Electrodeposited magnetic alloys for surface micromachining 2
Electrodeposited magnetic material is of high interest in surface micromachining. Both in actuators and in sensors it can be used for transformation of forces. Magnetic alloys of the ferrous metal family with different characteristics can easily be electrodeposited. An advanced lithographic process was performed to generate resist moulds for the electrodeposition. By means of standard UV aligners and immersion development photoresist layers up to 80 mu m could be patterned by a single shot. Repeated exposure and development were successfully used for structuring thicker resist layers. High aspect ratios and steep edges were achieved with a sufficiently high resolution. The obtained resist patterns were moulded by electroplating. For microsystem applications magnetic alloys like NiFe and NiCo are materials of special interest. The deposited material was characterised for its mechanical and magnetical properties. Some examples of microsystem components using magnetic properties were give n. The active part of a magnetically driven micro valve containing a membrane with integrated force amplifier from NiFe alloy and a micro turbine with NiCo rotator have been fabricated and tested.