A method of manufacturing a monolithically integrated three-mass mems capacitance differential three-axis accelerometer

Abstract

The invention discloses a preparation method of a single-chip-integrated three-quality-level MEMS capacitive differential type three-axis accelerometer and relates to the field of sensors, in particularly to a preparation method of a single-chip-integrated three-quality-level MEMS capacitive differential type three-axis accelerometer. The three axes of the three-axis accelerometer have respectivemass blocks. Meanwhile, an X-axis accelerometer, a Y-axis accelerometer and a Z-axis accelerometer are integrated on a single substrate. The X-axis accelerometer and the Y-axis accelerometer are respectively listed on the two sides of the Z-axis accelerometer and a flat-plate differential capacitor is arranged in each axial direction. According to the invention, three mass blocks are adopted by the accelerometer, and the cross interference among the three axes is minimum. The accelerometer is good in stability. The flat-plate differential capacitance detection is carried out in the three directions of X-axis, Y-axis and Z-axis and the detection accuracy is high. The SOI silicon wafer process is adopted, and accelerometers in the three axes of X-axis, Y-axis and Z-axis are simultaneously formed. The method is simple in process, easy in batch production and high in repeatability. The same as an existing single-chip-integrated three-axis accelerometer, the above three-axis accelerometer is small in size and free of manual calibration.

Description

technical field [0001] The invention relates to the field of sensors, in particular to a method for preparing a single-chip integrated three-mass MEMS capacitance differential three-axis accelerometer. Background technique [0002] Capacitive accelerometers are typical microsensors developed using MEMS technology. They are widely used not only in general aviation, vehicle control, high-speed railways, robots, industrial automation, prospecting, toys, mobile phones, etc., but also in missile guidance. There are also applications in aircraft navigation and other aspects. With the development of technology and further market demand, in order to more comprehensively understand the motion information of objects, the research and development of three-axis accelerometers has become a trend. At present, there are three ways to realize the three-axis accelerometer, which are hybrid integration, on-chip and off-chip integration, and single-chip integration. [0003] The hybrid integr...

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Problems solved by technology

[0006] However, a single mass block is used, that is, the X, Y, and Z directions share one mass block, such as an accelerometer based on an off-set structure. The preparation process of this structure is simple, but the acceleration detection in each direction will have serious interference, and the Z direction Differential detection cannot be realized, and the detection accuracy is not high

Two mass blocks are used, usually one mass block is used in the X and Y directions of the plane, and the vertical Z axis adopts a torsion bar type differential comb structure, such as a seesaw accelerometer, which also makes the Z direction be detected by the X and Y directions. signal interference, affecting the accuracy of detection; the use of more than three quality, usually adopts a nested structure, the preparation is complicated, and there are also signal interference problems between each other

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