Method of growing electrical conductors

• US 20030096468A1
• Filed: 11/19/2002
• Published: 05/22/2003
• Est. Priority Date: 05/15/2000
• Status: Active Grant

• Current Assignee: ASM International NV
• Original Assignee: ASM International NV
• Inventors: Soininen, Pekka J., Elers, Kai-Erik, Haukka, Suvi
• Granted Patent: US 6,887,795 B2
• Time in Patent Office: Days
• US Class Current: 438/200
• CPC Class Codes: H01L 21/02068 during, before or after processing of conductive layers, e.g. polysilicon or amorphous silicon layers
• CPC Class Codes: H01L 21/28562 Selective deposition
• CPC Class Codes: H01L 21/3105 After-treatment
• CPC Class Codes: H01L 21/321 After treatment
• CPC Class Codes: H01L 21/76807 for dual damascene structures
• 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 21/76823 transforming an insulating layer into a conductive layer
• CPC Class Codes: H01L 21/76831 in via holes or trenches, e.g. non-conductive sidewall liners
• 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 21/76838 characterised by the formation and the after-treatment of the conductors etching for patterning the conductors H01L21/3213
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76861 Post-treatment or after-treatment not introducing additional chemical elements into the layer
• CPC Class Codes: H01L 21/76862 Bombardment with particles, e.g. treatment in noble gas plasmas; UV irradiation
• CPC Class Codes: H01L 21/76873 for electroplating
• CPC Class Codes: H01L 21/76883 Post-treatment or after-treatment of the conductive material
• CPC Class Codes: H01L 21/76886 Modifying permanently or temporarily the pattern or the conductivity of conductive members, e.g. formation of alloys, reduction of contact resistances
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/45147 Copper (Cu) as principal constituent
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00011 : Not relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/12044 : OLED

Abstract

This invention relates to manufacturing of integrated circuits (ICs) and especially conductive layers suitable for use in an IC. According to the preferred method a metal oxide thin film is deposited on a substrate surface and reduced thereafter essentially into a metallic form with an organic reducing agent. The metal oxide is preferably deposited according to the principles of atomic layer deposition (ALD) using a metal source chemical and an oxygen source chemical. The reduction step is preferably carried out in an ALD reactor using one or more vaporized organic compounds that contain at least one functional group selected from the group consisting of —OH, —CHO and —COOH.

Claims

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

depositing a metal oxide thin film on a substrate by an atomic layer deposition (ALD) process; and

at least partially reducing said metal oxide thin film with one or more organic compounds.

2. The method of claim 1, wherein the organic compounds comprise at least one functional group selected from the group consisting of —

OH, —

CHO and —

COOH and the metal oxide is completely reduced.

3. The method of claim 1, wherein the metal oxide thin film is at least 1 nm thick.

4. The method of claim 1, wherein depositing comprises at least three cycles of an atomic layer deposition (ALD) process.

5. The method of claim 1, wherein the organic compounds are in the vapor phase.

6. The method of claim 1, wherein the metal oxide thin film is selected from the group consisting of ReO₂, Re₂O₅, ReO₃, RuO₂, OsO₂, CoO, Co₃O₄, Rh₂O₃, RhO₂, IrO₂, NiO, PdO, PtO₂, Cu₂O, CuO, Ag₂O and Au₂O₃.

7. The method of claim 1, wherein the ALD process comprises feeding into the reaction chamber and 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.

8. The method of claim 7, wherein the first source chemical is Cu(thd)₂ and the second source chemical is selected from the group consisting of ozone (O₃), oxygen (O₂) and a mixture of O₃ and O₂.

9. The method of claim 7, wherein the first source chemical is CuCl and the second source chemical is selected from the group consisting of ozone (O₃), oxygen (O₂) and a mixture of O₃ and O₂.

10. The method of claim 7, wherein the first source chemical is anhydrous metal nitrate and the second source chemical is vaporized aqueous solution of NH₃.

11. The method of claim 7, wherein the first source chemical is anhydrous copper nitrate (Cu(NO₃)₂) and the second source chemical is vaporized aqueous solution of NH₃.

12. The method of claim 7, wherein the first source chemical is Co(thd)₃ and the second source chemical is selected from the group consisting of ozone (O₃), oxygen (O₂), and a mixture of O₃ and O₂.

13. The method of claim 7, wherein the first source chemical is Pd(thd)₃ and the second source chemical is selected from the group consisting of ozone (O₃), oxygen (O₂), and a mixture of O₃ and O₂.

