PURPOSE: To significantly reduce the dielectric loss and eddy-current loss and enable the formation of a favorable inductor by removing part of a semiconductor substrate to form a cavitied first region and forming a wiring layer, acting as an inductor, on the major surface thereof with an insulating film in-between.

CONSTITUTION: Part of a silicon substrate 11 is removed to form a cavitied removal region 12, and an insulating layer 13 is formed on the removal region 12 and its peripheral area. A wiring layer 14 to be one outgoing line of an inductor is formed on the insulating layer 13, and further a layer insulating layer 15 is also formed thereon. A spiral wiring layer 16 to be the other outgoing line of the inductor is formed on the layer insulating layer 15, and an insulating layer 17 is formed thereon. A contact hole 15a is formed in a part of the layer insulating layer 15 to connect the wiring layer 14 with the wiring layer 16. As mentioned above, part of the substrate 11 is removed to form a cavity, or the first region, and the inductor is formed in correspondence to the region; this significantly reduces the dielectric loss and eddy-current loss.