Methods of metallization for microelectronic devices utilizing metal oxide

• US 20060019493A1
• Filed: 07/11/2005
• Published: 01/26/2006
• Est. Priority Date: 07/15/2004
• Status: Abandoned Application

• Current Assignee: ASM International NV
• Original Assignee: ASM International NV
• Inventors: Li, Wei Min
• Application Number:
  US11/179,791
• Publication Number:
  US 20060019493A1
• Time in Patent Office: Days
• US Class Current: 438/680
• CPC Class Codes: H01L 21/76823 transforming an insulating layer into a conductive layer
• CPC Class Codes: H01L 21/76838 characterised by the formation and the after-treatment of the conductors etching for patterning the conductors H01L21/3213
• CPC Class Codes: H01L 21/76873 for electroplating
• CPC Class Codes: H01L 29/517 the insulating material comprising a metallic compound, e.g. metal oxide, metal silicate H01L29/518 takes precedence
• CPC Class Codes: H01L 29/518 the insulating material containing nitrogen, e.g. nitride, oxynitride, nitrogen-doped material
• CPC Class Codes: H10B 12/038 the capacitor being in a trench in the substrate
• CPC Class Codes: H10B 12/05 Making the transistor
• CPC Class Codes: H10B 12/37 the capacitor being at least partially in a trench in the substrate

Abstract

A metal oxide is deposited on a substrate in a semiconductor fabrication metallization process is patterned and subsequently reduced to a more conductive form, such as elemental metal. The metal oxide is reduced by exposure to at least one reducing agent or current that is capable of removing oxygen from the metal oxide. Copper oxide, for example, can be dry etched for patterning prior to reduction to copper metal, and the patterned copper used as an ECD seed layer.

Claims

1. A method of producing a conductive thin film, comprising:

depositing metal oxide on a substrate by atomic layer deposition;

patterning the metal oxide; and

at least partially reducing the metal oxide to a more conductive form after patterning.

2. The method of claim 1, wherein patterning comprises dry etching the metal oxide before reducing.

3. The method of claim 1, wherein atomic layer deposition comprises contacting the substrate with alternating vapor phase pulses of:

at least one first source chemical comprising a compound capable of adsorbing no more than a monolayer of metal species on the substrate; and

at least one second source chemical comprising a compound capable of oxidizing the metal species on the substrate into the metal oxide.

4. The method of claim 3, wherein the first source chemical is Cu(thd)₂ and the second source chemical is selected from the group consisting of ozone, oxygen, and a mixture of ozone and oxygen.

5. The method of claim 3, wherein the first source chemical is CuCl.

6. The method of claim 3, wherein the first source chemical is anhydrous metal nitrate.

7. The method of claim 3, wherein the first source chemical is Co(thd)₃.

8. The method of claim 3, wherein the first source chemical is Pd(thd)₃ and the second source chemical is selected from the group consisting of ozone, oxygen, and a mixture of ozone and oxygen.

9. The method of claim 3, wherein the first source chemical is bis(ethylcyclopentadienyl)ruthenium ((EtCp)₂Ru) and the second source chemical is a mixture of oxygen and water gases.

10. The method of claim 1, wherein at least partially reducing the metal oxide comprises exposure to at least one organic reducing agent that is capable of removing oxygen from the metal oxide.

11. The method of claim 10, wherein the at least one organic reducing agent is in vapor form.

12. The method of claim 10, wherein the at least one organic reducing agent is selected from the group consisting of alcohol, aldehyde, and carboxylic acid.

13. The method of claim 1, wherein at least partially reducing the metal oxide comprises treatment with hydrogen plasma.

14. The method of claim 1, wherein at least partially reducing the metal oxide comprises treatment with thermal hydrogen.

15. The method of claim 1, wherein at least partially reducing the metal oxide comprises applying an electric current.

16. The method of claim 1, wherein the metal oxide is copper oxide.

17. The method of claim 16, wherein the copper oxide has a thickness of at least 1 nm.

18. The method of claim 1, further comprising placing the substrate into a metal compound solution after reducing and connecting the substrate to an external DC power supply.

19. The method of claim 1, further comprising:

depositing a first diffusion barrier layer on the substrate before depositing the metal oxide; and

depositing a second diffusion barrier layer over the substrate after at least partially reducing.

