A new sacrificial layer method of LIGA technology to fabricate movable part of a gripper

Movable microstructures are required for many applications in accelerator s ensors, microvalves, micromotors, grippers and so on. With the LIGA techniq ue, movable components can be fabricated directly by using sacrificial laye r technology. This is considerably extended by the application of the LIGA technique. Normally thin metallic layers are sputtered onto an insulating substrate (e .g. silicon wafer or ceramic) and patterned by conventional photolithograph y and wet etching. They are used as a metalized layer and a sacrificial lay er. The movable parts of the microstructures are positioned on the surface of the sacrificial layer, whereas the fixed parts are placed on the metaliz ed area of the substrate. After stripping the resist and the sacrificial la yer, the movable parts on the sacrificial layer are finished and the fixed parts remain firmly on the metalized layer. This process is rather complica ted. A new technology to produce the movable parts is developed in our Lab. Firs tly the normal LIGA process is used to make the sample with both metal and resist structures. The sacrificial layer pattern will be placed on the samp le surface with UV lithography. A metal layer is sputtered on the sample an d sacrificial layer surface as a metalized layer. By electroplating, the me talized layer will grow up to the milimeter thickness and be used as the fi xed substrate. Finally removing the nonmetal substrate, resist and the sacr ificial layer, the movable parts could be completed. As an example, a magne tic gripper structure is designed and fabricated by this method.