 wherein the tungsten bulk layer is deposited at a pressure within a range of about 10 torr to about 30 torr.

14. The method of claim 1 wherein the tungsten nucleation layers are deposited in a different process chamber than that used to deposit the tungsten bulk layers.

15. The method of claim 1 wherein the tungsten nucleation layers are deposited in the same process chamber used to deposit the tungsten bulk layers.

16. A method of forming a composite tungsten film, comprising:

sequentially depositing tungsten nucleation layers and tungsten bulk layers on a substrate to form a composite tungsten layer, wherein each of the tungsten nucleation layers is deposited by alternately adsorbing a tungsten-containing precursor and a reducing gas on the substrate and wherein each of the tungsten bulk layers is deposited by thermally decomposing a gas mixture comprising a tungsten-containing precursor.

17. The method of claim 16 wherein each of the tungsten bulk layers has a thickness within a range of about 150 Å

to about 250 Å

.

18. The method of claim 16 wherein each of the tungsten nucleation layers has a thickness within a range of about 15 Å

to about 50 Å

.

19. The method of claim 16 wherein the composite tungsten film has a thickness within a range of about 500 Å

to about 3000 Å

.

20. The method of claim 16 wherein the tungsten-containing precursor is selected from the group consisting of tungsten hexafluoride (WF₆) and tungsten carbonyl (W(CO)₆).

21. The method of claim 16 wherein the reducing compound 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).

22. The method of claim 16 wherein the tungsten nucleation layer is deposited at a temperature within a range of about 200°

C. to about 400°

C.

23. The method of claim 16 wherein the tungsten nucleation layer is deposited at a pressure within a range of about 1 torr to about 10 torr.

24. The method of claim 16 wherein the tungsten bulk layer is deposited at a temperature within a range of about 450°

C. to about 650°

C.

25. The method of claim 16 wherein the tungsten bulk layer is deposited at a pressure within a range of about 10 torr to about 30 torr.

26. The method of claim 16 wherein the tungsten nucleation layers are deposited in a different process chamber than that used to deposit the tungsten bulk layers.

27. The method of claim 16 wherein the tungsten nucleation layers are deposited in the same process chamber used to deposit the tungsten bulk layers.

28. A method of forming a composite tungsten film for use in a memory cell, comprising:

providing a substrate structure, wherein the substrate structure includes an insulating material having at least one aperture therein; and

sequentially depositing tungsten nucleation layers and tungsten bulk layers on a substrate to form a composite tungsten layer, wherein each of the tungsten nucleation layers and the tungsten bulk layers have a thickness less than about 300 Å

.

29. The method of claim 28 wherein each of the tungsten bulk layers has a thickness within a range of about 150 Å

to about 250 Å

.

30. The method of claim 28 wherein each of the tungsten nucleation layers has a thickness within a range of about 15 Å

to about 50 Å

.

31. The method of claim 28 wherein the composite tungsten film has a thickness within a range of about 500 Å

to about 3000 Å

.

32. The method of claim 28 wherein each of the tungsten nucleation layers is deposited by alternately adsorbing a tungsten-containing precursor and a reducing gas on the substrate.

33. The method of claim 32 wherein the tungsten-containing precursor is selected from the group consisting of tungsten hexafluoride (WF₆) and tungsten carbonyl (W(CO)₆).

34. The method of claim 32 wherein the reducing compound 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).

35. The method of claim 32 wherein the tungsten nucleation layer is deposited at a temperature within a range of about 200°

C. to about 400°

C.

36. The method of claim 32 wherein the tungsten nucleation layer is deposited at a pressure within a range of about 1 torr to about 10 torr.

37. The method of claim 28 wherein each of the tungsten bulk layers is deposited by thermally decomposing a gas mixture comprising a tungsten-containing precursor.

38. The method of claim 37 wherein the tungsten-containing precursor is selected from the group consisting of tungsten hexafluoride (WF₆) and tungsten carbonyl (W(CO)₆).

39. The method of claim 37 wherein the tungsten bulk layer is deposited at a temperature within a range of about 450°

C. to about 650°

C.

40. The method of claim 37 wherein the tungsten bulk layer is deposited at a pressure within a range of about 10 torr to about 30 torr.

41. The method of claim 32 wherein the tungsten nucleation layers are deposited in a different process chamber than that used to deposit the tungsten bulk layers.

42. The method of claim 32 wherein the tungsten nucleation layers are deposited in the same process chamber used to deposit the tungsten bulk layers.

43. The method of claim 32 wherein the composite tungsten film is used for at least one of word and bit metallization in the memory cell.