Etching method

An etching method of etching a film of a substrate,

• wherein the substrate has a mask provided with a pattern on the film and the etching method is performed in a state that the substrate is placed in a chamber of a plasma processing apparatus, and
• wherein the etching method comprises:
• generating plasma of a first processing gas including a first gas containing first fluorocarbon, a second gas containing second fluorocarbon, an oxygen-containing gas and a fluorine-containing gas within the chamber to etch the film;
• and
• generating plasma of a second processing gas including the first gas, the second gas, the oxygen-containing gas and the fluorine-containing gas within the chamber to etch the film,
• wherein the generating of the plasma of the first processing gas and the generating of the plasma of the second processing gas are performed alternately,
• a ratio of a number of fluorine atoms to a number of carbon atoms in a molecule of the second fluorocarbon is larger than a ratio of the number of fluorine atoms to the number of carbon atoms in a molecule of the first fluorocarbon,
• a flow rate of the first gas in the first processing gas is larger than a flow rate of the first gas in the second processing gas,
• a flow rate of the second gas in the second processing gas is larger than a flow rate of the second gas in the first processing gas,
• a flow rate of the oxygen-containing gas in the second processing gas is larger than a flow rate of the oxygen-containing gas in the first processing gas, and
• a flow rate of the fluorine-containing gas in the second processing gas is smaller than a flow rate of the fluorine-containing gas in the first processing gas.