Quartz girder resonant mode micro-pressure sensor chip with silicon substrate single island structure

Abstract

A quartz girder resonant mode micro-pressure sensor chip with a silicon substrate single island structure comprises a quartz girder which is bonded on the front of the silicon substrate through low stress adhesive glue. Four opposite angles of the quartz girder are directed at four alignment markers on the front of the silicon substrate. The back of the silicon substrate is connected with a glass substrate in a sealing mode. The front of the glass substrate corrodes a groove. A pressure hole is formed at the center of the groove. The pressure hole is communicated with the atmosphere to form a gauge pressure sensor, or is communicated with the other tested atmosphere to form a differential pressure type sensor. The back of the silicon substrate corrodes the groove to form a silicon island. The quartz girder is driven to self-oscillate with an inverse piezoelectric effect of the quartz and when vibration frequency is equal to the inherent frequency of the quartz girder, resonance oscillation occurs. Resonant frequency is tested under a closed-loop feedback control system. Variable quantity of the resonant frequency represents the size of air pressure to be tested, and therefore the measurement of the outside air to be measured can be realized. The quartz girder resonant mode micro-pressure sensor chip with the silicon substrate single island structure has the advantages of being high in sensitivity, high in accuracy and high in resolution ratio.

Description

technical field [0001] The invention relates to a quartz resonant pressure sensor, in particular to a silicon-based single island structure quartz beam resonant micro pressure sensor chip. Background technique [0002] The pressure sensors on the market mainly include capacitive, piezoresistive and resonant. Capacitive and piezoresistive outputs are analog quantities, and high-precision conditioning circuits must be used to process weak signals. These factors will inevitably lead to a decrease in measurement accuracy; and resonant The pressure sensor uses the pressure change to change the resonant frequency of the object, so as to indirectly measure the pressure by measuring the frequency change, and its output is a quasi-digital frequency signal, which has high measurement accuracy, high sensitivity, high resolution, strong anti-interference ability, and It is suitable for long-distance transmission without reducing its accuracy, and is more suitable for high-precision dete...

AI Technical Summary

Problems solved by technology

At present, the research on MEMS resonant pressure sensors at home and abroad is mainly silicon micro-resonant pressure sensors. The elastic elements and sensitive elements of the sensors are all made of silicon materials and processed by silicon technology. The disadvantage is that it is difficult to process complex high-quality factors. Resonator structure, and it is difficult to excite and detect the resonator

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