Si precursors for deposition of SiN at low temperatures

• US 9,564,309 B2
• Filed: 01/29/2014
• Issued: 02/07/2017
• 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: Niskanen, Antti J., Chen, Shang, Pore, Viljami, Fukazawa, Atsuki, Fukuda, Hideaki, Haukka, Suvi P.
• Primary Examiner(s): Stark, Jarrett
• Assistant Examiner(s): DINKE, BITEW A
• Application Number:
  US14/167,904
• Publication Number:
  US 20140273477A1
• Time in Patent Office: 1,105 Days
• Field of Search: 257/E27.1, 257/E29.117, 257/E29.137, 257/E29.145, 257/E29.147, 257/E29.182, 257/E29.202, 257/E29.273, 257/E29.314, 257/E29.32, 257/E21.411, 438/792, 438/485, 438/729
• US Class Current: 1/1
• 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 plasma enhanced atomic layer deposition (PEALD) 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 nitrogen is flowed continuously to the reaction space throughout steps (a)-(d) and steps (a) through (d) are repeated until a silicon nitride film of a desired thickness is formed;

wherein the silicon reactant is H₂SiI₂,

wherein the silicon nitride thin film is deposited on at least one three-dimensional feature, and

wherein a ratio of an etch rate of the silicon nitride thin film in 0.5% aqueous HF in a sidewall of the at least one three-dimensional feature to an etch rate of the silicon nitride thin film in 0.5% aqueous HF on a top surface of the at least one three-dimensional feature is less than 2.

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 0.5 cm to 5 cm between the showerhead and susceptor.

5. The method of claim 3, wherein there is a gap of 0.8 cm to 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 method is performed at a temperature between 200°

C. and 400°

C.

8. 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.

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

10. The method of claim 1, wherein the ratio is 1.

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

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

13. The method of claim 1, wherein the adsorbed silicon precursor is not contacted with a reactive species generated by a plasma from Ar.

14. A plasma enhanced atomic layer deposition (PEALD) 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 comprising a reactive species generated by a plasma from a nitrogen precursor, wherein the silicon reactant comprises H₂SiI₂:

wherein nitrogen is flowed continuously to the reaction space throughout each cycle,

wherein the silicon nitride thin film is deposited on at least one three-dimensional feature, and

wherein a ratio of an etch rate of the silicon nitride thin film in 0.5% aqueous HF in a sidewall of the at least one three-dimensional feature to an etch rate of the silicon nitride thin film in 0.5% aqueous HF on a top surface of the at least one three-dimensional feature is less than 2.

15. The method of claim 14, wherein the nitrogen precursor comprises nitrogen radicals, nitrogen atoms and/or nitrogen plasma.

16. The method of claim 14, wherein the substrate is not contacted with a reactive species generated by a plasma from Ar.