Methods and precursors for selective deposition of metal films
Methods and precursors for selectively depositing a metal film on a silicon nitride surface relative to a silicon oxide surface are described. The substrate comprising both surfaces is exposed to a blocking compound to selectively block the silicon oxide surface. A metal film is then selectively deposited on the silicon nitride surface.
1. A method of selectively depositing a metal film, the method comprising:
exposing a substrate with a first surface comprising SiO 2 and a second surface comprising silicon nitride to a blocking precursor to form a blocked first surface, the blocking precursor comprising a compound of the formula R 3 Si—X, where each R is independently C1-C4 alkyl and X is a reactive handle;
exposing the substrate to a metal precursor, the metal precursor comprising a compound of the formula M(NR′ 2 ) a where each R′ is independently C1-C4 alkyl and a is greater than or equal to one; and
exposing the substrate to a reagent to react with the metal precursor to form a metal film on the second surface.
2. The method of claim 1 , wherein each exposure occurs separately.
3. The method of claim 1 , wherein each R is methyl.
4. The method of claim 1 , wherein X is selected from halide, azide, amino, hydrazide, cyanide or isocyanate groups.
5. The method of claim 4 , wherein X comprises a primary, secondary or tertiary amine with linear C1-6 alkyl or branched C1-4 alkyl groups.
6. The method of claim 4 , wherein X is a pyrrolyl group.
7. The method of claim 1 , wherein the blocking precursor consists essentially of trimethylsilylpyrrolidine.
8. The method of claim 1 , wherein the metal precursor comprises one or more of Ti, Zr, Hf, or Ta.
9. The method of claim 1 , wherein the metal precursor does not contain any metal halides.
10. The method of claim 1 , wherein each R′ is methyl.
11. The method of claim 1 , wherein each R′ is ethyl.
12. The method of claim 1 , wherein a is greater than or equal to 4.
13. The method of claim 1 , wherein the metal precursor consists essentially of Ti(N(CH 3 ) 2 ) 4 (TDMAT).
14. The method of claim 1 , wherein the metal precursor consists essentially of Ti(N(C 2 H 5 ) 2 ) 4 (TDEAT).
15. The method of claim 1 , wherein the reagent comprises one or more of hydrogen, ammonia or water.
16. The method of claim 15 , wherein the reagent consists essentially of ammonia and the metal film is a metal nitride film.
17. The method of claim 15 , wherein the reagent consists essentially of water and the metal film is a metal oxide film.
18. The method of claim 1 , wherein the substrate is maintained at a temperature in the range of about 200° C. to about 400° C.
19. A method of selectively depositing a titanium nitride film, the method comprising:
exposing a substrate with a first surface comprising SiO 2 and a second surface comprising silicon nitride to a blocking precursor to form a blocked first surface, the blocking precursor comprising trimethylsilylpyrrolidine;
exposing the substrate to a metal precursor to deposit a layer of metal species on the second surface, the metal precursor comprising TDEAT; and
exposing the substrate to ammonia to react with the layer of metal species on the second surface to form a titanium nitride film.
20. A method of selectively depositing a hafnium oxide film, the method comprising:
exposing a substrate with a first surface comprising SiO 2 and a second surface comprising silicon nitride to a blocking precursor to form a blocked first surface, the blocking precursor comprising trimethylsilylpyrrolidine;
exposing the substrate to a metal precursor to deposit a layer of metal species on the second surface, the metal precursor comprising PDMAH; and
exposing the substrate to water to react with the layer of metal species on the second surface to form a hafnium oxide film.