A Wide Frequency Response Silicon Micromachined Accelerometer with High Mode Shape Stability

Abstract

The invention discloses a capacitive silicon micromachined accelerometer structure with high mode stability and wide frequency response characteristics, belonging to the fields of inertial technology and micro-electromechanical systems (MEMS). The accelerometer includes a base silicon body 3 , an anchor point 2 and a device layer 1 in sequence. The device layer 1 is suspended above the base silicon body 3 through the anchor point 2; the device layer 1 is composed of a frame structure 4 and an elastic beam group 5; the frame structure 4 is a square peripheral frame structure 4-2 and a connection center A "day"-shaped structure composed of beams 4‑1. The accelerometer structure has the characteristics of easy processing and immunity to process errors. The structure of the eight-claw configuration significantly improves the stability of the in-plane mode shape. The elastic beams and anchor points of the inner frame restrain the out-of-plane vibration. The device structure can Effectively compress the useful mode shape to the first-order mode, squeeze multiple harmful mode shapes to the second-order and above high-order modes, effectively isolate the influence of high-order harmful mode shapes on the first-order useful mode shape, and significantly improve the accelerometer structure in The mode shape stability in the high frequency response range improves the accuracy of the device.

Description

[0001] Field: [0002] The invention involves a capacitive silicon micro -mechanical acceleration meter structure with high vibration stability and broadband response characteristics, which belongs to the field of inertial technology and microcoperation system (MEMS). Background technique: [0003] MicroeletromeChanicalSystem (MEMS) refers to a batch -available micro -device or electromechanical system that integrates micro -mechanisms, micro -transmission, microcontroller, and signal processing and control circuits, and even communication and power.MEMS acceleration meters have gradually replaced the traditional acceleration meter due to their small volume, low power consumption, batch preparation, and low cost.At present, the research of silicon -based MEMS acceleration meters is mainly concentrated in low dynamic features such as high sensitivity, low noise, and small bandwidth. Due to the mechanical characteristics of silicon materials, it has applications with high frequency a...

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Problems solved by technology

However, the asymmetric geometric topology, complex array layout, numerous leads, and non-uniform aspect ratio of this structure have extremely high requirements on the manufacturing process, which can easily lead to the instability of the mode shape. The specific performance is: 1) cannot Avoided processing errors can easily separate the geometric centroid and centroid of the structure. When the external acceleration input acts, the actual mode shape of the structure deviates from the ideal mode shape, that is, the mode shape is unstable, resulting in detection errors 2) Acceleration signals in application environments such as impact, explosion, and instantaneous jump contain rich wide-frequency domain information, which can easily trigger harmful vibration modes of other orders of the structure, making structural vibration in these useless The mode shape leads to the instability of the useful mode shape, which greatly reduces the sensitive detection capability of the structure and reduces the performance of the device

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