Differential capacitive MEMS pressure sensor and manufacturing method thereof

摘要

The present invention discloses a differential capacitive MEMS pressure sensor and a manufacturing method thereof. The MEMS pressure sensor includes a sensitive structural layer, which includes a common sensitive part and a common supporting part located on the edge of the common sensitive part, a thickness of the common supporting part being larger than that of the common sensitive part; and the MEMS pressure sensor also includes an upper fixed electrode structural layer and a lower fixed electrode structural layer which are vertically symmetric relative to the sensitive structural layer and used for forming differential capacitors with the common sensitive part. According to the MEMS pressure sensor of the present invention, by the differential capacitor structures, inhibition of chips on common-mode signals is enhanced, and a signal to noise ratio of output signals is improved. Meanwhile, the thickness of the common supporting part of the present invention is larger than that of the common sensitive part, such that the peripheral common supporting part can shield strains caused by temperatures and stresses. Therefore, the strains transmitted to the common sensitive part because of temperature and stress changes are greatly reduced, and temperature stability and stress stability of the chips are improved.