硅基微半球陀螺的飞秒激光高精度调谐方法研究

Silicon-based micro-hemisphere resonator gyroscopes (SµHRGs) have outstanding advantages such as high precision, small size, low cost, and batch manufacturing. There are great application prospects for SµHRGs in advanced unmanned aerial vehicles (UAV), medium and short-range inertial guidance systems and other fields. SµHRGs are research hotspots for hemispherical gyros. The manufacturing error, material inhomogeneity, and package stress make the gyro unable to meet the design goals and require precise tuning. The technologies of mechanical trimming, electrostatic force attraction, and plasma etching cannot meet the needs of high-precision tuning of SµHRGs. For this reason, this project proposes an innovative idea for the precise tuning of SµHRGs: the femtosecond laser ablation method is adopted to remove the trace mass at a specific location on the SµHRGs (with accuracy better than 0.1μg), to detect the dynamic characteristics of SµHRGs by real-time precise detection and trimming. To make sure that the gyro frequency split is less than 0.1 Hz, and that the zero-bias stability is improved. In this project, with the aim of high-precision tuning of SµHRGs, a new SµHRGs will be designed and its fabricated process will be studied to produce a precision SµHR with the new adjusted-tooth structure firstly. Secondly, the accurate dynamic modeling of SµHRGs will be studied, to clarify the influence of micro-mass disturbance on the resonance characteristics of gyros. Thirdly, research on the interaction between femtosecond lasers and polysilicon will be carried out, to find out the mechanism of precision ablation (rapid melting and removal) of polysilicon film by femtosecond laser. Fourthly, research on femtosecond laser precision tuning method for SµHRGs will be carried out, to realize high-precision non-contact trimming of femtosecond laser for SµHRGs. The high-quality tuning of SµHRGs will be achieved by the femtosecond laser accurately fabrication, providing an innovative prototype for high-precision manufacturing of silicon-based micro-hemisphere gyroscopes of China.

硅基微半球陀螺具有精度高、尺寸小、成本低、可批量化制造等突出优点，在先进无人机、中短程惯性制导等领域有巨大应用前景。加工误差、材料不均匀性和封装应力等因素导致陀螺实际性能无法达到设计目标，而机械修调、静电力吸引和等离子刻蚀等方法均无法满足硅基微半球陀螺的高精度调谐需求。为此，本项目提出一种利用飞秒激光对陀螺进行精密质量调谐的创新思路：采用飞秒激光烧蚀去除硅基微半球陀螺上特定的微质量（精度优于0.1μg），对陀螺动力学特性进行实时精密检测、并反馈优化，使陀螺频率裂解小于0.1Hz，提高硅基微半球陀螺零偏稳定性。本项目以硅基微半球陀螺的高精度调谐为目标，将开展新型硅基微半球陀螺设计与工艺研究，制造调节齿型结构的精密硅基微半球谐振子；开展硅基微半球陀螺的微调谐机理研究，对硅基微半球陀螺进行精确的动力学建模，阐明微质量扰动对硅微陀螺性能的影响规律；开展飞秒激光精密烧蚀多晶硅薄膜机理研究，查明多晶硅薄膜在飞秒激光作用下的快速熔化与去除的精密加工机制；开展硅基微半球陀螺的飞秒激光精密调谐方法研究，实现硅基微半球陀螺的飞秒激光高精度非接触修调制造，为我国高硅基微半球陀螺的高精度制造提供创新技术原型。

硅基微半球陀螺具有精度高、尺寸小、成本低、可批量化制造等突出优点，在先进无人机、中短程惯性制导等领域有巨大应用前景。加工误差、材料不均匀性和封装应力等因素导致陀螺实际性能无法达到设计目标，需要进行精密调谐。为此，本项目研究了硅基微半球陀螺的飞秒激光精密调谐技术。设计了带调节齿的新型硅基微半球陀螺结构，提出台阶掩膜新工艺、防反溅刻蚀工艺、气体氟化氢释放防粘附工艺等新技术，批量化制造出硅基微半球陀螺。建立了硅基微半球陀螺振动的理论模型，从理论上阐明了质量和刚度对频率及其裂解值的影响，仿真分析了修形孔大小和位置对频率裂解的影响规律。提出了引导氮元素增加质量来精密调谐的新方法。开展飞秒激光烧蚀单晶硅和多晶硅薄膜工艺实验，实现了1.02pg的超精密加工精度，构建机器视觉、运动定位与激光加工集成的多功能集成装置，通过对光开关、光功率调节器、空间光调制器等元件的准确协同控制，实现了硅基微半球陀螺的飞秒激光高精度质量调谐，为我国高硅基微半球陀螺的高精度制造提供创新技术原型。