Method of forming conformal dielectric film having Si-N bonds by PECVD

• US 7,919,416 B2
• Filed: 01/21/2009
• Issued: 04/05/2011
• Est. Priority Date: 01/21/2009
• Status: Active Grant

• Current Assignee: ASM Japan K.K. (ASM International NV)
• Original Assignee: ASM Japan K.K. (ASM International NV)
• Inventors: Shimizu, Akira, Fukazawa, Atsuki, Lee, Woo-Jin
• Primary Examiner(s): SMITH, MATTHEW S
• Assistant Examiner(s): Baptiste; Wilner Jean
• Application Number:
  US12/357,174
• Publication Number:
  US 20100184302A1
• Time in Patent Office: 804 Days
• Field of Search: 438/149, 438/791, 438/792, 438/99, 438/723, 438/712, 438/711, 438/710, 438/763, 257/632, 257/324, 257/E21.266, 257/E21.487, 257/E29.165
• US Class Current: 438/792
• 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 16/45523 Pulsed gas flow or change of composition over time
• 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 21/02219 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
• CPC Class Codes: H01L 21/3185 of siliconnitrides

Abstract

A method of forming a conformal dielectric film having Si—N bonds on a semiconductor substrate by plasma enhanced chemical vapor deposition (PECVD) includes: introducing a nitrogen- and hydrogen-containing reactive gas and an additive gas into a reaction space inside which a semiconductor substrate is placed; applying RF power to the reaction space; and introducing a hydrogen-containing silicon precursor in pulses into the reaction space wherein a plasma is excited, thereby forming a conformal dielectric film having Si—N bonds on the substrate.

Claims

1. A method of forming a conformal dielectric film having Si—

N bonds on a semiconductor substrate by plasma enhanced chemical vapor deposition (PECVD), which comprises;

introducing a nitrogen- and hydrogen-containing reactive gas and an additive gas into a reaction space inside which the semiconductor substrate is placed;

applying RF power to the reaction space; and

introducing a hydrogen-containing silicon precursor in pulses into the reaction space wherein a plasma is excited, thereby forming a conformal dielectric film having Si—

N bonds on the substrate,

wherein the hydrogen-containing silicon precursor is introduced in pulses of a duration of approximately 0.1 sec to 1.0 sec with an interval between pulses of approximately 0.1 sec to 3.0 sec, while the reactive gas and the additive gas are continuously introduced, and the RF power is continuously applied.

2. The method according to claim 1, wherein the hydrogen-containing silicon precursor has a formula of Si_α

H_β

X_γ

, wherein α

, β and

γ

are integers (γ

includes zero), wherein X comprises N, F and/or C_mH_n, wherein m and n are integers.

3. The method according to claim 2, wherein the hydrogen-containing silicon precursor consists of Si, H, and N atoms constituting its molecule.

4. The method according to claim 1, wherein the substrate is kept at a temperature of about 0°

C. to about 400°

C. while the film is deposited thereon.

5. The method according to claim 1, wherein the hydrogen-containing silicon precursor is vaporized upstream of the reaction space.

6. The method according to claim 1, wherein the hydrogen-containing precursor is a liquid at room temperature.

7. The method according to claim 1, wherein the pulse duration is equal to or shorter than the interval between pulses.

8. The method according to claim 1, wherein the reactive gas comprises at least one of a mixture of N₂ and H₂, a mixture of NH₃ and H₂, and a nitrogen-boron-hydrogen gas.

9. The method according to claim 8, wherein the reactive gas comprises a mixture of N₂ and H₂ and has a molar flow rate ratio of N₂/H₂ of approximately 1/1 to 10/1.

10. The method according to claim 8, wherein the reactive gas comprises a mixture of NH₃ and H₂ and has a molar flow rate ratio of NH₃/H₂ of approximately 1:

1 to 1;

10.

11. The method according to claim 1, wherein the additive gas comprises a mixture of helium and argon or a mixture of helium and krypton.

12. The method according to claim 11, wherein the additive gas is a mixture of helium and argon and has a molar flow rate ratio of helium/argon of approximately 3/1 to 20/1.

13. The method according to claim 11, wherein the additive gas is a mixture of helium and krypton and has a molar flow rate ratio of helium/krypton of approximately 3/1 to 20/1.

14. The method according to claim 1, wherein the conformal dielectric film is a silicon nitride film.

15. The method according to claim 1, wherein the RF power is applied in the range of approximately 0.02 W/cm² to approximately 20 W/cm² per area of the substrate and a pressure in the reaction space is adjusted in the range of approximately 0.1 Torr to approximately 10 Torr.

16. The method according to claim 1, wherein pulse durations and intervals of the pulses of introducing the hydrogen-containing silicon precursor are such that the conformal dielectric film has a step coverage or conformality of at least 80%.

17. The method according to claim 16, wherein the pulse durations and intervals of the pulses of introducing the hydrogen-containing silicon precursor are such that the conformal dielectric film has an etching rate lower than thermal oxide film.

18. The method according to claim 16, wherein the pulse durations and intervals of the pulses of introducing the hydrogen-containing silicon precursor are such that the conformal dielectric film has a leakage current lower than 1.0E-08 A/cm² at a 1 MV charge.

19. The method according to claim 1, wherein the RF power is continuously applied.

20. The method according to claim 1, wherein the pulse duration is from approximately 0.1 sec to about 0.3 sec.