Selective organic dielectric deposition for encapsulation of MEMS structure

Microelectromechanical systems (MEMS) are attracting a great deal of interest because of their potential to provide highly integrated functional devices. A major issue in the development of MEMS devices is how to prevent adhesion and friction between the microstructures [l]. For this purpose, the formation of fluorocarbon films by plasma polymerization reaction has been attempted [2]. However, because this is basically a planar process, three-dimensional (3-D) structures cannot be deposited. The films are deposited all over the surface, so that further lithographic processes are necessary to achieve electrical contact. Selective or self-aligned encapsulation of conductors in 3-D MEMS structures with thn dielectric films is therefore urgently needed. This paper proposes selective organic dielectric deposition by electrodeposition, where the deposition occurs only on microstructures to which a voltage has been applied.