A kind of pressure sensor and its manufacturing method

Abstract

The invention relates to a pressure sensor and a manufacturing method thereof. The pressure sensor includes an SOI single crystal silicon wafer, a final passivation layer deposited on the buried oxide layer of the SOI single crystal silicon wafer, and a final passivation layer arranged between the buried oxide layer of the SOI single crystal silicon wafer A plurality of varistors, metal leads for connecting the varistors to each other, a pressure-sensitive thin film disposed under the buried oxide layer of the SOI single crystal silicon wafer and disposed inside the SOI single crystal silicon wafer , and a vacuum pressure chamber located below the pressure sensitive film. The present invention skillfully adopts (111) SOI single crystal silicon chip, combined with bulk silicon micromachining technology to realize the embedded vacuum pressure cavity structure in the bottom silicon in SOI single crystal silicon chip, by virtue of the special (111) silicon chip The crystal plane arrangement ensures the controllability and uniformity of the thickness of the pressure-sensitive film, thereby greatly improving the output characteristics of the sensor, reducing the size of the chip, and reducing the manufacturing cost.

Description

technical field [0001] The invention belongs to the field of manufacturing silicon micromechanical sensors, and in particular relates to a pressure sensor and a manufacturing method thereof. Background technique [0002] In recent years, with the continuous improvement of MEMS processing technology, the silicon-based piezoresistive pressure sensor based on MEMS micromachining technology has been widely used in aerospace, industrial electronics, etc. due to its small chip size, high precision, low cost and easy mass production. , biochemical medicine and other fields have been widely used. In addition, many applications also put forward higher and higher requirements for the high temperature resistance of pressure sensors, such as oil exploration, pressure control of combustion chambers of automobiles and aircraft engines, etc. Under the long-term reliable work. Therefore, the high temperature resistance application of silicon-based pressure sensors has become one of the ke...

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Problems solved by technology

[0004] In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a pressure sensor and its manufacturing method, which is used to solve the difficulty in controlling the thickness and uniformity of the pressure-sensitive film of the high-temperature silicon-based pressure sensor in the prior art, and Poor sensor temperature characteristics caused by vacuum pressure chamber bonding structure, large chip size, complex process and high cost

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