This paper presents the fabrication and electrical characterization of superconducting high-aspect ratio through-silicon vias DC-sputtered with aluminum. Fully conformal and void-free coating of 300 μm-deep and 50 μmwide vias with Al, a CMOS-compatible and widely available superconductor, was made possible by tailoring a funneled sidewall profile for the axisymmetric vias. Single-via electric resistance as low as 80.44 mΩ at room temperature and superconductivity below 1.28 K were measured by a crossbridge Kelvin resistor structure. This work thus demonstrates the fabrication of functional superconducting interposer layers, suitable for high-density 3D integration of silicon-based quantum computing architectures.
- through-silicon vias