Pressure sensor chip and preparation method, and absolute pressure sensor chip

Abstract

The embodiment of the invention discloses a pressure sensor chip and a preparation method, and an absolute pressure sensor chip. The pressure sensor chip includes a glass base, a silicon pedestal and a silicon diaphragm which are arranged in turn. The upper surface of the silicon pedestal is provided with a first cavity and a second cavity, and a through cavity connecting the second cavity and the lower surface of the silicon pedestal is arranged below the second cavity. The inner ring of the through cavity is located in the periphery of the inner ring of the second cavity and the distance between the inner ring and the outer ring of the through cavity is smaller than the distance between the inner ring and the outer ring of the second cavity. The silicon diaphragm is fixed to the upper surface of the silicon pedestal. An absolute pressure varistor and a first Wheatstone bridge outputting an absolute pressure signal are arranged at the region edge, corresponding to the first cavity, of the surface of the silicon diaphragm. A differential pressure varistor and a second Wheatstone bridge outputting a differential pressure signal are arranged at the region edge, corresponding to the second cavity, of the surface of the silicon diaphragm. The glass base is provided with a vent hole communicating with the through cavity and the outside of the glass base. The application has a large measuring range and can realize the synchronous measurement of differential pressure and absolute pressure .

Description

technical field [0001] The invention relates to the field of microelectronic machining, in particular to a pressure sensor chip and a preparation method. Background technique [0002] Pressure sensors are widely used in aviation, aerospace, navigation, petrochemical, automobile manufacturing and other fields. The pressure sensor belongs to the microelectromechanical piezoresistive sensor, that is, the sensor chip manufactured by using the piezoresistive effect of single crystal silicon through microelectronic machining technology. Existing pressure sensor chips are divided into differential pressure sensor chips and absolute pressure sensor chips, wherein the differential pressure sensor chip is used to measure the difference between two pressures. The absolute pressure sensor chip is used to sense absolute pressure and output the absolute pressure value. If it is necessary to realize the measurement of differential pressure and absolute pressure, it must be realized one b...

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Problems solved by technology

[0003] In addition, the existing large-range pressure sensor chip has a low output signal when measuring small pressure and cannot meet the detection requirements, while the small-range pressure sensor can meet the detection requirements of small pressure but cannot be applied to the measurement of high-pressure pressure, that is, the traditional pressure sensor chip There have always been technical difficulties in the small measurement range

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