Stacked-Via Metal Wall Suppressing Global Flying Crosstalk Validated in RF Switch Circuits in 45 nm SOI

Evolution of 5G and 6G wireless communications brings in new challenges to RF front-end module (FEM) integrated circuit (IC) designs. Higher frequencies, wider frequency spectrum and more frequency bands necessitate increasingly complex RF FEM IC architectures, which are extremely sensitive to global flying crosstalk occurring in the back-end-of-line (BEOL) stack containing complex metal interconnects. This paper reports a new 3D in-BEOL stacked-via vertical metal wall structure in standard CMOS to efficiently suppress global flying noises within BEOL, which is validated in silicon ICs using 38GHz single-pole double-throw (SPDT) traveling wave switch circuits fabricated in a foundry 45nm silicon-on-insulator (SOI) CMOS process technology. Measurement shows significant inter-switch flying crosstalk reduction of ~17 dB at 38GHz.