14. The method of claim 7, wherein the first source chemical is bis(ethylcyclopentadienyl)ruthenium ((EtCp)₂Ru) and the second source chemical is a mixture of oxygen and water gases.

15. The method of claim 5, wherein the vaporized organic compound used for reducing the metal oxide is an organic compound containing at least one alcohol (—

OH) group, said organic compound selected from the group consisting of primary alcohols;

secondary alcohols;

tertiary alcohols;

polyhydroxy alcohols;

cyclic alcohols which have an —

OH group attached to at least one carbon atom which is part of a ring of 1-10 carbon atoms;

aromatic alcohols having at least one —

-OH group attached either to the benzene ring or to a carbon atom in a side-chain attached to benzene ring;

halogenated alcohols; and

other derivatives of alcohols.

16. The method of claim 15, wherein said primary alcohols are primary alcohols according to the general formula (I)

R¹—

OH 

 

(I)

wherein R¹ is a linear or branched C₁-C₂₀ alkyl or alkenyl group.

17. The method of claim 16, wherein each R¹ is selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl and hexyl groups.

18. The method of claim 15, wherein said secondary alcohols are secondary alcohols according to formula (II)

19. The method of claim 18, wherein each R¹ is selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl and hexyl groups.

20. The method of claim 15, wherein said tertiary alcohols are tertiary alcohols according to the general formula (III)

21. The method of claim 20, wherein each R¹ is selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl and hexyl groups.

22. The method of claim 15, wherein said cyclic alcohols have an —

OH group attached to at least one carbon atom which is part of a ring of 5-6 carbon atoms.

23. The method of claim 5, wherein the vaporized organic compound used for reducing the metal oxide is a compound containing at least one aldehyde (—

CHO) group, said reducing agent being selected from the group consisting of;

compounds having the general formula (V)

R³—

CHO 

 

(V)

wherein R³ is hydrogen or linear or branched C₁-C₂₀ alkyl or alkenyl group, preferably methyl, ethyl, propyl, butyl, pentyl or hexyl; and

compounds having the general formula (VI)

OHC—

R⁴—

CHO 

 

(VI)

wherein R⁴ is a linear or branched C₁-C₂₀ saturated or unsaturated hydrocarbon or R⁴ is zero, when the aldehyde groups are bonded to each other; and

halogenated aldehydes; and

other derivatives of aldehydes.

24. The method of claim 5, wherein the vaporized organic compound used for reducing the metal oxide is a compound containing at least one carboxylic acid (—

COOH) group, said reducing agent being selected from the group consisting of;

compounds having the general formula (VII)

R⁵COOH 

 

(VII)

wherein R⁵ is hydrogen or linear or branched C₁-C₂₀ alkyl or alkenyl group, preferably methyl, ethyl, propyl, butyl, pentyl or hexyl; and

polycarboxylic acids; and

halogenated carboxylic acids; and

other derivatives of carboxylic acids.

25. A method of producing a conductive thin film comprising the steps of:

A. placing a substrate in a chamber;

B. exposing the substrate to a gaseous first reactant, wherein the first reactant adsorbs no more than a monolayer of metal species on the substrate;

C. removing gases from the chamber;

D. exposing the substrate to a second gaseous reactant comprising a compound that is capable of oxidizing the adsorbed metal species on the substrate into metal oxide;

E. removing gases from the chamber;

F. repeating the above steps B through E at least three times to form a metal oxide film; and

G. following step F, exposing the substrate to one or more organic compounds.

26. The method of claim 25, wherein the organic compounds comprise at least one functional group selected from the group consisting of —

OH, —

CHO and —

COOH and wherein the organic compound reduces the metal oxide.

27. The method of claim 25 wherein the organic compounds reduce the metal oxide film to metal.

28. The method of claim 25, wherein the organic compound is in the vapor phase.

29. The method of claim 25, wherein in step F, steps B through E are repeated at least 10 times to form a metal oxide film.

30. The method of claim 25, wherein steps B through G are repeated at least twice to increase the thickness of the conductive film on the substrate.

31. A method of producing a conductive thin film comprising:

depositing a metal oxide thin film of at least 1 nm thickness on a substrate; and

reducing said metal oxide thin film to metal by exposing the metal oxide thin film to one or more organic compounds

32. The method of claim 31, wherein the organic compounds comprise at least one functional group selected from the group consisting of —

OH, —

CHO and —

COOH.