Capacitive triaxial accelerometer capable of increasing Z-axis sensitivity and manufacturing method thereof

Abstract

The invention discloses a capacitive three-axis accelerometer capable of increasing Z-axis sensitivity and a manufacturing method of the capacitive three-axis accelerometer. The capacitive three-axisaccelerometer is made of an SOI silicon wafer and comprises an inertia mass block, a supporting beam, a sensitive structure and an external connection electrode. The inertia mass block is in a centralsymmetry shape like a Chinese character 'tian', and four vertexes of the mass block are connected with anchor points through supporting beams. A movable comb electrode is arranged on the inner side of the mass block and forms an X-axis and Y-axis sensitive structure with a fixed comb electrode on the internal fixed structure; and a movable comb electrode is also arranged on the outer side of themass block and forms a Z-axis sensitive structure with a fixed comb electrode on an external fixed structure. The external connection electrode comprises an anchor point electrode and a fixed electrode. The capacitive three-axis accelerometer manufactured by the invention integrally adopts a centrosymmetric square structure to independently detect Z-axis acceleration, so that cross-axis interference is avoided. And meanwhile, the Z-axis electrode and the supporting beams are arranged outside the mass block, so that the logarithm of Z-axis comb capacitance can be remarkably increased, and higher sensitivity can be obtained.

Description

technical field [0001] The invention belongs to the technical field of microelectromechanical systems, and in particular relates to a capacitive three-axis accelerometer with increased Z-axis sensitivity. The accelerometer has the characteristics of high stability and high sensitivity. Background technique [0002] Micro-electromechanical systems (MEMS, micro-electrical mechanical system) and miniaturized sensors, actuators, and resonators using micro-mechanical technology are known for their low cost, small size, high reliability, low power consumption, high integration, and large Features such as mass production have attracted a lot of attention in the past few decades. [0003] Microaccelerometers using MEMS technology are widely used in inertial navigation, guidance, automotive airbag deployment and motion control systems. Capacitive MEMS accelerometers have the advantages of low temperature coefficient, low power consumption, low manufacturing cost, and can be integrat...

AI Technical Summary

Problems solved by technology

In addition, some three-axis micro-accelerometers use the same comb electrode sensitive structure to simultaneously detect the acceleration in the plane (X-axis, Y-axis) and vertical direction (Z-axis), so the cross-axis interference of this micro-accelerometer is relatively large. Big

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