Semiconductor interconnect structure having graphene-capped metal interconnects
The present disclosure relates to a semiconductor device and a manufacturing method, and more particularly to a semiconductor interconnect structure incorporating a graphene barrier layer. The present disclosure provides a method of forming a graphene barrier layer by thermally annealing amorphous carbon layers on metal catalyst surfaces. The thickness of the graphene barrier layers can be selected by varying the thickness of the amorphous carbon layer.
1. A method of fabricating a semiconductor structure, the method comprising:
forming a dielectric layer over a metal layer;
forming an opening in the dielectric layer, wherein the opening exposes surfaces of the dielectric layer and a portion of the metal layer;
forming an amorphous carbon layer on the exposed surfaces of the dielectric layer and the portion of the metal layer;
disposing a conductor material on the amorphous carbon layer; and
performing an anneal process on the semiconductor structure to graphitize the amorphous carbon layer and form a graphene barrier layer.
2. The method of claim 1 , wherein the amorphous carbon layer has a thickness in a range of about 1 angstrom to about 300 angstroms.
3. The method of claim 1 , wherein the graphene barrier layer has a thickness in a range of about 1 angstrom to about 300 angstroms.
4. The method of claim 1 , wherein performing the anneal process on the semiconductor structure to graphitize the amorphous carbon layer comprises thermal dissociating the amorphous carbon layer and forming carbon clusters.
5. The method of claim 1 , wherein the annealing process comprises a first annealing step performed at about 200° C., a second annealing step performed at about 300° C., and a third annealing step performed at about 400° C.
6. The method of claim 5 , wherein the first annealing step is performed for a time period of about 300 s.
7. The method of claim 5 , wherein the second annealing step is performed for a time period of about 300 s.
8. The method of claim 5 , wherein the third annealing step is performed for a time period of about 60 s.
9. The method of claim 1 , wherein the anneal process is performed for a time period between about 30 s and about 300 s.
10. The method of claim 1 , wherein the anneal process is performed at a temperature between about 200° C. and about 1250° C.
11. A method of fabricating an interconnect structure, the method comprising:
depositing a dielectric layer on a first conductive layer;
patterning the dielectric layer to form an opening in the dielectric layer, wherein the opening comprises sidewalk of the dielectric layer and exposes a portion of the first conductive layer;
depositing an amorphous carbon layer on the sidewalls of the dielectric layer and the portion of the first conductive layer;
depositing a second conductive layer on the amorphous carbon layer, wherein the second conductive layer fills the opening; and
annealing the amorphous carbon layer to form a graphene barrier layer.
12. The method of claim 11 , wherein the annealing is performed at a temperature between about 200° C. and about 450° C.
13. The method of claim 11 , wherein the annealing process induces graphitization of the amorphous carbon layer.
14. The method of claim 11 , wherein the annealing process comprises a first annealing step performed at about 200° C., a second annealing step performed at about 300° C., and a third annealing step performed at about 400° C.
15. The method of claim 14 , wherein the first annealing step is performed for a time period of about 300 s.
16. The method of claim 14 , wherein the second annealing step is performed for a time period of about 300 s.
17. The method of claim 14 , wherein the third annealing step is performed for a time period of about 60 s.
18. The method of claim 11 , wherein the anneal process is performed for a time period between about 30 s and about 300 s.
19. A method of fabricating a semiconductor structure, the method comprising:
depositing a dielectric layer on a conductive interconnect layer;
patterning the dielectric layer to form an opening in the dielectric layer, wherein the opening comprises a trench over a via;
depositing a pre-fill layer in the via and on the conductive interconnect layer;
depositing an amorphous carbon layer on the pre-fill layer and in the trench;
depositing a conductive layer on the amorphous carbon layer, wherein the conductive layer fills the trench; and
annealing the amorphous carbon layer to form a graphene barrier layer.
20. The method of claim 19 , wherein the annealing is performed at a temperature between about 200° C. and about 450° C.