Wideband-response silicon micro-mechanical accelerometer with high vibration mode stability

Abstract

The invention discloses a capacitive silicon micro-mechanical accelerometer structure with high vibration mode stability and wideband response characteristics, which belongs to the field of inertial technology and micro-electro-mechanical systems (MEMS). The accelerometer sequentially comprises a substrate silicon body 3, an anchor point 2 and a device layer 1. The device layer 1 is suspended above the substrate silicon body 3 through the anchor point 2; the device layer 1 is composed of a frame type structure 4 and an elastic beam group 5; the frame type structure 4 is a structure shaped like a Chinese character 'ri' and composed of a square peripheral frame structure 4-2 and a connecting central cross beam 4-1. The accelerometer structure has the characteristics of easy processing, structural error immune process error and the like, the in-plane vibration mode stability is remarkably improved by the structure with the eight-claw configuration characteristic, out-plane vibration is restrained and inhibited by the elastic beams and the anchor points of the inner frame, and the device structure can effectively compress a useful vibration mode to a first-order mode, a plurality of harmful vibration modes are squeezed to a second-order or higher-order mode, the influence of the high-order harmful vibration modes on a first-order useful vibration mode is effectively isolated, the vibration mode stability of the accelerometer structure in a high-frequency response range is remarkably improved, and the device precision is improved.

Description

[0001] Field: [0002] The invention relates to a capacitive silicon micromechanical accelerometer structure with high vibration mode stability and wide frequency response characteristics, belonging to the fields of inertial technology and microelectromechanical systems (MEMS). Background technique: [0003] Micro Electro Mechanical System (MicroElectroMechanicalSystem, MEMS for short) refers to a micro-device or electromechanical system that can be produced in batches, integrating micro-mechanism, micro-sensor, micro-actuator, signal processing and control circuit, and even communication and power supply. MEMS accelerometers are gradually replacing traditional accelerometers in many application fields such as drones, automotive industry, and consumer electronics due to their advantages of small size, low power consumption, mass production, and low cost. At present, the research of silicon-based MEMS accelerometers mainly focuses on applications with low dynamic characteristic...

AI Technical Summary

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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