mems capacitive air pressure sensor based on pn junction electrical isolation and anodic bonding technology

Abstract

The invention discloses a MEMS capacitive air pressure sensor based on PN junction electrical isolation and anodic bonding technology, comprising an air pressure sensitive film, a glass substrate and a glass cover plate; one side of the air pressure sensitive film is anodically bonded with the glass substrate to form a vacuum reference chamber , the other side of the air pressure sensitive film is anodically bonded with the glass cover to form an open gas pressure sensitive film, the external air pressure is applied to the air pressure sensitive film, and the pressure difference with the vacuum reference chamber forms a pressure difference to deform the air pressure sensitive film, and then changes the air pressure sensitive film The distance between the capacitive plate and the glass substrate changes the capacitance value to reflect the external air pressure. The invention also discloses the processing technology of the MEMS capacitive air pressure sensor. The capacitive air pressure sensor of the invention has simple processing technology, high yield rate and good commercialization effect.

Description

Technical field [0001] The present invention relates to a MEMS capacitive air pressure sensor based on PN junction isolation and anode bonding technique, belonging to the field of MEMS micromechanical processing and manufacturing. Background technique [0002] The air pressure sensor is widely used in aerospace sectors, vacuum instrumentation equipment, industrial on-site control and testing, land, marine weather, health monitoring and smart medical and other fields, and is also spatial science, deep space, physical exploration (moon, Mars, Saturn One of the important sensors required to explore the field. It is different from traditional mechanical air pressure sensors, micro-electro-mechanical system, short-handed MEMS) air pressure sensor, due to its advantage of small size, light weight, low power consumption and integration, etc. Applications. How to achieve low cost small volume packages and reliable electrical coefficients is a key factor in determining the stability and c...

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Problems solved by technology

[0004] NASA of the United States and Vaisala of the Netherlands have cooperated to develop a MEMS capacitive air pressure sensor for the Mars rover. It adopts a silicon-glass anode bonding process, and prepares pits and electrode plates on silicon and glass at the same time. The resolution can reach 0.2Pa. However, due to the protection of technical secrets, its electrode lead technology has not been disclosed, and it has not been commercialized; The nano-manufacturing process uses multiple polysilicon growth, heavy doping, corrosion self-stop, silicon-silicon fusion bonding, anodic bonding, etc. The micro-nano processing process of this scheme is complicated and difficult, and requires more high-end micro-nano processing Instruments and equipment, and it is difficult to guarantee a high yield, so the commercialization effect is not very good

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