RF-TSVs compatible with harsh-environment post-processing for “via-first” 3D integration

Abstract

Platinum TSVs compatible with harsh-environment post-processing were fabricated on an SOI wafer. This study was part of a larger project for the development of a SWCNT resonator, 3D-integrated, in a “via-first” approach, with its driving electronics. After their passivation, they are compatible with the harsh-environment post-processes necessary for the fabrication of the SWCNT resonator: the growth of CNT at a high temperature of 850 °C in an oxidizing environment, and their release in concentrated HF solution. The TSV metallization formed a stable ohmic contact with the silicon device layer on which the CNT resonator will be standing. We present RF (radio frequency) simulations correlated with RF measurements of the Pt-TSVs from 0.3 to 5 GHz. A reflection coefficient of -20 dB and transmission coefficient of -4 dB were measured at 5 GHz.