Plasma processing method and computer readable storage medium

A plasma etching method comprising:

• disposing a first electrode and a second electrode in parallel to each other with a gap therebetween in a vacuum evacuable processing chamber;
• preparing a part in the processing chamber;
• supporting a substrate to be processed by the second electrode to face the first electrode;
• vacuum-evacuating the processing chamber to a predetermined pressure;
• supplying a first processing gas containing an etchant gas into a processing space between the first electrode and the second electrode;
• generating a plasma of the first processing gas in the processing space by applying a radio frequency power to the first electrode or the second electrode;
• and
• etching a film to be processed on the substrate by using the plasma while using as a mask a resist pattern formed on the film,
• wherein a resist modification process is performed on the substrate in the processing chamber before etching the film and includes:
• vacuum-evacuating the processing chamber to a desired pressure;
• supplying a second processing gas into the processing space;
• generating a plasma of the second processing gas in the processing space by applying the radio frequency power to the first electrode or the second electrode;
• and
• applying a negative DC voltage to the part exposed to the plasma, the part being disposed away from the substrate in the processing chamber and injecting electrons discharged from the part into the resist pattern on the substrate to thereby improve an etching resistance of the resist pattern,
• wherein the part includes a sidewall of the processing chamber.