Si PRECURSORS FOR DEPOSITION OF SiN AT LOW TEMPERATURES

• US 20140273477A1
• Filed: 01/29/2014
• Published: 09/18/2014
• Est. Priority Date: 03/14/2013
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM IP Holding B.V. (ASM International NV)
• Inventors: Pore, Viljami, Fukazawa, Atsuki, Fukuda, Hideaki, Haukka, Suvi P., Niskanen, Antti J., Chen, Shang
• Granted Patent: US 9,564,309 B2
• Time in Patent Office: Days
• US Class Current: 438/703
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/31111 by chemical means
• CPC Class Codes: H01L 21/823431 with a particular manufacturing method of transistors with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET

Abstract

Methods and precursors for depositing silicon nitride films by atomic layer deposition (ALD) are provided. In some embodiments the silicon precursors comprise an iodine ligand. The silicon nitride films may have a relatively uniform etch rate for both vertical and the horizontal portions when deposited onto three-dimensional structures such as FinFETS or other types of multiple gate FETs. In some embodiments, various silicon nitride films of the present disclosure have an etch rate of less than half the thermal oxide removal rate with diluted HF (0.5%).

Claims

1. A method of depositing a silicon nitride thin film on a substrate in a reaction space comprising:

(a) introducing a vapor-phase silicon reactant into the reaction space so that the silicon precursor is adsorbed to a surface of the substrate;

(b) removing excess silicon reactant and reaction byproducts;

(c) contacting the adsorbed silicon reactant with a reactive species generated by a plasma from a nitrogen precursor;

(d) removing excess reactive species and reaction byproducts;

wherein steps (a) through (d) are repeated until a silicon nitride film of a desired thickness is formed;

wherein the silicon reactant comprises a precursor having a formula of

H<sub>2n+2−

y−

z−

w</sub>Si_nI_yA_zR_w

wherein, n=1-10, y=1 or more (and up to 2n+2−

z−

w), z=0 or more (and up to 2n+2−

y−

w), w=0 or more (and up to 2n+2−

y−

z), A is a halogen other than I, R is an organic ligand and can be independently selected from the group consisting of alkoxides, alkylsilyls, alkyl, substituted alkyl, alkylamines, and unsaturated hydrocarbon.

2. The method of claim 1, wherein the reactive species comprises hydrogen, hydrogen atoms, hydrogen plasma, hydrogen radicals, N*, NH* or NH₂* radicals.

3. The method of claim 1, wherein the reaction space is part of a showerhead reactor and comprises a showerhead and a susceptor.

4. The method of claim 3, wherein there is a gap of about 0.5 cm to about 5 cm between the showerhead and susceptor.

5. The method of claim 3, wherein there is a gap of about 0.8 cm to about 3.0 cm between the showerhead and susceptor.

6. The method of claim 1, wherein the reactive species are generated directly above the substrate.

7. The method of claim 1, wherein the silicon reactant is H₂SiI₂.

8. The method of claim 1, wherein the method is performed at a temperature between about 200°

C. and about 400°

C.

9. The method of claim 1, wherein the nitrogen precursor is selected from the group consisting of NH₃, N₂H₄, an N₂/H₂ mixture, N₂, and any mixtures thereof.

10. The method of claim 1, wherein the silicon nitride thin film exhibits a step coverage and pattern loading effect of at least about 80%

11. The method of claim 1, wherein the silicon nitride thin film is formed on a three-dimensional structure.

12. The method of claim 11, wherein the structure comprises a sidewall and top regions and the sidewall wet etch rate (WER) of the silicon nitride film relative to the top region WER is about 1 in 0.5% dHF.

13. The method of claim 1, wherein an etch rate of the silicon nitride thin film is less than about 4 nm/min in 0.5% aqueous HF.

14. The method of claim 1, wherein nitrogen is used as a carrier gas.

15. The method of claim 1, wherein nitrogen is flowed continuously to the reaction space throughout steps (a)-(d).

16. The method of claim 1, wherein the silicon reactant comprises a precursor having the following formula:

H<sub>2n+2−

y−

z−

w</sub>Si_nX_yA_z(NR₁R₂)_w

wherein, n=1-10, y=1 or more (and up to 2n+2−

z−

w), z=0 or more (and up to 2n+2−

y−

w), w=1 or more (and up to 2n+2−

y−

z), X is I or Br, A is a halogen other an X, N is nitrogen, R₁ can be independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, silyl, alkylsilyl, and unsaturated hydrocarbon, and R₂ can be independently selected from the group consisting of alkyl, substituted alkyl, silyl, alkylsilyl, and unsaturated hydrocarbon.

17. The method of claim 16, wherein the silicon reactant comprises a precursor having one of the following formulas:

(SiI₂H)NHMe, (SiI₂H)NHEt, (SiI₂H)NMe₂, (SiI₂H)NMeEt, (SiI₂H)NEt₂, (SiI₂)(NHMe)₂, (SiI₂)(NHEt)₂, (SiI₂)(NMe₂)₂, (SiI₂)(NMeEt)₂, and (SiI₂)(NEt₂)₂.

18. An atomic layer deposition (ALD) method for forming a silicon nitride thin film, the method comprising a plurality of cycles, each cycle comprising alternately and sequentially contacting a substrate in a reaction space with a vapor phase pulse of a silicon reactant and a second reactant, wherein the silicon reactant comprises a precursor having the following formula:

H<sub>2n+2−

y−

w</sub>Si_nl_y(NR₁R₂)_w

wherein, n=1-10, y=1 or more (and up to 2n+2−

w), w=1 or more (and up to 2n+2−

y), N is nitrogen, and R₁ and R₂ can be independently selected from the group consisting of hydrogen, alkyl, substituted alkyl, silyl, alkylsilyl, and unsaturated hydrocarbon.

19. The method of claim 18, wherein the silicon reactant comprises a precursor having one of the following formulas:

(SiI₂H)NH₂, (SiI₂H)NHMe, (SiI₂H)NHEt, (SiI₂H)NMe₂, (SiI₂H)NMeEt, (SiI₂H)NEt₂, (SiI₂)(NH₂)₂, (SiI₂)(NHMe)₂, (SiI₂)(NHEt)₂, (SiI₂)(NMe₂)₂, (SiI₂)(NMeEt)₂, and (SiI₂)(NEt₂)₂.

20. The method of claim 18, wherein the second reactant comprises a nitrogen precursor.

21. The method of claim 20, wherein the nitrogen precursor comprises reactive species from a nitrogen containing plasma.

22. The method of claim 20, wherein the nitrogen precursor comprises nitrogen radicals, nitrogen atoms and/or nitrogen plasma.