Plasma etching method and computer readable storage medium

A plasma etching method comprising:

• disposing a first electrode and a second electrode to face each other in parallel with a predetermined 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 an etching gas into a processing space between the first electrode and the second electrode;
• generating a plasma of the etching gas in the processing space by applying a radio wave power to the first electrode or the second electrode;
• and
• etching a film to be processed on a surface of the substrate by using the plasma,
• wherein a DC voltage is applied to the part during a predetermined etching process, the part being disposed away from the substrate and being etched by reaction with reactant species in the plasma, and
• wherein the DC voltage is switched between a first voltage value and a second voltage value on a time axis in each of regular cycles in accordance with a preset time-duty function to thereby obtain desired etching characteristics with respect to the film and, during the etching process, at least process parameters related to the etching gas are not varied.