Comparison of Packaging Technologies for RF MEMS Switch

TLDR: In this article, an integrated approach for design, fabrication and encapsulation of RF MEMS switches in view of the optimal performance subsequent to packaging is described. But the authors focus on the bottom contact package (BCP), where the connection layout through silicon via holes is independent of the cavity geometry.

Abstract: The present paper describes an integrated approach for design, fabrication and encapsulation of RF MEMS switches in view of the optimal performance subsequent to packaging. 'Top and bottom contact' fabrication approaches are explored using different RF MEMS switch topologies. In the 'bottom contact package (BCP)' the packaging cap alignment is less critical as compared to the top contact packaging (TCP) approach where contact via is an integral part of the cap. In this case, the connection layout through silicon via holes is independent of the cavity geometry. For the devices under consideration, bulk etched silicon cavity height has been optimized to 50µm for optimal RF performance, e.g., isolation and insertion loss. Parasitic effects of top silicon cap are reduced by altering CPW impedance. Mechanical parameter damping is simulated for different cavity heights and found to be independent from cavity height after 20µ mo nwards.