Packaging-compatible wafer level capping of MEMS devices

0167-9317/$ see front matter 2012 Elsevier B.V. A http://dx.doi.org/10.1016/j.mee.2012.11.010 ⇑ Corresponding author. E-mail address: [email protected] (P.A. Kohl). A cost-effective, wafer-level package process for microelectromechanical devices (MEMS) is presented. The movable part of MEMS device is encapsulated and protected while in wafer form so that commodity, lead-frame packaging can be used. A polymer epoxycyclohexyl polyhedral oligomericsilsesquioxanes has been used as a mask material to pattern the sacrificial polymer as well as overcoat the air-cavity. The resulting air-cavities are clean, debris-free, and robust. The cavities have substantial strength to withstand molding pressures during lead-frame packaging of the MEMS devices. A wide range of cavities from 20 lm 400 lm to 300 lm 400 lm have been fabricated and shown to be mechanically stable. These could potentially house MEMS devices over a wide range of sizes. The strength of the cavities has been investigated using nano-indentation and modeled using analytical and finite element techniques. Capacitive resonators packaged using this protocol have shown clean sensing electrodes and good functionality. 2012 Elsevier B.V. All rights reserved.