Fabrication of a novel SEM microgripper by electrochemical and FIB techniques

Abstract

A novel type of microgripper has been developed that uses combined electrochemical etching and focused ion beam milling techniques to fabricate microgripper end-effecters from a single piece of metal wire. This ensures that the two end-effecters have well-aligned faces, can be made in a relatively simple manner to a flexible/chosen design and can be made from a wide range of materials. The wire used here is tungsten which is easy to etch and allows the gripping force to be maximized. Independent electrical connections to each of the end-effecters allow them to be grounded to prevent charging in the SEM beam and give the option of applying a voltage across an object that is picked up. Actuation of the gripper is accomplished using a trimorph piezo bender actuator giving very good resolution (typically ∼170 nm V−1) and a maximum possible span range of over 20 µm. The gripper has been successfully demonstrated in picking up and placing individual copper microspheres and carbon nanotubes in situ in the SEM.