Capacitive micro-electromechanical system (MEMS) accelerometer and manufacturing method thereof

Abstract

The invention provides a capacitive micro-electromechanical system (MEMS) accelerometer, which comprises a first silicon cover plate layer, a middle silicon layer and a second silicon cover plate layer which are arranged in sequence, wherein the middle silicon layer comprises a first silicon island and a second silicon island; the silicon islands are formed inside a silicon framework and separated from the silicon framework at intervals; the first silicon island is contacted with a metal electrode of the first silicon cover plate layer; the second silicon island is contacted with a metal electrode of the second silicon cover plate layer; the first silicon cover plate layer further comprises a first metal electrode through hole, a second metal electrode through hole and a silicon electrode through hole which are formed in a first silicon substrate; the first metal electrode through hole corresponds to the position of the first silicon island; the second metal electrode through hole corresponds to the position of the second silicon island; the silicon electrode through hole corresponds to the position of the silicon framework; and an insulating layer is arranged on the inner wall of each through hole, and each through hole is filled with metal electrically conductive material. By adopting the capacitive MEMS accelerometer, all electrodes of the accelerometer can be led out on the same silicon surface, so that wafer level bonding of the accelerometer is realized and the accelerometer can be packaged by adopting the flip chip technology.

Description

technical field [0001] The invention relates to a microelectromechanical system (MEMS) device and its manufacturing technology, in particular to a capacitive MEMS accelerometer and its manufacturing method. Background technique [0002] MEMS accelerometers are an indispensable link in MEMS inertial systems and are currently used in many fields. There are two main working principles of MEMS accelerometers: capacitive and piezoresistive. Among them, piezoresistive accelerometers have disadvantages such as low precision and poor temperature characteristics, and their application fields are limited. Capacitive accelerometers mainly adopt two schemes: comb tooth type and "sandwich" type. The comb-tooth accelerometer mainly has the following problems: the mechanical strength difference between the sensitive axis and the non-sensitive axis of the sensitive structure is not large, and the sensitivity of the non-sensitive axis of the accelerometer is difficult to suppress; the direc...

AI Technical Summary

Problems solved by technology

The comb-tooth accelerometer mainly has the following problems: the mechanical strength difference between the sensitive axis and the non-sensitive axis of the sensitive structure is not large, and the sensitivity of the non-sensitive axis of the accelerometer is difficult to suppress; the direction of the sensitive axis cannot provide a protective structure with sufficient mechanical strength , the impact resistance of the accelerometer is insufficient; the output value of the comb-tooth structure capacitance is small, and the sensitivity to external acceleration is low, so the comb-tooth accelerometer is mainly suitable for low-demand environments such as the consumer field

The traditional wire bonding technology is used for packaging. When the through hole of the accelerometer used to lead out the electrodes exceeds a certain depth, the difficulty of the wire bonding process will increase, and the yield and reliability will be significantly reduced; the repair is difficult and the flexibility is poor.

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