Through-Silicon Vias in SiGe BiCMOS and Interposer Technologies for Sub-THz Applications

In the dissertation "Through-Silicon Vias in SiGe BiCMOS and Interposer Technologies for sub-THz Applications", a through-silicon via (TSV) technology module is developed targeting high frequency packaging applications in the millimeter-wave and sub-THz frequency range.
Based on a high-performance 130 nm SiGe BiCMOS technology, TSVs are embedded in a via-middle integration approach. The TSV process module consists of the TSV integration, a carrier wafer handling and a wafer backside process to realize a redistribution layer. A process flow was developed to realize TSV structures with various geometries to ensure a high TSV design flexibility. The TSV process module can be applied for SiGe BiCMOS as well as for interposer technologies.
High-performance TSV interconnections have been simulated to optimize their electrical properties. TSVs were electrically characterized and 3D transitions with low insertion loss <1 dB up to 300 GHz have been demonstrated thus providing excellent RF performance up to sub-THz frequencies.
Different application areas like RF grounding, interposers with integrated waveguides as well as 300 GHz antennas are demonstrated. The potential of millimeter-wave packaging and 3D integration was evaluated.
In this work, the use of TSVs for the millimeter wave and sub-THz frequency range was demonstrated. This opens up new possibilities for system integration and packaging of ultra-high frequency systems.