Dielectric/metal barrier integration to prevent copper diffusion
An interconnect structure for use in semiconductor devices and a method for fabricating the same is described. The method includes positioning a substrate in a vacuum processing chamber, wherein the substrate comprises a copper layer having an exposed surface and a low-k dielectric layer having an exposed surface, forming a metal layer over the exposed surface of the copper layer, wherein the exposed surface of the low-k dielectric layer is free from the metal layer, and forming a metal-based dielectric layer over the metal layer and over at least part of the exposed low-k dielectric surface, wherein the metal-based dielectric layer comprises an aluminum compound.
1. A method for forming an interconnect structure, comprising
positioning a substrate in a first vacuum processing chamber of a vacuum processing system, wherein the substrate comprises a copper layer having an exposed surface and a low-k dielectric layer having an exposed surface;
forming a metal layer over the exposed surface of the copper layer in a second vacuum processing chamber of the vacuum processing system, wherein the exposed surface of the low-k dielectric layer is free from the metal layer; and
forming a metal-based dielectric layer directly on the metal layer and directly on at least part of the exposed surface of the low-k dielectric layer in a third vacuum processing chamber of the vacuum processing system, wherein the metal-based dielectric layer comprises an aluminum compound, and the formation of the metal layer and the formation of the metal-based dielectric layer are performed without an airbreak between the second vacuum processing chamber and the third vacuum processing chamber.
2. The method of claim 1 , wherein the metal layer comprises cobalt, cobalt tungsten phosphide, cobalt tungsten nitride, or cobalt tungsten phosphonitride.
3. The method of claim 1 , wherein the metal layer comprises a cobalt compound.
4. The method of claim 1 , wherein the thickness of the metal layer is from about 5 Å to about 100 Å.
5. The method of claim 1 , wherein the thickness of the metal-based dielectric layer is from about 10 Å to about 100 Å.
6. The method of claim 1 , wherein the aluminum compound comprises aluminum oxide, aluminum nitride, or aluminum oxynitride.
7. The method of claim 1 , wherein the metal-based dielectric layer is formed by physical vapor deposition.
8. The method of claim 1 , further comprising,
forming a second low-k dielectric layer directly over the metal-based dielectric layer;
forming a trench in the low-k dielectric layer; and
filling the trench at least partially with copper.
9. A method for forming an interconnect structure, the method comprising:
positioning a substrate in a first vacuum processing chamber of a vacuum processing system, wherein the substrate comprises a copper layer having an exposed surface and a low-k dielectric layer having an exposed surface;
forming a metal layer over the exposed surface of the copper layer in a second vacuum processing chamber of the vacuum processing system, wherein the exposed surface of the low-k dielectric layer is free from the metal layer, and the metal layer comprises comprises cobalt, cobalt tungsten phosphide, cobalt tungsten nitride, or cobalt tungsten phosphonitride;
forming a metal-based dielectric layer directly on the exposed surface of the low-k dielectric layer and directly on the metal layer in a third vacuum processing chamber of the vacuum processing system, wherein the metal-based dielectric layer comprises aluminum oxide, aluminum nitride, or aluminum oxynitride, and the formation of the metal layer and the formation of the metal-based dielectric layer are performed without an airbreak between the second vacuum processing chamber and the third vacuum processing chamber;
forming a second low-k dielectric layer directly over the metal-based dielectric layer;
forming a trench in the second low-k dielectric layer; and
filling the trench at least partially with copper.
10. The method of claim 9 , wherein the metal layer has a thickness of about 5 Å to about 100 Å, and wherein the metal-based dielectric layer has a thickness of about 10 Å to about 100 Å.
11. A method for forming an interconnect structure, the method comprising:
positioning a substrate in a first vacuum processing chamber of a vacuum processing system, wherein the substrate comprises a copper layer having an exposed surface and a low-k dielectric layer having an exposed surface;
forming a metal layer over the exposed surface of the copper layer but not over the exposed surface of the low-k dielectric layer in a second vacuum processing chamber of the vacuum processing system, wherein the metal layer comprises cobalt, cobalt tungsten phosphide, cobalt tungsten nitride, or cobalt tungsten phosphonitride;
forming a metal-based dielectric layer over the exposed dielectric surface and the metal layer in a third vacuum processing chamber of the vacuum processing system, wherein:
the metal-based dielectric layer comprises aluminum oxide, aluminum nitride, or aluminum oxynitride; and
wherein the formation of the metal layer and the formation of the metal-based dielectric layer are performed without an airbreak between the second vacuum processing chamber and the third vacuum processing chamber;
forming a second low-k dielectric layer directly over the metal-based dielectric layer;
forming a trench in the second low-k dielectric layer; and
filling the trench at least partially with copper.
12. The method of claim 11 , wherein the metal-based dielectric layer is formed by physical vapor deposition.
13. The method of claim 12 , wherein the metal layer has a thickness of about 5 Å to about 100 Å.
14. The method of claim 13 , wherein the metal-based dielectric layer has a thickness of about 10 Å to about 100 Å.