20. The method of claim 19, wherein the first diffusion barrier layer comprises a conductive diffusion barrier material.

21. A method of producing a transistor gate, comprising:

depositing an insulating layer on a substrate;

depositing a first diffusion barrier layer on the insulating layer;

depositing metal oxide on the first diffusion barrier layer by atomic layer deposition;

masking the metal oxide;

dry etching the metal oxide after masking;

at least partially chemically reducing the metal oxide after dry etching; and

depositing a second diffusion barrier layer on the substrate after at least partially chemically reducing the metal oxide.

22. The method of claim 21, wherein the first diffusion barrier layer comprises a conductive material.

23. The method of claim 21, wherein the atomic layer deposition comprises a plurality of cycles, each cycle comprising:

contacting the substrate with a vapor phase pulse of a first source chemical comprising a compound capable of adsorbing no more than a monolayer of metal species on the substrate;

removing any excess first source chemical and byproduct;

contacting the substrate with a second source chemical comprising a compound capable of oxidizing the metal species on the substrate into the metal oxide; and

removing any excess of the second source chemical and byproduct.

24. The method of claim 21, wherein at least partially reducing the metal oxide comprises exposure to at least one organic reducing agent that is capable of removing oxygen from the metal oxide.

25. The method of claim 24, wherein the at least one organic reducing agent is selected from the group consisting of alcohol, aldehyde, and carboxylic acid.

26. The method of claim 24, wherein the at least one organic reducing agent is in vapor form.

27. The method of claim 21, wherein the metal oxide is copper oxide.

28. The method of claim 21, wherein at least partially chemically reducing the metal oxide comprises treatment with hydrogen plasma.

29. The method of claim 21, wherein at least partially chemically reducing the metal oxide comprises treatment with thermal hydrogen.

30. The method of claim 21, wherein at least partially chemically reducing the metal oxide comprises applying an electric current to the metal oxide.

31. A method of forming copper features in an integrated circuit, comprising:

depositing a blanket layer of copper oxide by atomic layer deposition;

masking and dry etching the copper oxide to form a patterned copper oxide thin film; and

reducing the copper oxide to form copper metal.

32. The method of claim 31, wherein atomic layer deposition comprises contacting the substrate with alternating vapor phase pulses of at least one first source chemical comprising a compound capable of adsorbing no more than a monolayer of metal species on the substrate and at least one second source chemical comprising a compound capable of oxidizing the metal species on the substrate into the metal oxide.

33. The method of claim 31, wherein reducing the copper oxide comprises exposure to at least one organic reducing agent.

34. The method of claim 31, wherein reducing the copper oxide comprises exposure to at least one inorganic reducing agent.

35. The method of claim 31, wherein reducing the copper oxide comprises by exposure to an electrical current.

36. The method of claim 31, further comprising selectively depositing copper on the copper metal left by reducing the copper oxide.

37. The method of claim 36, wherein selectively depositing comprises electrochemical deposition.

38. The method of claim 31, further comprising depositing a blanket layer of diffusion barrier material prior to depositing the blanket layer of copper oxide.

39. The method of claim 38, further comprising encapsulating the copper metal with a diffusion barrier material after reducing the copper oxide.

40. The method of claim 31, wherein masking and dry etching comprises defining a pattern of interconnect lines.

41. The method of claim 31, wherein masking and dry etching comprises producing a pattern of a plurality of isolated capacitor electrodes.

42. The method of claim 31, wherein the copper metal is formed over a material layer defining a work function of a transistor gate electrode.

43. A method of forming patterned metal features in an integrated circuit, comprising:

depositing a blanket layer of metal oxide in an atomic layer deposition comprising a plurality of cycles, each cycle including;

saturating a substrate surface with a first chemical precursor containing metal, the first chemical precursor adsorbing no more than about one monolayer across the substrate,

removing excess gas phase first precursor and any by-product from the substrate,

exposing the substrate to a second chemical precursor containing oxygen, the second chemical precursor oxidizing the first chemical precursor adsorbed on the substrate to form no more than about a monolayer of metal oxide, and

removing excess gas phase second chemical precursor and by-product from the substrate;

masking and etching the metal oxide to form a patterned metal oxide; and

chemically or electrically reducing the patterned metal oxide to form a conductive layer.