Eddy-current microsensor based on thin-film technology

An eddy-current microsensor for proximity measurement was developed. To achieve an optimal design, the sensor was modeled using the finite-element method. By studying the sensor response, but staying within the technological boundaries, an optimal design was reached. The sensor had a soft-magnetic core and separate excitation and pickup coils. The fabrication technologies included electroplating for core and coil and sputter deposition for insulation and seed layers. Photoresists were used for creating micromolds for electroplating both core and coil, as well as for sensor embedding. Completed sensor samples had a frequency range of 100 kHz to 2 MHz and proved their capability of performing proximity measurement.