A mems fork beam capacitive accelerometer and its manufacturing method

Abstract

The invention relates to an MEMS cross beam capacitor accelerometer and a manufacture method thereof. The accelerometer adopts a glass-silicon-glass three-layer structure and comprises a first glass layer, a silicon layer and a second glass layer which are successively arranged, wherein the silicon layer comprises a rectangular outer frame, cantilever beams, cross beams, a quality block, silicon islands and a silicon layer electrode lead-out area; the two cross beams are arranged between the two cantilever beams and are disposed at the positions of the diagonal lines of the rectangular frame enclosed by the two cantilever beam, the quality block and the rectangular outer frame; and each cross beam is connected with the rectangular outer frame, the two cantilever beams and the quality block. The silicon layer structure in the accelerometer is designed in an innovative manner so that the frequency of the working modal of the accelerometer is over ten times less than the frequency of a neighboring modal, thus the cross interference is effectively inhibited, the dimension errors are reduced, and the device integrity is greatly enhanced. In the design with equal thickness, the sensitive structure of the silicon layer can be manufactured by etching once so that the process difficulties are substantially reduced and the process steps are simplified.

Description

technical field [0001] The invention relates to a microelectromechanical system (MEMS) device and its manufacturing technology, in particular to a MEMS fork beam capacitive accelerometer and its manufacturing method. Background technique [0002] Accelerometer is an instrument used to measure acceleration, and has important application value in the fields of aerospace, guidance, navigation and automobiles. With the rise of the MEMS industry, accelerometers are gradually developing in the direction of miniaturization and integration. Because the accelerometer has the advantages of small size, light weight, low cost, low power consumption, and easy mass production, it has a wide range of military and civilian prospects. Among them, the capacitive accelerometer has the advantages of small temperature coefficient, good stability, high sensitivity, and can work in force balance mode through electrostatic restoring force. Capacitive accelerometers work by detecting changes in ca...

AI Technical Summary

Problems solved by technology

The problem with the structure of the traditional "sandwich" accelerometer is the cross-interference between the working mode and the adjacent mode, that is, the interference signal can easily make the accelerometer deviate from the working mode

The problem in the manufacturing process is that in order to obtain the beam located in the middle of the structural layer, it needs to be etched multiple times to different depths, the process is difficult and the consistency is poor

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