Plasma processing method and plasma processing system
A plasma processing method performed in a plasma processing apparatus having a chamber is provided. This method comprises: (a) providing a substrate to a substrate support in the chamber, the substrate having a silicon-containing film and a mask film over the silicon-containing film; (b) supplying a processing gas to the chamber, the processing gas including a tungsten-containing gas and a hydrogen fluoride gas, the flow rate of the hydrogen fluoride gas being higher than the flow rate of the tungsten-containing gas; and (c) forming a plasma from the processing gas to etch the silicon-containing film.
1 . A plasma processing method performed in a plasma processing apparatus having a chamber, the method comprising:
(a) providing a substrate to a substrate support in the chamber, the substrate having a silicon-containing film and a mask film over the silicon-containing film;
(b) supplying a processing gas to the chamber, the processing gas including a tungsten-containing gas, a hydrogen fluoride gas, a phosphorus-containing gas, and at least one gas selected from the group consisting of carbon-containing gases, oxygen-containing gases, and halogen-containing gases other than fluorine, wherein a flow rate of the tungsten-containing gas is the lowest of gases included in the processing gas, and the flow rate of the tungsten-containing gas is 1% by volume or less relative to an overall flow rate of the processing gas; and
(c) forming a plasma from the processing gas to etch the silicon-containing film,
wherein, in (c), the etching of the silicon-containing film is conducted while forming a protective film on the mask film by tungsten in the tungsten-contained gas.
2 . The plasma processing method according to claim 1 , wherein the tungsten-containing gas is a WF a Cl b gas (where a and b are integers equal to or greater than 0 and equal to or less than 6, and sum of a and b is equal to or greater than 2 and equal to or less than 6).
3 . The plasma processing method according to claim 1 , wherein the tungsten-containing gas is at least one of WF 6 gas and WCl 6 gas.
4 . The plasma processing method according to claim 1 , wherein the flow rate of the hydrogen fluoride gas is the highest of the gases included in the processing gas.
5 . The plasma processing method according to claim 1 , wherein the flow rate of the hydrogen fluoride gas is at least 10 times that of the tungsten-containing gas.
6 . The plasma processing method according to claim 1 , wherein the carbon-containing gas is C x F y gas (where x, y are positive integers) or C s H t F u gas (where s, t, u are positive integers).
7 . The plasma processing method according to claim 1 , wherein the phosphorus-containing gas is a phosphorus halide gas.
8 . The plasma processing method according to claim 1 , wherein temperature of the substrate support in (c) is set to 0° C. or lower.
9 . The plasma processing method according to claim 8 , wherein the temperature of the substrate support in (c) is set to −50° C. or lower.
10 . The plasma processing method according to claim 1 , wherein the flow rate of the tungsten-containing gas is 0.5% by volume or less relative to the overall flow rate of the processing gas.
11 . The plasma processing method according to claim 1 , wherein the flow rate of the hydrogen fluoride gas is 70% by volume or more relative to a total flow rate of the processing gas.
12 . The plasma processing method according to claim 1 , wherein the flow rate of the hydrogen fluoride gas is at least 100 times that of the tungsten-containing gas.
13 . The plasma processing method according to claim 1 , wherein the protective film is formed at least on sidewalls of the mask film, and wherein forming the protective film suppresses bowing of the mask film.
14 . A plasma processing method performed in a plasma processing apparatus having a chamber, the method comprising:
(a) providing a substrate to a substrate support in the chamber, the substrate having a silicon-containing film and a mask film over the silicon-containing film;
(b) supplying a processing gas to the chamber; and
(c) forming a plasma from the processing gas to etch the silicon-containing film with an HF species included in the plasma,
wherein the processing gas in (b) includes a tungsten-containing gas, a hydrogen fluoride gas, a phosphorus-containing gas, and at least one gas selected from the group consisting of carbon-containing gases, oxygen-containing gases, and halogen-containing gases other than fluorine, wherein a flow rate of the tungsten-containing gas is the lowest of gases included in the processing gas, and the flow rate of the tungsten-containing gas is 1% by volume or less relative to an overall flow rate of the processing gas, and
wherein, in (c), the etching of the silicon-containing film is conducted while forming a protective film on the mask film by tungsten in the tungsten-contained gas.
15 . The plasma processing method according to claim 14 , wherein the HF species is produced from at least one gas selected from the group consisting of HF gases and hydrofluorocarbon gases.
16 . The plasma processing method according to claim 14 , wherein the HF species is produced from a hydrofluorocarbon gas with two or more carbon atoms.
17 . The plasma processing method according to claim 14 , wherein the HF species is produced from at least one gas selected from the group consisting of CH 2 F 2 gas, C 3 H 2 F 4 gas, C 3 H 2 F 6 gas, and C 4 H 2 F 6 gas.