Development of a new magnetic interconnection technology for magnetic MEMS device applications

In this work, a new method of magnetic interconnection has been introduced and demonstrated. This innovative interconnection method has been achieved by fabricating MEMS-based inductive components onto a silicon substrate that contains interconnecting vias filled with magnetic material, thus allowing for magnetic flux to be selectively guided to other surfaces for sensing or actuation. In this way, magnetic components are effectively linked together through low reluctance magnetic via connections in a manner similar to the way wires connect electrical components, hence the term magnetic interconnection. This new magnetic interconnection technology is one means of overcoming traditional problems associated with magnetic components such as high power dissipation, fabrication difficulty and incompatibility, and inefficiency due to large air-gaps.; In order to realize the magnetic interconnection scheme, two major components have been investigated: interconnecting magnetic vias and MEMS-based inductive components. In this work, interconnecting magnetic vias were fabricated in silicon substrates by anisotropic silicon etching, electroplating of Ni/Fe permalloy, and surface planarization. Then on top of these substrates, spiral-type and solenoid-type inductors were fabricated by means of the so-called UV-LIGA method. These inductors are basic building blocks for magnetic sensors and actuators, and together with the interconnecting vias, they form the basis for the new magnetic interconnection technology which allows for the efficient guiding of magnetic flux through silicon wafers.; Based on this new technology, three new devices have been realized: a universal electromagnetic microactuator, a magnetically actuated microvalve, and an eddy current sensor for proximity sensing and crack detection in metals. Design, modeling, and fabrication considerations were examined for each of these devices, and measured results were compared to those predicted by finite element and lumped parameter models. Individually, these new sensors and actuators showed very promising performance characteristics in actual applications, thus illustrating the potential and importance of this new; magnetic interconnection method.; Finally, in this work, an innovative magnetic interconnection concept has been introduced, demonstrated, and successfully implemented, resulting in the realization of a universal electromagnetic microactuator, a magnetically actuated microvalve, and an eddy current sensor.