Methods for forming roughened surfaces and applications thereof

• US 20070254488A1
• Filed: 04/28/2006
• Published: 11/01/2007
• Est. Priority Date: 04/28/2006
• Status: Active Grant

• Current Assignee: ASM International NV
• Original Assignee: ASM International NV
• Inventors: Haukka, Suvi, Huotari, Hannu
• Granted Patent: US 7,491,634 B2
• Time in Patent Office: Days
• US Class Current: 438/720
• 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 the substrate; and

depositing islands comprising metal on the surface.

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 1, wherein depositing comprises an atomic layer deposition process.

9. The method of claim 8, wherein the atomic layer deposition process comprises alternately and sequentially contacting the substrate with a metal source chemical and an oxygen-containing reactant.

10. The method of claim 9, wherein the metal source chemical is a cyclopentadienyl or betadiketonate compound.

11. The method of claim 10, wherein the metal source chemical is a noble metal cyclopentadienyl compound.

12. The method of claim 9, wherein the oxygen-containing reactant is selected from the group consisting of molecular oxygen, water, ozone and excited species of oxygen.

13. The method of claim 9, wherein the oxygen-containing reactant is molecular oxygen.

14. The method of claim 9, wherein the oxygen-containing reactant is water.

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

16. The method of claim 15, wherein the deposition enhancing reagent is a gaseous halide or metalorganic compound.

17. The method of claim 16, wherein the deposition enhancing reagent is a halide selected from the group consisting of hydrogen halides and metal halides.

18. The method of claim 16, wherein the deposition enhancing agent is a halide selected from the group consisting of HCl, AlCl₃. HfCl₄ and SiCl₄.

19. The method of claim 16, 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.

20. The method of claim 16, 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.

21. The method of claim 16, 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.

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

23. The method of claim 22, wherein the blocking reagent blocks isolated OH groups on the surface.

24. The method of claim 22, wherein the blocking reagent is selected from the group consisting of silanes and silazanes.

25. The method of claim 22, wherein the blocking reagent is hexamethyldisilazane (HMDS).

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

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

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

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

30. The method of claim 29, wherein the roughened surface has an RMS roughness between about 2.0 and 30 nm.

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

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

depositing a metal oxide on the substrate; and

reducing the metal oxide at a temperature at which agglomeration occurs.

33. The method of claim 32, wherein the temperature at which the metal oxide is reduced is between 350°

C. and 650°

C.

34. The method of claim 32, 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).

35. A method for forming a capacitor in an integrated circuit (IC), comprising:

providing a substrate in a reaction space;

forming discrete three-dimensional islands conductive material comprising metal on a surface of the substrate; and

depositing a layer of a high-k material over the islands.

36. The method of claim 35, further comprising deposition a gate electrode over the layer of the high-k material.

37. The method of claim 35, wherein the conductive material is a metal oxide.

38. The method of claim 35, wherein forming comprises depositing a metal oxide and reducing the metal oxide to metal.