Etching method and etching apparatus

An apparatus for etching a film with plasma, the apparatus comprising:

• a processing chamber;
• a substrate support provided in the processing chamber and configured to accommodate a substrate having a mask formed on a first film;
• a radio-frequency power supply;
• and
• a controller configured to control an overall operation of the apparatus,
• wherein the controller is programmed to:
• accommodate the substrate on the substrate support;
• generate plasma of a first gas using the radio-frequency power supply so that the first film is etched through the mask;
• and
• generate plasma of a second gas using the radio-frequency power supply so that a shape of the mask is corrected, and
• wherein the first gas contains Xe, Kr, or Rn so that an aspect ratio of a hole or a groove formed in the first film is 30 or more.