Horizontal axis micromechanical gyroscope and its preparation method

Abstract

The product comprises: an outer / inner frame, a drive electrode and a drive feedback electrode both with two group of lateral comb-tooth capacitors and movable electrodes connected to the outer frame, a drive-modal elastic beam, a detection electrode with two group of unequal vertical comb-tooth capacitors for difference detection with movable electrode connected to the inner frame, a detect-modal elastic beam as four group of combined torsion beams everyone with ends connected to former inner / outer frame respectively, and an anchor point fixed on substrate bottom and connected to the outer frame through the drive-modal beam. This invention is simple and fit to large-scale production, compatible to Z-axis gyro and accelerometer, and can be used for MIMU.

Description

technical field [0001] The invention relates to a capacitive micromechanical gyroscope and a preparation method thereof, in particular to a horizontal axis micromechanical gyroscope adopting vertical comb capacitance detection and a preparation method thereof. Background technique [0002] Micromachined gyroscopes are a class of inertial sensors that use the Coriolis force to measure the angular rate of rotation of an object. Due to the use of micro-electromechanical system (MEMS) technology, micro-mechanical gyroscopes have the advantages of small size, light weight, and low cost. They have very broad application prospects in inertial navigation, weapon guidance, automobiles, and consumer electronics. In order to obtain the complete information of the object's rotation, it is necessary to detect the angular velocity signals of three axes at the same time, which requires a three-axis gyroscope. A three-axis gyro can be realized by assembling three single-axis devices orthog...

AI Technical Summary

Problems solved by technology

A three-axis gyro can be realized by assembling three single-axis devices orthogonally, but the error during assembly makes it difficult for the three detection axes to be completely orthogonal, which limits the performance of the three-axis gyro and increases the processing cost.

For the X and Y axis gyroscopes that need to detect out-of-plane motion in the Z direction, it is difficult to realize variable area sensitive capacitors due to the limitations of MEMS technology. Existing solutions mostly use variable gap parallel plate capacitors, such as W. Geiger in Germany, etc. Human-designed gyro structure (Sensors & Actuators A, 95)

Since the sensitivity of the variable-gap plate capacitor is inversely proportional to the gap, in order to ensure high sensitivity, the gap between the plate electrodes should not be too large, which will cause a large air damping, and must work in a low-voltage or vacuum environment, and this type of capacitor Difficult to implement differential detection

Huikai Xie and others in the United States have designed a gyro structure (Sensors and Actuatorsa-Physical) that uses vertical comb capacitance for detection. This gyroscope is implemented in a CMOS MEMS process, but its sensitive capacitance depends on the interaction of the CMOS process. The number of layers and thickness of the wiring makes it difficult to obtain a large sensitive capacitance, and there is a large stress in the process, which limits the performance of the device

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