一种MEMS陀螺仪的飞秒激光修调方法

Trimming method for MEMS gyroscope by femtosecond laser

受微加工工艺条件限制,MEMS敏感结构的尺寸等关键参数的相对误差较大,使其在宏观上表现出非理想的运动特性,性能指标也难以满足高精度应用的要求。为消除加工误差的影响,分析了一种MEMS陀螺仪的运动特性和误差耦合机理,提出了一种通过飞秒激光对敏感结构的梁进行刻蚀修调的方法。MEMS陀螺修调前后的运动特性试验表明,修调后的误差系数比修调前降低了50%以上,而误差的稳定性则比修调前提高了约70%,证明提出的飞秒激光刻蚀方法能够抑制微加工误差的影响,提高MEMS陀螺仪的性能。

The micro-fabricated MEMS gyroscopes usually do not meet the high-precision application requirements due to the precision limits in micro-fabrication processes. In order to eliminate the fabrication defects, the motion modes and the error coupling mechanisms of the sensing element of a MEMS gyroscope are studied and analyzed, and a trimming method by femto-second laser etching on folded-beam structures is proposed to realize the high-quality etching process. The fabrication system is built based on the femtosecond laser, which integrates a series of units and their control system. Dynamic test results show that, after etched by laser pulses, the coupling error coefficient is reduced by more than 50%, and the error＇s stability is improved by nearly 70%, which prove the feasibility and effectiveness of the proposed trimming method in suppressing the fabrication errors and improving the gyroscope＇s performance.