Etching method
An etching method includes (a) providing a substrate in a chamber in a plasma processing apparatus. The substrate includes a silicon-containing film. The etching method further includes (b) etching the silicon-containing film with a chemical species in plasma generated from a process gas in the chamber. The process gas contains a hydrogen fluoride gas and a phosphorus-containing gas.
1 . A method of etching a substrate in a chamber of a plasma processing apparatus, the substrate including a silicon-containing film and a mask on the silicon-containing film, the method comprising:
(a) providing a process gas to the chamber; and
(b) etching the silicon-containing film with a chemical species in a plasma generated from the process gas,
wherein the process gas contains a hydrogen fluoride gas and a phosphorus-containing gas,
wherein the hydrogen fluoride gas has a highest flow rate of all gases in the process gas containing no noble gas or of all non-noble gas components of the process gas,
the silicon-containing film is an alternate stack of multiple silicon oxide films and multiple silicon nitride films or an alternate stack of multiple silicon oxide films and multiple silicon films, and
step (b) includes etching the layer of the alternate stack that is in contact with the mask.
2 . The method according to claim 1 , wherein the process gas further contains a halogen-containing gas.
3 . The method according to claim 2 , wherein the halogen-containing gas contains a CxFyBrz gas, where x and z are integers greater than or equal to 1, and y is an integer greater than or equal to 0.
4 . The method according to claim 2 , wherein the halogen-containing gas contains ClF 3 gas.
5 . The method according to claim 2 , wherein the halogen-containing gas contains at least one gas selected from the group consisting of a Cl 2 gas, a Br 2 gas, an HCl gas, an HBr gas, an HI gas, a BCl 3 gas, a CxHyClz gas, a CxFyBrz gas, a CxFyIz gas, a CxFyClz gas, a ClF 3 gas, an IF 5 gas, an IF 7 gas, and a BrF 3 gas, where x and z are integers greater than or equal to 1, and y is an integer greater than or equal to 0.
6 . The method according to claim 2 , wherein the halogen-containing gas contains carbon.
7 . The method according to claim 6 , wherein the halogen-containing gas contains two or more halogens.
8 . The method according to claim 2 , wherein the halogen-containing gas contains at least one selected from the group consisting of a CHCl 3 gas, a CH 2 Cl 2 gas, a CF 2 Br 2 gas, and a CxFyClz gas, where x and z are integers greater than or equal to 1, and y is an integer greater than or equal to 0.
9 . The method according to claim 1 , wherein the process gas further contains a carbon-containing gas.
10 . The method according to claim 9 , wherein the carbon-containing gas contains at least one of a fluorocarbon or a hydrofluorocarbon having one to six carbon atoms per molecule.
11 . The method according to claim 1 , wherein the process gas further contains at least one gas selected from the group consisting of an NF 3 gas, an O 2 gas, a CO 2 gas, a CO gas, an N 2 gas, a He gas, an Ar gas, a Kr gas, and a Xe gas.
12 . The method according to claim 1 , wherein the silicon-containing film further includes a polycrystalline silicon film.
13 . The method according to claim 1 , wherein the substrate includes a carbon-containing mask or a metal-containing mask on the silicon-containing film.
14 . The method according to claim 1 , wherein the substrate includes a mask comprising at least one metal-containing material selected from the group consisting of titanium nitride, titanium oxide, tungsten, and tungsten carbide on the silicon-containing film.
15 . A method of etching a substrate in a chamber of a plasma processing apparatus, the substrate including a silicon-containing film and a mask on the silicon-containing film, the method comprising:
(a) providing a process gas to the chamber; and
(b) etching the silicon-containing film with a chemical species in a plasma generated from the process gas,
wherein the process gas contains a hydrogen fluoride gas and a phosphorus-containing gas,
wherein the process gas further contains a carbon-containing gas, and
wherein the etching the silicon-containing film includes decreasing a flow rate of the carbon-containing gas in a stepwise manner.
16 . The method according to claim 15 , wherein the etching the silicon-containing film includes setting a pressure in the chamber to 0.666 to 2.666 Pa inclusive.
17 . A method of etching a substrate in a chamber of a plasma processing apparatus, the substrate including a silicon-containing film and a mask on the silicon-containing film, the method comprising:
(a) providing a process gas to the chamber; and
(b) etching the silicon-containing film with a chemical species in a plasma generated from the process gas,
wherein the process gas contains a hydrogen fluoride gas and a phosphorus-containing gas, and
wherein the etching the silicon-containing film includes decreasing a pressure in the chamber in a stepwise manner.