Post-deposition treatment to enhance properties of Si-O-C low K films
A method for providing a dielectric film having enhanced adhesion and stability. The method includes a post deposition treatment that densifies the film in a reducing atmosphere to enhance stability if the film is to be cured ex-situ. The densification generally takes place in a reducing environment while heating the substrate. The densification treatment is particularly suitable for silicon-oxygen-carbon low dielectric constant films that have been deposited at low temperature.
1. A method of depositing dielectric material upon a substrate, comprising:
providing the substrate to a deposition chamber; introducing a process gas in the deposition chamber, the process gas comprising an organosilane precursor selected from the group consisting of methylsilane, dimethylsilane, trimethylsilane, tetramethylsilane, and phenylmethylsilane, the deposition chamber having a first pressure and a first temperature about 125° C. or less during a first time period while depositing a carbon-doped silicon oxide layer; and
maintaining the process gas in the deposition chamber, the deposition chamber having a second pressure and a second temperature for a second time period while depositing the carbon-doped silicon oxide layer, the carbon-doped silicon oxide layer having a carbon content of at least about 8 atomic percent or more, wherein the first pressure is higher than the second pressure and the first temperature is less than the second temperature.
2. The method of claim 1 wherein the process gas comprises oxygen and helium.
3. The method of claim 2 wherein the process gas further comprises ozone.
4. The method of claim 1 wherein the first pressure is about 200 to 700 Torr.
5. The method of claim 4 wherein the second pressure is about 50 to 150 Torr.
6. The method of claim 1 wherein the first pressure is about 200 Torr and the second pressure is about 100 Torr.
7. A method of depositing a carbon-doped silicon oxide layer upon a substrate, the method comprising:
providing the substrate to a deposition chamber;
flowing a process gas comprising an organosilicon precursor having at least one silicon-carbon bond and ozone into the deposition chamber during a first deposition step while maintaining conditions of the deposition chamber at process conditions suitable for depositing carbon-doped silicon oxide material over the substrate using a thermal chemical vapor deposition process, the process conditions including maintaining a pressure level within the chamber during the first deposition step within a range of about 200 to 700 Torr and maintaining a temperature of about 125° C. or less; and
during a second deposition step subsequent to the first deposition step, continuing a flow of the process gas into the deposition chamber while maintaining the deposition chamber at process conditions suitable for depositing carbon-doped silicon oxide material over the substrate using a thermal chemical vapor deposition process, the process conditions including maintaining a pressure level within the chamber during the second deposition step within a range of about 50 to 150 Torr and maintaining a temperature of at least about 150° C.
8. The method of claim 7 wherein the temperature during the second deposition step is between about 150 to 170° C.
9. The method of claim 1 wherein the first temperature is at least about 25° C. less than the second temperature.
10. The method of claim 1 wherein the first temperature is about 125° C.
11. The method of claim 1 wherein the second temperature is between about 150 to 170° C.
12. The method of claim 1 wherein the first pressure is greater than about 200 ton.
13. The method of claim 1 wherein the second pressure is about 150 torr or less.
14. The method of claim 1 further comprising:
prior to introducing the process gas in the deposition chamber, flowing an inert gas and oxygen into the deposition chamber to establish a chamber pressure at the first pressure; and
after establishing the chamber pressure at the first pressure, substituting the flow of oxygen with a flow of ozone.
15. The method of claim 1 wherein the second temperature is greater than about 150° C.
16. The method of claim 1 wherein the carbon-doped silicon oxide has a density of about 1.2 g/cm 3 or less.
17. A method of depositing a carbon-doped silicon oxide layer on a substrate, comprising:
providing the substrate to a deposition chamber;
introducing a process gas comprising an organosilicon precursor having at least one silicon-carbon bond into the deposition chamber, the deposition chamber having a first pressure and a first temperature of about 125° C. or less during a first time period while depositing a first portion of the carbon-doped silicon oxide layer; and
maintaining the process gas in the deposition chamber, the deposition chamber having a second pressure and a second temperature of at least about 150° C. or more for a second time period while depositing a second portion of the carbon-doped silicon oxide layer, wherein the first pressure is higher than the second pressure.