Transistor-Level Metal Tube in Standard CMOS to Block Flying Crosstalk in BEOL Demonstrated in 38 GHz SPDT

Analog, mixed-signal and radio-frequency (AMX/RF) integrated circuits (IC) are sensitive to noises and interferers. Such crosstalk is particularly problematic to complex chips in advanced technologies. Global flying noises coupling through complex metal interconnects in the backend-of-the-line (BEOL) in CMOS become dominant that cannot be isolated using traditional in-substrate noise-isolation techniques. This letter reports a novel layout-only transistor-level stacked-via metal tube structure in standard CMOS BEOL to suppress global flying noises on a chip. The new technique is validated in simulation and measurement using 38GHz single-pole double-throw (SPDT) traveling wave switch circuits fabricated in a foundry 45nm silicon-on-insulator (SOI) CMOS technology, demonstrating ~7 dB global noise reduction.