A Novel Vacuum Packaging Design Process for Microelectromechanical System (MEMS) Quad-Mass Gyroscopes
Technical Report,01 May 2015,31 Aug 2016
US Army Research Laboratory Adelphi United States
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Gyroscopes are an integral component of inertial measurement units. They are important to Army systems as they provide Soldiers with information on position, navigation, and timing. The majority of microelectromechanical system MEMS gyroscopes in production today are vibratory rate gyroscopes, making them resonant systems. Of the various systematic performance parameters for resonant systems, the quality factor Q-factor is an important measure. Q-factor for resonant MEMS such as the quadruple-mass gyroscope QMG strongly depends on the pressure at which the system operates. To improve upon Q-factor of the existing MEMS gyroscope, a novel submilliTorr vacuum packaging approach was designed. The packaging process has been broken down into systematic steps with the goal in each step to reduce internal packaging pressure, which was measured using commercial off-the-shelf Pirani gauges. The process was then tested on in-house fabricated QMGs, where Q-factor was measured for both short- and long-term stability. The packaging process will be valuable for improving MEMS gyroscope performance and pursuing further development.