Hermeticity tests

Microelectromechanical systems often contain sensitive structures whose operating response strongly depends on ambient conditions. The demand for a hermetic package is therefore vital. A variety of test methods for hermeticity testing have been developed in the past years. In this chapter a review on these leak tests is given. Starting from basic aspects of the kinetic gas theory and vacuum physics the principles of leak rate measurement are explained. An overview on existing leak rate measurement methods and their sensitivity is given. Exemplarily, the Neon ultra-fine leak test is explained in detail. Finally, the influence of a getter on the device life time is discussed.