Optical semiconductor device

Patent metadata

Field	Value
Publication number	US-9508662-B2
Application number	US-201514827841-A
Country	US
Kind code	B2
Filing date	Aug 17, 2015
Priority date	Aug 21, 2014
Publication date	Nov 29, 2016
Grant date	Nov 29, 2016

Abstract

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.

First claim

What is claimed is:

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.

2. The optical semiconductor device according to claim 1 ,
wherein a concentration of impurities of the shielding semiconductor layer is higher than that of the optical waveguide of the optical signal transmission line.

3. The optical semiconductor device according to claim 2 ,
wherein the concentration of impurities of the shielding semiconductor layer is 10 20 cm −3 or more.

4. The optical semiconductor device according to claim 1 ,
wherein a first distance between the semiconductor substrate and the shielding semiconductor layer and a second distance between the shielding semiconductor layer and the electrical signal transmission line are 2 μm or more.

5. The optical semiconductor device according to claim 1 ,
wherein a second insulating film formed of SiOC, SiC, or SiCN is formed between the shielding semiconductor layer and the electrical signal transmission line.

6. The optical semiconductor device according to claim 1 ,
wherein the shielding semiconductor layer is formed of an integrated semiconductor layer having a plurality of openings in plan view.

7. The optical semiconductor device according to claim 6 ,
wherein the shielding semiconductor layer has a grid shape in plan view.

8. The optical semiconductor device according to claim 6 ,
wherein the shielding semiconductor layer has a stripe shape in plan view.

9. The optical semiconductor device according to claim 1 ,
wherein among the multilayer wiring of n layers (n≧2), from a first layer wiring located closer to the optical signal transmission line than a first distance between the semiconductor substrate and the semiconductor layer to an (n−1) th layer wiring does not overlap with the optical signal transmission line in plan view.

Assignees

• Renesas Electronics Corp

Inventors

• Kunishima Hiroyuki
• Nakashiba Yasutaka
• Wakabayashi Masaru
• Watanuki Shinichi
• Ozawa Ken
• Usami Tatsuya
• Yamamoto Yoshiaki
• Sakamoto Keiji

Classifications

• H10W42/60 Primary

  protecting against electrostatic charges or discharges, e.g. Faraday shields (integrated devices comprising arrangements for electrical protection H10D89/60) · CPC title

• G02F1/0121 Primary

  Operation of devices; Circuit arrangements, not otherwise provided for in this subclass · CPC title

• G02F1/025

  in an optical waveguide structure (G02F1/017, {G02F1/2257} take precedence) · CPC title

• G02B6/43

  Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections · CPC title

• G02B6/12 Primary

  of the integrated circuit kind (electric integrated circuits H10B, H10D84/00 - H10D89/00, H10F19/00, H10F39/00, H10H29/00, H10K19/00, H10K39/00, H10K59/00, H10N19/00, H10N39/00, H10N59/00, H10N69/00, H10N79/00, H10N89/00) · CPC title