Design and Fabrication of MEMS Micropumps using Double Sided Etching

In this paper, we report a simple technique for the fabrication of planar valveless micropumps. The technique utilizes MEMS fabrication methods by using a double sided etch technique. Instead of using several masks and process steps, an anisotropic wet etch technique at both sides of a silicon substrate is implemented at the same time for creating the pump membrane and the diffuser/ nozzle elements. A planar diffuser and a nozzle element of the pump, as well as a 150 mm thick silicon membrane, are designed and fabricated using only three pattern process steps. An actuatorchamber and a pump-chamber with depths of 250 mm are formed after 250 min KOH etching, while the diffuser/nozzle element with a depth of 50 mm are sequentially formed after chamber forming. The process is simple and reproducible which opens the opportunity for fast prototyping of MEMS micropumps.