A method for fabricating an inductor structure having an increased quality factor (Q) is provided. In one embodiment, a substrate is provided and a plurality of metal layers are formed on the substrate. A spirally patterned conductor layer is formed over and in the substrate and in the metal layers to produce a planar spiral inductor. A via hole is formed over and in the substrate and in the metal layers within the spirally patterned conductor layer, the via hole being formed by a through silicon via (TSV) process. Thereafter, the via hole is filled with a core layer, wherein the core layer extends from a bottom surface of the substrate to a top surface of the metal layers.