Fabrication of Superconducting Nb Airbridges in a 300 mm Pilot Line for Quantum Technologies

Superconducting Nb airbridges were fabricated in imec’s 300 mm pilot line utilizing an advanced production toolset. An optimized process flow, which does not rely on liftoff or shadow evaporation, results in high airbridge yield across full wafers, and is compatible with trilayer-based superconducting qubit fabrication methods. Airbridges integrated with resonators were characterized at millikelvin temperatures, showing that the addition of airbridges can have minimal contribution to microwave losses. This work demonstrates that airbridges can be incorporated into foundry compatible qubit fabrication flows.