Development of a new MEMS resonant differential pressure sensor with high accuracy and high stability

This paper presents the design method and manufacture of a new resonant differential pressure sensor where the sensitive element is assembled with packaging components through an embedded boss type stress isolation structure. The responses of differential pressure, temperature and static pressure are theoretically modeled, which provide guidance on sensor design. And a method based on finite-element is used to conduct dimensional optimization of sensitive elements and embedded boss type stress isolation structures based on device sensitivities and isolation effect. Fabrication based on bulk micromachining and packaging based on Au-Au bonding and Au/Sn welding are employed to manufacture the sensor. Experimental results indicate that the fabricated sensor yields a high differential pressure sensitivity of - 87.06 Hz/kPa, a low temperature sensitivity of 5.24 Hz/degrees C and a low static pressure sensitivity of - 0.48 Hz/kPa. Additionally, a high accuracy of 0.05 %FS is reported under full scale. Furthermore, the sensor demonstrates an excellent long-term stability with no decrease on accuracy within a 15-day experiment.