| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 540174 | Microelectronic Engineering | 2013 | 10 Pages |
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 μm × 400 μm to 300 μm × 400 μm 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.
Graphical abstractProcess sequence for new in-situ packaging approach.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A low-cost, high-volume, lead frame based packaging approach form MEMS devices is described. ► MEMS device is protected with sacrificial material during lead frame packaging and released in the final step. ► MEMS device is released after epoxy encapsulation structure is complete. ► Release after full encapsulation allows nearly any size MEMS device to be packaged.
