Electrostatically Driven Microgripper

In this work we report on microactuators and microgrippers fabricated from SOI (Silicon On Insulator) wafers by a surface and bulk micromachining fabrication technology. The main advantages of this technology are: a) large thickness of the devices (10 μm up to 40 μm) resulting in devices which are stable against disturbing forces perpendicular (z-direction) to the ground plate. b) the small number of fabrication steps required. Only 3 steps are required: lithography, trench etching of silicon, and release of movable parts (selective wet etching of the buried oxide layer). The linear motion ("pull action") of the microactuator is converted into a rotational gripping motion by a system of elastic spring beams. At a voltage of 80 V, the gripper tweezers are closed.