Abstract: Unwanted gasses created during bonding within micromachined vacuum cavities are reduced in a manner conducive to mass manufacturing. Two broad approaches may be applied separately or in combination according to the invention. One method is to deposit a barrier layer within the cavity (for example, on an exposed surface of the substrate). Such a layer not only provides a barrier against gases diffusing out of the substrate, but is also chosen so as to not outgas by itself. Another approach is to use a material which, instead of, or in addition to, acting as a barrier layer, acts as a getterer, such that it reacts with and traps unwanted gases. Incorporation of a getterer according to the invention can be as straightforward as depositing a thin metal layer on the substrate, which reacts to remove the impurities, or can be more elaborate through the use of a non-evaporable getter in a separate cavity in gaseous communication with the cavity.

Abstract: Structures and methods are disclosed in conjunction with the fabrication of electrical lead transfer feedthroughs with respect to a sealed cavity. In some applications such as capacitive pressure sensing, the cavity may include an outer wall, in which case the electrically insulating barrier is preferably U-shaped, with the ends of the U terminating at the outer wall. The feedthrough section may alternatively take the form of an island of conductive material surrounded by the electrically insulating barrier, thus assuming an O-shape. The cavity may be evacuated or filled with specific gases at specific pressures. As such, the invention finds application in the packaging (vacuum or controlled environment) and production of a variety of transducers including but not limited to pressure sensors, flow sensors, optical devices (e.g., infrared detectors, ccd camera, and flat-panel displays) and resonating devices, such as gyroscopes, accelerometers, yaw sensors, telecommunication devices, etc.