High-sensitivity silicon piezoresistive pressure sensor and its preparation method

Abstract

The invention relates to pressure sensors and preparation methods thereof, in particular to a high-sensitivity silicon piezoresistance pressure sensor and a preparation method thereof, and belongs to the technical field of semiconductor pressure sensors. According to the technical scheme, the high-sensitivity silicon piezoresistance pressure sensor comprises a silicon substrate which is provided with a strain membrane in an attached mode, and the upper portion of the inside of the silicon substrate is sealed by the strain membrane to form a vacuum cavity. A stress concentration area is arranged at the center area of the strain membrane in a concave mode, and the stress concentration area is located over the vacuum cavity. The strain membrane is provided with a strain resistor used for forming a Wheatstone bridge arm, and the strain resistor is placed on the outer circle of the stress concentration area and is placed above the vacuum cavity. The strain resistor on the strain membrane is electrically connected through a metal electrode above the strain membrane to form a Wheatstone bridge. The metal electrode and the strain membrane are isolated through a protection layer. The high-sensitivity silicon piezoresistance pressure sensor is compact in structure, the sensitivity is improved under the premise that the area of the pressure sensor and the technology difficulty are not increased, and safety and reliability are achieved.

Description

technical field [0001] The invention relates to a pressure sensor and a preparation method thereof, in particular to a high-sensitivity silicon piezoresistive pressure sensor and a preparation method thereof, belonging to the technical field of semiconductor pressure sensors. Background technique [0002] Due to the characteristics of small size, light weight, high precision, good temperature characteristics, and compatibility with semiconductor integrated circuit technology, semiconductor sensors have been applied to a very wide range of fields, such as automobiles, medicine, aerospace, and the environment. [0003] In recent years, MEMS pressure sensors have gradually replaced traditional mechanical quantity sensors in the fields of automotive electronics, consumer electronics and industrial electronics, and have broad market prospects, such as tire pressure monitoring pressure sensors, engine oil pressure sensors, automotive brake system air pressure sensors and automotive...

AI Technical Summary

Problems solved by technology

For sensors requiring high sensitivity, the sensitivity can only be improved by reducing the thickness of the film without increasing the area, but this increases the difficulty of the thinning process, and as the thickness of the film decreases, the rate of change of stress with position changes. Large, for pressure sensors with the same performance, this greatly increases the difficulty of making piezoresistors

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