Patent ID: 8072307
Filing Date: 2011-12-06
Classification: H01F,H01L

Abstract:
1. A transformer comprising: a semiconductor substrate comprising a first conductivity type semiconductor layer; a semiconductor layer coil comprising a semiconductor layer coil wiring composed of a second conductivity type semiconductor layer laminated on a surface side of the first conductivity type semiconductor layer; a trench coil electrically connected with the semiconductor layer coil in parallel; a coil insulating layer laminated on the surface side of the first conductivity type semiconductor layer, covering over both of the semiconductor layer coil and the trench coil; and a metal layer coil arranged on a surface of the coil insulating layer, wherein a trench is formed in the first conductivity type semiconductor layer, each of the semiconductor layer coil wiring and the trench has a spiral shape, the trench and the semiconductor layer coil wiring are alternately disposed in the radial direction thereof, the trench coil comprises (a) a trench insulating film arranged on an inner surface of the trench, and (b) a trench coil wiring composed of a conductive layer disposed within the trench and covered by the trench insulating film, and the metal layer coil opposes both of the semiconductor layer coil and the trench coil.