Method of Forming Stress-Tuned Dielectric Film Having Si-N Bonds by Modified PEALD

• US 20110014795A1
• Filed: 07/08/2010
• Published: 01/20/2011
• Est. Priority Date: 07/15/2009
• Status: Active Grant

• Current Assignee: ASM Japan K.K. (ASM International NV)
• Original Assignee: ASM Japan K.K. (ASM International NV)
• Inventors: Shimizu, Akira, Lee, Woo Jin, Hong, Kuo-Wei
• Granted Patent: US 8,334,219 B2
• Time in Patent Office: Days
• US Class Current: 438/761
• CPC Class Codes: C23C 16/345 Silicon nitride
• CPC Class Codes: C23C 16/45538 Plasma being used continuously during the ALD cycle
• CPC Class Codes: C23C 16/5096 Flat-bed apparatus
• CPC Class Codes: C23C 16/52 Controlling or regulating the coating process C23C16/45557, C23C16/279 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 21/02274 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 21/3141 Deposition using atomic layer deposition techniques [ALD]
• CPC Class Codes: H01L 21/3185 of siliconnitrides

Abstract

A method of forming stress-tuned dielectric films having Si—N bonds on a semiconductor substrate by modified plasma enhanced atomic layer deposition (PEALD), 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 using a high frequency RF power source and a low frequency RF power source; and introducing a hydrogen-containing silicon precursor in pulses into the reaction space wherein a plasma is excited, thereby forming a stress-tuned dielectric film having Si—N bonds on the substrate.

Claims

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

N bonds constituting a main structure of the film on a semiconductor substrate by plasma enhanced atomic layer deposition (PEALD), said target dielectric film having stress which is either tensile or compressive as its stress type which is opposite to a stress type of a reference dielectric film having Si—

N bonds constituting a main structure of the film on a semiconductor substrate by PEALD, comprising;

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

(ii) applying to the reaction space RF power which is a mixture of low-frequency RF power (LRF) and high-frequency RF power (HRF) at a ratio of LRF/HRF to obtain the target dielectric film having the stress type opposite to that of the reference dielectric film, said ratio being set by increasing a ratio of LRF/HRF used for the reference dielectric film when the stress type of the reference dielectric film is tensile, or by decreasing a ratio of LRF/HRF used for the reference dielectric film when the stress type of the reference dielectric film is compressive; and

(iii) introducing a hydrogen-containing silicon precursor in pulses into the reaction space while the RF power is applied, thereby forming by PEALD the target dielectric film on the semiconductor substrate, wherein as a result of the set ratio, the target dielectric film has the stress type opposite to that of the reference dielectric film.

2. The method according to claim 1, wherein the ratio of LRF/HRF is a primary parameter for controlling the stress type of the target dielectric film.

3. The method according to claim 2, wherein the ratio of LRF/HRF is the sole parameter for controlling the stress type of the target dielectric film.

4. The method according to claim 1, wherein the target dielectric film has compressive film stress, and in step (ii), the ratio of LRF/HRF is set by increasing the ratio of LRF/HRF used for the reference dielectric film, wherein the increased ratio of LRF/HRF is 2/10 to 10/10.

5. The method according to claim 1, wherein the target dielectric film has tensile film stress, and in step (ii), the ratio of LRF/HRF is set by decreasing the ratio of LRF/HRF used for the reference dielectric film, wherein the decreased ratio of LRF/HRF is 0/10 to 4/10.

6. The method according to claim 1, wherein the hydrogen-containing silicon precursor is introduced in pulses having a pulse duration of about 0.1 sec to about 1.0 sec with an interval of about 0.5 sec to about 3 sec while forming the films.

7. A method of forming a target dielectric film having Si—

N bonds constituting a main structure of the film on a semiconductor substrate by plasma enhanced atomic layer deposition (PEALD), said target dielectric film having a film stress value different from that of a reference dielectric film having Si—

N bonds constituting a main structure of the film on a semiconductor substrate by PEALD, comprising;

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

(ii) applying to the reaction space RF power which is a mixture of low-frequency RF power (LRF) and high-frequency RF power (HRF) at a ratio of LRF/HRF to obtain the stress type opposite to that of the reference dielectric film, said ratio being set by increasing a ratio of LRF/HRF used for the reference dielectric film to obtain the target dielectric film having a film stress value which is lower than that of the reference dielectric film, or by decreasing a ratio of LRF/HRF used for the reference dielectric film to obtain a film stress value which is higher than that of the reference dielectric film; and

(iii) introducing a hydrogen-containing silicon precursor in pulses into the reaction space while the RF power is applied, thereby forming by PEALD the target dielectric film on the semiconductor substrate, wherein the ratio of LRF/HRF is used as a primary parameter for differentiating the film stress value of the target dielectric film from that of the reference dielectric film.

8. The method according to claim 7, wherein the ratio of LRF/HRF is the sole parameter for differentiating the film stress value of the target dielectric film.

9. A method of forming multiple dielectric films each having Si—

N bonds constituting a main structure of the film on a semiconductor substrate by plasma enhanced atomic layer deposition (PEALD), wherein the multiple dielectric films include a tensile stress film and a compressive stress film, said method comprising;

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

(ii) applying to the reaction space RF power which is a mixture of low-frequency RF power (LRF) and high-frequency RF power (HRF) at a ratio of LRF/HRF;

(iii) introducing a hydrogen-containing silicon precursor in pulses into the reaction space while the RF power is applied, thereby forming by PEALD one of the tensile and compressive stress films on the semiconductor substrate; and

(iv) as a primary parameter for controlling stress of the depositing film, changing the ratio of LRF/HRF, and repeating steps (i) to (iii) at the changed ratio of LRF/HRF, thereby forming another of the tensile and compressive stress films on the semiconductor substrate.

10. The method according to claim 9, wherein the changing of the ratio of LRF/HRF is increasing the ratio of LRF/HRF wherein the another of the tensile or compressive stress films is the compressive stress film.

11. The method according to claim 10, wherein the increased ratio of LRF/HRF is 2/10 to 10/10.

12. The method according to claim 9, wherein the changing of the ratio of LRF/HRF is decreasing the ratio of LRF/HRF wherein the another of the tensile or compressive stress films is the tensile stress film.

13. The method according to claim 12, wherein the decreased ratio of LRF/HRF is 0/10 to 4/10.

14. The method according to claim 9, further comprising, as a secondary parameter for controlling stress of the depositing film, changing a ratio of nitrogen to hydrogen in the reactive gas in step (iv).

15. The method according to claim 9, further comprising, as a secondary parameter for controlling stress of the depositing film, changing quantity of the HRF in step (iv).

16. The method according to claim 9, wherein the hydrogen-containing silicon precursor is composed of a combination of silicon and hydrogen;

a combination of silicon, hydrogen, and nitrogen;

or a combination of silicon, hydrogen, carbon, and nitrogen.

17. The method according to claim 16, wherein the reaction gas is a combination of nitrogen gas and hydrogen gas or a combination of ammonia gas and hydrogen gas.

18. The method according to claim 9, wherein the hydrogen-containing silicon precursor is introduced in pulses having a pulse duration of about 0.1 sec to about 1.0 sec with an interval of about 0.5 sec to about 3 sec while forming the films.

19. The method according to claim 9, wherein the reactive gas, the rare gas, and the hydrogen-containing silicon precursor are different from each other.

20. The method according to claim 9, wherein a molar flow rate of the rare gas is greater than a molar flow rate of the hydrogen-containing silicon source.