Packaging of MEMS devices introduces new challenges to the package architecture. MEMS systems include interfaces, processes, and materials foreign to the IC packaging industry. To build reliable MEMS systems, failure modes must be identified and understood. In addition, measurement techniques must be developed to interrogate critical aspects of the package.
The present work addresses the architecture of the carrier-level packaging for a MEMS-based Safety and Arming device (S&A). The impact of moisture on packaged MEMS systems and test structures are investigated through an environmental conditioning program that includes thermal cycling and accelerated aging. MEMS switches are packaged in hermetic, non-hermetic, and ventilated configurations to facilitate in-situ monitoring of device health. A MEMS humidity sensor is included in these packages to allow interrogation of package environment characteristics.
Mechanical MEMS test structures are put through the same environmental conditions as the MEMS switches. These structures provide additional data on the failure modes of the packaged switches. Push test structures provide cumulative data on friction, stiction, and material properties and dog bone structures isolate material property influences.