Local silicidation of via bottoms in metallization systems of semiconductor devices
Electromigration behavior in complex metallization systems of semiconductor devices may be enhanced at critical areas between a metal line and a via by locally forming a copper/silicon compound. In some illustrative embodiments, the formation of the copper/silicon compound may be combined with other treatments for cleaning the exposed surface areas and/or modifying the molecular structure thereof.
1. A method of forming a metallization system of a semiconductor device, the method comprising:
forming an opening in a dielectric layer of a first metallization layer of said metallization system, said opening exposing a portion of a copper-containing metal region of a second metallization layer of said metallization system;
forming a trench in a portion of said dielectric layer so as to connect to said opening;
forming a copper/silicon compound selectively in said exposed portion of said copper-containing metal region; and
after forming said copper/silicon compound, filling said trench and said opening in a common deposition process with a metal-containing material.
2. The method of claim 1 , wherein forming said copper/silicon compound comprises treating said exposed portion in a silicon-containing plasma ambient.
3. The method of claim 2 , wherein said plasma ambient comprises at least one reactive component so as to remove contaminants generated during an etch process performed to form said opening.
4. The method of claim 3 , wherein said at least one reactive component comprises oxygen.
5. The method of claim 1 , wherein forming said copper/silicon compound comprises establishing a silicon-containing ambient and initiating diffusion of silicon species into said exposed portion and into exposed surface areas of said dielectric layer so as to modify a molecular structure of said exposed surface areas.
6. The method of claim 5 , wherein said dielectric layer comprises a material having a dielectric constant of 2.7 or less.
7. The method of claim 6 , wherein modifying said molecular structure comprises increasing a hardness of said exposed surface areas.
8. The method of claim 6 , wherein modifying said molecular structure comprises reducing damage created in said exposed surface areas during one or more preceding processes.
9. The method of claim 1 , further comprising forming a dielectric cap layer on said copper-containing metal region and depositing said dielectric layer on said dielectric cap layer.
10. The method of claim 9 , wherein said dielectric cap layer is formed on a copper-containing surface of said copper-containing metal region.
11. The method of claim 1 , wherein forming said silicon/copper compound comprises forming a precursor layer selectively on said exposed portion of said copper-containing metal region and initiating a decomposition of said precursor layer so as to initiate silicon diffusion into said exposed portion.
12. The method of claim 11 , wherein said precursor layer comprises a carrier material based on at least one of triazole and a derivative and silicon bonded to said carrier material.
13. A method, comprising:
forming a dielectric cap material on a copper-containing surface of a metal region of a first metallization layer of a metallization system of a semiconductor device;
forming a low-k dielectric material of a second metallization layer above said dielectric cap material;
forming an opening in said low-k dielectric material so as to expose a portion of said copper-containing surface; and
forming a silicon and copper-containing mixture in said metal region through said portion of said copper-containing surface, wherein forming said silicon and copper-containing mixture comprises establishing a silicon-containing plasma ambient, said plasma ambient comprising at least one reactive component so as remove organic material.
14. A method of forming a metallization system of a semiconductor device, the method comprising:
forming an opening in a dielectric layer of a first metallization layer of said metallization system, said opening exposing a portion of a copper-containing metal region of a second metallization layer of said metallization system; and
forming a copper/silicon compound selectively in said exposed portion of said copper-containing metal region, wherein forming said copper/silicon compound comprises treating said exposed portion in a silicon-containing plasma ambient, said plasma ambient comprising at least one reactive component so as to remove contaminants generated during an etch process performed to form said opening.
15. The method of claim 14 , wherein said at least one reactive component comprises oxygen.
16. A method of forming a metallization system of a semiconductor device, the method comprising:
forming an opening in a dielectric layer of a first metallization layer of said metallization system, said opening exposing a portion of a copper-containing metal region of a second metallization layer of said metallization system, and said dielectric layer comprising a material having a dielectric constant of approximately 2.7 or less; and
forming a copper/silicon compound selectively in said exposed portion of said copper-containing metal region, wherein forming said copper/silicon compound comprises establishing a silicon-containing ambient and initiating diffusion of silicon species into said exposed portion and into exposed surface areas of said dielectric layer so as to modify a molecular structure of said exposed surface areas.
17. The method of claim 16 , wherein modifying said molecular structure comprises increasing a hardness of said exposed surface areas.
18. The method of claim 16 , wherein modifying said molecular structure comprises reducing damage created in said exposed surface areas during one or more preceding processes.
19. A method of forming a metallization system of a semiconductor device, the method comprising:
forming an opening in a dielectric layer of a first metallization layer of said metallization system, said opening exposing a portion of a copper-containing metal region of a second metallization layer of said metallization system; and
forming a copper/silicon compound selectively in said exposed portion of said copper-containing metal region, wherein forming said silicon/copper compound comprises forming a precursor layer selectively on said exposed portion of said copper-containing metal region and initiating a decomposition of said precursor layer so as to initiate silicon diffusion into said exposed portion.
20. The method of claim 19 , wherein said precursor layer comprises a carrier material based on at least one of triazole and a derivative and silicon bonded to said carrier material.
21. A method, comprising:
forming a dielectric cap material on a copper-containing surface of a metal region of a first metallization layer of a metallization system of a semiconductor device;
forming a low-k dielectric material of a second metallization layer above said dielectric cap material;
forming an opening in said low-k dielectric material so as to expose a portion of said copper-containing surface; and
forming a silicon and copper-containing mixture in said metal region through said portion of said copper-containing surface, wherein forming said silicon and copper-containing mixture comprises establishing a silicon-containing ambient and modifying exposed surface areas of said low-k dielectric material, said silicon-containing ambient comprises hexamethyldisilazane (HMDS).