Integrated circuit and manufacturing method of copper germanide and copper silicide as copper capping layer

• US 7,858,519 B2
• Filed: 11/03/2008
• Issued: 12/28/2010
• Est. Priority Date: 11/27/2007
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: IMEC International, Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Liu, Chung-Shi, Yu, Chen-Hua
• Primary Examiner(s): Chu; Chris
• Application Number:
  US12/264,095
• Publication Number:
  US 20090134521A1
• Time in Patent Office: 785 Days
• Field of Search: 257/E21.476, 257/E23.141, 257/E21.582, 257/E21.592, 257/751, 257/758, 257/762, 257/774, 438/631, 438/653, 438/678, 438/687, 438/763
• US Class Current: 438/653
• CPC Class Codes: H01L 21/76846 Layer combinations
• CPC Class Codes: H01L 21/76849 the layer being positioned on top of the main fill metal
• CPC Class Codes: H01L 21/76856 by treatment in plasmas or gaseous environments, e.g. nitriding a refractory metal liner
• 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
• CPC Class Codes: H01L 21/76886 Modifying permanently or temporarily the pattern or the conductivity of conductive members, e.g. formation of alloys, reduction of contact resistances
• 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 is provided for forming a capping layer comprising Cu, N, and also Si and/or Ge onto a copper conductive structure, said method comprising the sequential steps of: forming, at a temperature range between 200° C. up to 400° C., at least one capping layer onto said copper conductive structure by exposing said structure to a GeH₄ and/or a SiH₄ comprising ambient, performing a NH₃ plasma treatment thereby forming an at least partly nitrided capping layer, forming a dielectric barrier layer onto said at least partly nitrided capping layer, wherein prior to said step of forming said at least one capping layer a pre-annealing step of said copper conductive structure is performed at a temperature range between 250° C. up to 450° C.

Claims

1. A method for forming a capping layer on a copper conductive structure, wherein the capping layer comprises copper, nitrogen and at least one of silicon and germanium, the method comprising sequential steps of:

pre-annealing a copper conductive structure at a temperature of from about 250°

C. to about 450°

C.;

forming at least one capping layer on the pre-annealed copper conductive structure by exposing the pre-annealed copper conductive structure to an ambient comprising at least one of GeH₄ and SiH₄ at a temperature of from about 200°

C. to about 400°

C.;

performing a NH₃ plasma treatment, whereby the capping layer is at least partly nitrided; and

forming a dielectric barrier layer on the at least partly nitrided capping layer.

2. The method of claim 1, wherein the pre-annealing step is performed for at least 15 minutes.

3. The method of claim 1, wherein the pre-annealing step is performed at 400°

C.

4. The method of claim 1, wherein the pre-annealing step is performed for at least 30 minutes.

5. The method of claim 1, wherein performing the NH₃ plasma treatment is performed by adding NH₃ gas to the ambient comprising at least one of GeH₄ and a SiH₄.

6. The method of claim 5, wherein the ambient comprises GeH₄ mixed with NH₃ gas, and wherein the at least partly nitrided capping layer is an at least partly nitrided copper germanide capping layer.

7. The method of claim 5, wherein the ambient comprises SiH₄ mixed with NH₃ gas, and wherein the at least partly nitrided capping layer is an at least partly nitrided copper silicide capping layer.

8. The method of claim 5, wherein the ambient comprises GeH₄ and SiH₄ mixed with NH₃ gas, and wherein the at least partly nitrided capping layer is an at least partly nitrided copper silicon germanide capping layer.

9. The method of claim 1, further comprising forming at least one additional capping layer on the pre-annealed copper conductive structure by exposing the pre-annealed copper conductive structure to an ambient comprising at least one of GeH₄ and SiH₄ at a temperature of from about 200°

C. to about 400°

C., wherein the at least one additional capping layer is formed after the step of forming the at least one capping layer or after the step of performing the NH₃ plasma treatment, whereby a stack comprising a partly nitrided copper germanide capping layer and a partly nitrided copper silicide capping layer are formed.

10. The method of claim 1, wherein the ambient further comprises an inert gas.

11. The method of claim 1, wherein the ambient further comprises an inert gas, and wherein the inert gas is N₂.

12. The method of claim 1, wherein a thermal anneal step is performed after at least one of the step of forming at least one capping layer, the step of performing a NH₃ plasma treatment, and the step of forming the dielectric barrier layer.

13. The method of claim 1, wherein the step of pre-annealing the copper structure and at least one of step of forming at least one capping layer and the step of performing a NH₃ plasma treatment are performed in a same chamber.

14. The method of claim 1, wherein the step of pre-annealing the copper structure and at least one of step of forming at least one capping layer and the step of performing a NH₃ plasma treatment are performed in different chambers.

15. A self aligned at least partly nitrided copper silicon germanide capping layer on top of an embedded copper conductive structure, obtained by the method of claim 1.

16. The self-aligned at least partly nitrided copper silicon germanide capping layer of claim 15, wherein a thickness of the capping layer is from about 3 nm to about 20 nm.