Capacitive pressure sensor and a method of fabricating the same

摘要

The invention discloses a capacitive pressure sensor and a method of fabricating the same. The capacitive pressure sensor includes a fixed plate configured as a back plate, a movable plate configured as diaphragm for sensing pressure, wherein a cavity is formed between the fixed plate and the movable plate, an isolation layer between the fixed plate and the movable plate and electrical contacts thereof for minimizing the leakage current, plurality of damping holes for configuring the contour of the fixed plate as the deflected diaphragm when pressure is exerted, a vent hole extending to the cavity having resistive air path for providing equilibrium to the diaphragm and an extended back chamber for increasing the sensitivity of the capacitive pressure sensor. The capacitive pressure sensor is also configured for minimizing parasitic capacitance.

主权项

1. A capacitive pressure sensor comprising:
a fixed plate defining a back plate for being anchored at the edges to keep the remaining area afloat for minimizing parasitic capacitance, the fixed plate including a contoured surface; a moveable plate configured as diaphragm for sensing pressure, wherein a cavity is formed between the fixed plate and the movable plate to allow deflection of the diaphragm, the moveable plate in electrical communication with the fixed plate by electrical contacts; an isolation layer between the fixed plate and the moveable plate and the electrical contacts, for minimizing the leakage current; a plurality of damping holes arranged on the fixed plate along the contoured surface of the fixed plate, such that the exertion of pressure on the diaphragm deflects the diaphragm to conform to the contoured surface of the fixed plate; a vent hole extending to the cavity having resistive air path for providing equilibrium to the diaphragm when exposed to the environmental pressure; a pedestal extending from the back plate; and, a cut-away area in the pedestal defining an extended back chamber with extended volume for increasing the sensitivity of the capacitive pressure sensor.