Quasi-differential capacitive MEMS pressure sensor and manufacturing methods thereof

A manufacturing method of a quasi-differential capacitive MEMS pressure sensor, the method comprising the following steps:

• a), depositing a first oxide layer as an insulating layer on a substrate;
• b), depositing and etching a first metal layer on the insulating layer to form a first lower electrode and a second lower electrode independent of each other;
• c) depositing and etching a second oxide layer on the first lower electrode and the second lower electrode to form a supporting part and a supporting post corresponding to the second lower electrode;
• and d), bonding a pressure-sensitive film on the supporting part and the supporting post to form a closed cavity between the pressure-sensitive film and the first lower electrode to enable the pressure-sensitive film, which acts as a first upper electrode, and the first lower electrode to constitute an air pressure-sensitive type capacitor, and to form a second upper electrode supported by the supporting post, to enable the second upper electrode and the second lower electrode to constitute a reference capacitor whose capacitance does not vary with external air pressure.

A manufacturing method of a quasi-differential capacitive MEMS pressure sensor, the method comprising the following steps:

• a), depositing a first oxide layer as an insulating layer on a substrate;
• b), depositing and etching a first metal layer on the insulating layer to form a first lower electrode and a second lower electrode independent of each other;
• c) depositing and etching a second oxide layer on the first lower electrode and the second lower electrode to form a supporting part;
• d), bonding a pressure-sensitive film on the supporting part to form a closed cavity between the pressure-sensitive film and the first lower electrode to enable the pressure-sensitive film, which acts as a first upper electrode, and the first lower electrode to constitute an air pressure-sensitive type capacitor, and to form another closed cavity between the pressure-sensitive film and the second lower electrode;
• and e) etching the pressure-sensitive film to enable the another closed cavity to become a cavity communicating with the outside, enabling the pressure-sensitive film, which acts as a second upper electrode, and the second lower electrode to constitute a reference capacitor whose capacitance does not vary with external air pressure.