micro-Torr Vacuum Packaging of Gettered Ceramic Chip Carriers

This paper reports for the first-time accurate sub 1 μTorr vacuum package pressure measurement for getter-activated leadless ceramic chip carriers (LCCs) sensor packages. This has been accomplished by creating a de-lidding vacuum chamber fixture to open a packaged quad-mass gyroscope (QMG) in a vacuum chamber and, thus, minimize any environmental contaminants the sensor would see if it was otherwise opened in atmosphere. Quality factor measurements have been shown to decrease by 15-25% when exposing moderate-to-high Q QMGs to atmosphere and re-measuring in a vacuum chamber. After exposing a sensor to atmosphere, contaminants are introduced, and vacuum packaging pressure cannot be accurately measured without subjecting the same sensor to the high temperature bakes seen in vacuum packaging.