Symmetrical straight beam structure condenser type micro-acceleration sensor and manufacturing method thereof

Abstract

The invention relates to a capacitive micro-acceleration sensor with a symmetrical straight beam structure and a manufacturing method thereof. It is characterized in that the acceleration sensor is composed of a centrally symmetrical mass block, an external support frame, eight vertically symmetrical straight elastic beam structures connected to the mass block and the external support frame, and upper and lower cover plates. One end of each straight elastic beam is connected to the top or bottom side of the mass block parallel to the elastic beam, and the other end is connected to the inner side of the external support frame perpendicular to the elastic beam. The capacitive acceleration sensor with a symmetrical straight beam structure provided by the invention can significantly reduce the lateral effect and improve sensitivity at the same time. It is manufactured by a micro-electro-mechanical system process and is a high-performance micro-mechanical acceleration sensor.

Description

technical field [0001] The invention relates to a capacitive micro-acceleration sensor with a symmetrical straight beam structure and a manufacturing method thereof, belonging to the field of micro-electromechanical systems. Background technique [0002] Acceleration sensors manufactured using micromechanical technology have the advantages of small size, light weight, low cost, high reliability, mass production, and easy integration with electronic circuits, and can be widely used in many fields such as aviation, aerospace, automobiles, robots, and oil exploration. , has a huge market application prospect. At present, the micromachined acceleration sensor has become the mainstream development direction. According to the sensitive principle, micro-mechanical acceleration sensors can be divided into capacitive, piezoresistive, piezoelectric, electromagnetic, thermal convection and resonant. Compared with the piezoresistive or piezoelectric type, the capacitive acceleration s...

AI Technical Summary

Problems solved by technology

But usually the elastic beam of this structure is not in the same plane as the center of the sensitive mass block, which will cause a large lateral sensitivity, that is, the acceleration signal in the non-sensitive direction will also cause a large output, such as Kampen R.P.V., Wolffenbuttel R.F., Modeling the mechanical behavior of bulk-micromachined silicon ccelerometers, Sensors and Actuators, A64, 1998, 137-150. In order to reduce the lateral effect, the two silicon wafers were etched on one side of the quality block pattern and then silicon-silicon bonded. Erosion forms an intermediate mass with elastic beams on both sides, such as Henrion W.S., et.al, Sensors structure with L-shaped spring legs, US Patent No. 5,652,384, because its elastic beam is an L-shaped beam, the first order mode is Detection mode, the frequency of the second and third modes is about 3-4 times of the frequency of the first mode, which cannot significantly reduce the cross-axis sensitivity of the device

Images