Formation of SiN thin films

• US 10,410,857 B2
• Filed: 08/24/2015
• Issued: 09/10/2019
• Est. Priority Date: 08/24/2015
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM IP Holding B.V. (ASM International NV)
• Inventors: Suzuki, Toshiya, Pore, Viljami J., Chen, Shang, Yamada, Ryoko, Ishikawa, Dai, Namba, Kunitoshi
• Primary Examiner(s): Hargrove, Frederick B
• Application Number:
  US14/834,290
• Publication Number:
  US 20170062204A1
• Time in Patent Office: 1,478 Days
• CPC Class Codes: C23C 16/045 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• CPC Class Codes: C23C 16/345 Silicon nitride
• CPC Class Codes: C23C 16/45542 Plasma being used non-continuously during the ALD reactions
• CPC Class Codes: C23C 16/45553 characterized by the use of precursors specially adapted for ALD
• 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 21/02208 the precursor containing a compound comprising Si
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02219 the compound comprising silicon and nitrogen
• 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

Abstract

Methods of forming silicon nitride thin films on a substrate in a reaction space under high pressure are provided. The methods can include a plurality of plasma enhanced atomic layer deposition (PEALD) cycles, where at least one PEALD deposition cycle comprises contacting the substrate with a nitrogen plasma at a process pressure of 20 Torr to 500 Torr within the reaction space. In some embodiments the silicon precursor is a silyl halide, such as H₂SiI₂. In some embodiments the processes allow for the deposition of silicon nitride films having improved properties on three dimensional structures. For example, such silicon nitride films can have a ratio of wet etch rates on the top surfaces to the sidewall of about 1:1 in dilute HF.

Claims

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

a plurality of super-cycles comprising;

a plurality of silicon nitride deposition sub-cycles comprising alternately and sequentially contacting the substrate with a silicon precursor and a nitrogen plasma at a pressure of 5 Torr or less; and

a plurality of high-pressure treatment sub-cycles, wherein at least one of the plurality of high-pressure treatment sub-cycles comprises contacting the substrate with a nitrogen plasma at a pressure of greater than 20 Torr,

wherein the silicon nitride thin film is deposited on a three-dimensional structure on the substrate and a wet etch rate ratio of a wet etch rate of silicon nitride formed on a sidewall surface of the three-dimensional structure to a wet etch rate of the silicon nitride formed on a top surface of the three-dimensional structure is from about 0.8 to about 1.33 in dilute HF.

2. The method of claim 1, wherein the silicon precursor is H₂SiI₂.

3. The method of claim 1, wherein the nitrogen-containing plasma is generated from a nitrogen precursor selected from the group consisting of NH₃, N₂H₄, an N₂/H₂ mixture, N₂, and any mixtures thereof.

4. The method of claim of claim 1, wherein a wet etch rate ratio of a wet etch rate of silicon nitride formed on a sidewall surface of the three-dimensional structure to a wet etch rate of the silicon nitride formed on a top surface of the three-dimensional structure is 1:

1 in dilute HF.

5. The method of claim 1, wherein the at least one silicon nitride deposition sub-cycle further comprises flowing a carrier gas throughout the at least one silicon nitride deposition sub-cycle.

6. The method of claim 1, wherein the at least one silicon nitride deposition sub-cycle further comprises flowing a hydrogen-containing gas and a nitrogen-containing gas throughout the at least one silicon nitride deposition sub-cycle.

7. The method of claim 6, wherein the hydrogen-containing gas and the nitrogen-containing gas are used to form the nitrogen-containing plasma.

8. The method of claim 1, wherein the at least one high-pressure treatment sub-cycle further comprises flowing a carrier gas throughout the at least one high-pressure treatment sub-cycle.

9. The method of claim 1, wherein the pressure in the high pressure treatment sub-cycles is 20 Torr to 500 Torr.

10. The method of claim 1, wherein the pressure in the high pressure treatment sub-cycles is 20 Torr to 30 Torr.