Characterization of a polymer-based MEMS packaging technique

This paper presents characterization of a low-cost polymer-based technique for wafer-level packaging of nucroelectromechartical systems (MEMS). The packaging process does not impose any size limitation to the device and can be applied to a wide variety of MEMS devices regardless of substrate type. Our technique utilizes thermal decomposition of a sacrificial polymer through a polymer overcoat cap, followed by metal deposition to create hermiticity. The method has been applied to surface and bulk micromachined silicon structures including resonators, tunable capacitors and accelerometers. Mechanical and electrical characterization of the packaged devices is reported to be very close to the corresponding values before packaging.