CPW Interconnects for MMIC Applications on Low Resistivity CMOS Grade Silicon Using Micromachined SU8 Negative Resist

In this work we present measured and modelled RF behaviour of a coplanar waveguide (CPW) fabricated on CMOS grade low resistivity Silicon 2¿-cm using a novel micromachined SU8 negative resist interface layer. CPW lines were designed and fabricated on the SU8 interface layer of different thickness from 25 ¿m to 125 ¿m. An attenuation of less than 0.6dB/mm at 60GHz was achieved. Physical line modelling and E-M simulations were performed to support the experimental results and to determine the SU8 dielectric parameters. Micromachining of CPW structures were also investigated where a reduction in loss by more than 30% was achieved.