Patent ID: 6433665
Filing Date: 2002-08-13
Classification: H01F

Abstract:
A thin film inductor, comprising:a first dielectric layer; on the first dielectric layer, a thin film conductor having the shape of a wire spiral that has a number of turns, said spiral having an inner end that is a starting point of the spiral and an outer end that is an ending point of the spiral; a second dielectric layer over the wire spiral; a first conductive plug extending downwards from said inner end through the first dielectric layer and projecting below it; a second conductive plug extending upwards from said outer end through the second dielectric and projecting above it; adjacent to the first conductive plug, a core plug of a ferromagnetic material that extends upwards through the second dielectric layer and downwards through the first dielectric layer, the core plug not contacting the spiral at any point; a frame of ferromagnetic material that surrounds the spiral and that further comprises: on the second dielectric layer, a first rectangular horizontal part extending outwards from said ferromagnetic plug for a distance sufficient for its outer, edges to fully overlap the spiral; below the first dielectric layer, a second rectangular horizontal part exactly underlying said first rectangular part; and two rectangular vertical parts extending downwards through said first and second dielectric layers and connecting the first and second horizontal parts at their outer edges, thereby providing a low reluctance path that increases the inductance of the inductor.