Plasma processing apparatus and plasma processing method

A plasma processing method comprising:

• disposing a wafer to be processed in a processing chamber inside a vacuum chamber;
• forming plasma in the processing chamber;
• and
• performing etching to a film to be processed of a film structure that has previously been disposed on the upper surface of the wafer and that includes a plurality of film layers,
• wherein the film structure includes:
• a lower film including at least one film layer and a groove structure;
• and
• an upper film including at least one film layer that covers an inside and an upper end of the groove structure and that is laminated above,
• the plasma processing method comprising:
• removing the upper film by etching until an upper end of the groove structure of the lower film is exposed;
• performing etching to a film layer of the upper film inside the groove structure;
• and
• determining an end point of the performing, by using a value of thickness of the film layer inside the groove structure of the lower film upon completion of the removing.