| Most silicon-based devices need a robust packaging material to protect themselves against mechanically harsh environments in many applications. The use of a robust material for packaging or for use as a housing, as well as for the substrate of the micromachined device would offer several advantages over conventional silicon-based devices that are packaged separately for a harsh environment application. In conventional sensor technology, the packaging accounts for the majority of the cost incurred in manufacturing the sensors. One of the advantages offered by using robust substrates is that by co-fabricating micromachined devices and their packages together, for example, by using the robust substrate itself as an integral part of the sensor package, the fabrication may be simplified and cost savings may be realized. Another advantage is that due to substrate robustness, these co-packaged devices may be used in mechanically harsh environments, such as aerospace and oceanographic applications, where the fragility of conventional silicon substrates would preclude their use or involve extensive packaging to protect it from shock.; In this thesis, stainless steel was studied as a robust substrate material for micromachined devices. Lamination combined with traditional micromachining processes was investigated as suitable fabrication methods for this robust substrate. Three types of capacitive pressure sensors were designed, fabricated, and characterized by using lamination processing using kapton polyimide, stainless steel, and titanium films as diaphragms on the stainless steel shim stock substrate. Finally, three different stages were undertaken in the development of the read-out circuitry for the capacitance pressure microsensors. Particularly, the MS3110 IC in its un-packaged, die-type was integrated via wirebonding to the microfabricated sensors and tested. |
