Preparation method of low-stress acceleration meter

Abstract

The invention relates to a preparation method of a low-stress acceleration meter. The low-stress acceleration meter comprises a substrate layer (13), an electrode structure layer (1), a movable structure layer (14) and a cap layer (18). The preparation method comprises the following steps: 1, manufacturing of the substrate(13), a floating electrode flexible shallow cavity (2), substrate layer anchor points (15) and anti-adhesion bumps (12) are formed on a double polishing silicon wafer through photoetching and etching; 2 bonding of an SOI silicon wafer and the substrate layer (13), a shallow cavity (11), center anchor points (5), anti-adhesion bumps (8) and a suspension electrode (4) are formed through photoetching and etching; 3, bonding of the SOI silicon wafer and an electrode structure, a movable structure (10) and movable layer anchor points (22) are formed through photoetching and etching.; and 4 packaging of a cap (8). Advantages of the preparation method are that influence of thermal stress on the electrode structure can be greatly reduced so that consistency and repetition of the fixed support suspension electrode structure can be guaranteed, the processing technology is relatively simple and the preparation method is suitable for mass production.

Description

technical field [0001] The invention belongs to the technical field of micro-mechanical electronics, in particular to a method for preparing a low-stress accelerometer. Background technique [0002] Micromachined accelerometer is a kind of mechanical quantity sensor made based on microelectromechanical system processing technology, which can be used to measure inertial parameters such as inertial force, tilt angle, vibration and impact. The capacitive accelerometer made by micro-machining technology has unique advantages in measurement accuracy, temperature characteristics, closed-loop measurement and self-inspection using electrostatic force, and easy integration with electronic circuits. It has been used in transportation, industrial control, and inertial navigation. , medicine, instrument testing, military and many other fields have been widely used. [0003] The microstructure of a capacitive MEMS accelerometer usually includes a sensitive structure as well as an electr...

AI Technical Summary

Problems solved by technology

As a force sensitive device, the thermal stress caused by the change of ambient temperature will cause the deformation of the sensitive structure or fixed electrode, which will cause the zero output drift of the accelerometer, reduce the full temperature performance of the sensor, and reduce the overall accuracy of the sensor.

[0004] At present, a related technical solution reduces the thermal stress of the chip caused by the change of ambient temperature by reducing the contact area between the bottom of the shell and the chip. The consistency and reliability of the area in the process of processing is poor

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