微静电陀螺仪的结构设计与工艺实现

Design and Fabrication of an Electrostatically Suspended Micromachined Gyroscope

为了探索微机械陀螺突破精度极限的新途径,设计了一种基于环形转子、体硅加工工艺、转子5自由度悬浮的硅微静电陀螺仪.采用玻璃-硅-玻璃键合的三明治式微陀螺结构,提出了包括双边光刻、反应离子刻蚀(RIE)、电感耦合等离子体(ICP)刻蚀、玻-硅静电键合、硅片减薄、多层金属溅射等关键工艺的加工路线.在工艺设计中采用铝牺牲层对转子进行约束,在第2次玻-硅键合后再通过湿法去除牺牲层,以得到可自由活动的转子.基于提出的体硅工艺路线,成功加工出了微陀螺敏感结构,并完成了转子5自由度悬浮和加转实验,测试结果表明大气环境下转子转速可达73.3 r/min.

In order to explore new inertial sensors aiming at higher precision than the current micromechanical gyroscopes,a bulk micromachining based electrostatically suspended gyroscope was designed with a ring-shaped rotor levitated stably in five degrees of freedom（DOFs）.The proposed device was based mainly on glass-silicon-glass triple stack structure and silicon micromachining technology.The fabrication process of the gyroscope including bilateral photolithography,reactive ion etching（RIE）,inductively coupled plasma（ICP）,Si substrate etching,anodic bonding and metal sputtering was presented in the paper.Al-sacrificial-layer was introduced to restrict the motion of the rotor during the second bonding,and then removed by wet etching at the end of the process to let the rotor move freely.The experimental results with the prototype device show that the rotor can be suspended stably in five DOFs,and the speed of the rotor can be maintained at 73.3 r/min in atmospheric environment.