Process for producing metal thin films by ALD

• US 20050020060A1
• Filed: 08/10/2004
• Published: 01/27/2005
• Est. Priority Date: 01/29/2002
• Status: Active Grant

• Current Assignee: Markku Leskela, Mikko Ritala, Petra Alen, Titta Aaltonen
• Original Assignee: Markku Leskela, Mikko Ritala, Petra Alen, Titta Aaltonen
• Inventors: Ritala, Mikko, Leskela, Markku, Aaltonen, Titta, Alen, Petra
• Granted Patent: US 7,220,451 B2
• Time in Patent Office: Days
• US Class Current: 438/650
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: C23C 16/18 from metallo-organic compounds
• CPC Class Codes: C23C 16/45553 characterized by the use of precursors specially adapted for ALD
• CPC Class Codes: G11B 5/66 the record carriers consisting of several layers
• CPC Class Codes: G11B 5/85 Coating a support with a magnetic layer by vapour deposition
• CPC Class Codes: H01F 10/325 the spacer being noble metal
• CPC Class Codes: H01L 21/02183 the material containing tantalum, e.g. Ta2O5
• CPC Class Codes: H01L 21/02186 the material containing titanium, e.g. TiO2
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/28562 Selective deposition
• CPC Class Codes: H01L 21/3162 on a silicon body
• CPC Class Codes: H01L 21/7687 Thin films associated with contacts of capacitors
• CPC Class Codes: H01L 28/60 Electrodes

Abstract

The invention relates generally to processes for producing electrically conductive noble metal thin films on a substrate by atomic layer deposition. According to one embodiment of the invention a substrate with a surface is provided in a reaction chamber and a vaporised precursor of a noble metal is pulsed into the reaction chamber. By contacting the vaporised precursor with the surface of the substrate, no more than about a molecular layer of the metal precursor is formed on the substrate. In a next step, a pulse of molecular oxygen-containing gas is provided in the reaction chamber, where the oxygen reacts with the precursor on the substrate. Thus, high-quality metal thin films can be deposited by utilising reactions between the metal precursor and oxygen. In one embodiment, electrically conductive layers are deposited in structures that have high aspect ratio vias and trenches, local high elevation areas or other similar surface structures that make the surface rough.

Claims

1. A method of forming a dual damascene structure comprising depositing a seed layer by an atomic layer deposition process, the seed layer comprising at least one noble metal.

2. The method of claim 1, wherein the noble metal is selected from the group consisting of ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium and platinum.

3. The method of claim 1, wherein the seed layer comprises ruthenium.

4. The method of claim 1, wherein the atomic layer deposition process comprises:

providing sequential and alternating vapor phase pulses of a noble metal source chemical and an oxygen source chemical.

5. The method of claim 4, wherein the noble metal source chemical is selected from the group consisting of a metallocene compound and a beta-diketonate compound of the noble metal.

6. The method of claim 4, wherein the oxygen source chemical comprises free oxygen.

13. The process of claim 1-2, wherein copper is deposited by a method selected from the group consisting of electroplating and chemical vapor deposition.

7. A process for copper metallization comprising forming a seed layer on trenches and vias in a damascene structure by:

placing a substrate with trenches and vias in a reaction chamber; and

providing alternating and sequential vapor phase pulses of a metal source chemical and an oxygen source chemical into the reaction chamber, wherein the metal source chemical comprises a metal selected from the group consisting of ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium and platinum.

8. The process of claim 7, wherein excess source chemical is removed from the reaction chamber between pulses of the metal source chemical and the oxygen source chemical.

9. The process of claim 7, wherein the pulses of the metal source chemical and the oxygen source chemical are separated by a pulse of an inactive gas.

10. The process of claim 9, wherein the inactive gas is argon or nitrogen.

11. The process of claim 7, wherein the thickness of the seed layer is from approximately 1 nm to 30 nm.

12. The process of claim 7, additionally comprising depositing copper on the seed layer.

14. The process of claim 7, wherein the metal source chemical comprises ruthenium.

15. The process of claim 7, wherein metal source chemical is selected from the group consisting of metallocene compounds and beta-diketonate compounds.

16. The process of claim 15, wherein the metal source chemical is a metallocene compound of ruthenium.

17. The process of claim 15, wherein the metal source chemical is a beta-diketonate compound of ruthenium.

18. The process of claim 7, wherein the oxygen source chemical is free oxygen

19. The process of claim 18, wherein the oxygen source chemical is molecular oxygen.

20. The process of claim 7, wherein the oxygen source chemical is a precursor that releases oxygen.

21. The process of claim 20, wherein the oxygen source chemical is selected from the group consisting of H₂O₂ and organic peroxides.

22. A method of depositing a ruthenium seed layer on a substrate in a reaction chamber comprising:

providing a vaporized ruthenium precursor into the reaction chamber to form no more than about one monolayer of the precursor on the substrate;

removing excess ruthenium precursor from the reaction chamber;

providing a second reactant gas pulse comprising oxygen to the reaction chamber;

removing excess second reactant gas from the reaction chamber; and

repeating until a ruthenium seed layer of the desired thickness is formed.

23. The method of claim 22, wherein the ruthenium precursor is selected from the group consisting of a metallocene ruthenium compound and a beta-diketonate ruthenium compound.

24. The method of claim 23, wherein the metallocene ruthenium compound is selected from the group consisting of bis(cyclopentadienyl)-ruthenium and a derivative of bis(cyclopentadienyl)-ruthenium.

25. The method of claim 23, wherein the beta-diketonate ruthenium compound is selected from the group consisting of tris(2,2,6,6-tetramethyl-3,5-heptanedionato)ruthenium(III), a derivative of tris(2,2,6,6-tetramethyl-3,5-heptanedionato)ruthenium(III), bis(2,2,6,6,-tetramethyl-3,5-heptanedionato)ruthenium(II) and a derivative of bis(2,2,6,6,-tetramethyl-3,5-heptanedionato)ruthenium(II)

26. The method of claim 22, wherein the second reactant gas comprises a mixture of oxygen and an inert gas.

27. The method of claim 22, wherein the second reactant gas comprises an oxygen-containing chemical selected from the group consisting of H₂O₂ and an organic peroxide.

28. The method of claim 27, wherein the oxygen-containing chemical is catalytically decomposed prior to entering the reaction chamber.

29. A method of depositing a diffusion barrier on a dual damascene structure, comprising the steps of:

placing a substrate with trenches and vias in a reaction chamber;

growing a seed layer on the substrate from alternating vapor phase pulses of a metal source chemical and an oxygen source chemical that are separated from each other, the metal being selected from the group consisting of ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium and platinum; and

depositing copper on the seed layer.

30. The process of claim 29, wherein the thickness of the seed layer is from approximately 1 nm to up at least 30 nm.

31. The process of claim 29, wherein copper is deposited on the seed layer by electroplating or by chemical vapor deposition.

32. The process of claim 29, wherein the metal is ruthenium.