微纳电子技术

为了减小正交误差对硅MEMS陀螺仪性能的影响,进一步提高陀螺精度和工程化成品率,对MEMS陀螺正交耦合的影响因素进行了研究。通过MEMS陀螺的运动学简化模型,分析了正交耦合的起因;计算了MEMS陀螺的静电驱动力和阻尼系数,建立了MEMS陀螺有限元参数化模型,利用谐波分析模拟了陀螺在驱动模态下的运动状态;在谐波分析的基础上,研究了不同误差来源对正交耦合的影响。结果表明:侧壁垂直度误差不是正交耦合的起因;科氏质量重心偏移对正交耦合的影响很小,即使在误差敏感方向上,正交耦合系数的敏感度也只有0.003 2%/μm;振动结构支撑梁的加工误差是引起结构刚度不对称并产生正交耦合的主要因素,其中正交耦合系数对梁宽误差的敏感度可达2.15%/μm(梁宽误差为±0.1μm),对梁倾斜误差的敏感度高达16%/(°)(梁角度误差为±0.05°)。

In order to reduce the influence of the orthogonal error on the performance of silicon MEMS gyroscope and improve the gyroscope accuracy and engineering yield rate,the influence factors of the orthogonal coupling of the MEMS gyroscope were studied. The cause of the ortho-gonal coupling was analyzed using a MEMS gyroscope simplified kinematic model. Through calculating the electrostatic driving force and damping coefficient of the MEMS gyroscope,the MEMS gyroscope finite element parametric model was established,and the motion state of the gyroscope in the driving mode was simulated with the harmonic analysis. On the basis of the harmonic analysis,the influences of different error sources on the orthogonal coupling were studied. The results show that the perpendicularity error of side walls has a negligible effect on the orthogonal coupling. The Coriolis mass gravity center shift has a little influence on the orthogonal coupling,and the sensitivity of the orthogonal coupling coefficient is only 0. 003 2%/μm even in the error sensitive direction. The machining error of the vibration structural support beam is the main factor resulting in the asymmetry of the structural stiffness and orthogonal coupling. The sensitivities of the orthogonal coupling coefficient to the width error and obliquity error of beam reach 2. 15%/μm(beam width error of ± 0. 1 μm) and 16%/(°)(beam angle error of ± 0. 05°),respectively.