Plasma etching method

A plasma etching method comprising steps of:

• placing a sample on a stage disposed in a decompression chamber;
• introducing a first gas into the decompression chamber;
• supplying electric field into the decompression chamber, through a dielectric window member that is disposed above the stage and from an outside the decompression chamber, and generating plasma from the first gas in an upper portion of an inside space of the decompression chamber;
• supplying a first RF power of a first frequency to the stage, which is capable of generating a bias voltage in the sample for etching the sample with radicals which are generated in the plasma while the plasma is generated;
• introducing a second gas from a position of the stage in outer periphery of a surface of the stage, on the surface on which the sample is placed;
• and
• supplying a second RF power of a second frequency higher than the first frequency to the stage and generating plasma from the second gas in a lower portion of the inside space of the decompression chamber above the stage that causes radicals to be generated in the plasma generated from the second gas,
• wherein the plasma from the second gas is generated by using a lateral electric field supplied by the second RF power which is generated in a ring-shaped region at the outer periphery of the surface of the sample inside the decompression chamber.