Low stress accelerometer

Abstract

The invention relates to a low stress accelerometer, including: a. a substrate (13) in which shallow cavities (2) and a substrate anchor point (5) are arranged; b. a central anchor point (16) arranged in a middle part of an electrode structure layer (1), two sides of the central anchor point (16) being symmetrically provided with at least one suspension electrode (4), the suspension electrodes (4) being correspondingly matched with the shallow cavities (2) below, and upper surfaces of the suspension electrodes (4) are provided with upward movable gaps (11); c. a movable structure layer (15) and a movable structure (10) arranged therein, a middle part of the movable structure layer being provided with an upper layer anchor point (18) which is in bonding connection with the central anchor point (16); and d. a cap (14). The low stress accelerometer provided by the invention has the advantages that influence of thermal stress on electrode structures is substantially reduced, so that deformation of the electrode structures hardly occurs in a full-temperature range, thereby ensuring symmetry of capacitance after left and right sides of the device in the full-temperature range, and improving full-temperature performance of a sensor.

Description

technical field [0001] The invention belongs to the technical field of micro-mechanical electronics, in particular to a low-stress accelerometer. Background technique [0002] The development of MEMS has greatly promoted the progress of sensor technology and realized the miniaturization of acceleration sensors. There are various forms such as capacitive, piezoelectric, piezoresistive, thermal convection, tunnel current and resonance. Capacitive accelerometers manufactured by micromachining technology have unique advantages in measurement accuracy, temperature characteristics, closed-loop measurement and self-inspection using electrostatic force, and easy integration with electronic circuits. They can be widely used in aerospace, oil exploration, Seismic monitoring, medical equipment and many other fields have broad market application scenarios. [0003] The microstructure of a capacitive MEMS accelerometer usually includes a sensitive structure as well as an electrode stru...

AI Technical Summary

Problems solved by technology

[0005] The present invention aims to solve the problem of the influence of thermal stress on device performance caused by temperature changes in the existing Z-axis capacitive MEMS accelerometer, and provides an accelerometer that can reduce the influence of thermal stress on the device, using MEMS bulk silicon technology, processing The process is simple, the reliability and consistency of the product are good, and batch manufacturing can be realized

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