  Nanoimprint lithography (NIL) is an attractive nonconventional lithographic
technique in the fabrication of superconducting nanowires for superconducting
nanowire single-photon detectors (SNSPDs) with large effective detection areas
or multi-element devices consisting of hundreds of SNSPDs, due to its low cost
and high throughput. In this work, NIL was used to pattern superconducting
nanowires with meander-type structures based on ultra-thin (~4 nm) Nb films
deposited by DC-magnetron sputtering at room temperature. A combination of
thermal-NIL and UV-NIL was exploited to transfer the meander pattern from the
imprint hard mold to Nb films. The hard mold based on Si wafer was defined by
e-beam lithography (EBL), which was almost nonexpendable due to the application
of IPS as a soft mold to transfer the patterns to the imprint resist in the NIL
process. The specimens fabricated by NIL keep good superconducting properties
which are comparable to that by conventional EBL process.
