A kind of capacitive pressure sensor and preparation method thereof

Abstract

The invention discloses a capacitive pressure sensor. The capacitive pressure sensor comprises a plate capacitor, and further comprises a conductive monocrystal silicon substrate and a conductive supporting structure, wherein the plate capacitor comprises a conductive monocrystal silicon movable electrode plate and a metallic fixed electrode; the conductive supporting structure is arranged between the conductive monocrystal silicon movable electrode plate and the conductive monocrystal silicon substrate; a closed cavity is defined by the conductive monocrystal silicon movable electrode plate, the conductive monocrystal silicon substrate and the conductive supporting structure; the metallic fixed electrode is arranged on the conductive monocrystal silicon substrate inside the closed cavity; the conductive monocrystal silicon substrate comprises a plurality of conductive monocrystal silicon blocks which are insulated from each other; the conductive monocrystal silicon blocks are not simultaneously connected with the conductive monocrystal silicon movable electrode plate and the metallic fixed electrode, but at least one of the conductive monocrystal silicon blocks is connected with the conductive monocrystal silicon movable electrode plate and the metallic fixed electrode respectively. The capacitive pressure sensor disclosed by the invention is high in change value of capacitance, simplified in circuit, high in Young modulus of structure, accurate in measuring result, and not prone to be subjected to influence from the external environment.

Description

technical field [0001] The invention belongs to the field of pressure sensors, and relates to a capacitive pressure sensor and a preparation method thereof, in particular to a capacitive pressure sensor with large capacitance change. Background technique [0002] Pressure sensors are sensors that test pressure changes by detecting changes in parameters such as resistance, capacitance, current, and light due to pressure. Pressure sensors, like acceleration sensors, are sensors with a large quantity and wide range, and the annual demand has reached dozens. billion. [0003] There are many types of pressure sensors, mainly silicon piezoresistive pressure sensors, resonant pressure sensors, capacitive pressure sensors, etc. Silicon piezoresistive pressure sensors detect pressure by detecting changes in the resistance of silicon resistance with pressure. Because the silicon resistance of the sensor is a semiconductor resistance, the resistance value changes with temperature, and...

AI Technical Summary

Problems solved by technology

Although this method can achieve large capacitance changes and reduce the requirements for peripheral detection circuits, the vibrating diaphragm can be made of stainless steel with high Young's modulus to improve fatigue resistance and further improve reliability. Poor production capacity

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