An easy fabrication process of fully-sealed parylene microfluidic channels with a single deposition step

We present a simple fabrication method for microfluidic channels in which all walls consist of parylene. Only one parylene deposition step is required to achieve monolithical integration of fully-sealed parylene structures. Thus, the commonly used polymer-to-polymer bonding procedures are not needed. A pattern of grooves was etched into a silicon substrate, determining the shape and depth of the channels to be fabricated. A polyvinyl chloride (PVC) foil was affixed to the top of the wafer. After a single deposition step, a 15 µm-thick film of parylene C conformally coated all surfaces. The PVC foil was peeled off from the parylene surface leaving fully-sealed parylene channels embedded in the silicon. The channels were characterized optically and by scanning electron microscopy. Their functionality was verified by flow tests with polystyrene microbeads dispersed in deionized water and the robustness of the structures was confirmed by hydrostatic tests. The fabricated channels are shown to be fully sealed and mechanically stable.