Selective formation of metal layers in an integrated circuit

• US 7,476,618 B2
• Filed: 10/18/2005
• Issued: 01/13/2009
• Est. Priority Date: 10/26/2004
• Status: Active Grant

• Current Assignee: ASM Japan K.K. (ASM International NV)
• Original Assignee: ASM Japan K.K. (ASM International NV)
• Inventors: Leinikka, Miika, Koh, Wonyong, Huotari, Hannu A., Kilpelä, Olli V., Tuominen, Marko
• Primary Examiner(s): Nguyen; Ha Tran T
• Assistant Examiner(s): WHALEN, DANIEL B
• Application Number:
  US11/254,071
• Publication Number:
  US 20060121733A1
• Time in Patent Office: 1,183 Days
• Field of Search: 438/584, 438/597, 438/598, 438/618, 438/622, 438/623, 438/627, 438/650, 438/686, 257/E21.597, 257/E21.006, 257/E21.17, 257/E23.162
• US Class Current: 438/686
• CPC Class Codes: C23C 16/18 from metallo-organic compounds
• CPC Class Codes: C23C 16/45525 Atomic layer deposition [ALD]
• CPC Class Codes: H01L 21/28562 Selective deposition
• CPC Class Codes: H01L 21/32051 Deposition of metallic or metal-silicide layers
• CPC Class Codes: H01L 21/76814 post-treatment or after-treatment, e.g. cleaning or removal of oxides on underlying conductors
• CPC Class Codes: H01L 21/76834 formation of thin insulating films on the sidewalls or on top of conductors H01L21/76831 takes precedence
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76849 the layer being positioned on top of the main fill metal

Abstract

A method for enhancing the reliability of copper interconnects and/or contacts, such as the bottom of vias exposing top surfaces of buried copper, or at the top of copper lines just after CMP. The method comprises contacting the exposed copper surface with a vapor phase compound of a noble metal and selectively forming a layer of the noble metal on the exposed copper surface, either by a copper replacement reaction or selective deposition (e.g., ALD or CVD) of the noble metal.

Claims

1. A method for selectively forming a conductive layer in an integrated circuit, comprising:

providing a copper-exposed surface as a first surface and a non-copper surface as a second surface; and

contacting the first surface and the second surface with a vapor phase compound of a noble metal for replacing copper on the first surface with the noble metal dissociated from the compound, thereby depositing the noble metal predominantly on the first surface relative to the second surface as a result of replacing copper on the first surface with the noble metal dissociated from the compound.

2. The method according to claim 1, wherein the second surface comprises an insulator in which copper is inlaid.

3. The method according to claim 2, wherein the insulator comprises a low k material.

4. The method according to claim 1, wherein the first surface comprises the bottom of a via and the second surface is defined by an insulator in which the via is formed.

5. The method of claim 4, wherein the via extends downwardly from a trench in a dual damascene structure.

6. The method according to claim 1, wherein the first surface comprises an upper surface of a copper line.

7. The method of claim 1, wherein the second surface is defined by an insulating material.

8. The method of claim 1, wherein the noble metal is selected from the group of Pt, Au, Ru, Rh, Ir and Pd.

9. The method of claim 1, wherein depositing the noble metal further comprises selectively depositing by atomic layer deposition (ALD) or chemical vapor deposition (CVD) additional noble metal onto the noble metal that is formed by replacing.

10. The method of claim 1, wherein the vapor phase compound of the noble metal is selected from the group of bis(2,2,6,6-tetramethyl-3,5-heptanedionato)( 1 ,5-cyclooctadiene)ruthenium (II), ruthenium (III) acetylacetonate, tris(2,2,6,6-tetramethyl-3 ,5-heptanedionato)ruthenium (III), 1 ,5-cyclooctadiene(acetylacetonato)iridium (I) dicarbonyl(acetylacetonato)iridium (I), iridium (III) acetylacetonate, platinum (II) hexafluoroacetylacetonate, (acetylacetonato)bis(cyclooctene)rhodium (I), (acetylacetonato)bis(ethylene)rhodium (I), acetylacetonato(1 ,5-cyclooctadiene)rhodium (I), rhodium (III) acetylacetonate, palladium (II) hexafluoroacetylacetonate, tris(N,N'"'"'-diisopropylacetamidinato)ruthenium(III) and bis(N,N'"'"'-diisopropylacetamidinato)ruthenium(II) dicarbonyl.

11. The method according to claim 1, further comprising forming a vapor phase compound of copper (Cu) by replacing the noble metal in the vapor phase with the copper as a result of replacing the copper on the first surface with the noble metal.

12. The method according to claim 11, wherein the vapor phase compound of copper and the vapor phase compound of the noble metal comprise at least one ligand.

13. The method according to claim 12, wherein the ligand comprises a neutral ligand which can be removed in free molecular form when dissociated from the compounds.

14. The method according to claim 13, wherein the neutral ligand comprises 1 ,5-cyclooctadiene.

15. The method according to claim 1, further comprising supplying a reactive cleaning gas for reducing copper oxide before contacting.

16. The method according to claim 1, wherein depositing the noble metal comprises depositing atoms of the noble metal on the first surface.

17. The method according to claim 16, wherein an incubation time of depositing atoms of the noble metal on the first surface is zero or much shorter than an incubation time of depositing atoms of the noble metal on the second surface.

18. The method according to claim 16, wherein a conductive layer of the noble metal is formed by chemical vapor deposition (CVD) by supplying a reactant gas with the vapor phase compound of the noble metal.

