Subtractive metals and subtractive metal semiconductor structures
Embodiments of the present disclosure generally relate to subtractive metals, subtractive metal semiconductor structures, subtractive metal interconnects, and to processes for forming such semiconductor structures and interconnects. In an embodiment, a process for fabricating a semiconductor structure is provided. The process includes performing a degas operation on the semiconductor structure and depositing a liner layer on the semiconductor structure. The process further includes performing a sputter operation on the semiconductor structure, and depositing, by physical vapor deposition, a metal layer on the liner layer, wherein the liner layer comprises Ti, Ta, TaN, or combinations thereof, and a resistivity of the metal layer is about 30 μΩ·cm or less.
1. A process for fabricating a semiconductor structure, comprising:
performing a degas operation on the semiconductor structure;
depositing a liner layer on the semiconductor structure;
performing a sputter operation on the liner layer of the semiconductor structure while applying a bias to the semiconductor structure via an alternating current to at least partially amorphize the liner layer; and
depositing, by physical vapor deposition, a metal layer on the liner layer, wherein:
the liner layer comprises Ti, Ta, TaN, or combinations thereof, and
a resistivity of the metal layer is about 30 μΩ·cm or less.
2. The process of claim 1 , wherein the degas operation, depositing the liner layer, the sputter operation, and depositing the metal layer are performed in a single cluster tool.
3. The process of claim 1 , wherein a thickness of the liner layer is about 25 Å or less.
4. The process of claim 1 , wherein the resistivity of the metal layer is about 20 μΩ·cm or less.
5. The process of claim 1 , wherein:
a thickness of the liner layer is about 20 Å or less;
the resistivity of the metal layer is about 15 μΩ·cm or less; or
a combination thereof.
6. A process for fabricating a semiconductor structure, comprising:
performing a degas operation on the semiconductor structure;
depositing, by physical vapor deposition, an etch stop layer on the semiconductor structure after the degas operation;
depositing, by physical vapor deposition, a metal seed layer on the etch stop layer;
performing a sputter operation on the semiconductor structure while applying a bias to the semiconductor structure via an alternating current, the sputter operation being performed after depositing the metal seed layer to at least partially amorphize the metal seed layer; and
depositing, by physical vapor deposition, a metal layer on the semiconductor structure after performing the sputter operation.
7. The process of claim 6 , wherein the degas operation, depositing the etch stop layer, depositing the metal seed layer, performing the sputter operation, and depositing the metal layer are performed in a single cluster tool.
8. The process of claim 6 , wherein
performing the sputter operation on the semiconductor structure comprises performing the sputter operation on the metal seed layer.
9. The process of claim 8 , wherein:
the sputter operation is performed for about 30 seconds or less;
the metal seed layer has a thickness of about 80 Å or less;
the metal layer has a thickness of about 100 Å or more; or
combinations thereof.
10. The process of claim 6 , wherein the metal layer has a resistivity of about 40 μΩ·cm or less.
11. The process of claim 10 , wherein the resistivity of the metal layer is about 30 μΩ·cm or less.
12. The process of claim 6 , wherein:
the etch stop layer comprises Ti, TiN, Ta, TaN, Mo, W, Ru, or combinations thereof; and
the metal layer comprises Ru, Mo, W, Cu, Co, Ir, or combinations thereof.
13. The process of claim 10 , wherein the metal layer comprises Ru, W, or both.
14. The process of claim 6 , wherein the etch stop layer is deposited at a pressure of about 5 mTorr to about 20 mTorr.
15. The process of claim 6 , wherein the etch stop layer comprises a thickness from about 5 Å to about 50 Å.
16. The process of claim 6 , wherein the sputter operation comprises bombarding the etch stop layer with one or more suitable ions selected from the group consisting of He ions, Ne ions, Ar ions, Kr ions, and Xe ions.
17. The process of claim 6 , wherein the sputter operation is performed for about 5 minutes or less.
18. The process of claim 6 , wherein the alternating current substrate bias power is from about 0 W to about 500 W.
19. The process of claim 7 , wherein one or more of the degas operation, depositing the etch stop layer, depositing the metal seed layer, performing the sputter operation, and depositing the metal layer are performed without a vacuum break.
20. The process of claim 6 , wherein the metal seed layer comprises a thickness of about 5 Å to about 50 Å.