In this work, we focus on the study of tiny plastic packaging with a central opening. Employing a
patterned ultra-thick photoresist to pack the MEMS-based pressure sensors, two packaging approaches,
sacrifice-replacement and dam-ring, were used. These packaged pressure sensors are fully compliant
with the SMD and compatible with batch manufacturing processes. To verify the proposed packaging
schemes, a FE model and experimental measurement are used to explore the characteristics of the
packaged and unpackaged pressure sensors. The packaging effect and characterization of the packaged
pressure sensors for both packaging approaches are conducted and then compared with the
performance. The proposed packaging of piezoresistive pressure sensor using a patterned ultra-thick
photoresist may be an adequate solution for use in other open-cavity sensors, such as gas sensors,
image sensors, and humidity sensors.