Methods for forming roughened surfaces and applications thereof

• US 7,491,634 B2
• Filed: 04/28/2006
• Issued: 02/17/2009
• Est. Priority Date: 04/28/2006
• Status: Active Grant

• Current Assignee: ASM International NV
• Original Assignee: ASM International NV
• Inventors: Haukka, Suvi, Huotari, Hannu
• Primary Examiner(s): LE, DUNG ANH
• Application Number:
  US11/414,510
• Publication Number:
  US 20070254488A1
• Time in Patent Office: 1,026 Days
• Field of Search: 438/398, 438592-584, 438687-689
• US Class Current: 438/592
• CPC Class Codes: H01L 21/32051 Deposition of metallic or metal-silicide layers
• CPC Class Codes: H01L 28/84 being a rough surface, e.g. using hemispherical grains
• CPC Class Codes: H10B 12/033 the capacitor extending over the transistor
• CPC Class Codes: Y10S 977/742 Carbon nanotubes, CNTs
• CPC Class Codes: Y10S 977/773 Nanoparticle, i.e. structure having three dimensions of 100 nm or less

Abstract

Methods of forming a roughened metal surface on a substrate are provided, along with structures comprising such roughened surfaces. In preferred embodiments roughened surfaces are formed by selectively depositing metal or metal oxide on a substrate surface to form discrete, three-dimensional islands. Selective deposition may be obtained, for example, by modifying process conditions to cause metal agglomeration or by treating the substrate surface to provide a limited number of discontinuous reactive sites. The roughened metal surface may be used, for example, in the manufacture of integrated circuits.

Claims

1. A method for forming a roughened surface on a substrate, the method comprising:

forming a discontinuous surface termination on a surface of the substrate; and

depositing islands comprising metal on the surface having the discontinuous surface termination.

2. The method of claim 1, wherein the substrate surface comprises SiO₂.

3. The method of claim 1, wherein the islands comprise one or more metals selected from the group consisting of Cu, Ni, Fe, Co, Zn, Ru, Rh, Pd, Ag, Re, Os, Ir, Pt, Mo and W.

4. The method of claim 1, wherein the islands comprise metal oxide.

5. The method of claim 4, wherein the metal oxide is conductive.

6. The method of claim 1, wherein the metal islands comprise one or more noble metals.

7. The method of claim 1, wherein depositing islands comprising metal comprises depositing metal oxide and subsequently reducing the metal oxide to elemental metal.

8. The method of claim 7, wherein reducing comprises exposing the metal oxide to a reducing agent selected from the group consisting of alcohols (—

OH), aldehydes (—

CHO) and carboxylic acids (—

COOH).

9. The method of claim 7, further comprising growing carbon nanotubes from said elemental metal.

10. The method of claim 1, wherein depositing comprises an atomic layer deposition process.

11. The method of claim 10, further comprising growing carbon nanotubes on said islands.

12. The method of claim 10, wherein the atomic layer deposition process comprises alternately and sequentially contacting the substrate with a metal source chemical and an oxygen-containing reactant.

13. The method of claim 12, wherein the metal source chemical is a cyclopentadienyl or betadiketonate compound.

14. The method of claim 12, wherein the oxygen-containing reactant is selected from the group consisting of molecular oxygen, water, ozone and excited species of oxygen.

15. The method of claim 12, wherein the oxygen-containing reactant is molecular oxygen.

16. The method of claim 12, wherein the oxygen-containing reactant is water.

17. The method of claim 13, wherein the metal source chemical is a noble metal cyclopentadienyl compound.

18. The method of claim 1, wherein forming the discontinuous surface termination comprises contacting the substrate with a deposition enhancing reagent to modify a portion of reactive surface sites on the substrate.

19. The method of claim 18, wherein the deposition enhancing reagent is a gaseous halide or metalorganic compound.

20. The method of claim 19, wherein the deposition enhancing reagent is a halide selected from the group consisting of hydrogen halides and metal halides.

21. The method of claim 19, wherein the deposition enhancing agent is a halide selected from the group consisting of HCl, AlCl₃, HfCl₄ and SiCl₄.

22. The method of claim 19, wherein the metalorganic compound is selected from the group consisting of trimethylaluminum, tetrakis(ethylmethyl)aminohafnium, tetrakis(dimethyl)aminohafnium, tetrakis(diethyl)aminohafnium, tetrakis(ethylmethyl)aminozirconium, tetrakis(dimethyl)aminozirconium and tetrakis(diethyl)aminozirconium.

23. The method of claim 19, wherein after contacting the substrate with a gaseous halide or metalorganic compound the halide or metalorganic surface terminations are at a concentration between about 0.001 terminations/nm² to 10 terminations/nm².

24. The method of claim 19, wherein after contacting the substrate with a gaseous halide or metalorganic compound the halide or metalorganic surface terminations are at a concentration between about 0.1 terminations/nm² to 1.5 terminations/nm².

25. The method of claim 18, wherein forming a discontinuous surface termination comprises contacting the substrate with a less than saturating pulse of the deposition enhancing agent.

26. The method of claim 18, wherein forming a discontinuous surface termination encompasses selecting a deposition temperature at which a discontinuous surface termination is formed.

27. The method of claim 1, wherein forming the discontinuous surface termination comprises contacting the substrate with a blocking reagent.

28. The method of claim 27, wherein the blocking reagent blocks isolated OH groups on the surface.

29. The method of claim 27, wherein the blocking reagent is selected from the group consisting of silanes and silazanes.

30. The method of claim 27, wherein the blocking reagent is hexamethyldisilazane (HMDS).

31. The method of claim 1, wherein the islands have a concentration between about 0.001 particles/nm² to 10 particles/nm².

32. The method of claim 1, wherein the islands have a concentration less than 0.001 particles/nm₂.

33. The method of claim 1, wherein the islands have a thickness between about 5 nm and 100 nm.

34. The method of claim 1, wherein the roughened surface has an RMS roughness between about 0.5 and 100 nm.

35. The method of claim 34, wherein the roughened surface has an RMS roughness between about 2.0 and 30 nm.

36. The method of claim 1, wherein the roughened surface is used to form a capacitor structure.

37. The method of claim 1, wherein the islands serve as nucleation points for growing carbon nanotubes.

38. A method for forming a roughened surface on a substrate, the method comprising:

forming a discontinuous surface termination on a SiO₂ surface of the substrate; and

depositing islands comprising metal on the surface by an atomic layer deposition (ALD) process.