Process for producing integrated circuits

• US 20050215053A1
• Filed: 04/19/2005
• Published: 09/29/2005
• Est. Priority Date: 05/15/2000
• Status: Active Grant

• Current Assignee: Kai-Erik Elers, Pekka Juha Soininen
• Original Assignee: Kai-Erik Elers, Pekka Juha Soininen
• Inventors: Elers, Kai-Erik, Soininen, Pekka Juha
• Granted Patent: US 7,241,677 B2
• Time in Patent Office: Days
• US Class Current: 438/658
• 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 concerns a process for producing integrated circuits containing at least one layer of elemental metal which during the processing of the integrated circuit is at least partly in the form of metal oxide, and the use of an organic compound containing certain functional groups for the reduction of a metal oxide layer formed during the production of an integrated circuit. According to the present process the metal oxide layer is at least partly reduced to elemental metal with a reducing agent selected from organic compounds containing one or more of the following functional groups: alcohol (—OH), aldehyde (—CHO), and carboxylic acid (—COOH).

Claims

1. A process for producing an integrated circuit comprising providing a substrate comprising a via through an insulating layer and at least partially reducing a metal oxide layer on the via bottom to elemental metal with a gaseous organic compound comprising one or more functional groups selected from the group consisting of alcohol (—

OH), aldehyde (—

CHO) and carboxylic acid (—

COOH).

2. The process of claim 1, wherein the metal oxide layer comprises copper oxide.

3. The process of claim 1, wherein the elemental metal is selected from the group consisting of copper (Cu), molybdenum (Mo), tungsten (W), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), indium (In), germanium (Ge), tin (Sn), lead (Pb), antimony (Sb) and bismuth (Bi).

4. The process of claim 1, wherein the metal oxide layer is formed by the oxidation of a metal layer.

5. The process of claim 1, wherein the metal oxide layer is formed after an etch stop is removed from the via bottom.

6. The process of claim 5, wherein the etch stop comprises silicon nitride.

7. The process of claim 1, additionally comprising subsequently depositing a diffusion barrier onto the reduced surface.

8. The process of claim 1, wherein the reduced metal oxide is a seed layer for an electrochemically deposited metal layer.

9. The process of claim 1, wherein the reduction is carried out at a temperature of 400°

C. or less.

10. The process of claim 1, wherein the gaseous organic compound is selected from the group consisting of primary alcohols, secondary alcohols, tertiary alcohols, polyhydroxy alcohols, cyclic alcohols, aromatic alcohols, halogenated alcohols and other derivatives of alcohols.

11. The process of claim 10, wherein the organic compound comprises a primary alcohol having the general formula (I)

R¹—

OH 

 

(I)

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

12. The process of claim 10, wherein R¹ is selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl and hexyl.

13. The process of claim 10, wherein the organic compound comprises a secondary alcohol having the general formula (II)

14. The process of claim 13, wherein each R¹ is selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl and hexyl.

15. The process of claim 10, wherein the organic compound comprises a tertiary alcohol having the general formula (III)

16. The process of claim 15, wherein each R¹ is selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl and hexyl.

17. The process of claim 10, wherein the organic compound comprises a cyclic alcohol having an —

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

18. The process of claim 10, wherein the organic compound comprises an aromatic alcohol 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,

19. The process of claim 1, wherein the gaseous organic compound is selected from the group consisting of:

(i) compounds having the general formula (V)

R³—

CHO 

 

(V)

wherein R³ is hydrogen or a linear or branched C₁-C₂₀ alkyl or alkenyl group.

(ii) compounds having the general formula (VI)

OHC—

R⁴—

CHO 

 

(VI)

wherein R⁴ is zero or a linear or branched C₁-C₂₀ saturated or unsaturated hydrocarbon,

(iii) halogenated aldehydes, and

(iv) other derivatives of aldehydes.

20. The process of claim 19, wherein R³ is selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl and hexyl.

21. The process of claim 1, wherein the gaseous organic compound is selected from the group consisting of:

(i) compounds having the general formula (VII)

R⁵COOH 

 

(VII)

wherein R⁵ is hydrogen or a linear or branched C₁-C₂₀ alkyl or alkenyl group,

(ii) polycarboxylic acids,

(iii) halogenated carboxylic acids, and

(iv) other derivatives of carboxylic acids.

22. The process of claim 21, wherein R⁵ is selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl and hexyl.

23. The process of claim 1, wherein the via is part of a dual damascene structure.

24. A method for reducing copper oxide on the bottom of a via on a substrate prior to deposition of a diffusion barrier comprising exposing the copper oxide to one or more gaseous organic compounds selected from the group consisting of alcohols, aldehydes and carboxylic acids.

25. The method of claim 24, wherein the copper oxide is partially reduced to copper.

26. The method of claim 24, wherein the copper oxide layer is deposited by ALD.

27. The method of claim 24, additionally comprising electrochemically depositing copper in the via.

28. A method for forming an integrated circuit on a substrate comprising at least one metal layer, the method comprising:

depositing a first dielectric layer on the substrate;

forming a via through the first dielectric layer whereby the metal layer is at least partially exposed and oxidized at the bottom of the via; and

reducing the oxidized metal at the bottom of the via with an organic reducing agent selected from the group consisting of alcohols, aldehydes and carboxylic acids.

29. The method of claim 28, additionally comprising depositing a second dielectric layer.

30. The method of claim 28, additionally comprising depositing a diffusion barrier on the reduced metal at the bottom of the via.