Photon induced formation of metal comprising elongated nanostructures

• US 8,114,483 B2
• Filed: 06/27/2008
• Issued: 02/14/2012
• Est. Priority Date: 07/05/2007
• Status: Active Grant

• Current Assignee: Katholieke Universiteit Leuven
• Original Assignee: IMEC International, Katholieke Universiteit Leuven
• Inventors: Dictus, Dries
• Primary Examiner(s): Le, Emily
• Assistant Examiner(s): Zhu, Weiping
• Application Number:
  US12/147,856
• Publication Number:
  US 20090011147A1
• Time in Patent Office: 1,327 Days
• Field of Search: 438/637, 427/576, 427/584
• US Class Current: 427/576
• CPC Class Codes: H01L 21/32136 using plasmas
• CPC Class Codes: Y10T 428/239 Complete cover or casing

Abstract

The preferred embodiments provide a method for forming at least one metal comprising elongated nanostructure on a substrate. The method comprises exposing a metal halide compound surface to a photon comprising ambient to initiate formation of the at least one metal comprising elongated nanostructure. The preferred embodiments also provide metal comprising elongated nanostructures obtained by the method according to preferred embodiments.

Claims

1. A method for forming in a reaction chamber at least one metal comprising elongated nanostructure onto a substrate, the method comprising:

converting at least part of a metal surface layer of a substrate into a metal halide compound;

exposing the metal halide compound to a photon comprising ambient generated by a plasma comprising at least one gas selected from the group consisting of He and Ar, whereby volatile metal halide products are formed in the reaction chamber at a concentration above a saturation level; and

redepositing the volatile metal halide products on the substrate, whereby at least one metal comprising elongated nanostructure is formed.

2. The method of claim 1, wherein the metal is copper and the elongated nanostructure is a copper comprising elongated nanostructure, wherein the substrate comprises at least a copper surface layer and wherein converting at least part of the metal surface layer into a metal halide compound is performed by converting at least part of the copper surface layer into a copper halide compound.

3. The method of claim 1, wherein converting at least part of the metal surface layer into a metal halide compound is performed by exposing at least part of the metal surface layer to a gas comprising halogen.

4. The method of claim 1, wherein converting at least part of the metal surface layer into a metal halide compound is performed by exposing at least part of the metal surface layer to a plasma comprising halogen.

5. The method of claim 3, wherein exposing at least part of the metal surface layer to a plasma comprising halogen is performed at about 600 Watt and about 10 mTorr during an exposure time period of about 10 seconds.

6. The method of claim 3, wherein the halogen is selected from the group consisting of HBr or Cl₂.

7. The method of claim 1, wherein exposing the metal halide compound to a photon comprising ambient is performed by exposing the metal halide compound to a He plasma.

8. The method of claim 7, wherein the metal halide compound is CuCl_x and the photon comprising ambient is a He plasma, wherein exposing the metal halide compound to a photon comprising ambient is performed at about 1000 Watt and about 30 mTorr without substrate bias during an exposure time period of at least about 30 seconds.

9. The method of claim 7, wherein the metal halide compound is CuBr_x and the photon comprising ambient is a He plasma, wherein exposing the metal halide compound to a photon comprising ambient is performed at about 1000 Watt and about 80 mTorr without substrate bias during an exposure time period of at least about 30 seconds.

10. The method of claim 7, wherein the metal halide compound is exposed to the photon comprising ambient for an exposure time period of about 120 seconds.

11. The method of claim 1, further comprising a step of providing a metal surface layer onto a substrate, wherein the step is performed before the step of converting at least part of a metal surface layer of a substrate into a metal halide compound.

12. The method of claim 11, further comprising, before providing a metal surface layer onto the substrate, a step of providing at least one of a protective layer and a barrier layer onto the substrate.

13. The method of claim 1, further comprising, before converting at least part of the metal surface layer into a metal halide compound, a step of providing a pattern onto the metal surface layer.

14. The method of claim 13, wherein providing a pattern onto the metal surface layer is performed by:

providing a layer of material onto the metal surface layer; and

providing at least one hole in the layer of material.

15. The method of claim 14, wherein providing a layer of material is performed by providing a layer of dielectric material.

16. The method of claim 13, further comprising, after formation of the metal comprising elongated nanostructure, a step of removing the pattern.

17. The method of claim 1, further comprising, before exposing the metal halide compound to a photon comprising ambient, a step of cleaning the substrate.

18. The method of claim 17, wherein cleaning the substrate is performed by a H₂ or N₂ plasma.

19. The method of claim 1, wherein the metal comprising elongated nanostructure is a copper comprising elongated nanostructure.

20. The method of claim 1, wherein the metal comprising elongated nanostructure comprises a combination of a metal and a metal halide compound, wherein the metal forms a core of the elongated nanostructure and the metal halide compound forms a shell of the elongated nano structure, the shell substantially completely surrounding the core.

21. The method of claim 20, wherein the metal comprising elongated nanostructure comprises from about 60% to about 99% metal and from about 1% to about 40% metal halide.

22. The method of claim 21, wherein the metal comprising elongated nanostructure comprises more than about 95% metal and less than about 5% metal halide.

23. The method of claim 20, wherein a length of the metal comprising elongated nanostructure is from about 500 nm to about 40 μ

m and wherein a diameter of the metal comprising elongated nanostructure is from about 50 nm to about 200 nm.

24. The method of claim 20, wherein the metal is copper and the metal halide is a copper halide.

25. The method of claim 24, wherein the copper halide is CuCl_x or CuBr_x.

26. The method of claim 20, wherein the metal comprising elongated nanostructure is a metal comprising nanowire.

27. The method of claim 1, wherein exposing the metal halide compound to a photon comprising ambient is performed by exposing the metal halide compound to an Ar plasma.