This Small Business Innovation Research Program Phase I (SBIR) project will test and confirm a novel approach to the manufacture of small cantilevered MEMS electrical switches. The approach obviates or ameliorates a multitude of problems which exist using the present surface machining approach to the fabrication of these switches. The approach divides the switch components between two substrates, with the moving cantilevered portion on an upper substrate, and the stationary contacts on the lower substrate. The moving portion may be formed from a stress-free layer of single crystal silicon, and therefore has no tendency to warp or distort. Using two substrates allows the contacts to be fully exposed throughout processing, until the substrates are bonded together to form the switch. Because the contacts are exposed, they can be effectively cleaned just prior to sealing in the hermetic seal between the two wafers, thereby reducing the contact resistance of the junctions. In addition, the dual substrate approach affords a number of design options not available using the surface machining approach.
If successful, the approach described here will be used to produce MEMS cantilevered switches for a broad range of applications, from DC power handling applications to RF and radar applications. Because of their high current-carrying, high frequency characteristics with small size and low cost, the MEMS switches may serve as viable replacements for FET switches or micro relays in a wide range of devices. The approach may also be applicable to other sorts of MEMS devices, such as sensors and actuators, which may have a movable component suspended over a substrate which interacts with a fixed component on the substrate. This approach may therefore fundamentally alter how these devices are manufactured, and open up a wide range of applications not presently served by MEMS devices.
