Integrated circuit and manufacturing method of copper germanide and copper silicide as copper capping layer
View Patent ↗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 GeH 4 and/or a SiH 4 comprising ambient, performing a NH 3 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.
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 GeH 4 and SiH 4 at a temperature of from about 200° C. to about 400° C.;
performing a NH 3 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 NH 3 plasma treatment is performed by adding NH 3 gas to the ambient comprising at least one of GeH 4 and a SiH 4 .
6. The method of claim 5 , wherein the ambient comprises GeH 4 mixed with NH 3 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 SiH 4 mixed with NH 3 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 GeH 4 and SiH 4 mixed with NH 3 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 GeH 4 and SiH 4 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 NH 3 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 N 2 .
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 NH 3 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 NH 3 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 NH 3 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.