An investigation on technologies to fabricate magnetic microcomponents for miniaturized actuator systems
Soft magnetic yokes, cores, and poles, as well as permanent magnets are the potential magnetic components of an electromagnetic microactuator system. Depending on the requirements of the actuator, soft magnetic materials, hard magnetic materials or a combination of both have to be applied. Their design and fabrication as well as their integration into coil systems is one aspect of the Collaborate Research Center Design and Fabrication of Active Microsystems (Sonderforschungsbereich 516). The investigations presented in this paper cover alternative technologies for depositing various magnetic materials as well as their capability of being utilized for fabricating electromagnetic Microsystems. In the area of soft magnetic materials, the application of NiFe (Permalloy) in various compositions was investigated. Technologies utilized for their deposition were electroplating, sputtering, and gas flow sputtering. For fabricating rather thick soft magnetic micro structures with heights of up to 70 m, electroplating is particularly well suited. In the area of hard magnetic materials, sputtering was applied for depositing Samarium-Cobalt (SmCo). Hereby, layers with a thickness of up to 50 m with very good hard magnetic properties were deposited and patterned using wet chemical etching. This work was sponsored in part by the German Research Foundation as part of their support for the collaborative research center Design and Fabrication of Active Microsystems.