High-sensitivity resonant differential pressure sensor and preparation method thereof

Abstract

The invention provides a high-sensitivity resonant differential pressure sensor and a preparation method thereof, and the high-sensitivity resonant differential pressure sensor comprises a sensor bodywhich comprises a device layer, an insulating layer and a substrate layer which are sequentially stacked, a first pressure sensitive film is arranged at the central position of the substrate layer, and the two sides of the first pressure sensitive film are respectively provided with a lead hole; a first resonator and a second resonator are arranged at the positions, corresponding to the first pressure sensitive film, of the device layer respectively, and wiring terminals are arranged on the periphery of the first resonator and the periphery of the second resonator respectively; the insulatinglayer is used for separating the substrate layer from the device layer; in addition to retaining a portion of the substrate layer necessary to achieve vacuum below the first resonator and the secondresonator, the first pressure sensitive film retains a layer of thinner small seal cap only below the first resonator and the second resonator to seal the first resonator and the second resonator. Thespecial design that the resonator is located close to the surface of the pressure sensitive film is achieved, and the sensitivity can be greatly improved.

Description

technical field [0001] The invention relates to the technical field of MEMS microsensors, in particular to a high-sensitivity resonant differential pressure sensor and a preparation method thereof. Background technique [0002] The resonant differential pressure sensor is a quasi-digital output, which has the advantages of high precision, good reliability, and strong anti-interference ability, and can obtain better accuracy and stability. It is widely used in aerospace, industrial control, metallurgical power, petrochemical, Medical electronics, automotive electronics and other fields. [0003] There are generally one or more resonators in the structure of the resonant differential pressure sensor. Since the resonator is a movable part, in order to realize its low-damping vibration working environment and protect it from external dust, humidity, corrosion, etc. , the resonator often needs to be sealed in a vacuum environment. Therefore, how to package the resonator in the ...

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Problems solved by technology

[0007] (1) The resonator is located in the middle part of the two-layer structure of the sensor body and the cover plate. According to the stress distribution of the pressure-sensitive film after being deformed by pressure, the differential pressure sensitivity of the differential pressure sensor is low, which is not conducive to the subsequent realization of high-precision sensors;

[0008] (2) The getter groove is located at the four corners of the chip. When the getter is sputtered through the hard mask plate, the getter groove can not be sputtered on the edge of the getter groove, so the utilization rate of the getter groove is low. , which is not conducive to the improvement of the vacuum degree of the vacuum chamber;

[0009] (3) The resonator vibration cavity and the getter groove made on the cover glass cause the glass to be easily broken when subjected to high pressure, which makes the pressure resistance of the sensor low

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