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In contrast to existing microelectromechanical systems (MEMS), this paper describes the development, fabrication, and testing of an anisotropic magnetoresistance (AMR) microsensor using a 7 \mum thick polymer foil as substrate material. The modular magnetic field micro sensors are fabricated on a standard 4 in Si Wafer due to handling purposes during the sensor fabrication process. To enable a release of the micro sensors at the end of the fabrication process, initial investigations concentrated on the proof of principle applying a deep reactive-ion etching (DRIE) process to structure the Si wafer. The DRIE process was used to structure Si frames, which serve as carriers for the modular magnetic field micro sensors. For the evaluation of the fabricated modular magnetic field micro sensors, electrical resistance measurements were accomplished. The aim of these investigations was the characterization of the magnetic field dependence of the electrical resistance. The electrical output signal of the AMR sensors were subsequently compared to electrical resistance measurements of AMR sensors fabricated on a Si substrate and served as reference. The measurement results show a marginal effect of the substrate material on the characteristics of the AMR sensors. [ABSTRACT FROM AUTHOR]

In order to provide a contactless measurement technique to examine products during the fabrication process, a modular design of an eddy current micro sensor was developed and fabricated in thin-film technology. The sensor consists of two parts, a single-turn excitation coil and an anisotropic magneto-resistance (AMR) sensor. The AMR sensor detects the change of the magnetic field induced in a sample by the excitation coil. Initial investigations were conducted to prove the capability of the completed eddy current micro sensor. A defect was created on the surface of a Cu probe. The electrical output signal of the AMR sensor was subsequently compared to optical measurements of the surface profile of the crack. There is a high correlation between the optical measurements and to those of the eddy current micro sensor. [ABSTRACT FROM AUTHOR]