Method for forming dielectric film in trenches by PEALD using H-containing gas

• US 9,455,138 B1
• Filed: 11/10/2015
• Issued: 09/27/2016
• Est. Priority Date: 11/10/2015
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM IP Holding B.V. (ASM International NV)
• Inventors: Takamure, Noboru, Zaitsu, Masaru, Fukazawa, Atsuki, Fukuda, Hideaki
• Primary Examiner(s): Nhu, David
• Application Number:
  US14/937,053
• Time in Patent Office: 322 Days
• Field of Search: 438/680, 438/700, 438/142, 438/474, 438/475, 438/513, 438/515, 438/743, 438/744, 438/769, 438/791, 257/E21.006, 257/E21.054, 257/E21.17, 257/E21.267, 257/E21.278, 257/E21.293, 257/E21.311, 257/E21.319, 257/E21.321, 257/E21.327
• US Class Current: 1/1
• CPC Class Codes: H01L 21/02123 the material containing silicon
• 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

Abstract

A method for forming a dielectric film in a trench on a substrate by plasma-enhanced atomic layer deposition (PEALD) performs one or more process cycles, each process cycle including: (i) feeding a silicon-containing precursor in a pulse; (ii) supplying a hydrogen-containing reactant gas at a flow rate of more than about 30 sccm but less than about 800 sccm in the absence of nitrogen-containing gas; (iii) supplying a noble gas to the reaction space; and (iv) applying RF power in the presence of the reactant gas and the noble gas and in the absence of any precursor in the reaction space, to form a monolayer constituting a dielectric film on a substrate at a growth rate of less than one atomic layer thickness per cycle.

Claims

1. A method for forming a dielectric film in a trench on a substrate by plasma-enhanced atomic layer deposition (PEALD) performing one or more process cycles, each process cycle comprising:

(i) feeding a silicon-containing precursor in a pulse to a reaction space where the substrate is placed, said silicon-containing precursor being constituted by one or more hydrocarbon-containing compounds selected from the group consisting of;

SiH₂R₂, Si₂H₂R₄, SiR₂X₂, Si₂R₆, SiH₃R, Si₂H₄R₂, SiH₂RX, C₃H₆SiH₂, C₂H₄SiH₂, C₂H₄Si₂H₂, SiNHSiR₄H₂, SiNHSiR₆, and SiHX₂R, wherein each X is independently chain or cyclic CxHy, and each R is independently chain or cyclic C_xH_y, cyclic N_xC_yH_z, N(C_xH_y)₂, N(C_xH_y)H, O(C_xH_y), or OH, wherein x, y, and z are integers;

(ii) supplying a hydrogen-containing reactant gas to the reaction space at a flow rate of more than about 30 sccm but less than about 800 sccm in the absence of nitrogen-containing gas;

(iii) supplying a noble gas to the reaction space; and

(iv) applying RF power to the reaction space in the presence of the hydrogen-containing reactant gas and the noble gas and in the absence of any precursor in the reaction space, to form a monolayer constituting a dielectric film on a substrate at a growth rate of less than one atomic layer thickness per cycle.

2. The method according to claim 1, wherein the growth rate of the monolayer is less than 0.1 nm/cycle.

3. The method according to claim 1, wherein the precursor has a chemical formula where at least one of X or R is an unsaturated hydrocarbon.

4. The method according to claim 1, wherein the precursor has a cyclic structure.

5. The method according to claim 1, wherein the silicon-containing precursor is one or more compounds selected from the group consisting of:

dimethylsilane, divinylsilane, dipyridylsilane, tertamethyldisilane, divinyldimethylsilane, dimethyldipyridylsilane, hexamethydisilane, silylacetylene, allylsilane, divinyldisilane, dimethyldisilane, viylmethylsilane, silacyclobutane, silacycloethane, di silacycloethane, tetramethyldisilazane, hexamethyldisilazane, and dimethylpridyldisilane.

6. The method according to claim 1, wherein the reactant gas is hydrogen gas.

7. The method according to claim 1, wherein the noble gas is argon.

8. The method according to claim 1, wherein the reactant gas is supplied continuously to the reaction space throughout each process cycle.

9. The method according to claim 1, wherein the noble gas is continuously supplied to the reaction space throughout the process cycle.

10. The method according to claim 1, wherein a ratio of flow rate of the noble gas to flow rate of the reactant is about 10:

1 to about 60;

1.

11. The method according to claim 1, wherein in step (iii), the noble gas is supplied to the reaction space at a flow rate of about 1,000 sccm to about 5,000 sccm.

12. The method according to claim 1, wherein in step (iv), no gas other than the reactant gas and the noble gas is supplied to the reaction space.

13. The method according to claim 1, wherein in step (i), the silicon-containing precursor is fed in an amount of about 0.00002 g/cycle to about 0.01 g/cycle and in a pulse having a duration of about 0.1 seconds to about 1.0 second.

14. The method according to claim 1, wherein each process cycle further comprises a purging step between steps (i) and (iv), and between steps (iv) and (i) when the process cycle is repeated.

15. The method according to claim 1, wherein in step (iv), RF power is applied to the reaction space in two occurrences between which a purging step is conducted.

16. The method according to claim 1, wherein in step (iv), RF power applied to the reaction space is about 0.028 W/cm² to about 0.28 W/cm².

17. The method according to claim 1, wherein the temperature during the process cycle is about 50°

C. to about 500°

C.

18. The method according to claim 1, wherein the dielectric film is a film of SiC, SiCN, SiN, SiOCN, or SiO.

19. The method according to claim 1, wherein a sidewall coverage of the deposited dielectric film is about 80% or higher, wherein the sidewall coverage is defined as a ratio of thickness of film on a sidewall of the trench to thickness of film on a blanket surface of the trench.

20. A method for increasing a sidewall coverage of a dielectric film deposited according to claim 1 wherein in step (i), the precursor is fed in a pulse having a first duration, in step (ii), the reactant gas is supplied at a first flow rate, and in step (iv), RF power is applied in a pulse having a first duration, and the dielectric film has a first sidewall coverage, said sidewall coverage being defined as a ratio of thickness of film on a sidewall of the trench to thickness of film on a blanket surface of the trench, said method comprising:

(a) setting a second duration of the pulse of the precursor in step (i), a second flow rate of the reactant gas in step (ii), and a second duration of the pulse of RF power in step (iv), wherein at least one of the second flow rate of the reactant gas and the second duration of the pulse of RF power is higher than the first flow rate of the reactant gas and the first duration of the pulse of RF power, respectively, and/or the second duration of the pulse of the precursor is shorter than the first duration of the pulse of the precursor; and

(b) repeating steps (i) to (iv) using the second flow rate of the reactant gas and the second duration of the pulse of RF power, thereby depositing a dielectric film having a second sidewall coverage which is higher than the first sidewall coverage.