Eddy-current microsensor based on thin-film technology

Abstract

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.

Induction coil sensors—a review

“…In such cases, sensitivity is not as important as the spatial resolution and compactness of the whole device. Such sensors are often manufactured as a flat planar coil (made in PCB or thin film technology [21][22][23][24][25]) connected to an on-chip CMOS electronic circuit [22]. An example of such a sensor with dimensions of 400 × 400 µm 2 (7 turns) is presented in figure 4.…”

Advances in Magnetic Micro Thin-Film Transducers

“…A miniaturized version of such a sensor was developed to provide a simple and reliable method for non-contact proximity measurements (18). Miniaturization may be best accomplished by applying thin-film technology to such a sensor (19).…”

A Compact and High-Performance Eddy-Current Sensor Based on Meander-Spiral Coil

“…In general, planar coils have better thermal stability and better coil parameter consistency compared with other coils [12]. The printed circuit board (PCB) [13], thick film [14], electron beam or photo-lithography, and low temperature co-fired ceramic technologies [15] can all be employed to manufacture planar coils [16]. Through these technologies, high-quality ECS probes can be manufactured in bulk at an extremely low cost.…”