OPTICAL SEMICONDUCTOR DEVICE

摘要

A technique is provided which can prevent the quality of an electrical signal from degrading in an optical semiconductor device.;In a cross-section perpendicular to an extending direction of an electrical signal transmission line, the electrical signal transmission line is surrounded by a shielding portion including a first noise cut wiring, second plugs, a first layer wiring, first plugs, a shielding semiconductor layer, first plugs, a first layer wiring, second plugs, and a second noise cut wiring, and the shielding portion is fixed to a reference potential. Thereby, the shielding portion blocks noise due to effects of a magnetic field or an electric field from the semiconductor substrate, which affects the electrical signal transmission line.

主权项

1. An optical semiconductor device comprising:
a semiconductor substrate; a first insulating film formed over the semiconductor substrate; an optical waveguide of an optical signal transmission line formed from a semiconductor layer formed in a first region over the first insulating film; a shielding semiconductor layer formed from the semiconductor layer formed in a second region different from the first region over the first insulating film; a multilayer wiring of n layers (n≧2); an electrical signal transmission line which is formed by mth layer wiring (n≧m≧1) in the second region and which propagates an electrical signal converted from an optical signal; a first noise cut wiring and a second noise cut wiring which are respectively formed on both sides of the electrical signal transmission line and which are formed from the mth layer wiring (n≧m≧1) that is away from and in parallel with the electrical signal transmission line; a first conductive portion that electrically couples the first noise cut wiring and the shielding semiconductor layer; and a second conductive portion that electrically couples the second noise cut wiring and the shielding semiconductor layer, wherein, in a cross-section perpendicular to an extending direction of the electrical signal transmission line, the electrical signal transmission line is surrounded by a shielding portion including the first noise cut wiring, the second noise cut wiring, the first conductive portion, the second conductive portion, and the shielding semiconductor layer, the shielding portion being fixed to a reference potential.