Fabrication of double rectangular type FeTaN film inductors

Abstract

A double rectangular spiral inductor is fabricated using FeTaN films. The inductor is composed of internal coils sandwiched by magnetic layers. Characteristics of inductor performance are investigated with an emphasis on planarization of magnetic films. In the absence of the planarizaton process, the grating topology of upper magnetic films over coil arrays degrades the soft magnetic properties and the inductor performance. It also induces a uniaxial magnetic anisotropy with the easy axis aligned to the magnetic flux direction. This alignment prevents the upper magnetic films from contributing to the total induction. Glass bonding is a viable method for achieving a completely planar inductor structure. The planar inductor with glass bonding shows excellent performance : inductance of 1.1 mu H, Q factor of 7 (at 5 MHz), and the de current capability up to 100 mA.