Institute of Microelectronics

Bai Xu

Uppili Sridhar

Pang Dow Foo

Hanhua Feng

Shuming Xu

The invention relates to a method of making an integrated circuit inductor that comprises a silicon substrate and an oxide layer on the silicon substrate. In one aspect, the method comprises depositing an inductive loop on the oxide layer, and making a plurality of apertures in the oxide layer beneath the inductive loop. The method also comprises providing a plurality of bridges adjacent the apertures and provided by portions of the oxide layer between an inner region within the inductive loop and an outer region of the oxide layer without the inductive loop, the inductive loop being supported on the bridges. The method comprises forming a trench in the silicon substrate beneath the bridges, to provide an air gap between the inductive loop and the silicon substrate.

Method of making an integrated circuit inductor wherein a plurality of apertures are formed beneath an inductive loop

An inductor has a spiral aluminum track deposited on an oxide layer over a silicon substrate. The substrate is etched away to form a trench, which extends around beneath the track and provides an air gap having a low dielectric constant. The oxide layer has an inner region within the track, an outer region outside the track and a bridging region extending between the other regions. The bridging region is comprised of intact bridges and gaps therebetween, which are open to the trench and through which an etchant has access to the silicon substrate to form the trench by etching.

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Albany, NY, United States of America

Bai Xu