Preconditioning Procedure for the Better Estimation of the Long-Term Lifetime in Microelectromechanical Switches

The study of long-term reliability of RF-MEMS switches subjected to continuous biasing involves different failure mechanisms: 1) short-to-medium-term stress inducing permanent phenomena, such as permanent mechanical degradation, and 2) long-term stress inducing recoverable phenomena related to mechanical viscoelastic mechanism. The lifetime prediction should consider all the long-term effects after the saturation of all the short-to-medium-term degradation effects. In fact, the lifetime estimation is affected by both the different short-term and long-term degradation mechanisms and not separating the different effects may lead to wrong lifetime prediction. In this paper, we define a preconditioning technique to be applied to each RF-MEMS switch before any stress test. The main purpose is to eliminate all the short-term permanent effects to obtain a lifetime estimation only related to the long-term phenomena.