Interconnect structure and method for forming the same
Interconnect structures and methods for forming the same are described. A method for forming an interconnect structure may include: forming a low-k dielectric layer over a substrate; forming an opening in the low-k dielectric layer; forming a conductor in the opening; forming a capping layer over the conductor; and forming an etch stop layer over the capping layer and the low-k dielectric layer, wherein the etch stop layer has a dielectric constant ranging from about 5.7 to about 6.8.
1. A method, comprising:
forming a first etch stop layer and an adhesion layer over a substrate;
forming a low-k dielectric layer over the first etch stop layer and the adhesion layer;
forming an opening in the low-k dielectric layer;
forming a conductor in the opening;
forming a capping layer over the conductor; and
forming a second etch stop layer over the capping layer and the low-k dielectric layer, wherein the second etch stop layer has a dielectric constant ranging from about 5.7 to about 6.8.
2. The method of claim 1 , wherein the forming the low-k dielectric layer over the substrate comprises use of a precursor comprising a silane, a siloxane, or a combination thereof.
3. The method of claim 1 , wherein the second etch stop layer includes:
a silicon element with a content ratio less than about 50 at %;
a carbon element with a content ratio ranging from about 5 at % to about 25 at %; p 1 and
a nitrogen element with a content ratio ranging from about 25 at % to about 40 at %.
4. The method of claim 1 , wherein the forming the second etch stop layer comprises a low-pressure chemical vapor deposition, atmospheric-pressure chemical vapor deposition, plasma-enhanced chemical vapor deposition, physical vapor deposition, sputtering, or combinations thereof.
5. The method of claim 1 , wherein the forming the first etch stop layer and the adhesion layer over the substrate comprises:
forming the adhesion layer over the substrate;
forming the first etch stop layer over the adhesion layer; and
forming the low-k dielectric layer over the first etch stop layer.
6. The method of claim 5 , wherein the adhesion layer comprises a carbon-containing layer with a carbon content ratio ranging from about 15 at % to about 30 at %.
7. The method of claim 5 , wherein the adhesion layer has a thickness in a range from about 5 Angstroms to about 300 Angstroms.
8. The method of claim 5 , wherein forming the adhesion layer comprises:
flowing an inert gas at a first flow rate; and
applying a first radiofrequency power during formation of the adhesion layer.
9. The method of claim 8 , wherein forming the low-k dielectric layer comprises:
flowing the inert gas at a second flow rate less than the first flow rate; and
applying a second radiofrequency power during formation of the low-k dielectric layer, the second radiofrequency power being less than the first radiofrequency power.
10. A semiconductor device, comprising:
a first etch stop layer and an adhesion layer over a substrate;
a low-k dielectric layer over the first etch stop layer and the adhesion layer;
a conductor extending through the low-k dielectric layer;
a capping layer over a surface of the conductor facing away from the substrate, wherein surfaces of the low-k dielectric layer facing away from the substrate are free from the capping layer; and
a second etch stop layer over the capping layer and the low-k dielectric layer, wherein the second etch stop layer a dielectric constant ranging from about 5.7 to about 6.8.
11. The semiconductor device of claim 10 , wherein the low-k dielectric layer is a carbon-containing layer with a carbon content ratio ranging from about 10 at % to about 13 at %.
12. The semiconductor device of claim 10 , wherein the low-k dielectric layer has a dielectric constant ranging from about 2.3 to about 2.6.
13. The semiconductor device of claim 10 , wherein the second etch stop layer is in physical contact with the low-k dielectric layer.
14. The semiconductor device of claim 10 , wherein the second etch stop layer comprises silicon oxide, silicon nitride, silicon carbide, silicon oxynitride, or combinations thereof.
15. The semiconductor device of claim 10 , wherein the adhesion layer is disposed between the low-k dielectric layer and the first etch stop layer.
16. The semiconductor device of claim 15 , wherein the adhesion layer comprises a carbon-containing layer with a carbon content ratio ranging from about 15 at % to about 30 at %.
17. A method, comprising:
forming a first etch stop layer over a substrate;
forming an adhesion layer over the first etch stop layer;
forming a low-k dielectric layer over the adhesion layer;
forming an opening in the low-k dielectric layer, the adhesion layer, and the first etch stop layer;
forming a metal line in the opening, wherein a surface of the metal line facing away from the substrate and a surface of the low-k dielectric layer facing away from the substrate are substantially co-planar;
selectively forming a capping layer over the metal line, wherein no portion of the capping layer is disposed over the low-k dielectric layer; and
forming a second etch stop layer over the capping layer and the low-k dielectric layer, wherein the second etch stop layer has a dielectric constant ranging from about 5.7 to about 6.8.
18. The method of claim 17 , wherein the adhesion layer comprises a first adhesion layer proximal the substrate, and a second adhesion layer proximal the low-k dielectric layer.
19. The method of claim 18 , wherein the first adhesion layer comprises an SiOx-containing material, and wherein the second adhesion layer comprises a carbon-containing layer having a carbon content ratio ranging from about 15 at % to about 30 at %.
20. The method of claim 17 , wherein the second etch stop layer includes an N element with a content ratio ranging from about 25 at % to about 40 at %.