Abstract: It is the object to minimize a magnetic influence, on the outside, of a semiconductor chip which is formed on a substrate includes inductor conductors. A semiconductor chip 2 including inductor conductors is mounted on a substrate 1 and a plurality of through holes 8 are formed in the area on the outside of the mounting position. Shielding members 4 are formed on the chip mounting side and the opposite side of the substrate 1 and in the through holes 8 so as to cover the semiconductor chip 2 with the shielding members 4 from both sides of the substrate 1. Therefore, magnetic fluxes from a circuit formed on the semiconductor chip 2 do not leak out from the shielding members 4, but circulate inside the shielding members 4.

Abstract: A variable inductance element comprising an inductor conductor 10 having a predetermined shape formed on an insulation layer 40 on the surface of a semiconductor substrate 42, switches 16 and 24 for shorting portions of the inductor conductor 10, and input/output terminals 12 and 14 provided at the respective ends of the inductor conductor 10. When switches 16 and/or 24 is in the on state, the function as an inductor having a smaller inductance than the overall inductor conductor 10 is obtained. The inductance of this variable inductance element can be changed by external control, while manufacturing is easy and formation in a unitized manner with an integrated circuit or other semiconductor device is enabled.

Abstract: A noise filter used in a signal transmission or power supply circuit and the like for suppressing noise passing therethrough comprises a first spiral electrode formed on an insulating substrate and a second spiral electrode formed over the first spiral electrode by way of a dielectric layer. The noise filter could also include a dielectric layer formed over the first spiral electrode and the insulating substrate with the second spiral electrode formed in such a manner to partly overlap with the first spiral electrode. Preferably, a high purity semiconductor substrate having a large bulk resistance is used as the insulating substrate.