Etching process method
An etching process method is provided that includes outputting a first high frequency power from a first high frequency power supply in a cryogenic temperature environment where the temperature of a substrate is controlled to be less than or equal to −35° C., supplying a sulfur fluoride-containing gas and a hydrogen-containing gas, generating a plasma from the supplied sulfur fluoride-containing gas and hydrogen-containing gas, and etching a laminated film made up of laminated layers of silicon-containing films having different compositions with the generated plasma.
1. An etching process method comprising:
outputting a first high frequency power from a first high frequency power supply in an environment where a temperature of the substrate is controlled to be less than or equal to −35° C.;
supplying a sulfur fluoride-containing gas and a hydrogen-containing gas;
generating a plasma from the supplied sulfur fluoride-containing gas and hydrogen-containing gas;
etching a laminated film made up of laminated layers of silicon-containing films having different compositions, the silicon-containing films including a SiO 2 (silicon-oxide) film, with the generated plasma, wherein the supplied sulfur fluoride-containing gas and hydrogen-containing gas does not include a gas having carbon, and
introducing a substrate including laminated layers of SiO 2 (silicon-oxide) films and SiN (silicon nitride) films that are alternately laminated on each other and a mask film formed on the laminated layers into a chamber,
wherein the etching etches the SiO 2 (silicon-oxide) films and the SiN (silicon nitride) films by the plasma that is generated from the supplied sulfur fluoride-containing gas and hydrogen-containing gas,
the SiO 2 (silicon-oxide) film is etched by liquid hydrofluoric acid that is generated from the supplied sulfur fluoride-containing gas and hydrogen-containing gas, and
the etching of the SiO 2 (silicon-oxide) films is performed by a plasma that is generated from gases that are same as gases by which the etching of the SiN (silicon nitride) films is performed.
2. The etching process method according to claim 1 , wherein a hydrocarbon-containing gas is supplied as the hydrogen-containing gas.
3. The etching process method according to claim 2 , wherein the hydrocarbon-containing gas is at least one of CH 4 (methane), C 2 H 8 , C 2 H 2 (acetylene), C 2 H 4 (ethylene), C 2 H 6 (ethane), C 3 H 6 (propylene), C 3 H 8 (propane), and C 3 H 4 (propyne).
4. The etching process method according to claim 1 , wherein a hydrofluorocarbon-containing gas is supplied as the hydrogen-containing gas.
5. The etching process method according to claim 4 , wherein the hydrofluorocarbon-containing gas is at least one of CH 2 F 2 (methane difluoride), CH 3 F (fluoromethane), and CHF 3 (trifluoro methane).
6. The etching process method according to claim 1 further comprising:
adding a fluorocarbon-containing gas to the sulfur fluoride-containing gas and the hydrogen-containing gas that are supplied.
7. The etching process method according to claim 6 , wherein the fluorocarbon-containing gas is at least one of CF 4 (carbon tetrafluoride), C 3 F 8 (propane octafluoride), C 2 F 4 (tetrafluoroethylene), C 3 F 6 (hexafluoropropene), C 4 F 6 (hexafluoro-1,3-butadiene), and C 4 F 8 (cyclobutane octafluoride).
8. The etching process method according to claim 1 , wherein the sulfur fluoride-containing gas is SF 6 (sulfur hexafluoride).
9. The etching process method according to claim 1 , further comprising:
controlling an internal pressure of a processing chamber in which etching is performed on the laminated film to 15 to 25 mTorr.
10. The etching process method according to claim 1 , wherein the method further comprises:
repeating a cycle of switching the first high-frequency power and a second high-frequency power that is lower than the first high-frequency power on and off synchronously during the etching process.
11. The etching process method according to claim 1 , wherein the method further comprises:
forming a protective film, during the etching, on the side wall of an etched hole, the protective film including sulfur from the sulfur fluoride-containing gas.
12. The etching process method according to claim 1 , wherein the mask film is an amorphous carbon film.
13. The etching process method according to claim 1 , wherein the method further comprises controlling a temperature of an internal wall of the chamber to be equal to or above 70° C.
14. The etching process method according to claim 1 , wherein the hydrogen-containing gas includes one of H 2 , HF and NH 3 .
15. The etching process method according to claim 1 , wherein the method further comprises controlling the temperature of the substrate at less than or equal to −35° C. throughout the etching.