Silicon-based high-Q inductors incorporating electroplated copper and low-K BCB dielectric

Abstract

We have fabricated high-Q copper inductors using low-K benzocyclobutene (BCB) dielectric as an interface layer on standard CMOS silicon substrate. Metal ohmic loss and substrate loss, the two major factors that degrade the Q-factors of on-chip inductors, are suppressed by the employment of electroplated copper and the BCB dielectric, respectively. The inductors exhibit Q-factors as high as 25 at 2 GHz. The dependence of inductor's high-frequency performance on inductor's parameters, such as BCB and copper thickness, has been investigated in detail. The inductor fabrication process is low-cost and low-temperature, making it suitable for post-IC process for high-performance RFICs and MMICs.