Copper interconnect barrier layer structure and formation method

• US 20030059980A1
• Filed: 09/25/2001
• Published: 03/27/2003
• Est. Priority Date: 09/25/2001
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Chang, Mei, Cao, Wei, Chen, Ling, Ganguli, Seshadri, Marcadal, Christophe, Mosely, Roderick C.
• Granted Patent: US 6,607,976 B2
• Time in Patent Office: Days
• US Class Current: 438/118
• CPC Class Codes: H01L 21/28556 by chemical means, e.g. CVD, LPCVD, PECVD, laser CVD H01L21/28518 - H01L21/28537 and H01L21/28568 take precedence
• CPC Class Codes: H01L 21/28562 Selective deposition
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76846 Layer combinations
• CPC Class Codes: H01L 21/76876 for deposition from the gas phase, e.g. CVD
• CPC Class Codes: H01L 23/53238 Additional layers associated with copper layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A method for forming a tungsten-containing copper interconnect barrier layer (e.g., a tungsten [W] or tungsten-nitride [W_XN] copper interconnect barrier layer) on a substrate with a high (e.g., greater than 30%) sidewall step coverage and ample adhesion to underlying dielectric layers. The method includes first depositing a thin titanium-nitride (TiN) or tantalum nitride (TaN) nucleation layer on the substrate, followed by the formation of a tungsten-containing copper interconnect barrier layer (e.g., a W or W_XN copper interconnect barrier layer) overlying the substrate. The tungsten-containing copper interconnect barrier layer can, for example, be formed using a Chemical Vapor Deposition (CVD) technique that employs a fluorine-free tungsten-containing gas (e.g., tungsten hexacarbonyl [W(CO)₆]) or a WF₆-based Atomic Layer Deposition (ALD) technique. The presence of a thin TiN (or TaN) nucleation layer facilitates the formation of a tungsten-containing copper interconnect barrier layer with a sidewall step coverage of greater than 30% and ample adhesion to dielectric layers. A copper interconnect barrier layer structure includes a thin titanium-nitride (TiN) (or tantalum nitride [TaN]) nucleation layer disposed directly on the dielectric substrate (e.g., a single or dual-damascene copper interconnect dielectric substrate). The copper interconnect barrier layer structure also includes a tungsten-containing copper interconnect barrier layer (e.g., a W or W_XN copper interconnect barrier layer) formed on the thin TiN (or TaN) nucleation layer using, for example, a CVD technique that employs a fluorine-free tungsten-containing gas (e.g., [W(CO)₆]) or a WF₆-based ALD technique.

Claims

1. A method for the formation of a copper interconnect barrier layer on a substrate comprising:

depositing one of a thin titanium-nitride nucleation layer and a thin tantalum-nitride nucleation layer on the substrate; and

forming a tungsten-containing copper interconnect barrier layer overlying the substrate.

2. The method of claim 1 wherein the forming step uses a Chemical Vapor Deposition (CVD) technique that employs a fluorine-free tungsten-containing gas.

3. The method of claim 1 wherein the forming step uses a WF₆-based Atomic Layer Deposition (ALD) technique.

4. The method of claim 1, further comprising during the depositing step, depositing one of a titanium-nitride nucleation layer and a tantalum-nitride nucleation layer directly on a dual-damascene copper interconnect substrate.

5. The method of claim 4, further comprising during the depositing step, depositing one of a titanium-nitride nucleation layer and a tantalum-nitride nucleation layer directly on the dual-damascene copper interconnect substrate with at least one trench formed therein.

6. The method of claim 1, further comprising during the depositing step, depositing one of a titanium-nitride nucleation layer and a tantalum-nitride nucleation layer directly on a single-damascene copper interconnect substrate.

7. The method of claim 1, further comprising after the forming step, depositing a copper interconnect layer on the tungsten-containing copper interconnect barrier layer.

8. The method of claim 1, wherein the forming step forms a tungsten copper interconnect barrier layer.

9. The method of claim 8 wherein the depositing step deposits a thin titanium-nitride nucleation layer on the substrate.

10. The method of claim 9, wherein the forming step results in the formation of a titanium-nitride-tungsten interfacial layer between the tungsten layer and the substrate.

11. The method of claim 2, wherein the forming step uses a CVD technique that employs tungsten hexacarbonyl as the fluorine-free tungsten-containing gas to form the tungsten copper interconnect barrier layer.

12. The method of claim 11, wherein the forming step uses a CVD technique conducted at a temperature in the range of 300°

C. to 500°

C. and a pressure in the range of 10 milli-Torr to 200 milli-Torr.

13. The method of claim 1, wherein the forming step forms a tungsten-nitride copper interconnect barrier layer.

14. The method of claim 13 wherein the depositing step deposits a thin titanium-nitride nucleation layer on the substrate.

15. The method of claim 14, wherein the forming step results in the formation of a titanium-nitride-tungsten interfacial layer between the tungsten-nitride copper interconnect barrier layer and the substrate.

16. The method of claim 13, wherein the forming step uses a CVD technique that employs tungsten hexacarbonyl and ammonia to from the tungsten-nitride copper interconnect barrier layer.

