  Quantum hardware based on circuit quantum electrodynamics makes extensive use
of airbridges to suppress unwanted modes of wave propagation in
coplanar-waveguide transmission lines. Airbridges also provide an interconnect
enabling transmission lines to cross. Traditional airbridge fabrication
produces a curved profile by reflowing resist at elevated temperature prior to
metallization. The elevated temperature can affect the coupling energy and even
yield of pre-fabricated Josephson elements of superconducting qubits, tuneable
couplers and resonators. We employ grayscale lithography in place of reflow to
reduce the peak airbridge processing temperature from $200$ to
$150^\circ\mathrm{C}$, showing a substantial yield increase of transmon qubits
with Josephson elements realized using Al-contacted InAs nanowires.
