Etching method

An etching method for etching an organic etching target film, the method comprising:

• forming the organic etching target film on a protective film placed inside an airtight processing chamber, the organic etching film containing Si;
• introducing a processing gas into the airtight processing chamber, the processing gas containing at least CF4, N2, and Ar;
• generating a plasma in the airtight processing chamber for etching the organic etching target film;
• and
• etching the organic etching target film until the protective film is exposed,
• wherein a resist layer is used as a mask on the organic etching target film,
• wherein the etching process ceases once the protective film is exposed,
• wherein a flow rate ratio of CF4 and N2 in the processing gas is set within a following range:
• (N2 flow rate/CF4 flow rate)≧1 to prevent an occurrence of an etching stop and (N2 flow rate/CF4 flow rate)≦4 to prevent an occurrence of bowing, and
• wherein a volume percentage density ratio of CF4, N2, and Ar is within a range:
• 1:1:6≦vol. % of CF4:
• vol. % of N2:
• vol. % of Ar≦1:4:6.