Improved fabrication of micro air-channels by incorporation of a structural barrier

The fabrication of air-channels for microelectromechanical systems and microfluidic devices using polynorbornene and polycarbonates as thermally or photolitically decomposable materials to form air-gaps in dielectric materials has been reported. In this study, the incompatibility of some overcoat polymers with the sacrificial materials was addressed. SiO2 was used as a barrier layer for the fabrication of single- and multi-layer air-channels via different sacrificial and overcoat materials. The structural rigidity of SiO2 mitigates problems associated with overcoat polymers that can easily deform at the processing temperature (overcoat cure or sacrificial decomposition temperature). The chemical inertness and low permeability of SiO2 allows the use of solvent-cast polymers, for which the solvents would have otherwise dissolved the sacrificial material.