Publications
On Gas Ingression of Hermetic Packages
In this paper, a closed-form mathematic equation that governs gas ingression of hermetic packages is derived from first principles and applied to moist air and water vapor ingression conditions. The equation models internal gas partial pressure change as a function of time, external conditions, and package characteristics. The equation provides the theoretical basis for direct comparisons of ingression behaviors of different gases into hermetic packages. Comparing the rates of internal air pressure increase due to air ingression and water vapor partial pressure buildup due to water vapor ingression, the authors theorize that vacuum decay may present a greater challenge to the performance of microelectromechanical systems (MEMS) devices within hermetic packages than that of water vapor content induced corrosion failures. This paper also examines gas ingression of hermetic enclosures with multiple layers of seals.