Method of manufacturing optical semiconductor integrated circuit device

Abstract

In an existing optical semiconductor integrated circuit device, a silicon nitride film that is an anti-reflection film is used as an etching stopper film at the etching of an insulating film and by means of wet etching the insulating film is removed once for all. Accordingly, there is a problem in that the processing accuracy is poor. In an optical semiconductor integrated circuit device according to the present invention, after a multi-layered wiring layer is formed on a top surface of a silicon substrate, an insulating layer on a top surface of an anti-reflection film of a photodiode is removed by means of dry etching. At this time, a polycrystal silicon film is used as an etching stopper film. Thereby, in the photodiode according to the invention, although the dry etching is used, since a silicon nitride film that is an anti-reflection film is not over-etched, the dispersion of film thickness thereof can be inhibited from occurring. As a result, a photodiode according to the present invention can realize an improvement in the sensitivity of incident light and a miniaturization structure can be realized.

Dependencies are inferred from the claim text.