Metal interconnect structure and fabrication method thereof
The present disclosure provides metal interconnect structures and fabrication methods thereof. An exemplary fabrication method of the metal interconnect structure includes providing a semiconductor substrate having a surface; forming a first metal layer on the surface of the semiconductor substrate; forming a dielectric layer on the first metal layer; forming contact through holes exposing a surface of the first metal layer, and trenches being over the contact through holes and connecting with the contact through holes in the dielectric layer; forming a first metal barrier layer on inner surfaces of the trenches and the contact through holes; forming a metal nitride barrier layer covering the first metal barrier layer on the inner surfaces of the trenches and the contact through holes; and forming a second metal layer to fill the trenches and the contact through holes.
1. A method for fabricating a metal interconnect structure, comprising:
providing a semiconductor substrate having a surface;
forming a first metal layer on the surface of the semiconductor substrate;
forming a dielectric layer on the first metal layer;
forming contact through holes exposing a surface of the first metal layer, and trenches being over the contact through holes and connecting with the contact through holes in the dielectric layer;
forming a first metal barrier layer on inner surfaces of the trenches and the contact through holes;
forming a metal nitride barrier layer covering the first metal barrier layer on the inner surfaces of the trenches and the contact through holes;
forming a second metal barrier covering the metal nitride barrier layer on the inner
surfaces of the trenches and the contact through holes;
performing an ion bombarding process on the second metal barrier layer and the metal nitride barrier layer; and
forming a second metal layer to fill the trenches and the contact through holes.
2. The method according to claim 1 , after the ion bombarding process, further comprising:
forming a third metal barrier covering the second metal barrier layer on the inner surfaces of the trenches and the contact through holes.
3. The method according to claim 2 , after forming the third metal barrier layer, further comprising:
forming a seed layer covering the third metal barrier layer on the inner surfaces of the trenches and the contact through holes.
4. The method according to claim 3 , wherein:
the seed layer is made of copper; and
a thickness of the seed layer is in a range of approximately 200 Å-800 Å.
5. The method according to claim 3 , wherein:
the seed layer is formed by a physical vapor deposition process; and
a DC power of the physical vapor deposition process is in a range of approximately 10 kW-50 kW.
6. The method according to claim 2 , wherein:
a thickness of the third metal barrier layer is in a range of approximately 20 Å-50 Å.
7. The method according to claim 2 , wherein:
the first metal barrier layer is made of one of Ta and Ti;
the second metal barrier layer is made of one of Ta and Ti;
the third metal barrier layer is made of one of Ta and Ti; and
the metal nitride barrier layer is made of one of TaN and TiN.
8. The method according to claim 1 , wherein:
the ion bombarding process is an argon ion bombarding process,
a flow rate of argon gas is in a range of approximately 5 sccm-50 sccm;
an AC power is in a range of approximately 500 W-1000 W; and
a processing time of the argon ion bombarding process is in a range of approximately 2 s-5 s.
9. The method according to claim 1 , wherein:
a thickness of the second metal barrier layer is in a range of approximately 20 Å-50 Å.
10. The method according to claim 1 , wherein:
the first metal barrier layer formed by a physical vapor deposition process; and
a DC power of the physical vapor deposition process is in a range of approximately 10 kW-30 kW.
11. The method according to claim 1 , wherein forming the second metal layer comprises:
filling the second metal layer in the trenches and the contact through holes; and
performing a planarization process.
12. The method according to claim 11 , wherein:
the second metal layer is formed by an electro-chemical plating process.
13. The method according to claim 1 , wherein:
a width of the trenches and the contact through holes is in a range of approximately 30 nm-100 nm; and
a depth of the trenches and the contact through-holes is in a range of approximately 100 nm-300 nm.
14. The method according to claim 1 , wherein:
the first metal barrier layer formed by a physical vapor deposition process; and
a DC power of the physical vapor deposition process is in a range of approximately 10 kW-30 kW.
15. The method according to claim 1 , wherein forming the second metal layer comprises:
filling the second metal layer in the trenches and the contact through holes; and
performing a planarization process.
16. The method according to claim 1 , wherein:
a width of the trenches and the contact through holes is in a range of approximately 30 nm-100 nm; and
a depth of the trenches and the contact through-holes is in a range of approximately 100 nm-300 nm.