19. The method according to claim 18, wherein the conductive layer is formed at a temperature between about 150°

C and about 400°

C.

20. The method according to claim 18, wherein the conductive layer is formed at a pressure between about 1mbar and 10mbar.

21. The method according to claim 18, wherein the vapor phase compound of the noble metal is supplied for a duration of about 1 second to about 1000 seconds.

22. The method according to claim 18, wherein the reactant gas comprises oxygen (0₂) or ammonia (NH₃).

23. The method according to claim 18, wherein the vapor phase compound of the noble metal is selected from the group of(1,3-cyclohexadiene)Ru(CO)₃, Ru(Cp)₂, Ru(EtCp)₂and Ru(MeCp)(EtCp).

24. The method according to claim 18, wherein the vapor phase compound of the noble metal comprises metallocene compounds.

25. The method of claim 16, wherein a conductive layer of the noble metal is formed by atomic layer deposition (ALD) by alternately supplying a reactant gas with the vapor phase compound of the noble metal.

26. The method of claim 25, wherein the conductive layer is formed at a pressure between about 1and 10mbar.

27. The method of claim 25, wherein the conductive layer is formed at a temperature between about 150°

C and about 400°

C.

28. The method according to claim 25, wherein the vapor phase noble metal compound comprises metallocene compounds.

29. The method according to claim 24, wherein the vapor phase noble metal compound comprises beta-diketonate compounds and acetamidinato compounds.

30. The method according to claim 25, wherein the reactant gas comprises oxygen (O₂), ozone (O₃), ammonia (NH₃) or ammonia plasma.

31. The method according to claim 25, wherein the vapor phase noble metal compound is selected from the group of bis(cyclopentadienyl)ruthenium, tris(2,2,6,6-tetramethyl-3 ,5-heptanedionato)ruthenium, tris(N,N'"'"'-diisopropylacetamidinato)ruthenium(III), bis(N,N'"'"'-diisopropylacetamidinato)ruthenium(II) dicarbonyl, bis(ethylcyclopentadienyl)ruthenium, bis(pentamethylcyclopentadienyl)ruthenium, bis(2,2,6,6-tetramethyl-3 ,5-heptanedionato)( 1 ,5-cyclooctadiene)ruthenium(II), bis(ethylcyclopentadienyl) ruthenium (Ru(EtCp)₂), (trimethyl)methylcyclopentadienylplatinum(IV), platinum (II) acetylacetonato, bis(2,2,6,6-tetramethyl-3 ,5-heptanedionato)platinum(II) and their derivatives.

32. The method according to claim 1, further comprising forming a dielectric layer on top of the conductive layer.

33. A method for selectively forming a conductive layer in an integrated circuit, comprising:

providing a copper-exposed surface as a first surface and a non-copper surface as a second surface, the first surface being defined by a metal feature of the integrated circuit, the metal feature comprising copper;

contacting the first surface and the second surface with a vapor phase compound of a noble metal; and

performing a replacement reaction, wherein the copper of the metal feature is replaced with the noble metal dissociated from the vapor phase compound of the noble metal, thereby depositing the noble metal predominantly on the first surface relative to the second surface.

34. The method according to claim 33, wherein the second surface is defined by an insulator in which the conductor is inlaid.

35. The method according to claim 33, wherein the first surface comprises the bottom of a via.

36. The method according to claim 33, wherein the metal feature comprises a conductive line and the first surface comprises an upper surface of the conductive line.

37. The method of claim 33, wherein the noble metal is selected from the group of Pt, Au, Ru, Rh, Ir and Pd and Ag.

38. The method of claim 33, wherein the vapor phase compound of the noble metal is selected from the group of bis(2,2,6,6-tetramethyl-3,5-heptanedionato)(1,5- cyclooctadiene)ruthenium (II), ruthenium (III) acetylacetonate, tris(2,2,6,6-tetramethyl-3 ,5- heptanedionato)ruthenium (III), 1 ,5-cyclooctadiene(acetylacetonato)iridium (I), dicarbonylacetylacetonato iridium (I), iridium (III) acetylacetonate, platinum (II) hexafluoroacetylacetonate, acetylacetonatobis(cyclooctene)rhodium (I), acetylacetonatobis(ethylene)rhodium (I), acetylacetonato( 1,5-cyclooctadiene)rhodium (I), rhodium (III) acetylacetonate, palladium (II) hexafluoroacetylacetonate, tris(N,N'"'"'-diisopropylacetamidinato)ruthenium(III) and bis(N,N'"'"'-diisopropylacetamidinato)ruthenium(II) dicarbonyl.

39. The method according to claim 33, further comprising forming a vapor phase compound of copper by replacing the noble metal in the vapor phase with the copper as a result of replacing the copper on the first surface with the noble metal.

40. The method according to claim 39, further comprising removing by-products and other contaminants including the vapor phase compound of copper.

41. The method according to claim 33, wherein the replacement reaction is conducted at a temperature of about room temperature to about 400°

C.

42. The method according to claim 33, wherein the vapor phase compound of the noble metal is supplied with an inert gas.

43. The method according to claim 33, further comprising supplying a reactive reducing gas to the first surface for reducing an oxide of the material of the first surface prior to contacting.

44. The method according to claim 43, wherein the reactive reducing gas is selected from the group of NH₃, H₂, hydrogen radicals, alcohols and carboxylic acids.

45. The method according to claims 33, further comprising selectively depositing additional noble metal by chemical vapor deposition (CVD) or atomic layer deposition (ALD) on the conductive layer comprising the noble metal.