Micromechanical silicon resonant accelerometer with different resonant frequencies

Abstract

The invention discloses a micromechanical silicon resonant accelerometer with different resonant frequencies. The accelerometer is characterized by comprising a glass substrate, a lead wire layer, a bonding layer and a silicon structure layer, wherein the lowermost layer is the glass substrate, metal is sputtered on the upper surface of the glass substrate to serve as the lead wire layer, and thesilicon structure layer is suspended above the glass substrate through the bonding layer; the silicon structure layer comprises an upper mass block (1a), a lower mass block (1b) connected with the upper mass block (1a), a first folding beam (6a) and a second folding beam (6b); and the upper mass block (1a) and the lower mass block (1b) are symmetrically arranged relative to the horizontal shaft of the silicon structure layer, and are connected through the first folding beam (6a) and the second folding beam (6b). The micromechanical silicon resonant accelerometer with different resonant frequencies provided by the invention can be used for eliminating the influence of mode coupling within a full scale range, removing a measuring dead area, releasing residual stress generated in a structureprocessing process, and reducing the stress generated by material thermal expansion.

Description

technical field [0001] The invention relates to a silicon micro-acceleration inertial sensor in a micro-electro-mechanical system (MEMS). Background technique [0002] Silicon micro accelerometer is a typical MEMS (Micro Electromechanical system, microelectromechanical system) inertial sensor, its processing technology is compatible with microelectronics processing technology, can realize mass production, and has the advantages of small size, light weight, low cost and low energy consumption , high reliability, easy intelligence and digitization, and can meet harsh environment applications, etc., is one of the hot spots in the development of accelerometers today, with important military value and broad civilian prospects. [0003] Different from the general capacitance detection accelerometer, the silicon microresonance accelerometer obtains the magnitude of the input acceleration by detecting the change of the resonant frequency. Its basic feature is to output frequency si...

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Problems solved by technology

However, when the external acceleration load is very small—in the range of plus or minus several milligrams (1g=9.8 m / s2), the two resonators vibrate at the same frequency, that is, the two The resonator generates modal coupling through the same mass block, and the input acceleration cannot be measured at this time, forming a measurement blind zone

[0005]Silicon microresonator accelerometers are sensitive to input acceleration by measuring frequency changes. Temperature changes will not only lead to changes in elastic modulus, which will cause frequency drift of the resonator, but will also Causes structural and package stress changes, also causes changes in resonator frequency and quality factor

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