Characterization of High Q Transmission Line Structure for Advanced CMOS Processes

A new transmission line structure is presented in this work for advanced CMOS processes. This structure has a high quality factor and low attenuation. It allows slow-waves to propagate which results in low dispersion for a given characteristic impedance. It is also designed to satisfy the stringent density requirements of advanced CMOS processes. A model is developed to characterize this structure by analyzing the physical current flowing in the substrate and the shield structure. Test structures were fabricated using CMOS 90 nm process technology with measurements made up to 110 GHz using a transmission-reflection module on a network analyzer. The results correspond well to the proposed model. key words: transmission line, slow-waves, quality-factor, attenuation, CMOS