METHOD OF FORMING CONFORMAL DIELECTRIC FILM HAVING Si-N BONDS BY PECVD

• US 20100144162A1
• Filed: 09/03/2009
• Published: 06/10/2010
• 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: Lee, Woo Jin, Shimizu, Akira
• Granted Patent: US 8,142,862 B2
• Time in Patent Office: Days
• US Class Current: 438/791
• 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: C23C 16/5096 Flat-bed apparatus
• CPC Class Codes: H01L 21/02167 the material being a silicon carbide not containing oxygen, e.g. SiC, SiC:H or silicon carbonitrides H01L21/02126 and H01L21/0214 take precedence
• 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 21/02274 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 21/3185 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/or hydrogen-containing reactive gas and a rare gas into a reaction space inside which the semiconductor substrate is placed;

applying RF power to the reaction space; and

introducing a precursor comprising a hydrogen-containing silicon gas in pulses of less than 5-second duration into the reaction space while introducing the reactive gas and the rare gas without interruption, wherein a plasma is excited, thereby forming a conformal dielectric film having Si—

N bonds on the substrate.

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 1, wherein the hydrogen-containing silicon precursor is a liquid at room temperature and vaporized upstream of the reaction space.

4. The method according to claim 1, wherein the hydrogen-containing silicon precursor is introduced in pulses while the reactive gas and the additive gas are continuously introduced and the RF power is continuously applied.

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

6. The method according to claim 5, 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.

7. 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.

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

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

10. The method according to claim 1, wherein the hydrogen-containing silicon gas has no carbon atom in its molecule and constitutes a first precursor, and the precursor further comprises a hydrocarbon-containing gas as a second precursor.

11. The method according to claim 10, wherein the first precursor and the second precursor are introduced in pulses at the same timing.

12. The method according to claim 11, wherein the pulse duration of the second precursor is different from that of the first precursor.

13. The method according to claim 10, wherein the conformal dielectric film is a carbon-doped silicon nitride film.

14. A method of forming dielectric films having Si—

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

(i) introducing a nitrogen- and/or hydrogen-containing reactive gas and an rare gas into a reaction space inside which the semiconductor substrate is placed;

(ii) applying RF power to the reaction space;

(iii) introducing as a first precursor a hydrogen-containing silicon gas in pulses of less than a 5-second duration into the reaction space while introducing the reactive gas and the inert gas without interruption, wherein a plasma is excited, thereby forming a first dielectric film having Si—

N bonds on the substrate; and

(iv) forming a second dielectric film having Si—

N bonds on the substrate by repeating steps (i) to (iii), wherein step (iii) further comprises introducing a second precursor in pulses while introducing the first precursor in pulses at the same timing, thereby increasing wet etching resistance of the second dielectric film as compared with that of the first dielectric film, said second precursor having more hydrocarbons in its molecule than the first precursor.

15. The method according to claim 14, wherein step (iv) further comprises prolonging the pulse duration of the second precursor relative to that of the first precursor.

16. The method according to claim 14, wherein step (iv) further comprises reducing nitrogen gas flow relative to that for the first dielectric film.

17. A method of forming dielectric films having Si—

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

(i) introducing a nitrogen- and/or hydrogen-containing reactive gas and an rare gas into a reaction space inside which the semiconductor substrate is placed;

(ii) applying RF power to the reaction space;

(iii) introducing a first precursor and a second precursor each in pulses of less than a 5-second duration at the same timing into the reaction space while introducing the reactive gas and the inert gas without interruption, wherein a plasma is excited, thereby forming a first dielectric film having Si—

N bonds on the substrate, said first precursor being a hydrogen-containing silicon gas, said second precursor having more hydrocarbons than the first precursor; and

(iv) forming a second dielectric film having Si—

N bonds on the substrate by repeating steps (i) to (iii), wherein step (iii) further comprises introducing another second precursor in pulses while introducing the first and second precursors in pulses at the same timing, thereby changing wet etching resistance of the second dielectric film as compared with that of the first dielectric film.

18. The method according to claim 17, wherein step (iv) further comprises changing the pulse duration of the another second precursor relative to that of the second precursor.

19. The method according to claim 17, wherein step (iv) further comprises changing nitrogen gas flow relative to that for the second dielectric film.