Medium insertion type capacitive pressure sensor and preparation method thereof

Abstract

The invention belongs to the field of pressure sensors, and particularly relates to a medium insertion type capacitive pressure sensor and a preparation method thereof. The medium insertion type capacitive pressure sensor comprises a base body, a supporting layer and a pressure sensing layer, the base body comprises a substrate and a comb-shaped electrode, the pressure sensing layer comprises an elastic film and a pressure sensing array located below the elastic film and connected with the elastic film, an array unit of the pressure sensing array is located over comb tooth gaps of the comb-shaped electrode, and the elastic film, the substrate and the supporting layer form a closed vacuum cavity structure, so that the elastic film drives the pressure sensing array to move downwards under the action of pressure, the position of the comb-shaped electrode is fixed, the pressure sensing array is inserted between two polar plates of a comb tooth electrode parallel plate capacitor, the relative dielectric constant of dielectric between the polar plates is changed, the capacitance is changed, and the pressure can be measured by detecting the capacitance. According to the capacitive pressure sensor, the sensitivity can be improved while the linearity is improved.

Description

technical field [0001] The invention belongs to the field of pressure sensors, and more specifically relates to a medium-inserted capacitive pressure sensor and a preparation method thereof. Background technique [0002] Pressure sensors based on MEMS technology are widely used in many fields such as industrial production, medical and health care, environmental monitoring, and scientific research. Among them, the capacitive pressure sensor is a main type of MEMS pressure sensor, and its fundamental principle is to convert pressure changes into capacitance changes. According to the capacitance calculation formula: Among them, ε 0 is the vacuum dielectric constant, which is a fixed value; ε r is the relative permittivity, which is the equivalent relative permittivity of the dielectric between the capacitor electrode plates; A is the facing area of ​​the capacitor electrode plates; d is the distance between the capacitor electrode plates. In the existing capacitive pressur...

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Problems solved by technology

[0006] Aiming at the defects or improvement needs of the prior art, the present invention provides a medium-inserted capacitive pressure sensor and its preparation method. By redesigning the structure of the capacitive pressure sensor, a new working principle is provided. Capacitive pressure sensor, the pressure sensor can change the relative permittivity ε between the capacitive plates r To change the output capacitance value; the simulation of the pressure sensor working in the large deflection deformation area shows that not only the sensitivity is greatly improved, but also the linearity is greatly improved, and finally the high sensitivity is obtained. At the same time, high linearity can be obtained, which solves the technical problem that the linearity and sensitivity of capacitive pressure sensors in the prior art are mutually restricted and cannot be taken into account.

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