Novel fabrication process of freestanding metallic microstructures using double electroplating

A simple electroplating surface micromachining process for fabricating freestanding microstructures using UV lithography of thick photoresist and double electroplating is presented. Compared with the conventional surface micromachining process, this process can be used to fabricate various shapes of freestanding "out-of-plane" microstructure. Two different materials electroplated continuously in a single mold are used as a sacrificial and a structural layer, respectively. Shape of the sacrificial layer is determined by changing width and space of the patterned plating base electrodes. The released structure is obtained after selective etching of the sacrificial layer. The shape of released structure is automatically determined by shape of sacrificial layer. The gap and thickness of the structure are easily controlled by electroplating times. Using this process, a simple microactuator with inclined side-support beams is successfully fabricated. This technique can be applied to fabricate a novel type of surface micromachined actuating component.