MEMS capacitor film vacuum gauge

Abstract

The invention provides an MEMS (Micro Electro Mechanical System) capacitor film vacuum gauge, which can realize the measurement of the vacuum degree in a range of 1-1000Pa, and the measurement resolution is 0.5 Pa. A pressure sensing film is a circular film with an island-shaped structure film. The circular film is very uniform in radial stress and strain, and under the same pressure, the deflection of the circular film is larger than that of a square film, so that the sensitivity of the pressure sensing film is higher. The island-shaped structure film can increase the rigidity of the film, sothat the deflection of the pressure sensing film is reduced, the basic capacitance is increased, the resolution ratio is improved, and meanwhile, the linearity of the pressure-capacitance relationship is better. Meanwhile, the circular film with the island-shaped structure film is of a double-side electrode differential type sensitive capacitor structure. When the pressure sensing film deforms due to pressure, the sensitive capacitor outputs two capacitances which are equal in variation and opposite in direction, and a double-differential structure is formed through a subsequent differentialmeasurement circuit, so that the common-mode rejection ratio is improved, the influence of parasitic capacitance, temperature and other factors on a measurement result is eliminated, and the measurement resolution is improved.

Description

technical field [0001] The invention belongs to the technical field of mechanical design and vacuum gauge, and in particular relates to a MEMS capacitive film vacuum gauge. Background technique [0002] Capacitance film vacuum gauge is a kind of vacuum measuring instrument, which uses elastic film to generate displacement under the action of pressure difference, which causes the change of the distance between the electrode and the diaphragm, resulting in the change of capacitance. By measuring the change of capacitance, the pressure and steam can be measured. Full pressure, the measurement result has nothing to do with the gas composition and type, and can be used as a reference standard for low vacuum and a transfer standard in the process of value transfer. It has high measurement accuracy, good linearity, good output repeatability and long-term stability, and can measure gas pressure. However, the traditional mechanical capacitive film vacuum gauge has a large volume, hi...

AI Technical Summary

Problems solved by technology

The current MEMS capacitive film vacuum gauge has a pressure-sensitive film that is mostly a square or rectangular film, and its fixed electrode is only located on one side of the pressure-sensitive film, and the getter is placed in a centralized manner. The measurement range of the vacuum degree is limited and the measurement resolution is low

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