Method of Fabrication of Integrated Spiral Inductor with Low Substrate Loss

摘要

In the manufacturing method according to an embodiment of the present disclosure, the front side of the silicon wafer is permanently bonded to the carrier wafer after the front side CMOS manufacturing process is completed. The carrier wafer is a high resistivity silicon wafer or a wafer of dielectric or ceramic material. The silicon substrate of the device wafer is thinned from the back side so that the remaining silicon thickness is only a few micrometers. In the area dedicated to the spiral inductor, the substrate material is completely removed by a masked etch process and the resulting gap is filled with a dielectric material. A spiral inductor coil is formed on the backside of the wafer on top of the dielectric material. The inductor coil is connected to the CMOS circuitry on the front side via a through-silicon via.