Interconnection structures and fabrication methods thereof

Patent metadata

Field	Value
Publication number	US-10453797-B2
Application number	US-201715821581-A
Country	US
Kind code	B2
Filing date	Nov 22, 2017
Priority date	Nov 29, 2016
Publication date	Oct 22, 2019
Grant date	Oct 22, 2019

Abstract

A method for fabricating an interconnection structure includes providing a substrate, forming a dielectric layer on the substrate, forming a conductive structure in the dielectric layer, forming a cap layer doped with silicon on the conductive structure and the dielectric layer, and performing an annealing process on the conductive structure and the cap layer. During the annealing process, the silicon ions in the cap layer react with the material of the conductive structure and form chemical bonds. As such, the connection strength between the cap layer and the conductive structure is improved, which is conducive to suppressing electro migration in the formed interconnection structure. Therefore, the reliability of the formed interconnection structure is improved.

First claim

What is claimed is:

1. A method for fabricating an interconnection structure, comprising:
providing a substrate;
forming a dielectric layer on the substrate;
forming a conductive structure in the dielectric layer;
forming a cap layer doped with silicon on the conductive structure and the dielectric layer, wherein the cap layer has a bi-layer structure; and
performing an annealing process on the conductive structure and the cap layer, wherein along a direction away from the conductive structure, a doping concentration of silicon in the cap layer gradually decreases.

2. The method for fabricating the interconnection structure according to claim 1 , wherein:
the cap layer is made of a material including silicon-doped AlN.

3. The method for fabricating the interconnection structure according to claim 1 , wherein:
the cap layer is formed by an atomic layer deposition.

4. The method for fabricating the interconnection structure according to claim 3 , wherein forming the cap layer further includes:
forming an AlSiN layer on the conductive structure and the dielectric layer; and
forming an AlN layer on the AlSiN layer.

5. The method for fabricating the interconnection structure according to claim 4 , wherein:
a ratio between a thickness of the AlSiN layer and a thickness of the AlN layer is in a range of 3:1 to 2:1.

6. The method for fabricating the interconnection structure according to claim 1 , wherein:
an atomic percentage of the silicon doped in the cap layer is in a range of approximately 10% to approximately 20%.

7. The method for fabricating the interconnection structure according to claim 1 , after forming the conductive structure and prior to forming the cap layer, further including:
performing a plasma pre-treatment process on a surface of the dielectric layer.

8. The method for fabricating the interconnection structure according to claim 1 , wherein performing the plasma pre-treatment process includes:
using plasma of trisilylamine to treat the surface of the dielectric layer.

9. The method for fabricating the interconnection structure according to claim 1 , wherein:
the dielectric layer is made of an ultra-low-k dielectric material with a dielectric constant lower than 2.5; and
the conductive structure is made of Cu.

10. A method for fabricating an interconnection structure, comprising:
providing a substrate;
forming a dielectric layer on the substrate;
forming a conductive structure in the dielectric layer;
forming a cap layer doped with silicon on the conductive structure and the dielectric layer;
controlling a doping concentration of the silicon in the cap layer to gradually decrease along a direction away from the conductive structure; and
performing an annealing process on the conductive structure and the cap.

11. The method for fabricating the interconnection structure according to claim 10 , wherein:
forming the cap layer further includes at least one time of deposition of a silicon-doped material;
each time of the deposition of the silicon-doped material includes absorbing an Al-containing atomic layer, absorbing a Si-containing atomic layer on the Al-containing atomic layer, and performing a nitrogen treatment process on the Al-containing atomic layer and the Si-containing atomic layer; and
absorbing the Si-containing atomic layer on the Al-containing atomic layer includes introducing a Si-containing reaction gas including SiH 4 , and removing remaining Si-containing reaction gas by purging.

12. The method for fabricating the interconnection structure according to claim 11 , wherein:
deposition of the silicon-doped material is performed multiple times; and
a flow rate of SiH 4 gradually decreases during the multiple times of deposition of the silicon-doped material.

13. The method for fabricating the interconnection structure according to claim 11 , wherein:
deposition of the silicon-doped material is performed for multiple times; and
a process time to introduce SiH 4 gradually decreases during the multiple times of the deposition of the silicon-doped material.

14. An interconnection structure, comprising:
a substrate;
a dielectric layer formed on the substrate;
a conductive structure formed in the dielectric layer; and
a cap layer doped with silicon and formed on the conductive structure and the dielectric layer, wherein along a direction away from the conductive structure, a doping concentration of silicon in the cap layer gradually decreases.

15. The interconnection structure according to claim 14 , wherein:
the cap layer is made of a material including silicon-doped AlN.

16. The interconnection structure according to claim 14 , wherein:
an atomic percentage of the silicon doped in the cap layer is in a range of approximately 10% to approximately 20%.

17. The interconnection structure according to claim 14 , wherein the cap layer has a bi-layer structure including:
an AlSiN layer; and
an AlN layer formed on the AlSiN layer.

18. The interconnection structure according to claim 17 , wherein:
a ratio between a thickness of the AlSiN layer and a thickness of the AlN layer is in a range of 3:1 to 2:1.

19. The interconnection structure according to claim 14 , wherein:
the dielectric layer is made of an ultra-low-k dielectric material with a dielectric constant lower than 2.5; and
the conductive structure is made of Cu.

Assignees

• Semiconductor Mfg Int Shanghai Corp
• Semiconductor Mfg Int Beijing Corp

Inventors

• Deng Hao

Classifications

• H10P14/69391

  the material containing aluminium, e.g. Al2O3 · CPC title

• H10P14/6929

  the material containing aluminium, e.g. AlSiOx · CPC title

• H10P14/6682

  the compound being a silane, e.g. disilane, methylsilane or chlorosilane · CPC title

• H10P14/6514

  by exposure to a plasma · CPC title

• H10P14/6339

  deposition by cyclic CVD, e.g. ALD, ALE or pulsed CVD · CPC title