Impact of 3D copper TSV integration on 32SOI FEOL and BEOL reliability
We integrated a copper TSV (Through Silicon Via) cell in a qualified 32SOI CMOS logic technology with high-K/metal gate and DT (Deep Trench) capacitors. Extensive wafer level characterization and reliability stressing were performed to evaluate the impact of the TSVs and 3D (3-Dimensional) integration processing on device and back end of line reliability performance. This included bias temperature instability stress, hot carrier injection, thermal cycling, wiring electromigration testing, and time-dependent dielectric breakdown studies. The integration of the TSV and process shows an equivalent reliability performance with respect to the 2D baseline for FEOL (Front End of Line) and BEOL (Back End of Line) structures within the assigned 3D design rules. In particular it is demonstrated that this TSV design allows BEOL structures at zero proximity to the KOZ (Keep Out Zone). Further, device and functional data indicate that there is no change in end of life reliability targets from TSV processing and/or proximity.