A structure of millimeter-wave on-chip transmission line using redistributed copper wire and ground shield

This paper presents a structure of millimeter-wave (mmW) on-chip transmission line using redistributed thick copper wires with ground shields. All the layers from standard BEOL layers to the aluminum pad layer can be selected as the ground shield. From electromagnetic field simulations and measurements up to 80 GHz, we prove that global-copper-wire ground shields produce minimum attenuation: less than 0.5 dB/mm at 60 GHz. This stands comparison with transmission lines on SOI substrate or gold-wire transmission lines on GaAs semi-insulating substrate. An mmW silicon on-chip transmission line on a standard 40 nm CMOS process was fabricated successfully.