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 (10-40 mum) 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 three 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 90 V, the gripper tweezers are closed. (C) 2002 Elsevier Science B.V. All rights reserved.