Wafer level encapsulation technology for MEMS devices using an HF-permeable PECVD SIOC capping layer

In this paper, a novel technology for the encapsulation of MEMS devices using a porous capping material is presented. The capping material consists of a low temperature PECVD layer of SiOC and is shown to be permeable to HF-vapor and H₂O and therefore allows for removal of a SiO₂ sacrificial layer. Furthermore, it is demonstrated that a cavity defined underneath the capping layer can be evacuated to allow for high-Q operation of a MEMS resonator. Finally, it is shown that a sealing layer can be deposited on top of the capping layer without contaminating the cavity.