Thin Film Encapsulation for RF MEMS in 5G and Modern Telecommunication Systems

• Published in: Sensors
• Main Authors: Anna Persano, Fabio Quaranta, Antonietta Taurino, Pietro Aleardo Siciliano, Jacopo Iannacci
• Format: Article
• Language: English
• Published: MDPI AG 2020-04-01
• Subjects: 5G; RF MEMS; thin film encapsulation; silicon nitride; oxygen plasma etching
• Online Access: https://www.mdpi.com/1424-8220/20/7/2133

In this work, SiN_x/a-Si/SiN_x caps on conductive coplanar waveguides (CPWs) are proposed for thin film encapsulation of radio-frequency microelectromechanical systems (RF MEMS), in view of the application of these devices in fifth generation (5G) and modern telecommunication systems. Simplification and cost reduction of the fabrication process were obtained, using two etching processes in the same barrel chamber to create a matrix of holes through the capping layer and to remove the sacrificial layer under the cap. Encapsulating layers with etch holes of different size and density were fabricated to evaluate the removal of the sacrificial layer as a function of the percentage of the cap perforated area. Barrel etching process parameters also varied. Finally, a full three-dimensional finite element method-based simulation model was developed to predict the impact of fabricated thin film encapsulating caps on RF performance of CPWs.