Piezoresistive pressure sensor chip with stress concentration structure and preparation method thereof

Abstract

The invention discloses a piezoresistive pressure sensor chip with a stress concentration structure and a preparation method thereof. The sensor chip is composed of a shallow groove film structure layer and a back cavity structure layer. The shallow groove thin film structure is divided into a shallow groove structure and a thin film structure. The shallow groove structure is composed of four shallow grooves distributed along the edge of the thin film and square shallow grooves distributed in the thin film, stress is concentrated between the ends of the two shallow groove structures, the distributed square shallow grooves further concentrate and adjust stress distribution, and the sensitivity of the sensor is improved. Four piezoresistor strips are evenly arranged at the stress concentration position, the four piezoresistor strips are connected through metal leads to form a semi-open-loop Wheatstone full bridge, and the bridge is connected with five bonding pads arranged on a substrateto achieve input and output of electric signals. The back cavity consists of a peninsula and an island, and a gap between the peninsula and the island corresponds to the end parts of the two shallowgroove structures. The peninsula and the island improve the stress concentration effect, and improve the rigidity of the sensor, so that the linearity of the sensor is improved.

Description

technical field [0001] The invention belongs to the technical field of micro-electromechanical sensors, and in particular relates to a piezoresistive pressure sensor chip with a stress concentration structure and a preparation method thereof. Background technique [0002] With the development of micro-mechanical electronic system technology, micro-pressure sensors have been widely used in aerospace, smart home, invasive medical equipment and other fields; with the rapid development of various fields, there are stricter requirements on the performance and volume of sensors. MEMS sensors are undoubtedly an ideal choice, especially in the field of biomedicine, which is in urgent need of micro-pressure measurement sensors with stable performance, high dynamics, and high sensitivity to guarantee. [0003] There are many measurement principles used by MEMS micro-pressure sensors, mainly piezoresistive, piezoelectric, capacitive, resonant, etc., but compared with other principles o...

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Problems solved by technology

However, there is a mutual restrictive relationship between sensitivity and linearity, which affects the further improvement of sensor performance.

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