17. The method of claim 16, wherein the forming step uses a CVD technique conducted at a temperature in the range of 250°

C. to 400°

C. and a pressure of approximately 100 milli-Torr to 50 Torr.

18. The method of claim 1 wherein the depositing step deposits a thin titanium-nitride nucleation layer on the substrate.

19. The method of claim 18, further comprising during the depositing step, depositing a thin titanium-nitride nucleation layer with a thickness in the range of 3 angstroms to 20 angstroms.

20. The method of claim 19, further comprising during the depositing step, depositing a thin titanium-nitride nucleation layer using thermal decomposition of a titanium and nitrogen-containing compound.

21. The method of claim 20, further comprising during the depositing step, depositing a thin titanium-nitride nucleation layer using thermal decomposition of tetradimethyl-amino-titanium (TDMAT).

22. The method of claim 20, further comprising during the depositing step, depositing a thin titanium-nitride nucleation layer using thermal decomposition of tetradiethyl-amino-titanium (TDEAT).

23. The method of claim 1, wherein the depositing and forming steps are conducted without exposing the thin TiN nucleation layer to atmospheric conditions.

24. The method of claim 1 wherein the depositing step deposits a thin tantalum-nitride nucleation layer on the substrate.

25. The method of claim 24, further comprising during the depositing step, depositing a thin tantalum nitride nucleation layer using thermal decomposition of a tantalum and nitrogen-containing compound.

26. The method of claim 25, further comprising during the depositing step, depositing a thin tantalum-nitride nucleation layer using thermal decomposition of tantalum containing chemical selected from the group consisting of penta-dimethyl-amino-tantalum (PDMAT) and penta-ethyl-methyl-amino-tantalum (PEMAT).

27. A copper interconnect barrier layer structure on a dielectric substrate comprising:

a thin titanium-nitride nucleation layer disposed directly on the dielectric substrate;

a tungsten-containing copper interconnect barrier layer formed on the thin titanium-nitride nucleation layer; and

a copper interconnect layer on the tungsten-containing copper interconnect barrier layer.

28. The copper interconnect barrier layer structure of claim 27, further comprising a titanium-nitride-tungsten transition layer between the titanium-nitride layer and the tungsten-containing copper interconnect barrier layer.

29. The copper interconnect barrier layer structure of claim 27, wherein the tungsten-containing layer is a tungsten copper interconnect barrier layer.

30. The copper interconnect barrier layer structure of claim 27, wherein the tungsten-containing layer is a tungsten-nitride copper interconnect barrier layer.

31. The copper interconnect barrier layer structure of claim 27, wherein the dielectric substrate has a feature with at least one sidewall and the tungsten-containing copper interconnect barrier layer has a sidewall step coverage of at least 30%.

32. A method for the formation of a copper interconnect barrier layer on a substrate comprising:

depositing one of a thin tantalum-nitride nucleation layer and a thin titanium-nitride nucleation layer on the substrate; and

forming a tungsten-containing copper interconnect barrier layer overlying the substrate using a Chemical Vapor Deposition (CVD) technique that employs a fluorine-free tungsten-containing gas.

33. A method for the formation of a copper interconnect barrier layer on a substrate comprising:

depositing one of a thin tantalum-nitride nucleation layer and a thin titanium-nitride nucleation layer on the substrate; and

forming a tungsten-containing copper interconnect barrier layer overlying the substrate using a Chemical Vapor Deposition (CVD) technique that employs tungsten hexacarbonyl.

34. A method for the formation of a copper interconnect barrier layer on a substrate comprising:

depositing one of a thin tantalum-nitride nucleation layer and a thin titanium-nitride nucleation layer on the substrate;

forming a tungsten-containing copper interconnect barrier layer overlying the substrate using a Chemical Vapor Deposition (CVD) technique that employs tungsten hexacarbonyl; and

depositing a copper interconnect layer on the tungsten-containing copper interconnect barrier layer.

35. A method for the formation of a copper interconnect barrier layer on a substrate comprising:

depositing one of a thin tantalum-nitride nucleation layer and a thin titanium-nitride nucleation layer on the substrate; and

forming a tungsten-containing copper interconnect barrier layer overlying the substrate using a WF₆-based Atomic Layer Deposition (ALD) technique.

36. A method for the formation of a copper interconnect barrier layer on a substrate comprising:

depositing one of a thin tantalum-nitride nucleation layer and a thin titanium-nitride nucleation layer on the substrate;

forming a tungsten-containing copper interconnect barrier layer overlying the substrate using a WF₆-based Atomic Layer Deposition (ALD) technique; and

depositing a copper interconnect layer on the tungsten-containing copper interconnect barrier layer.

37. A method for the formation of a copper interconnect barrier layer on a substrate comprising:

depositing one of a thin tantalum-nitride nucleation layer and a thin titanium-nitride nucleation layer on the substrate;

forming a tungsten-containing copper interconnect barrier layer overlying the substrate using a WF₆-based Atomic Layer Deposition (ALD) technique conducted at a temperature in the range of 200°

C. to 400°

C. and a pressure in the range of 0.1 Torr to 50 Torr; and

depositing a copper interconnect layer on the tungsten-containing copper interconnect barrier layer.