具有双重电机的高加速高精度光刻微动台的驱动技术研究

扫描式光刻机是集成电路装备中技术难度最高、价格最昂贵的关键设备。光刻机的套刻和产率等性能指标是由其最核心的具有粗微动结构的掩模台和工件台进行高加速高精度同步运动来保证的，而其微动台的驱动模式及控制技术是实现高加速和纳米级精度的关键。提高微动台加速度面临着现有电机无法提供如此大推力和发热等难题。为此本项目提出一种新的双重电机驱动模式来满足光刻微动台同时高加速度和高精度的需求。首先研制一种高性能磁阻式直线电机，使其具有小体积、小电流并产生大推力的特点。采用该电机作为加速度前馈控制驱动机构为微动台提供高加速段所需大推力，同时采用音圈电机作为反馈控制驱动机构来保证匀速段和定位精度，结合两种电机的优势，构成一种新型双通道双驱动机构的伺服控制系统。最后搭建实验台对所提方法进行验证和优化，为下一代光刻微动台的高加速度和高精度需求提供技术支撑，也可为相关精密机床及军工设备提供微驱动所需电机与技术。

Lithography is the critical driver for state-of-the-art integrated circuit(IC) manufacturing, and is also the most expensive key equipment. Because of exposure is done during quick synchronous scanning between reticle stage and wafer stage, both high acceleration and nanometer level precision is required. Usually, reticle and wafer stage use coarse and fine two layer structure to achieve high acceleration and high precision. The coarse stage moves in long stroke with high acceleration to realizes micrometer level positioning precision, and fine stage moves in a short stroke to realize nanometer- level positioning precision. Therefore, the fine stage is playing the key role in lithography . .In order to achieve high acceleration and nano-positioning precision, the fine stage must be very light, and have a high stiffness for high bandwidth control performance. Voice coil motor (VCM) is widely used as driving actuator for fine stage due to the small size, low disturbance and high response frequency characteristic. But the drawback is the low efficiency and high power dissipation. With lithography emerging as the central technology for 22 nm nodes and beyond, the accuracy and throughput requirements demanded from next generation lithography is exacting, which means the more higher acceleration and precision of fine stage are needed. If VCM is still used to achieve greater force, its size will become very large and the heat dissipation problem will be very difficult to solve. Therefore, the VCM is no longer the best choice as main driving actuator of fine stage. Thus to study the drive and control method for fine stage with high acceleration and high precision for next generation lithography is very challenging. .This project presents a new double motor-driven mode for fine stage to meet requirements of high acceleration and high precision. First, a high performance reluctance magnetic type linear motor will be developed, that has the unique characteristics of small volume, low current producing greater force. Then, a new dual-path servo control system with double driving motors is presented for fine stage, where taking reluctance motor as driving actuator in feedforward control path to provide high force required in stage acceleration procedure, the common VCM as driving actuator in feedback control path to guarantee scanning and positioning accuracy. The proposed method combined with the advantages of the two kind of motors and given a new driving mode for fine stage. Finally, a prototype stage with coarse and fine structure will be constructed for the purpose of validation and optimization the effectiveness of developed reluctance motor and proposed driving mode. .The study of this project will provide a technical solution for driving fine stage in next generation lithography, and the developed motor and driving control technology can be applied in other precision machine tools and related military equipment with same requirement.