Method for preparing metal nitride thin films

• US 6,706,115 B2
• Filed: 03/15/2002
• Issued: 03/16/2004
• Est. Priority Date: 03/16/2001
• Status: Expired due to Term

• Current Assignee: ASM International NV
• Original Assignee: ASM International NV
• Inventors: Alén, Petra, Juppo, Marika, Leskelä, Markku, Ritala, Mikko
• Primary Examiner(s): CHEN, BRET P
• Application Number:
  US10/100,500
• Publication Number:
  US 20020182320A1
• Time in Patent Office: 732 Days
• Field of Search: 427/255.394, 427/255.391, 117/84, 117/88
• US Class Current: 117/84
• CPC Class Codes: C23C 16/34 Nitrides C23C16/303 takes precedence
• CPC Class Codes: C23C 16/45553 characterized by the use of precursors specially adapted for ALD
• CPC Class Codes: H01L 21/28568 the conductive layers comprising transition metals H01L21/28518 takes precedence

Abstract

Methods for producing metal nitride thin layers having low resistivity by means of atomic layer deposition processes comprising alternate surface reactions of metal and nitrogen source materials include using nitrogen source materials that have better reducing properties than ammonia and 1,1-dimethyl hydrazine. Suitable compounds for that purpose include those in which a hydrocarbon group bound to nitrogen, when dissociating in a homolytic manner, generates a radical that serves as a reducing agent and reacts further to generate atomic hydrogen. The nitride thin layers produced are especially suitable for use as diffusion barrier layers in integrated circuits.

Claims

1. A method of growing transition metal nitride thin films by an atomic layer deposition (ALD) process in which a nitride thin film is grown on a substrate by means of alternate surface reactions of metal and nitrogen source materials, wherein the nitrogen source material comprises a compound having a hydrocarbon, amino or silyl group bound to nitrogen, and wherein hydrolytic dissociation of the hydrocarbon, amino or silyl group from nitrogen generates a radical.

2. The method of claim 1, wherein the radical serves as a reducing agent.

3. The method of claim 1, wherein the radical reacts further to generate atomic hydrogen.

4. The method of claim 1, wherein the nitrogen source material comprises a compound of formula (I)

5. The method of claim 4, wherein at least one R is a hydrocarbon group.

6. The method of claim 4, wherein the bond energy between the amine and the hydrocarbon group is less than 460 kJ/mol.

7. The method of claim 4, wherein at least one R is a substituted or unsubstituted cyclic, linear or branched alkyl, alkenul, allyl, aryl, alkylaryl, or arylalkyl group.

8. The method of claim 4, wherein at least one R is a linear or branched C₁-C₁₀ alkyl.

9. The method of claim 8, wherein at least one R is a tertiary alkyl.

10. The method of claim 1, wherein the nitrogen source material additionally comprises a compound selected from the group consisting of ammonia, hydrazine and hydrazine derivatives.

11. The method of claim 1, wherein the metal source material comprises a compound of formula (II)

12. The method of claim 11, wherein the metal M belongs to one of groups 3, 4, 5, 6, 7, 8, 9,10, 11 and 12 of the periodic table.

13. The method of claim 1, wherein the metal source material is selected from the group consisting of halides and alkylamides of transition metals.

14. The method of claim 1, wherein the metal source material is selected from the group consisting of TaCl₅, TaBr₅ and TaI₅ and the nitrogen source material is selected from the group consisting of tert-butylamine and allylamine.

15. The method of claim 1, wherein the metal source material is selected from the group consisting of TiCl₄, TiBr₄ and TiI₄ and the nitrogen source material is selected from the group consisting of tert-butylamine and allylamine.

16. A method of producing an electrically conductive diffusion barrier layer between a conductor and an isolation layer on a substrate comprising integrated circuits, the method comprising:

introducing the substrate into the reaction space of a reactor; and

growing a conductive metal nitride layer on the substrate by an atomic layer deposition (ALD) process comprising alternate surface reactions of metal and nitrogen source materials,

wherein the nitrogen source material comprises a compound having a hydrocarbon, amino or silyl group attached to the nitrogen and wherein dissociation of the hydrocarbon, amino or silyl group from the nitrogen generates a reducing agent.

17. The method of claim 16, wherein the reducing agent is a radical.

18. The method of claim 16, wherein the dissociation directly produces a radical that decomposes further to generate the reducing agent.

19. The method of claim 18, wherein the reducing agent is atomic hydrogen.

26. The method of claim 16, wherein growing comprises lining trenches and vias in the substrate.

27. The method of claim 16, which is part of a dual damascence process.

20. A method of producing a conductive TaN diffusion barrier layer on a substrate comprising integrated circuits, said method comprising:

introducing the substrate into the reaction space of a reactor; and

growing a conductive metal nitride thin layer on the substrate by an atomic layer deposition (ALD) process comprising alternate surface reactions of tantalum and nitrogen source materials,

wherein the nitrogen source comprises a compound having such a hydrocarbon, amino or silyl group attached to the nitrogen and wherein dissociation of the hydrocarbon, amino or silyl group from the nitrogen generates a radical.

21. The method of claim 20, wherein the radical serves as a reducing agent.

22. The method of claim 20, wherein the radical reacts further and generates a second radical.

23. The method of claim 20, wherein the radical reacts further and atomic hydrogen.

24. The method of claim 20, wherein the tantalum source material is selected from the group consisting of tantalum pentachloride, tantalum pentaiodide and tantalum pentabromide and the nitrogen source material comprises a compound selected from the group consisting of tert-butyl amine and allyl amine.

25. The method of claim 24, wherein the nitrogen source material additionally comprises ammonia.