A silicon resonant air pressure sensor based on microelectromechanical technology

Abstract

The invention discloses a silicon resonant air pressure sensor based on Micro-Electro-Mechanical Systems (MEMS), the air pressure sensor mainly comprises a resonance beam membrane silicon chip, a lower cover substrate, a support substrate, a metal tube seat and a tube cap. The lower cover substrate and the resonance beam membrane silicon chip are in vacuum bonding to form a reference vacuum cavity, and the support substrate which is relatively small is fixed on the metal tube seat to isolate packaging stress and thermal stress. According to pressure difference between atmosphere to be measured and the reference vacuum cavity, axial direction stress of a clamped microstructure beam on a pressure membrane is changed, thus resonant frequency of the beam is changed, change of the resonant frequency is detected and air pressure measurement is realized. According to the invention, a resonator is placed in an air pressure medium, packaging difficulty is lowered substantially, and the packaging stress and thermal stress are isolated through cantilever supporting. The silicon resonant air pressure sensor has the advantages of simple manufacture and packaging, good stability and the like, and is suitable for high performance air pressure measurement.

Description

technical field [0001] The invention belongs to the technical field of microelectronic machinery, and relates to a silicon resonance type air pressure sensor. Background technique [0002] Air pressure sensors based on microelectromechanical technology (MEMS) technology are mainly divided into three categories: piezoresistive, capacitive and resonant. The micromechanical resonant pressure sensor is known as a new generation of pressure sensor due to its high precision, good stability, small size, and easy mass production. Another typical application after that. Comparing several resonant pressure sensors that have been practical in the world, there is a common feature that the resonator works in a high vacuum environment, and the manufacturing process requirements are too high. For example, the electromagnetic excitation resonant pressure sensor of Yokogawa Corporation of Japan requires On-chip high vacuum sealing is achieved, and the on-chip vacuum sealing also has proble...

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Problems solved by technology

Comparing several resonant pressure sensors that have been put into practical use in the world, one common feature is that the resonator works in a high-vacuum environment, and the manufacturing process requirements are too high. Realize on-chip high-vacuum sealing, and on-chip vacuum sealing still has problems such as electrode leads and electrical insulation, and the package between the chip and the tube seat has the problem of effective isolation of mechanical stress and thermal stress

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