Patent ID: 7365433

Claim:
A high-frequency semiconductor device comprising: a semiconductor substrate having a main surface; a first wiring provided over said main surface of said semiconductor substrate; a second wiring provided over said main surface of said semiconductor substrate; and a grounding conductor layer continuously covering a periphery of said first wiring with a first insulator interposed therebetween and a periphery of said second wiring with a second insulator interposed therebetween in a direction of extension of said first wiring, wherein said grounding conductor layer transmits a grounding potential, wherein said grounding conductor layer includes a first portion constituted by only unit covering an upper surface and two side surfaces of said first wiring and an upper surface and two side surfaces of said second wiring and a second portion covering a bottom surface of said first wiring and a bottom surface of said second wiring and wherein said first wiring is electrically connected to said semiconductor substrate through a conductor plug filled in a through hole selectively formed in said grounding conductor layer with a side insulating film interposed therebetween in a part taken in said direction of extension of said first wiring.