HAREM: High aspect ratio etching and metallization

We report a novel bulk micromachining method for the fabrication of high aspect ratio monocrystalline silicon MicroElectroMechanical Systems (MEMS) on a standard silicon wafer. The two-mask process combines double-side etching and metallization to create a micromechanical system with 'insulating walls' on its backside. The insulating walls ensure a proper electrical insulation between the different actuation and sensing elements situated on either fixed or movable parts of the device. To demonstrate the many potential applications of this simple microfabrication method, we have machined and characterized electrostatically actuated microtweezers with an integrated differential capacitive sensor.