INCREASING RELIABILITY OF COPPER-BASED METALLIZATION STRUCTURES IN A MICROSTRUCTURE DEVICE BY USING ALUMINUM NITRIDE

• US 20080179741A1
• Filed: 11/30/2007
• Published: 07/31/2008
• Est. Priority Date: 01/31/2007
• Status: Active Grant

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: GlobalFoundries, Inc.
• Inventors: Kahlert, Volker, Streck, Christof
• Granted Patent: US 7,829,460 B2
• Time in Patent Office: Days
• US Class Current: 257/740
• CPC Class Codes: C23C 16/303 Nitrides
• CPC Class Codes: C23C 16/45525 Atomic layer deposition [ALD]
• CPC Class Codes: H01L 21/02178 the material containing aluminium, e.g. Al2O3
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/318 composed of nitrides
• CPC Class Codes: H01L 21/76832 Multiple layers
• CPC Class Codes: H01L 21/76834 formation of thin insulating films on the sidewalls or on top of conductors H01L21/76831 takes precedence
• CPC Class Codes: H01L 21/76849 the layer being positioned on top of the main fill metal
• CPC Class Codes: H01L 21/76867 characterized by methods of formation other than PVD, CVD or deposition from a liquids PVD H01L21/2855; CVD H01L21/28556; deposition from liquids H01L21/288

Abstract

By forming an aluminum nitride layer by a self-limiting process sequence, the interface characteristics of a copper-based metallization layer may be significantly enhanced while nevertheless maintaining the overall permittivity of the layer stack at a lower level.

Claims

1. A method, comprising:

forming a nitrogen-containing layer on an exposed surface of a metal region formed in a dielectric layer; and

exposing said nitrogen-containing layer to an ambient established on the basis of an aluminum-containing gas to form an aluminum and nitrogen-containing first barrier layer on said metal region.

2. The method of claim 1, wherein said metal region comprises copper.

3. The method of claim 2, wherein forming said nitrogen-containing layer comprises treating said exposed surface to convert copper oxide into copper nitride.

4. The method of claim 3, wherein treating said exposed surface comprises establishing an ammonium (NH₃) containing ambient.

5. The method of claim 1, wherein said aluminum-containing gas comprises Al(CH₃)₃.

6. The method of claim 1, further comprising forming a second dielectric barrier layer on said first barrier layer and forming a low-k dielectric material above said second dielectric barrier layer.

7. The method of claim 6, wherein said first barrier layer and said second dielectric layer are formed in an in situ process.

8. The method of claim 3, wherein treating said exposed surface comprises thermal activation in the absence of a plasma.

9. The method of claim 1, further comprising forming a low-k dielectric material on said aluminum and nitrogen-containing first barrier layer.

10. The method of claim 3, further comprising forming said copper oxide in an oxidizing ambient as a substantially continuous copper oxide layer.

11. The method of claim 1, wherein said aluminum and nitrogen-containing first barrier layer is formed on said dielectric layer.

12. The method of claim 11, further comprising forming said dielectric layer so as to have OH groups at least at a surface thereof.

13. A method, comprising:

providing a substrate having formed thereabove an exposed copper-containing metal region formed in a dielectric layer; and

forming a dielectric barrier layer on said exposed copper-containing metal region and said dielectric layer by using a self-limiting reaction mechanism performed in a gaseous ambient.

14. The method of claim 13, wherein said dielectric barrier layer comprises aluminum and nitrogen.

15. The method of claim 14, wherein forming said dielectric barrier layer comprises forming a copper nitride layer on said exposed copper-containing metal region and treating said copper nitride layer with an aluminum-containing gas.

16. The method of claim 15, wherein forming said dielectric barrier layer further comprises exposing said substrate to an ammonium-containing ambient after the treatment with said aluminum-containing gas.

17. The method of claim 15, wherein said copper nitride layer is formed in a thermally activated treatment in the absence of a plasma.

18. The method of claim 13, further comprising forming an etch stop layer on said dielectric barrier layer, forming a second dielectric layer on said etch stop layer and patterning said second dielectric layer using said etch stop layer.

19. The method of claim 18, wherein at least said etch stop layer and said dielectric barrier layer are formed in situ.

20. A semiconductor device, comprising:

a copper-containing region formed in a dielectric layer;

an aluminum nitride layer formed on said copper-containing region and said dielectric layer;

a second dielectric layer formed above said aluminum nitride layer; and

a metal via formed in said dielectric layer and connecting to said copper-containing region.

21. The device of claim 20, wherein said dielectric layer is comprised of a low-k dielectric material.

22. The semiconductor device of claim 20, wherein said dielectric layer is formed on said aluminum nitride layer.

23. The semiconductor device of claim 20, further comprising a dielectric barrier layer located between said aluminum nitride layer and said dielectric layer, said dielectric barrier layer having a superior diffusion blocking characteristics relative to said dielectric layer.