Patent ID: 7279349

Claim:
A method of manufacturing a semiconductor optical device comprising the steps of: forming a ridge waveguide channel with a trench on both sides of the ridge waveguide channel on a semiconductor substrate; forming a passivation film on the semiconductor substrate containing the ridge waveguide channel and said trench on both sides; forming an organic material film on the passivation film; mounting the semiconductor substrate on a lower electrode of a dry etching apparatus, removing the organic material film by planarizing a portion of the organic material film outside of said trench while leaving another portion of the organic material film only within said trench by etching and, simultaneously, removing reaction products deposited on the semiconductor substrate accompanying removal of the organic material film with fluoro-radicals formed in plasmas from a fluorine-containing member disposed to the outer periphery of the substrate mounting surface of the lower electrode; removing the passivation film in the ridge waveguide channel by dry etching succeeding to the step of removing the organic material film; and forming an electrode to the region from which the passivation film has been removed.