METHOD FOR FORMING DIELECTRIC SiOCH FILM HAVING CHEMICAL STABILITY

• US 20090148964A1
• Filed: 12/07/2007
• Published: 06/11/2009
• Est. Priority Date: 12/07/2007
• Status: Active Grant

• Current Assignee: ASM Japan K.K. (ASM International NV)
• Original Assignee: ASM Japan K.K. (ASM International NV)
• Inventors: Kato, Manabu, Takamure, Noboru, Matsushita, Kiyohiro, Tsuji, Naoto
• Granted Patent: US 7,807,566 B2
• Time in Patent Office: Days
• US Class Current: 438/7
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: H01L 21/02126 the material containing Si, O, and at least one of H, N, C, F, or other non-metal elements, e.g. SiOC, SiOC:H or SiONC
• CPC Class Codes: H01L 21/02203 the layer being porous
• CPC Class Codes: H01L 21/02216 the compound being a molecule comprising at least one silicon-oxygen bond and the compound having hydrogen or an organic group attached to the silicon or oxygen, e.g. a siloxane
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/02348 treatment by exposure to UV light
• CPC Class Codes: H01L 21/31633 Deposition of carbon doped silicon oxide, e.g. SiOC
• CPC Class Codes: H01L 21/31695 Deposition of porous oxides or porous glassy oxides or oxide based porous glass
• CPC Class Codes: H01L 22/12 for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions electrical measurement of diffusions H01L22/14
• CPC Class Codes: H01L 22/20 Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps

Abstract

A method for determining conditions for forming a dielectric SiOCH film, includes: (i) forming a dielectric SiOCH film on a substrate under conditions; (ii) evaluating the conditions using a ratio of Si—CH3 bonding strength to Si—O bonding strength of the film as formed in step (i); (iii) if the ratio is 2.50 % or higher, confirming the conditions, and if the ratio is less than 2.50 %, changing the conditions by changing at least one of the susceptor temperature, the distance between upper and lower electrodes, the RF power, and the curing time; and (iv) repeating steps (i) to (iii) until the ratio is 2.50 % or higher.

Claims

1. A method for determining conditions for forming a dielectric SiOCH film, comprising:

(i) forming a dielectric SiOCH film on a substrate under conditions including a susceptor temperature, a distance between upper and lower electrodes, an RF power, and a curing time;

(ii) evaluating the conditions using a ratio of Si—

CH3 bonding strength to Si—

O bonding strength of the film as formed in step (i);

(iii) if the ratio is 2.50% or higher, confirming the conditions, and if the ratio is less than 2.50%, changing the conditions by changing at least one of the susceptor temperature, the distance between upper and lower electrodes, the RF power, and the curing time; and

(iv) repeating steps (i) to (iii) until the ratio is 2.50% or higher.

2. The method according to claim 1, wherein the film as formed in step (i) has a dielectric condition (k) and an elastic modulus (EM) which satisfy 2.4<

k<

2.6 and 8 GPa<

EM.

3. The method according to claim 1, wherein the ratio is determined based on an FT-IR spectrum of the film.

4. The method according to claim 1, wherein step (iii) comprises, if the ratio is less than 2.50%, reducing the susceptor temperature, increasing the distance between the upper and lower electrodes, decreasing the RF power, and/or shortening the curing time.

5. The method according to claim 1, wherein the curing time is a time of UV curing.

6. The method according to claim 1, wherein step (i) comprises:

introducing a silicon-containing hydrocarbon gas having a crosslinkable group, a porogen gas, an oxidizing gas, and an inert gas into a reaction chamber wherein the substrate is placed on the susceptor;

applying RF power to the reaction chamber between the upper and lower electrodes to generate a plasma reaction region in the reaction chamber, thereby depositing a thin film on a substrate; and

curing the thin film until a dielectric condition (k) and an elastic modulus (EM) of the film satisfy 2.4<

k<

2.6 and 8 GPa<

EM.

7. The method according to claim 1, wherein in step (iii), under the confirmed conditions, a decrease of thickness of the film and an increase of dielectric constant of the film are less than 3% and less than 0.25, respectively, before and after the curing.

8. A method for forming a dielectric SiOCH film on a substrate, comprising:

confirming the conditions for forming a dielectric SiOCH film according to claim 1; and

forming a dielectric SiOCH film on a substrate under the conditions.

9. The method according to claim 8, wherein the curing is UV curing.

10. The method according to claim 8, wherein the forming step comprises:

introducing a silicon-containing hydrocarbon gas having a crosslinkable group, a porogen gas, an oxidizing gas, and an inert gas into a reaction chamber wherein the substrate is placed on the susceptor;

applying RF power to the reaction chamber between the upper and lower electrodes to generate a plasma reaction region in the reaction chamber, thereby depositing a thin film on a substrate; and

curing the thin film until a dielectric condition (k) and an elastic modulus (EM) of the film satisfy 2.3<

k<

2.8 and 5 GPa<

EM.

11. The method according to claim 8, wherein a decrease of thickness of the film and an increase of dielectric constant of the film are less than 3% and less than 0.25, respectively, before and after the curing.

12. The method according to claim 10, wherein the silicon-containing hydrocarbon gas is at least one selected from the group consisting of silicon-containing hydrocarbon gases having alkoxyl group and/or vinyl group as the crosslinkable group.

13. The method according to claim 10, wherein the porogen gas is at least one selected from the group consisting of hydrocarbon gases of linear or cyclic CnHm wherein n is an integer of 4-14 and m is an integer of 4-30.

14. The method according to claim 13, wherein the porogen gas is at least one selected from the group consisting of α

-terpinene, β

-terpinene, γ

-terpinene, hexane, and cyclohexane.

15. The method according to claim 10, wherein the oxidizing gas is at least one selected from the group consisting of )2 and N2O.

16. The method according to claim 10, wherein the inert gas is at least one selected from the group consisting of He, Ar, Kr, and Xe.

17. The method according to claim 10, wherein the curing is conducted by UV light for a time period of less than 700 seconds.

18. A method for forming an interconnect structure on a substrate, comprising:

forming a dielectric SiOCH film on a substrate according to claim 10; and

forming an interconnect structure on the substrate by single or dual damascene.