Effect of packaging on dielectric charging in RF MEMS capacitive switches

A novel technique was used to evaluate the effectiveness of packaging in maintaining a dry ambient atmosphere for electrostatically actuated RF MEMS capacitive switches and in preventing the charging of the dielectric surface after prolonged operation. It was found that as-packaged switches exhibited different degrees of surface charging, probably due to different amounts of moisture inadvertently sealed in the essentially hermetic packages. However, after the switches were delidded and baked dry, all switches showed minimum surface charging. The results imply that the switches can have consistently long lifetimes by improving the yield of the packaging process.