Multilayered copper structure for improving adhesion property

• US 20030013302A1
• Filed: 08/23/2002
• Published: 01/16/2003
• Est. Priority Date: 03/07/2000
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Tegal Corp. (Rennova Health, Inc.)
• Inventors: Nguyen, Tue
• Granted Patent: US 6,777,331 B2
• Time in Patent Office: Days
• US Class Current: 438/687
• CPC Class Codes: H01L 21/28562 Selective deposition
• CPC Class Codes: H01L 21/76862 Bombardment with particles, e.g. treatment in noble gas plasmas; UV irradiation
• CPC Class Codes: H01L 21/76886 Modifying permanently or temporarily the pattern or the conductivity of conductive members, e.g. formation of alloys, reduction of contact resistances
• CPC Class Codes: H01L 2221/1078 Multiple stacked thin films not being formed in openings in dielectrics

Abstract

A multilayered copper structure has been provided for improving the adhesion of copper to a diffusion barrier material, such as TiN, in an integrated circuit substrate. The multilayered copper structure comprises a thin high-resistive copper layer to provide improved adhesion to the underlying diffusion barrier layer, and a low-resistive copper layer to carry the electrical current with minimum electrical resistance. The invention also provides a method to form the multilayered copper structure.

Claims

1. A method to form a multilayered copper structure for improving adhesion to an underlying diffusion barrier layer, the method comprising the steps of:

a) Forming a thin high-resistive copper layer, whereby this high-resistive layer serves to improve the adhesion of copper to the underlying diffusion barrier layer;

b) Treating the thin high-resitive copper layer to reduce the resistance of the thin high-resistive copper layer, whereby the treatment step improves the conductivity of the high-resistive copper layer without destroying the adhesion property; and

c) Forming a low-resistive copper layer, in which the resistivity of the low-resistive layer is lower than the resistivity of the treated high-resistive layer, whereby this layer serves to carry the electrical current with minimum electrical resistance.

2. A method as in claim 1 in which the higher value in resistivity of the high-resistive copper layer is due to the presence of oxygen.

3. A method as in claim 1 in which the steps a) and b) are repeated a plurality of times before continuing to step c) to achieve a desired thickness.

4. A method as in claim 1 in which the total thickness of the treated high-resistive copper layer is less than 5 nm.

5. A method as in claim 1 in which the resistivity of the high-resistive copper layer is between 10 to 500 μ

Ω

-cm.

6. A method as in claim 1 in which the resistivity of the treated high-resistive copper layer is between 3 to 400 μ

Ω

-cm.

7. A method as in claim 1 in which the thickness of the high-resistive copper layer in step a) is less than one monolayer for ease of treatment in step b).

8. A method as in claim 1 in which the formation of the high-resistive copper layer in step a) is by adsorption of a copper-carrying precursor.

9. A method as in claim 1 in which the high-resistive copper layer is deposited by the chemical vapor deposition method employing a combination of process precursors and process conditions to achieve a resistivity between 10 to 500 μ

Ω

-cm.

10. A method as in claim 9 in which the process precursors are exposed to a plasma power source, whereby this exposure serves to break up the precursors for easier incorporation of impurities into the high-resistive copper layer.

11. A method as in claim 9 in which the process precursors comprises a liquid copper precursor and an oxygen-contained precursor, whereby the liquid copper precursor serves to deposit a copper layer, and the oxygen-contained precursor serves to incorporate oxygen into the deposited copper layer to achieve the resistivity between 10 to 500 μ

Ω

-cm.

12. A method as in claim 11 in which the oxygen-contained precursor is a precursor comprising an oxygen species, the oxygen species being selected from a group consisting of O₂, N₂O, NO₂, air, water vapor, alcohol vapor, OH ligand, chemicals containing OH ligand, chemicals releasing OH ligand upon annealing.

13. A method as in claim 1 in which the treating of the high-resistive copper layer is by the method of oxygen gettering.

14. A method as in claim 1 in which the treating of the high-resistive copper layer is by the reaction of plasma hydrogen.

15. A method as in claim 1 in which the treating of the high-resistive copper layer is by the introduction of organic compounds to reduce copper oxide to copper metal and volatile organic by-products.

16. A method as in claim 1 in which the treating of the high-resistive copper layer is by the introduction of a gettering metal precursor, the gettering metal is selected from a group of metals that its oxide conducts electricity.

17. A method as in claim 1 in which the treating of the high-resistive copper layer is by the introduction of an alloying metal precursor, the alloying metal is selected from a group of metals that forms an alloy with copper oxide such that the alloy is not non-conducting of electricity.

18. A method as in claim 1 in which the low-resistive copper layer is deposited with the resistivity less than 3 μ

Ω

-cm.

19. A method as in claim 1 in which the low-resistive copper layer is deposited by the electrochemical deposition method.

20. A method as in claim 1 in which the low-resistive copper layer is deposited by the chemical vapor deposition method.

21. A method as in claim 1 in which the low-resistive copper layer is deposited sequentially by the chemical vapor deposition method and then by the electrochemical deposition method.

22. A method as in claim 1 comprising a further step, preceding step

a):

c) Depositing the underlying diffusion barrier structure on a substrate, whereby the diffusion barrier structure serves to prevent the diffusion of copper into the substrate.