NOBLE METAL CAP FOR INTERCONNECT STRUCTURES

• US 20090189287A1
• Filed: 01/29/2008
• Published: 07/30/2009
• Est. Priority Date: 01/29/2008
• Status: Active Grant

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Yang, Chih-Chao, Edelstein, Daniel C., McFeely, Fenton R.
• Granted Patent: US 7,998,864 B2
• Time in Patent Office: Days
• US Class Current: 257/769
• CPC Class Codes: H01L 21/76826 by contacting the layer with gases, liquids or plasmas
• CPC Class Codes: H01L 21/76849 the layer being positioned on top of the main fill metal
• CPC Class Codes: H01L 21/76883 Post-treatment or after-treatment of the conductive material
• 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

An interconnect structure that includes a dielectric material having a dielectric constant of about 3.0 or less is provided. This low k dielectric material has at least one conductive material having an upper surface embedded therein. The dielectric material also has a surface layer that is made hydrophobic prior to the formation of the noble metal cap. The noble metal cap is located directly on the upper surface of the at least one conductive material. Because of the presence of the hydrophobic surface layer on the dielectric material, the noble metal cap does not substantially extend onto the hydrophobic surface layer of the dielectric material that is adjacent to the at least one conductive material and no metal residues from the noble metal cap deposition form on this hydrophobic dielectric surface.

Claims

1. An interconnect structure comprising:

a dielectric material having a dielectric constant of about 3.0 or less, said dielectric material having a hydrophobic surface layer and at least one conductive material having an upper surface embedded within said dielectric material; and

a noble metal cap located directly on said upper surface of said at least one conductive material, said noble metal cap does not substantially extend onto said hydrophobic surface layer of said dielectric material that is adjacent to said at least one conductive material and no noble metal residues are present on the hydrophobic surface layer of said dielectric material.

2. The interconnect structure of claim 1 wherein an upper surface of said at least one conductive material is substantially coplanar with said hydrophobic surface layer of said dielectric material.

3. The interconnect structure of claim 1 wherein said noble metal cap is selected from the group consisting of Ru, Ir, Rh, Pt and alloys thereof.

4. The interconnect structure of claim 3 wherein said noble metal cap comprises Ru or a Ru alloy.

5. The interconnect structure of claim 1 further comprising a dielectric capping layer located atop said dielectric material and said noble metal cap.

6. An interconnect structure comprising:

a dielectric material having a dielectric constant of about 3.0 or less, said dielectric material having a hydrophobic surface layer and at least one Cu-containing conductive material having an upper surface embedded within said dielectric material; and

a Ru-containing noble metal cap located directly on said upper surface of said at least one Cu-containing conductive material, said Ru-containing noble metal cap does not substantially extend onto said hydrophobic surface layer of said dielectric material that is adjacent to said at least one Cu-containing conductive material and no Ru-containing noble metal residues are present on the hydrophobic surface layer of said dielectric material.

7. The interconnect structure of claim 6 wherein an upper surface of said at least one Cu-containing conductive material is substantially coplanar with said hydrophobic surface layer of said dielectric material.

8. The interconnect structure of claim 6 further comprising a dielectric capping layer located atop said dielectric material and said noble metal cap.

9. A method of forming an interconnect structure comprising:

providing a dielectric material having a dielectric constant of about 3.0 or less, said dielectric material having at least one conductive material having an upper surface embedded within said dielectric material;

forming a hydrophobic surface layer on exposed surfaces of the dielectric material; and

forming a noble metal cap directly on said upper surface of said at least one conductive material, said noble metal cap does not substantially extend onto said hydrophobic surface layer of said dielectric material that is adjacent to said at least one conductive material, said noble metal cap forming does not result in noble metal residues on the hydrophobic surface layer of said dielectric material.

10. The method of claim 9 wherein said forming a noble metal cap includes a chemical deposition process that is performed at a temperature of about 300°

C. or less.

11. The method of claim 10 wherein said chemical deposition process includes a chemical vapor deposition process or atomic layer deposition.

12. The method of claim 9 wherein an upper surface of said at least one conductive material is substantially coplanar with said hydrophobic surface layer of said dielectric material.

13. The method of claim 9 further comprising forming a dielectric capping layer located atop said dielectric material and said noble metal cap.

14. The method of claim 9 wherein said forming a noble metal cap includes selecting one of Ru, Ir, Rh, Pt and alloys thereof.

15. The method of claim 9 wherein said forming a hydrophobic surface layer on exposed surfaces of the dielectric material includes thermal treating in a hydrogen-containing ambient.

16. The method of claim 15 wherein said thermal treating is performed at a temperature from about 100°

C. to about 450°

C.

17. The method of claim 15 wherein said hydrogen-containing ambient includes from about 2% to about 100% hydrogen.

18. The method of claim 9 wherein said forming a hydrophobic surface layer on exposed surfaces of the dielectric material includes plasma treating in a hydrogen-containing plasma.

19. The method of claim 18 wherein said hydrogen-containing plasma includes from about 2% to about 100% hydrogen.

20. A method of fabricating an interconnect structure comprising:

providing a dielectric material having a dielectric constant of about 3.0 or less, said dielectric material having at least one conductive material having an upper surface embedded within said dielectric material;

forming a hydrophobic surface layer on exposed surfaces of the dielectric material by thermal treating in a hydrogen-containing ambient; and

forming a noble metal cap directly on said upper surface of said at least one conductive material, said noble metal cap does not substantially extend onto said hydrophobic surface layer of said dielectric material that is adjacent to said at least one conductive material, said noble metal cap forming does not result in noble metal residues on the hydrophobic surface layer of said dielectric material.

21. The method of claim 20 wherein said forming a noble metal cap includes a chemical deposition process that is performed at a temperature of about 300°

C. or less.

22. The method of claim 20 wherein said chemical deposition process includes a chemical vapor deposition process or atomic layer deposition.

23. The method of claim 20 wherein an upper surface of said at least one conductive material is substantially coplanar with said hydrophobic surface layer of said dielectric material.

24. The method of claim 20 further comprising forming a dielectric capping layer located atop said dielectric material and said noble metal cap.

25. The method of claim 20 wherein said forming a noble metal cap includes selecting one of Ru, Ir, Rh, Pt and alloys thereof.