Damascene metal interconnects using highly directional deposition of barrier and/or seed layers including (III) filling metal

• US 6,281,121 B1
• Filed: 03/06/1998
• Issued: 08/28/2001
• Est. Priority Date: 03/06/1998
• Status: Expired due to Term

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: Advanced Micro Devices, Inc.
• Inventors: Brown, Dirk Dewar, Nogami, Takeshi, Morales, Guarionex
• Primary Examiner(s): Bowers, Charles
• Assistant Examiner(s): Brewster, William M.
• Application Number:
  US09/036,127
• Time in Patent Office: 1,271 Days
• Field of Search: 438/633, 438/637, 438/638, 438/672, 257/758
• US Class Current: 438/672
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric

Abstract

An improved damascene metal interconnect for use in a semiconductor integrated circuit. By using highly directional deposition of barrier and/or seed layers the texture of the damascene structure is improved. A first barrier metal layer is deposited in a standard deposition manner, and a second barrier metal is then applied in a highly directional manner. For example, tungsten, titanium and tantalum nitrides can be used as barrier metals. Copper or aluminum based metal is deposited over the second barrier metal, and is then polished by using a chemical mechanical polish. A passivation layer can then be deposited over the interconnect.

Claims

1. A damascene metal interconnect for a semiconductor integrated circuit, comprising:

a dielectric material;

a damascene structure etched in the dielectric material;

a first barrier material deposited on the damascene structure;

a second barrier material applied to the first barrier material using a highly directional deposition technique, wherein said second barrier material is a refractory metal; and

a metalization layer deposited over the damascene structure, wherein said metalization layer consists essentially of a (111) crystal oriented structure, and wherein the metalization layer comprises a member selected from the group consisting of copper, aluminum, and alloys thereof.

2. The improved damascene metal interconnect defined in claim 1, wherein the metalization layer comprises aluminum, or an aluminum alloy.

3. The improved damascene metal interconnect defined in claim 1, wherein the metalization layer comprises copper, or a copper alloy.

4. The improved damascene metal interconnect defined in claim 1, wherein the first barrier material is selected from the group consisting of titanium nitride, tantalum nitride, and tungsten nitride.

5. The improved damascene metal interconnect defined in claim 1, wherein the metalization layer is polished using chemical mechanical polish.

6. The improved damascene metal interconnect defined in claim 1, further comprising an overhang on the side walls of the damascene structure.

7. The improved damascene metal interconnect defined in claim 1, wherein the damascene structure has a barrel shaped appearance.

8. The improved damascene metal interconnect defined in claim 1, further comprising an enhanced fill region disposed at the bottom of the damascene structure.

9. The improved damascene metal interconnect defined in claim 1, further comprising, a passivation layer deposited over the metalization layer.

10. A semiconductor device formed on a semiconductor substrate and comprising:

a dielectric material formed on the semiconductor substrate;

a damascene structure formed in the dielectric material and having a bottom and a side wall;

a first metallic barrier layer deposited on the dielectric material including on the bottom and the side wall of the damascene structure;

a second metallic barrier layer formed by directional deposition on the dielectric material to substantially cover the bottom of the damascene structure with substantially no coverage of the side wall of the damascene structure, wherein said second metallic barrier layer is a refractory metal; and

a metalization layer deposited on the dielectric material and filling the damascene structure, wherein the metalization layer consists essentially of a (111) crystal-oriented structure induced by the second metallic barrier layer, and wherein the metalization layer comprises a member selected from the group consisting of copper, aluminum, and alloys thereof.

11. The semiconductor device of claim 10 wherein the damascene structure comprises a trench etched in a surface of the dielectric material.

12. A semiconductor device of claim 10 wherein the first metallic barrier layer is selected from the group consisting of titanium nitride, tantalum nitride and tungsten nitride.

13. The semiconductor device of claim 10 further comprising:

an overhang formed on the side wall of the damascene structure to minimize side wall coverage of the second metallic barrier layer in the damascene structure.

14. The semiconductor device of claim 10 wherein the side wall and bottom of the damascene structure are barrel shaped.

15. The semiconductor device of claim 14 wherein the metallization layer is formed in part by growth from the bottom of the damascene structure.

16. The semiconductor device of claim 14 wherein the metallization layer comprises copper formed by depositing a physical vapor deposition (PVD) copper seed followed by copper electroplating.

17. A damascene metal interconnect with improved (111) texture that is formed in a dielectric material used for a semiconductor integrated circuit, the damascene metal interconnect comprising:

a damascene structure formed in the dielectric material to have a bottom and a side wall;

a refractory metal having texture enhancement properties, wherein the refractory metal is applied to the bottom of the damascene structure using a highly directional deposition technique to achieve almost no coverage of the side wall;

a barrier material having good diffusion barrier properties but poor texture enhancement properties applied with maximum step coverage on the bottom and the side wall of the damascene structure; and

a metalization layer applied to overlie the refractory metal and the barrier material, wherein the metalization layer has (111) texture induced by the refractory metal.

18. The damascene metal interconnect of claim 17 wherein the refractory metal is applied to contact the dielectric material that forms the bottom of the damascene structure.

19. The damascene metal interconnect of claim 17 wherein the barrier material is applied to contact the dielectric material that forms the bottom and the side wall of the damascene structure.

20. The damascene metal interconnect of claim 19, wherein the metalization layer is applied to contact the barrier material on the side wall of the damascene structure and is separated by the refractory metal from the barrier material on the bottom of the damascene structure.

21. The damascene metal interconnect of claim 17 wherein the (111) texture of the metalization layer is further enhanced by annealing techniques.

22. The damascene metal interconnect of claim 17 wherein the refractory metal comprises titanium.

23. The damascene metal interconnect of claim 17 wherein the refractory metal comprises tantalum.

24. The damascene metal interconnect of claim 17 wherein the metalization layer comprises copper.

25. The damascene metal interconnect of claim 17 wherein the metalization layer comprises copper alloy.

26. The damascene metal interconnect of claim 17 wherein the metalization layer comprises aluminum.

27. The damascene metal interconnect of claim 17 wherein the metalization layer comprises aluminum alloy.

28. The damascene metal interconnect of claim 17 wherein the metalization layer is grown primarily from the bottom of the damascene structure.

29. A damascene metal interconnect, comprising:

a dielectric material;

a damascene structure in the dielectric material, the damascene structure comprising a bottom and a side wall;

a first barrier material on the damascene structure;

a seed layer over the bottom of the damascene structure;

a metalization layer in the damascene structure, the metalization layer consisting essentially of (111) grains, and comprising a member selected from the group consisting of copper, aluminum, and alloys thereof.

30. The damascene metal interconnect of claim 29, wherein the first barrier material is along the bottom and the side wall of the damascene structure.

31. The damascene metal interconnect of claim 29 wherein the first barrier material is selected from the group consisting of titanium nitride, tantalum nitride, tungsten nitride, and combinations thereof.

32. The damascene metal interconnect of claim 29, wherein the metalization layer is polished.

33. The damascene metal interconnect of claim 29, wherein the seed layer overhangs the side wall.

34. The damascene metal interconnect of claim 29, wherein the damascene structure comprises a barrel shaped appearance.

35. The damascene metal interconnect of claim 29, wherein the bottom of the damascene structure comprises an enhanced fill region.

36. The damascene metal interconnect of claim 29, further comprising a passivation layer over the metalization layer.

37. The damascene metal interconnect of claim 29, wherein the dielectic material comprises silicon dioxide.

38. The damascene metal interconnect of claim 29, wherein the metalization layer is separated from the seed layer by the first barrier material.