Piezoresistive beam stress concentration micro-pressure sensor chip and preparation method thereof

Abstract

The invention discloses a piezoresistive beam stress concentration micro-pressure sensor chip and a preparation method thereof, the sensor chip comprises a silicon substrate and a glass substrate, the back surface of the silicon substrate is etched with a back cavity, the bottom surface of the back cavity is a pressure-bearing film, and the front surface of the pressure-bearing film is provided with a first piezoresistive beam, a second piezoresistive beam, a third piezoresistive beam and a fourth piezoresistive beam; the first piezoresistive beam, the second piezoresistive beam, the third piezoresistive beam and the fourth piezoresistive beam are respectively provided with piezoresistor strips respectively, the length direction of each piezoresistor strip is the same as the length direction of the piezoresistive beam where the piezoresistor strip is located, and the piezoresistor strips are connected through metal leads and metal bonding pads to form a Wheatstone bridge. The problem that the beam structure cannot be narrower because the width of the beam structure must be larger than the width of the piezoresistor strips due to the fact that the piezoresistor strips on a traditional beam structure are arranged perpendicular to the straight line where the beam structure is located is solved.

Description

technical field [0001] The invention belongs to the technical field of micro-electromechanical sensors, in particular to a piezoresistive beam stress concentration micro-pressure sensor chip and a preparation method thereof. Background technique [0002] With the development of MEMS technology, micro-pressure sensors have been widely used in aerospace, food industry, smart home, biomedical and other fields; with the rapid development of various fields, there are higher requirements for the performance and volume of sensors. Especially in the field of biomedicine, there is an urgent need for micro-pressure measurement sensors with stable performance, high dynamics, and high sensitivity to guarantee. [0003] According to different measurement principles, MEMS micro-pressure sensors are mainly divided into piezoresistive, piezoelectric, capacitive, and resonant. Compared with MEMS micro-pressure sensors with other principles, MEMS piezoresistive micro-pressure sensors are wid...

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Problems solved by technology

For beam-membrane structures and beam-membrane island structures including beam structures, the varistor strips need to be arranged in a straight line perpendicular to the beam structure, and the width of the beam structure cannot be lower than the width of the varistor strips, so the beam structure cannot be made narrower. , and the sensitivity of the sensor is inversely proportional to the width of the beam structure, resulting in a low sensitivity of the sensor

[0005]In addition, there is an irreconcilable contradiction between the sensitivity and dynamic performance of the micro pressure sensor

In order to obtain higher sensitivity, it is usually necessary to increase the stress concentration effect by reducing the stiffness of the pressure-bearing diaphragm and increasing the deflection of the diaphragm, which will affect the linearity and dynamic performance of the sensor to a certain extent

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