Implementation of a metal barrier in an integrated electronic circuit
A metal barrier is realized on top of a metal portion of a semiconductor product, by forming a metal layer on the surface of the metal portion, with this metal layer comprising a cobalt-based metal material. Then, after an optional deoxidation step, a silicidation step and a nitridation step of the cobalt-based metal material of the metal layer are performed. The antidiffusion properties of copper atoms (for example) and the antioxidation properties of the metal barrier are improved.
1. A method of forming a metal barrier, comprising:
forming a metal portion of a semiconductor product;
forming a metal layer on a surface of the metal portion, with said metal layer comprising a cobalt-based metal material; and then:
siliciding the cobalt-based metal material of the metal layer; and
nitriding the cobalt-based metal material of the metal layer.
2. The method according to claim 1 , wherein siliciding and nitriding are separately performed.
3. The method according to claim 2 , wherein siliciding is performed before nitriding.
4. The method according to claim 1 , wherein siliciding and the nitriding are preceded by deoxidation to deoxidize the metal layer comprising the cobalt-based metal material.
5. The method according to claim 4 , wherein deoxidation is performed using a nitrogen plasma.
6. The method according to claim 1 , wherein siliciding is performed using a silane and/or disilane flow under pressure.
7. The method according to claim 6 , wherein the silane and/or disilane are diluted in dinitrogen during siliciding.
8. The method according to claim 1 , wherein nitriding is performed using a nitrogen plasma.
9. The method according to claim 8 , wherein the nitrogen plasma comprises an RF plasma of ammonia.
10. The method of claim 1 wherein nitriding is performed before siliciding.
11. The method of claim 1 wherein nitriding and siliciding are performed simultaneously.
12. A method, comprising:
forming a metal portion inside a body of dielectric material and having an exposed top surface;
depositing a layer of cobalt-based metal material on the exposed top surface;
siliciding the layer of cobalt-based metal material to form a metal barrier; and
nitriding the metal barrier.
13. The method of claim 12 wherein the cobalt-based metal material is compound of cobalt and an element selected from the group consisting of tungsten, phosphorous and boron.
14. The method of claim 12 wherein the metal barrier has a thickness including diffused silicon atoms of between about 360 and 2000 Angstroms.
15. The method of claim 12 wherein nitriding diffuses nitrogen atoms into the metal barrier.
16. The method of claim 12 further comprising, after depositing and before siliciding or nitriding, deoxidation of the layer of cobalt-based metal material.
17. A method, comprising:
forming a metal portion inside a body of dielectric material and having an exposed top surface;
depositing a layer of cobalt-based metal material on the exposed top surface;
simultaneously siliciding and nitriding the layer of cobalt-based metal material to form a metal barrier.