Enabling 300 mm Wafer-Scale Fabrication of Superconducting Quantum Devices

Superconducting quantum computing has demonstrated exponential improvements in coherence times over the past two decades, bringing us to the present Noisy Intermediate Scale Quantum (NISQ) era. Improvements in materials and fabrication techniques are still required along with circuit and algorithm innovations to move beyond the NISQ era. We discuss several aspects of the process development work that enables the fabrication of superconducting quantum devices and circuits at 300 mm wafer scale, using materials, processes and tools that are entirely compatible with high-volume integrated circuit fabs. Damascene structures of superconducting tantalum and aluminum (embedded in high resistivity silicon substrates) are described along with examples of process control. The use of such structures for coplanar waveguide resonators in quantum circuits is described, along with modifications to enable integration of normal metal traps to mitigate quasiparticle poisoning. This paper also includes a description of the considerable process development required to enable ALD-TaN based Josephson junctions fabricated with entirely 300 mm compatible processes, in contrast to the lift-off based processes currently in wide use for qubit fabrication. It concludes with a description of how these efforts help with establishing a Quantum Foundry at NY CREATES (a non-profit organization) that can democratize access to advanced qubit fabrication by offering an open superconducting quantum Process Design Kit (PDK).