A method of forming an integrated spiral inductor having low substrate loss, said method comprising the following operations: - providing a semiconductor wafer having a semiconductor substrate, said semiconductor substrate having a first surface and a second surface , the first and second surfaces disposed on opposite sides of the substrate; - disposing a multilayer isolation structure on said first surface ; - forming metal wiring embedded in the multilayer isolation structure ; - providing a high resistivity carrier wafer and attaching the carrier wafer to said semiconductor wafer so that the first surface of said semiconductor substrate faces towards the carrier wafer; - thinning said semiconductor substrate from said second surface ; - creating at least one trench gap in the remaining semiconductor substrate from the thinned second surface ; - filling said at least one trench gap with dielectric layer ; - forming through-silicon vias , said through-silicon vias connecting the metal wiring embedded in the multilayer isolation structure ; - forming a spiral inductor on the dielectric layer using at least one conductive layer characterized in that said spiral inductor has an inductor coil with more than one winding, the step of forming a spiral inductor on the dielectric layer comprises the formation of a metal wire embedded in the multilayer isolation structure , the formation of through-silicon vias (16a, 16b, 16c and16d), and the formation-of a conductive layer on the dielectric layer , embedded in a passivation layer , said through-silicon vias (16a, 16b, 16c and16d) and said metal wire defining at least one underpass and said conductive layer defining the inductor coil. - providing a semiconductor wafer having a semiconductor substrate, said semiconductor substrate having a first surface and a second surface , the first and second surfaces disposed on opposite sides of the substrate; - disposing a multilayer isolation structure on said first surface ; - forming metal wiring embedded in the multilayer isolation structure ; - providing a high resistivity carrier wafer and attaching the carrier wafer to said semiconductor wafer so that the first surface of said semiconductor substrate faces towards the carrier wafer; - thinning said semiconductor substrate from said second surface ; - creating at least one trench gap in the remaining semiconductor substrate from the thinned second surface ; - filling said at least one trench gap with dielectric layer ; - forming through-silicon vias , said through-silicon vias connecting the metal wiring embedded in the multilayer isolation structure ; - forming a spiral inductor on the dielectric layer using at least one conductive layer said spiral inductor has an inductor coil with more than one winding, the step of forming a spiral inductor on the dielectric layer comprises the formation of a metal wire embedded in the multilayer isolation structure , the formation of through-silicon vias (16a, 16b, 16c and16d), and the formation-of a conductive layer on the dielectric layer , embedded in a passivation layer , said through-silicon vias (16a, 16b, 16c and16d) and said metal wire defining at least one underpass and said conductive layer defining the inductor coil. <EOS>