Fabrication of superficial neuromast inspired capacitive flow sensors

A fabrication process is presented which allows realizing the dense arrays of fully supported flexible SU-8 membranes with integrated electrodes underneath that support cylindrical hair-like structures on the top. Electrodes have been insulated from liquid to prevent short circuit or electrolysis. The process allows a controllable distance between counter electrodes. The excess squeeze film damping is eliminated with a closed membrane configuration with backside openings. A low-power differential capacitive measurement mechanism is employed as a sensor readout. These flow sensors provide a distributed sensing mechanism inspired by the superficial neuromast as found in the lateral line system of fish. This paper focuses on the fabrication of the sensors with preliminary mechanical results demonstrating the functionality of the fabricated devices.