Patent ID: 9739943
Date: 2017-08-22
CPC Classifications: G02B,G02F,H01L

Claim:
1. A manufacturing method of a semiconductor device comprising: (a) preparing an SOI substrate including a semiconductor substrate, a first insulating film formed on a main surface of the semiconductor substrate, a semiconductor layer formed on an upper surface of the first insulating film, and a rear insulating film formed on a rear surface opposite to the main surface of the semiconductor substrate; (b) processing the semiconductor layer to form, in an element formation region, an optical waveguide formed of the semiconductor layer; (c) forming, in the first insulating film, a trench having a first depth from the upper surface of the first insulating film at a position not overlapping with the optical waveguide when seen in a plan view; (d) forming a second insulating film on the first insulating film, including an inside of the trench, so as to cover the optical waveguide; (e) forming, in the second insulating film, a connection hole reaching the optical waveguide; (f) forming, on the second insulating film, a wiring electrically connected to the semiconductor layer through the connection hole; and (g) removing the rear insulating film after (b) and prior to (f).