A semiconductor structure includes: a substrate; a first passivation layer over the substrate; a second passivation layer over the first passivation layer; and a magnetic core in the second passivation layer; wherein the magnetic core includes a first magnetic material layer and a second magnetic material layer over the first magnetic material layer, the first magnetic material layer and the second magnetic material layer are separated by a high resistance isolation layer, and the high resistance isolation layer has a resistivity greater than about 1.3 ohm-cm.