Method of depositing transition metal nitride thin films

• US 6,863,727 B1
• Filed: 10/13/2000
• Issued: 03/08/2005
• Est. Priority Date: 10/15/1999
• Status: Expired due to Term

• Current Assignee: ASM International NV
• Original Assignee: ASM International NV
• Inventors: Haukka, Suvi Päivikki, Elers, Kai-Erik, Soininen, Pekka Juha, Saanila, Ville Antero, Kaipio, Sari Johanna
• Primary Examiner(s): Norton, Nadine G.
• Assistant Examiner(s): ANDERSON, MATTHEW A
• Application Number:
  US10/110,730
• Time in Patent Office: 1,607 Days
• Field of Search: 117/88, 117/104, 117/89, 117/93, 117/102
• US Class Current: 117/93
• CPC Class Codes: C23C 16/32 Carbides
• CPC Class Codes: C23C 16/34 Nitrides C23C16/303 takes precedence
• CPC Class Codes: C23C 16/44 characterised by the method of coating C23C16/04 takes precedence
• CPC Class Codes: C23C 16/4401 Means for minimising impurities, e.g. dust, moisture or residual gas, in the reaction chamber
• CPC Class Codes: C23C 16/45531 specially adapted for making ternary or higher compositions
• CPC Class Codes: C23C 16/45534 Use of auxiliary reactants other than used for contributing to the composition of the main film, e.g. catalysts, activators or scavengers
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 29/02 Elements
• CPC Class Codes: C30B 29/36 Carbides
• CPC Class Codes: C30B 29/38 Nitrides
• CPC Class Codes: H01L 21/28562 Selective deposition
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric

Abstract

This invention concerns a method for depositing transition metal nitride thin films by an Atomic Layer Deposition (ALD) type process. According to the method vapor-phase pulse of a source material, a reducing agent capable of reducing metal source material, and a nitrogen source material capable of reacting with the reduced metal source material are alternately and sequentially fed into a reaction space and contacted with the substrate. According to the invention as the reducing agent is used a boron compound which is capable of forming gaseous reaction byproducts when reacting with the metal source material.

Claims

1. An atomic layer deposition (ALD) process for growing a metal nitride thin film on a substrate comprising alternately and sequentially contacting a substrate in a reaction space with vapor phase pulses of:

a metal source material that forms a monolayer on the substrate surface;

a boron compound that reduces the metal source material on the substrate surface; and

a nitrogen source material that reacts with the reduced metal source material,

wherein an inert gas is provided to the reaction space after every pulse.

2. An atomic layer deposition (ALD) process for growing a metal nitride film on a substrate in a reaction space comprising the sequential steps of:

a) feeding a vapor-phase pulse of a metal source chemical into the reaction space with an inert carrier gas;

b) purging the reaction space with an inert gas;

c) feeding a vapor-phase pulse of a boron source chemical into the reaction space with an inert carrier gas;

d) purging the reaction space with an inert gas;

e) feeding a vapor-phase pulse of a nitrogen source chemical into the reaction space;

f) purging the reaction space with an inert gas; and

g) repeating steps a) through f) until a metal nitride film of a desired thickness is formed.

3. The process of claim 2, wherein the metal in the metal source chemical is selected from the group consisting of W, Mo, Cr, Ta, Nb, V, Hf, Zr and Ti.

4. The process of claim 2, wherein the metal source chemical is selected from the group consisting of metal halides and metal organic compounds.

5. The process of claim 4, wherein the metal source chemical is selected from the group consisting of metal fluorides, metal chlorides, metal bromides and metal iodides.

6. The process of claim 4, wherein the metal source chemical is selected from the group consisting of alkylamino compounds, cyclopentadienyl compounds, dithiocarbamate compounds and betadiketonate compounds.

7. The process of claim 2, wherein the metal source chemical is a tungsten compound selected from the group consisting of tungsten halides, tungsten carbonyls, tungsten cyclopentadienyls, and tungsten β

-diketonates.

8. The process of claim 7, wherein the metal source chemical is selected from the group consisting of WF_x, WCl_y, WBr_m and WI_n wherein x, y, m and n are integers from 1 to 6.

9. The process of claim 8, wherein the metal source chemical is WF₆.

10. The process of claim 7, wherein the metal source chemical is selected from the group consisting of tungsten hexacarbonyl (W(CO)₆) and tricarbonyl(mesitylene)tungsten.

11. The process of claim 7, wherein the metal source chemical is selected from the group consisting of bis(cyclopentadienyl)tungsten dihydride, bis(cyclopentadienyl)tungsten dichloride and bis(cyclopentadienyl)ditungsten hexacarbonyl.

