Thin film encapsulation technology for harms using sacrificial CF-polymer

This paper reports on a new method for thin film encapsulation of microelectromechanical systems (MEMS) using plasma enhanced chemical vapor deposited (PECVD) fluorocarbon polymer as sacrificial material and a stress optimized SiO/SiN/Al capping layer. Because of the oxygen plasma-based removal of the sacrificial organic layer, this technique is applicable for a wide range of MEMS technologies-from surface to high aspect ratio microstructures. It saves die area compared with bonding techniques and enables standard packaging processes such as dicing, pick and place and plastic injection molding. Beside of the fabrication technology, we present results of the finite element analysis (FEA) regarding the deflection and the mechanical stress in the cap. The results of the FEA have been verified on fabricated structures by interferometric measurements. (C) 2007 Elsevier B.V. All rights reserved.