Combining UV-and electron-beam lithography for superconducting bandpass filters in mm/sub-mm astronomy

Microfabrication of on-chip filterbanks, such as DESHIMA 2.0, would greatly benefit from reliable fabrication with sub-micrometer resolution. This enables smaller devices and reduces scatter in parameters such as filter bandwidth and resonant frequency. Here we present “mix-and-match” processing by combining optical and electron-beam exposures of a single layer of negative ma-N1405 resist from Micro-Resist-Technology GmbH. This allows for minimal features down to 300 nm where needed and large structure exposure with UV, limiting e-beam writing time. Relative alignment is possible to less than 500 nm on a regular basis.