一种基于FIB刻蚀的MEMS陀螺修调方法

A trimming method for MEMS gyroscopes by focused ion beam etching

受微加工工艺条件限制,MEMS传感器的结构尺寸等参数总是偏离设计值,使其性能水平难以满足高精度应用的要求。为了抑制一种MEMS陀螺敏感结构的加工误差,分析了其主要运动模态的特性以及耦合误差的主要来源,提出了通过FIB刻蚀手段对陀螺十字型梁结构进行修调的方法,并对修调前后陀螺的耦合误差以及误差的温度稳定性进行了分析比较。对陀螺性能的测试结果表明,两种FIB刻蚀方式分别使陀螺零偏误差比修调前降低约35%和72%,而误差的温度稳定性则分别提高了80%和55%,证明修调方法能够抑制陀螺误差、提升陀螺的性能。

Due to deficiency in micro-machining processes, the structural parameters of MEMS sensors are usually deviated from their designed values and failed to meet the requirement of high-precision applications. In order to suppress the fabrication errors of MEMS gyroscopes, their primary modes of motions and the sources of coupling errors were analyzed. A trimming method by FIB etching on gyro's folded-beams was also developed. Moreover, the performance tests of gyroscopes before and after trimming were conducted. Test results show that the zero-rate outputs were reduced by 35% and 72%, while the bias' stability over temperature were increased by 80% and 55% respectively, after trimmed by two FIB etching strategies, which confirm the effectiveness of FIB trimming in suppressing the errors and improving the performance of gyroscopes.