High Aspect Ratio CPW Fabricated Using a Micromachining Process Combining DRIE, Thermal Oxidation, Electroplating, and Planarization

A micromachining process has been developed to fabricate high aspect ratio CPW. The tall conductor sidewall created from the high aspect ratio process reduces the resistance per length of the transmission line which lowers the attenuation. The micromachining process combines Si DRIE, thermal oxidation, electroplating, and planarization to create tall CPW with Au conductors and SiO2 dielectrics. Transmission lines with characteristic impedances of 16 - 21 � have been fabricated on high resistivity Si. Transmission line characteristics were measured from 1 - 50 GHz and showed propagation loss of 1.1 - 1.3 dB/cm at 10 GHz.