【作者】 邓习树；

【导师】 吴运新；

【作者基本信息】 中南大学 ， 机械设计及理论， 2007， 博士

【摘要】 步进扫描光刻机在工作过程中,由于工件台和掩模台等分系统具有较高的运动加速度,其运动产生的惯性力将引起光刻机工作核心部分(工作平台)的振动,进而影响曝光的质量。在曝光过程中如何保证工作平台的相对稳定是一个非常关键的技术问题,为了保证光刻机在工作过程中具有极高的光刻精度,运动部分产生的振动必须与内部世界进行隔离,步进扫描光刻机采用了振动隔离和主动减振技术。本课题受国家自然科学基金委重大项目课题(编号:50390064)及其上海市科委联合资助项目《精密机械减振隔振技术研究》支持,以半导体工业应用中的步进扫描光刻机精密隔振系统为研究对象,主要进行了以下几个方面研究:(1)设计了一种能够完全再现步进扫描光刻机运动的模拟隔振试验平台,首次在国内对步进扫描光刻机的主动精密减振系统进行了研究。平台分为内部世界和外部世界两大部分,两者之间采用能够6自由度减振的主动压电式精密减振系统相连接;工件台定位系统采用H型精密滚珠丝杠平台结构,掩模台定位系统采用精密直线电机定位平台;工件台和掩模台与外界驱动电机之间采用的是气浮轴承结构,工件台、掩模台底部采用真空气垫。该结构认为真空气垫和其底部支撑平台的摩擦力为零,也能部分隔离运动系统产生的振动传递到内部世界。(2)运用虚拟样机技术研究了试验平台主动减振系统的结构参数,给出了步进扫描光刻机减振系统设计的基本原则及注意事项。建立了步进扫描光刻机模拟隔振试验平台的ADAMS多体动力学仿真模型,对减振系统主要结构参数进行了选择。分析了减振系统主要参数变化对内部世界工作平台的动态特性影响,提出了相关的解决办法;研究了系统不同支撑点数量(3点或4点)以及减振器非线性刚度和阻尼对试验平台内部世界动态特性的影响。(3)研究了确定步进扫描光刻机主动减振系统固有特性的方法。建立了步进扫描光刻机模拟试验平台内部世界的坐标系系统,根据此坐标系系统建立了内部世界的6自由度动力学模型,计算了系统固有频率和振型向量,理论计算结果、有限元计算结果、试验模态参数识别结果比较吻合,证明了建立主动减振系统动力学模型的正确性。(4)提出了步进扫描光刻机模拟隔振试验平台减振系统6自由度主动减振的主动控制方法,并进行了仿真研究。分析了6自由度减振协同控制策略,建立了ADAMS和MATLAB联合仿真模型,分别对减振器彼此独立以及相互协作两种减振控制方式进行了研究,结果表明,采用后者可以得到更好的减振控制效果。进行独立控制和协同控制研究时,分别采用了普通PID控制和不完全微分PID控制两种方法进行了比较,结果证明,采用后者可以得到更好的控制效果。(5)分析了引起光刻机内部世界振动的主要因素以及传播途径,并试验研究了主动减振系统对外界环境微振动的适应能力。内部因素主要是由于工件台、掩模台高速运动而引起的振动,通过真空气垫及基座传到内部世界;外部因素主要包括大地脉动性振动如地震、人员走动、说话、空调运行、建筑物外面车辆行驶及空气压力波动所产生的干扰等,其主要振动频率范围为1-100Hz,振幅为5μm以下,通过地面或者空气传播到内部世界。试验研究了环境噪声对步进扫描光刻机模拟隔振试验平台内部世界微振动的影响,验证了减振系统对外界环境微振动具有一定的适应能力。(6)搭建了步进扫描光刻机模拟隔振试验平台的物理平台,对减振系统的静动态减振性能进行了试验研究。对设计的地基隔振效果以及主动减振平台的减振效果进行了试验研究,结果表明减振要求达到设计指标;测试了工件台定位系统运动、掩模台定位系统运动及整个系统运动时步进扫描光刻机内部世界的振动情况,结果表明,试验平台减振效果满足设计要求。对步进扫描光刻机精密隔振系统的研究,国外仅有少量报道,国内尚无相关研究报道。本论文的研究内容、方法及结论,对步进扫描光刻机精密隔振系统的分析、设计具有一定的指导意义。更多还原

