A kind of preparation method of low stress accelerometer

Abstract

The invention relates to a method for preparing an accelerometer, comprising a substrate layer (13), an electrode structure layer (1), a movable structure layer (14) and a cap layer (18), comprising the following steps: 1, a substrate (13) The production of floating electrode active shallow cavity (2), anchor point of substrate layer (15), anti-adhesion bump (12) is formed in double-thrown silicon wafer photolithography and etching; 2, SOI silicon wafer and substrate layer (13) Bonding, photolithography and etching to form a shallow cavity (11), a central anchor point (5), an anti-adhesion bump (8), and a floating electrode (4); 3. Bond the SOI silicon wafer to the electrode structure layer, and After photolithography and etching, a movable structure (10) and an anchor point (22) of the movable layer are formed; 4. A cap (8) is encapsulated. The invention has the advantages that: the influence of thermal stress on the electrode structure is greatly reduced, the consistency and repeatability of the fixed-supported and suspended electrode structure are guaranteed, the processing technology is relatively simple, and it 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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