Method of making a semiconductor device including barrier layers for copper interconnect
A method of making a semiconductor device includes forming a dielectric layer over a semiconductor substrate. The method further includes forming a copper-containing layer in the dielectric layer, wherein the copper-containing layer has a first portion and a second portion. The method further includes forming a first barrier layer between the first portion of the copper-containing layer and the dielectric layer. The method further includes forming a second barrier layer at a boundary between the second portion of the copper-containing layer and the dielectric layer wherein the second barrier layer is adjacent to an exposed portion of the dielectric layer. The first barrier layer is a dielectric layer, and the second barrier layer is a metal oxide layer, and a boundary between a sidewall of the copper-containing layer and the first barrier layer is free of the second barrier layer.
1. A method of making a semiconductor device, the method comprising:
forming a dielectric layer over a semiconductor substrate;
forming a copper-containing layer in the dielectric layer, wherein the copper-containing layer has a first portion and a second portion;
forming a first barrier layer between the first portion of the copper-containing layer and the dielectric layer; and
forming a second barrier layer at a boundary between the second portion of the copper-containing layer and the dielectric layer, wherein the second barrier layer is adjacent to an exposed portion of the dielectric layer, and the first barrier layer separates the dielectric layer from a sidewall of the second barrier layer closest to the dielectric layer;
wherein, the first barrier layer is a dielectric layer, and the second barrier layer is a metal oxide layer, and a boundary between a sidewall of the copper-containing layer and the first barrier layer is free of the second barrier layer.
2. The method of claim 1 , further comprising forming an etch stop layer over the semiconductor substrate, wherein the etch stop layer is between the semiconductor substrate and the dielectric layer.
3. The method of claim 2 , wherein forming the etch stop layer comprises forming the etch stop layer having a thickness ranging from about 10 angstroms (Å) to about 1000 Å.
4. The method of claim 2 , wherein forming the etch stop layer comprises forming the etch stop layer using low-pressure chemical vapor deposition (LPCVD), atmospheric-pressure chemical vapor deposition (APCVD), plasma-enhanced chemical vapor deposition (PECVD), physical vapor deposition (PVD), or sputtering.
5. The method of claim 1 , wherein forming the first barrier layer comprises forming the first barrier layer using chemical vapor deposition (CVD), PECVD, or LPCVD.
6. The method of claim 1 , further comprising etching the first barrier layer to form the exposed portion of the dielectric layer.
7. The method of claim 1 , wherein forming the second barrier layer comprises:
forming a copper alloy liner over the first barrier layer and the exposed portion of the dielectric layer; and
performing a thermal treatment on the copper alloy liner.
8. A method of making a semiconductor device, the method comprising:
forming a dielectric layer over a semiconductor substrate;
forming an opening in the dielectric layer, wherein the opening comprises an upper trench section and a lower via-hole section, the upper trench section comprises a first sidewall portion and a bottom portion, and the lower via-hole section comprises a second sidewall portion;
forming a copper-containing layer filling the opening formed in the dielectric layer, wherein the copper-containing layer comprises a first portion adjacent the first sidewall portion, a second portion adjacent the bottom portion, and a third portion adjacent the second sidewall portion;
forming a dielectric barrier layer between the first portion of the copper-containing layer and the dielectric layer, and between the third portion of the copper-containing layer and the dielectric layer; and
forming a metal oxide layer at a boundary between the second portion of the copper-containing layer and the dielectric layer, wherein the metal oxide layer is adjacent to an exposed portion of the dielectric layer, wherein a boundary between the first portion of the copper-containing layer and the dielectric barrier layer is free of the metal oxide layer, and wherein the metal oxide layer overlays the dielectric barrier layer formed between the third portion of the copper-containing layer and the dielectric layer.
9. The method of claim 8 , further comprising etching the dielectric barrier layer to form the exposed portion of the dielectric layer.
10. The method of claim 8 , wherein forming the metal oxide layer comprises:
forming a copper alloy liner over the dielectric barrier layer and the exposed portion of the dielectric layer; and
performing a thermal treatment on the copper alloy liner.
11. The method of claim 10 , wherein forming the copper alloy liner comprises forming the copper alloy liner comprising copper and an additive metal, wherein the additive metal comprises at least one of Mg, Ti, Al, Nb, Cr, V Y, Tc or Re.
12. The method of claim 8 , wherein forming the copper-containing layer comprises forming the copper-containing layer comprising electro-chemical plating (ECP).
13. The method of claim 8 , further comprising performing a chemical mechanical polishing CMP process to remove portions of the copper-containing layer outside the opening in the dielectric layer.
14. The method of claim 8 , wherein forming the metal oxide layer comprises forming the metal oxide layer comprising manganese oxide.
15. A method of making a semiconductor device, the method comprising:
forming a dielectric layer over a semiconductor substrate;
forming an opening in the dielectric layer, wherein the opening comprises an upper trench section and a lower via-hole section, the upper trench section comprises a first sidewall portion and a bottom portion, and the lower via-hole section comprises a second sidewall portion;
forming a copper-containing layer in the opening formed in the dielectric layer, wherein the copper-containing layer comprises a first portion adjacent the first sidewall portion, a second portion adjacent the bottom portion, and a third portion adjacent the second sidewall portion;
forming a first barrier layer between the first portion of the copper-containing layer and the dielectric layer, and between the third portion of the copper-containing layer and the dielectric layer; and
forming a second barrier layer at a boundary between the second portion of the copper-containing layer and the dielectric layer, wherein the second barrier layer is adjacent to an exposed portion of the dielectric layer,
wherein a boundary between the first portion of the copper-containing layer and the first barrier layer is free of the second barrier layer, and a boundary between the third portion of the copper-containing layer and the first barrier layer is free of the second barrier layer,
wherein the first barrier layer between the first portion of the copper-containing layer and the dielectric layer is between a sidewall of the second barrier layer and the dielectric layer.
16. The method of claim 15 , further comprising etching the first barrier layer to form the exposed portion of the dielectric layer.
17. The method of claim 15 , wherein forming the second barrier layer comprises:
forming a copper alloy liner over the first barrier layer and the exposed portion of the dielectric layer; and
performing a thermal treatment on the copper alloy liner.
18. The method of claim 17 , wherein forming the copper alloy liner comprises forming the copper alloy liner comprising copper and manganese.
19. The method of claim 18 , wherein forming the second barrier layer further comprises reacting the manganese in the copper alloy liner with oxygen in the dielectric layer to form manganese oxide.
20. The method of claim 15 , further comprising forming an etch stop layer between the dielectric layer and the semiconductor substrate, wherein forming the opening comprises forming the opening in the etch stop layer.