Silicon capacitance pressure sensor

Abstract

The invention relates to a silicon capacitance pressure sensor, comprising a silicon wafer layer and a glass layer. The silicon capacitance pressure sensor is characterized in that: a silicon fixed polar plate is respectively connected with the upper side and the lower side of a movable polar plate at the silicon center of an island film structure, and the silicon fixed polar plate comprises the silicon wafer layer and the glass layer, both of which are statically sealed in vacuum, and the thickness of the glass layer is 50-200 microns; a central pressure leading hole is formed at the middle part of the silicon fixed polar plate, and an aluminum film layer is arranged on the outer surface of the silicon fixed polar plate in the central pressure leading plate and close to the central pressure leading hole. The invention provides a new design realization scheme aiming at a core component of a present silicon capacitance pressure sensor. Even through silicon polar plates are connected through thin-layer glass through a static seal process without a high-temperature bonding furnace and an ultraclean environment, the process condition is simple and is directly compatible with the present processes, especially the thickness of the glass thin layer can be regulated, and interlayer parasitic capacitors are controlled in a certain range. Through the performance of the silicon capacitance pressure sensor disclosed by the invention, an effect approximating a silicon-silicon-silicon scheme is realized.

Description

technical field [0001] The invention belongs to the technical field of sensors, in particular to a silicon capacitive pressure sensor made of single crystal silicon material and fusion technology of microelectronics and micromachining. Background technique [0002] Silicon capacitive differential pressure sensor is a new type of structural differential pressure sensor. Its core sensitive device is made of single crystal silicon material, which is made by the fusion technology of microelectronics and micromachining. Compared with the previous metal capacitance sensors, capacitive sensors have more obvious advantages in terms of measurement accuracy and stability. The core sensitive device of the silicon capacitive sensor converts the two external pressure signals into the corresponding capacitance changes, and the detection circuit converts the capacitance changes into the required electrical signals, and the corresponding output signals can be obtained by processing the elec...

AI Technical Summary

Problems solved by technology

In addition, if the silicon-silicon bonding process is directly used in the production of capacitive sensors, since silicon-silicon needs to be electrically isolated, it is generally bonded through a silicon dioxide insulating film layer, which will generate a large parasitic capacitance between the silicon plates. Interference with the capacitive signal of the normal sensor is extremely unfavorable for improving the measurement accuracy of the capacitive sensor

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