Methods for forming a silicon nitride film

• US 10,381,219 B1
• Filed: 10/25/2018
• Issued: 08/13/2019
• Est. Priority Date: 10/25/2018
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM IP Holding B.V. (ASM International NV)
• Inventors: Ueda, Shinya, Takayama, Tomomi, Ebisudani, Taishi, Suzuki, Toshiya, Kubota, Tomohiro
• Primary Examiner(s): Tran, Thien F
• Application Number:
  US16/171,098
• Time in Patent Office: 292 Days
• Field of Search: None
• 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: 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 21/0234 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/31111 by chemical means

Abstract

Methods for forming a silicon nitride film by a plasma enhanced atomic layer deposition (PEALD) process are provided. The methods may include: providing a substrate into a reaction chamber; and performing at least one unit deposition cycle of a PEALD process, wherein a unit cycle comprises, contacting the substrate with a vapor phase reactant comprising a silicon precursor; and contacting the substrate with a reactive species generated from a gas mixture comprising a nitrogen precursor and an additional gas. Methods for improving the etch characteristics of a silicon nitride film utilizing a post deposition plasma treatment are also provided.

Claims

1. A method for forming a silicon nitride film by a plasma enhanced atomic layer deposition (PEALD) process, the method comprising:

providing a substrate into a reaction chamber; and

performing at least one unit deposition cycle of a PEALD process, wherein a unit cycle comprises;

contacting the substrate with a vapor phase reactant comprising a silicon precursor; and

contacting the substrate with a reactive species generated from a plasma produced from a gas mixture comprising a nitrogen precursor and an additional gas, wherein the additional gas comprises at least one of helium or neon and the gas mixture is introduced into the reaction chamber at a flow rate ratio of additional gas to nitrogen precursor greater than 4;

1.

2. The method of claim 1, wherein the gas mixture is introduced into the reaction chamber at a flow rate ratio of additional gas to nitrogen precursor greater than 10:

1.

3. The method of claim 1, wherein the gas mixture is introduced into the reaction chamber at a flow rate ratio of additional gas to nitrogen precursor greater than 15:

1.

4. The method of claim 1, further comprising regulating the pressure within the reaction chamber during the PEALD process to greater than 3000 Pascals.

5. The method of claim 1, wherein the gas mixture consists essentially of the nitrogen precursor and helium.

6. The method of claim 1, wherein the gas mixture further comprises argon.

7. The method of claim 6, wherein the gas mixture consists essentially of the nitrogen precursor, helium, and argon.

8. The method of claim 6, wherein the silicon nitride film has a wet etch rate ratio (WERR) in dilute hydrofluoric acid (1:

100) of less than 0.15.

9. The method of claim 1, wherein the nitrogen precursor comprises at least one of nitrogen (N₂), ammonia (NH₃), hydrazine (N₂H₄), or an alkyl-hydrazine.

10. The method of claim 1, wherein the silicon precursor comprises a silicon halide precursor.

11. The method of claim 10, wherein the silicon halide precursor comprises at least one of a silicon chloride precursor, a silicon iodide precursor, or a silicon bromide precursor.

12. The method of claim 11, wherein the silicon iodide precursor comprises at least one of HSiI₃, H₂SiI₂, H₃SiI, H₂Si₂I₄, H₄Si₂I₂, or H₅Si₂I.

13. The method of claim 1, further comprising contacting the substrate with the reactive species for a time period of less than 1 second.

14. The method of claim 1, wherein the growth rate of the silicon nitride film per unit deposition cycle of the PEALD process is greater than 0.035 nanometers per cycle at a substrate temperature of less than 450°

C.

15. The method of claim 1, wherein the growth rate of the silicon nitride film per unit deposition cycle of the PEALD process is greater than 0.027 nanometers per cycle at a substrate temperature of less than 350°

C.

16. The method of claim 1, wherein the growth rate of the silicon nitride film per unit deposition cycle of the PEALD process is greater than 0.024 nanometers per cycle at a substrate temperature of less than 250°

C.

17. The method of claim 1, wherein the silicon nitride film has a wet etch rate ratio (WERR) in dilute hydrofluoric acid (1:

100) of less than 0.35.

18. The method of claim 1, further comprising contacting the silicon nitride film post-deposition with a reactive species generated from a plasma produced from a gas mixture comprising a nitrogen precursor and an additional gas, wherein the additional gas comprises at least one of helium or neon and the gas mixture comprises a percentage volume content of the additional gas greater than 70 percent.