12. The process of claim 2, wherein the boron source chemical is selected from the group consisting of boranes of formula (I)

B_nH_n+_x, 

 

(I)

wherein is an integer from 1 to 10 and x is an even integer;

boranes of formula (II)

B_nH_m, 

 

(II)

wherein n is an integer from 1 to 10 and m is an integer different than n, m being from 1 to 10; and

complexes thereof.

13. The process of claim 12, wherein the boron source chemical is selected from the group consisting of boranes of formula (I)

B_nH_n+_x, 

 

(I)

wherein n is an integer from 2 to 6, and

x is 4, 6 or 8;

boranes of formula (II)

B_nH_m, 

 

(II)

wherein n is an integer from from 2 to 6, and m is an integer different than n, m being from 2 to 6; and

complexes thereof.

14. The process of claim 12, wherein the boranes are selected from the group consisting of nido-boranes of formula B_nH_n+4, arachno-boranes of formula B_nH_n+6, hypho-boranes of formula B_nH_n+8, and conjuncto-boranes B_nH_m, wherein n is an integer from 1 to 10 and m is an integer from 1 to 10 that is different than n.

15. The process of claim 2, wherein the boron source chemical is selected from the group consisting of carboranes according to formula (IV)

C₂B_nH_n+x, 

 

(IV)

wherein n is an integer from 1 to 10 and x is an even integer.

16. The process of claim 15, wherein n is an integer from 2 to 6, and x is 2, 4 or 6.

17. The process of claim 15, wherein the carboranes are selected from the group consisting of closo-carboranes (C₂B_nH_n+2), nido-carboranes (C₂B_nH_n+4) and arachno-carboranes (C₂B_nH_n+6), wherein n is an integer from 1 to 10.

18. The process of claim 2, wherein the boron source chemical is selected from the group consisting of amine-borane adducts according to formula (V)

R₃NBX₃, 

 

(V)

wherein R is linear or branched C₁-C₁₀, and

X is linear or branched C₁-C₁₀.

19. The process of claim 18, wherein R is selected from the group consisting of linear or branched C₁-C₄ alkyl and H, and X is selected from the group consisting of linear or branched C₁-C₄ alkyl, H and a halogen.

20. The process of claim 2, wherein the boron source chemical is selected from the group consisting of aminoboranes wherein one or more of the substituents on B is an amino group according to formula (VI)

R₂N, 

 

(VI)

wherein R is linear or branched C₁-C₁₀.

21. The process of claim 20, wherein R is selected from the group consisting of a C₁-C₄ alkyl group, a substituted aryl group and an unsubstituted aryl group.

22. The process of claim 2, wherein the boron source chemical is selected from the group consisting of alkyl borons and alkyl boranes, wherein the alkyl is a linear or branched C₁-C₁₀ alkyl.

23. The process of claim 22, wherein the alkyl is a linear or branched C₂-C₄ alkyl.

24. The process of claim 2, wherein the boron source chemical is a boron halide.

25. The process of claim 24, wherein the boron source chemical is selected from the group consisting of B₂F₄, B₂Cl₄ and B₂Br₄.

26. The process of claim 2, wherein the boron source chemical is selected from the group consisting of halogenoboranes of formula (III)

B_nX_n, 

 

(III)

wherein X is Cl or Br, n=4, 8-12 when X=Cl and n=7-10 when X=Br.

27. The process of claim 2, wherein the boron source chemical is selected from the group consisting of cyclic borazine (—

BH—

NH—

)₃ and the volatile derivatives thereof.

28. The process of claim 2, wherein the boron source chemical is selected from the group consisting of borane halides and complexes thereof.

29. The process of claim 2, wherein the nitrogen source chemical is selected from the group consisting of ammonia (NH₃) and its salts, hydrogen azide (HN₃) and the alkyl derivates thereof, hydrazine (N₂H₄) and salts of hydrazine, alkyl derivates of hydrazine, nitrogen fluoride NF₃, hydroxyl amine (NH₂OH) and salts thereof, primary, secondary and tertiary amines, nitrogen radicals, and excited state nitrogen (N₂*), wherein * is a free electron capable of bonding.

30. The process of claim 29, wherein the nitrogen source chemical is selected from the group consisting of ammonium fluoride, ammonium chloride, CH₃N₃, hydrazine hydrochloride dimethyl hydrazine, hydroxylamine hydrochloride, methylamine, diethylamine and triethylamine.

31. The process of claim 2, wherein the substrate comprises one or more materials selected from the group consisting of silicon, silica, coated silicon, copper metal and nitride.

32. The process of claim 2, wherein the metal nitride thin film comprises a diffusion barrier in an integrated circuit.