In-Die Through-BEOL Metal Wall for Noise Isolation in 180-nm FD-SOI CMOS

This letter reports a conceptual in-die through-back-end-of-the-line metal wall structure for noise isolation demonstrated in a foundry 180-nm fully depleted silicon-on-insulator (FD-SOI) CMOS technology. The near-closed-loop isolation wall was made of a trench ring etched by focused ion beam and filled with silver nano powder in a post-CMOS process module developed. Crosstalk suppression was confirmed in measurement that shows a reduction of around 9 dBm in the third-order intermodulation interferers as predicted full-wave electromagnetic co-simulation. The structure can be readily integrated into the foundry technologies as a potential crosstalk reduction solution for mixed-signal integrated circuits in FD-SOI CMOS processes.