【Abstract】 The vibration of the work stage of the stepping and scanning lithography caused by the high acceleration of the exposure chuck and the reticle chuck will significantly affect the exposure quality. It is a key technology problem to enhance the relative stability of the chucks. In order to keep super precision of the lithography, the exposure parts must be isolated from the vibration caused by moving parts, which demanded vibration isolation and the active vibration reduction technology.This research work is sponsered by the project "Research on Vibration-Reduction and Vibration-Isolation Technology for Precision Machine" (granted number: 50390064) of the National Natural Science Foundation of China and Shanghai Committee of Science and Technology. Aimed at the precision vibration-isolation system of stepping and scanning lithography in the semiconductor industry application, the following several aspects have chiefly been carried on:(1)Precision active reduction vibration for the Lithography has been researched in China for the first time. The simulated vibration-isolation device is designed which can completely realize the given motion of the lithography. The H model precision ball-screw stages are applied as the positioning systems for the wafer stage and the linear motor stage is used as the positioning for the stencil stage. The active piezo-ceramic vibration-reduction system which can reduce vibration at 6 degrees is applied as the vibration system of the inner world form the outsides world of the simulated device. The air-bearing structures are used as the link between the driving systems and the wafer stage and the stencil stage. The bottoms of the wafer stage and the stencil stage are used vacuum air cushion. The friction between the bottoms and the supported stage can be avoided and vibration of the inner world from the motion systems partly can be reduced ,too.(2)Virtual model technology is applied to research structure parameters of the reduction vibration system for the testing table and principles and noticed proceedings are gived during the desgn of the reduction vibration system for lithography. The ADAMS multi-body dynamic model for the simulated vibration-isolation testing device of the stepping and scanning lithography is established to carry on optimized design and choice for the main structure parameters of the active vibration reduction system. Based on the model, the article analyses the dynamic performance affection of the working stage of the inner world when the main parameters of the vibration -reduction system are varied and some advice in allusion to the simulation results are put up to reform the dynamic performance of the inner world. At the same time, how to affect the dynamic performance of the inner world when other conditions are changed such as the difference for the quantity of the supporting points (3 points or 4 points), the nonlinear stiffness and damping for the vibration isolators.(3)Methods about confirmation for nature features of the active reduction vibration for lithography are research. The reference frame system of the inner world for the simulated vibration-isolation device is established and the six-degree dynamic model of the inner world is set up based on the reference frame system. According to the given parameters of the vibration isolators, the nature frequencies and the vibration model vectors are calculated. The results are very close to the results which are calculated by ANSYS software and results which are recongnized by experiment model parameter identifition method. The validity of the established mathematic model is proved.(4)The active control methods including single PID control and unioning PID control of the six-degree active vibration-reduction system for the simulated testing device are discussed and the associated simulation model using ADAMS software and MATLAB software is established. According to the model, the control methods of the PID controller and the uncompleted PID controller are researched and the results indicate that this method can improve the dynamic performance of the inner world and reduce the vibration from the outsides world effectively. Simlation results proves that the unioning PID control own better control effection than single PID control.(5)The key factors caused the vibration of the inner world and the transfer paths are analyzed amply and the testing research about the micro-vibration affection of the inner world caused by environment noise are carried on. The outside vibration frequency range is between 1Hz and 100Hz and the vibration magnitude is below 5um. Testing results that the designed system owns acceptable adaptation to enviroment vibration.(6)The testing stage for the simulated vibration-isolation testing device of the stepping and scanning lithography is put up and some experiments are completed. The results indicate that the vibration reduction parameters of the working stage for the inner world can meet the requirement of the designed targets.Research on precision vibration isolation system of Stepping and Scanning Lithography has a little relative report in overseas and no report in China. The research contexts, methods and results are both practical value and academic value to the analysis and design of the precision vibration-isolation for Stepping and Scanning lithography.更多还原