Micromachine-based electromagnetic excitation resonant pressure sensor

Abstract

The invention discloses a micromachine-based electromagnetic excitation resonant pressure sensor, and relates to a micromachine sensing technology. The sensor is provided with three groups of resonators which are clamped by anchor points on a pressure membrane, arranged on a diagonal line of a frame, and provided with electrodes. The resonators applied with excitation signals are excited by magnetic field force under the action of an external magnetic field; and when pressure to be tested is present outside, the pressure membrane generates strain, and the strain is transmitted to the resonators through the anchor points to change the rigidity of the resonators, so that the natural frequency of the resonators is changed, and the pressure to be tested outside can be measured by detecting the frequency of output signals of vibration pickup electrodes. The sensor has two packaging modes, and is subjected to stress isolation through a ceramic ring of which the coefficient of thermal expansion is basically same as monocrystalline silicon. The resonators of the sensor work in a horizontal vibration mode; the shift caused by external factors such as temperature and the like is inhibited through differential output, and the sensitivity is improved; and the resonators are released by a heavy boron-diffusion self-stop corrosion technology, a process is simple and the consistency is high.

Description

technical field [0001] The invention belongs to the technical field of micro-mechanical sensing, and relates to an electromagnetic excitation resonant beam type pressure sensor based on micro-electro-mechanical technology (MEMS). Background technique [0002] The resonant beam pressure sensor consists of two parts: the pressure sensitive membrane and the resonant beam. When the external pressure to be measured changes, the pressure sensitive membrane will generate strain, and the strain will be transferred to the resonator, which will change the stiffness of the resonator, thereby changing the frequency of the resonator. , detecting the frequency change of the resonator can obtain the magnitude of the external pressure to be measured. [0003] The microstructure resonant beam pressure sensor made by MEMS technology is mainly made of single crystal silicon and polycrystalline silicon materials so far. The micro-mechanical silicon resonant pressure sensor is mainly used for h...

AI Technical Summary

Problems solved by technology

The disadvantage is that the resonant beam is easy to be mechanically coupled with the pressure film, and the surface processing process is very complicated

[0006] In addition, when the external environment changes (except for changes in air pressure), the resonant pressure sensor will also generate output, that is, drift, which will affect the stability of the sensor

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