Patent ID: 7751456

Claim:
A method for manufacturing a semiconductor optical device, comprising: forming a dielectric film on a top surface of a laminated semiconductor structure, the laminated semiconductor structure including a first semiconductor layer of a first conductivity type, an active layer, and a second semiconductor layer of a second conductivity type, in sequence, on a substrate; forming by photolithography a first resist pattern of a first resist film disposed on a surface of the dielectric film, the first resist pattern having a stripe-shaped portion corresponding to a waveguide ridge; partially removing the dielectric film by etching, using the first resist pattern as a mask, to expose the second semiconductor layer; removing portions of an upper surface side of the second semiconductor layer by dry etching, using the first resist pattern as a mask, to form concave portions, leaving part of the second semiconductor layer, and to form the waveguide ridge between said concave portions; forming a first insulating film on surfaces of the concave portions and the waveguide ridge, with the dielectric film on a top surface of the waveguide ridge, after removing the first resist pattern; forming a second resist pattern covering the first insulating film in the concave portions, adjacent the waveguide ridge, and exposing the surface of the first insulating film on the top of the waveguide ridge, the second resist pattern having a top surface in the concave portions that is closer to the substrate than a top surface of the first insulating film on the top surface of the waveguide ridge; removing the first insulating film and the dielectric film by etching, including wet etching, using the second resist pattern as a mask, to expose the second semiconductor layer in the waveguide ridge, and removing the second resist pattern; and forming a metal electrode layer on the second semiconductor layer exposed in the waveguide ridge.