METHOD OF DEPOSITING DIELECTRIC FILM HAVING Si-N BONDS BY MODIFIED PEALD METHOD

• US 20110086516A1
• Filed: 10/08/2010
• Published: 04/14/2011
• Est. Priority Date: 10/14/2009
• Status: Active Grant

• Current Assignee: ASM Japan K.K. (ASM International NV)
• Original Assignee: ASM Japan K.K. (ASM International NV)
• Inventors: Hong, Kuo-wei, Jeong, Deakyun, Lee, Woo Jin, Shimizu, Akira
• Granted Patent: US 8,173,554 B2
• Time in Patent Office: Days
• US Class Current: 438/792
• CPC Class Codes: C23C 16/345 Silicon nitride
• CPC Class Codes: C23C 16/4554 Plasma being used non-continuously in between ALD reactions C23C16/56 takes precedence
• CPC Class Codes: C23C 16/5096 Flat-bed apparatus
• 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 21/02274 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 21/3141 Deposition using atomic layer deposition techniques [ALD]
• CPC Class Codes: H01L 21/3185 of siliconnitrides

Abstract

A method of forming dielectric film having Si—N bonds on a semiconductor substrate by plasma enhanced atomic layer deposition (PEALD), includes: introducing a nitrogen- and hydrogen-containing reactive gas and a rare gas into a reaction space inside which the semiconductor substrate is placed; introducing a hydrogen-containing silicon precursor in pulses of less than 1.0-second duration into the reaction space wherein the reactive gas and the rare gas are introduced; exiting a plasma in pulses of less than 1.0-second duration immediately after the silicon precursor is shut off; and maintaining the reactive gas and the rare gas as a purge of less than 2.0-second duration.

Claims

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

N bonds on a semiconductor substrate by plasma enhanced atomic layer deposition (PEALD), which comprises;

selecting a combination of gases for forming a dielectric film having Si—

N bonds by PEALD, said gases comprising a reactive gas, a rare gas, and a Si—

containing precursor, which are different from each other;

continuously introducing the reactive gas and a the rare gas without interruption into a reaction space inside which the semiconductor substrate is placed;

introducing the precursor in pulses into the reaction space;

exciting an RF plasma in pulses in the reaction space, wherein each pulse of exciting the RF plasma starts immediately after each pulse of introducing the precursor, wherein one cycle is defined by one pulse of introducing the precursor with no pulse of exciting the RF plasma as a first period, one pulse of exciting the RF plasma with no pulse of introducing the precursor as a second period, and no pulse of introducing the precursor and no pulse of exciting the RF plasma as a third period; and

forming a dielectric film having Si—

N bonds on the substrate by repeating the cycle multiple times.

2. The method according to claim 1, wherein the Si-containing precursor comprises Si, N, H, and optionally C in its molecule.

3. The method according to claim 2, wherein the Si-containing precursor has a formula of Siα

Hβ

Xγ

, wherein α and

β

are integers and γ

is an integer including zero, X is N and/or CmHn wherein m and n are integers.

4. The method according to claim 1, wherein the Si-containing precursor is a carbon-free precursor which is a first precursor, and the method further comprises introducing a second precursor in one cycle, wherein the second precursor is different from the first precursor and comprises a Si—

N, C—

H, or N—

H bond in its molecule.

5. The method according to claim 4, wherein the second precursor has a formula of Si_α

A_β

B_γ

, wherein α

, β and

γ

are integers and y includes zero, A is H or Cl, and B is N.

6. The method according to claim 4, wherein the second precursor is selected from a hydrocarbon-containing silicon gas, a hydrocarbon gas, and an ammonium gas.

7. The method according to claim 6, wherein the hydrocarbon-containing silicon gas is selected and has a formula of Si_aH_bN_c(C_mH_n) wherein a is an integer of 1 to 5, b is an integer of 1 to 10, and c is an integer of 0 to 6, m is an integer of 2 to 18, and n is an integer of 6 to 30.

8. The method according to claim 1, wherein the Si-containing precursor is vaporized upstream of the reaction space.

9. The method according to claim 1, wherein the Si-containing precursor is introduced in pulses of a duration of approximately 0.1 sec to 1.0 sec.

10. The method according to claim 1, wherein the excitation of the RF plasma is conducted in pulses of a duration of approximately 0.1 sec to 1.0 sec and starts 0 to 0.1 seconds after the shutting off of the Si-containing precursor in each cycle.

11. The method according to claim 1, wherein the introduction of the reactive gas and the rare gas is maintained in each cycle as a purge for approximately 0.5 to 2.0 sec after the excitation of the PF plasma ends.

12. The method according to claim 11, wherein the duration of the purge is equal to or longer than the duration of the RF plasma excitation in one cycle.

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

14. 4. The method according to claim 13, wherein the reactive gas is the mixture of N2 and H2 wherein a molar flow rate ratio of N₂/H₂ in the mixture is approximately 1/1 to 10/1.

15. The method according to claim 13, wherein the reactive gas is the mixture of NH3 and H2 wherein a molar flow rate ratio of NH3/H2 in the mixture is approximately 1/1 to 1/10.

16. The method according to claim 1, wherein the rare gas is at least a mixture of helium and argon.

17. The method according to claim 16, wherein the rare gas is a mixture of helium and argon wherein a molar flow rate ratio of helium/argon is approximately 1/1 to 20/1.

18. The method according to claim 1, wherein the dielectric film having Si—

N bonds is deposited at a deposition rate of at least 0.1 nm/cycle.

19. The method according to claim 18, wherein the dielectric film having Si—

N bonds has a step coverage or conformality of at least 90%.

20. The method according to claim 18, wherein the dielectric film having Si—

N bonds has an etching rate lower than that of a thermal oxide film.