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Here we discuss the wafer-scale fabrication process flow of aluminium airbridges for microwave (MW) interconnects on lithium niobate on Damascene silicon nitride (LNOD) photonic chips. We also discuss the subsequent chip release procedure that preserves the bridges allowing for safe release of these delicate structures.

This short article describes a method to separate a wafer into photonic chips or dice, using dry etching and backside grinding. This method enables smooth chip facets that are advantageous for edge coupling with fibers or other chips.

Thin silicon nitride nanomembranes are attracting growing attention following a novel fabrication method which consists in patterning them with a phononic crystal. In engineering the vibrational mode profile, the dominant mechanisms of loss, radiation loss and intrinsic material loss, are simultaneously addressed and mitigated. The fabrication method employed by the optomechanics group at the Laboratoire Kastler Brossel is here presented, only employing basic lithography techniques and wet etching processes.

A few important points in data conversion and mask processing of multilayered Ebeam lithography is discussed. The conversion is done using Layout Beamer software at EPFL CMi cleanroom.

A fabrication method for large-area, high-stress LPCVD \mathrm{Si_3N_4} membranes is presented. These devices can be used as mechanical resonators with very low dissipation, exploiting dissipation dilution. A phononic crystal pattern allows to work with a high-order localized mode, shielded from acoustic radiation in the substrate. The procedure is amenable to most research clean rooms, requiring conventional lithography techniques and wet etching in KOH for device undercut.