一种基于扫描探针的微纳结构原位在线读写方法

基于扫描探针的弯月形液滴限制电化学沉积方法(Meniscus confined electrochemical deposition,MCED)能够在微纳尺度进行结构制造和表面修饰,近年来受到了众多研究者的广泛关注.然而,在三维微纳结构制造("写")过程中,无法在线原位检测("读")加工结构形貌,导致其应用受到一定的限制.本研究对比分析了 MCED微纳制造方法和扫描电化学池显微镜检测方法(Scanning electrochemical cell microscopy,SECCM)在系统物理配置和原理上的异同;提出SECCM交流调制模式对采用MCED方法制造的微纳结构进行在线原位成像,通过对比SECCM直流和交流模式的检测结果,发现交流模式能够有效克服直流模式对样本表面造成损伤的缺点,且抗干扰能力明显提高,成像图像的MSE降低了 27.85％.对比扫描电子显微镜成像结果,验证了交流扫描模式能够较好的对样本进行在线原位成像,增加了 MCED试验操作的在线可观测性和操作的准确性.因此,该方法使得在线MCED微纳操作可视、续接、定点修饰等功能成为可能,对扩宽MCED在微纳领域的应用具有重要意义.     

空间超大幅宽低畸变红外成像扫描控制

本文以空间超大幅宽低畸变红外变焦扫描成像系统为研究对象,分析给出地面畸变与成像系统瞬时视场角的关系,提出变速扫描成像并推导了扫描角速度公式。为解决匀速360°旋转扫描效率低和双向摆动扫描成像需安装扫描线矫正器所导致的系统复杂性高、可靠性低的缺点,设计了一种正弦加速度快速回扫的方法。对变速扫描以及正弦加速度快速回扫方法进行了仿真及实验,结果表明扫描控制系统慢速扫描与快速回扫之间状态切换稳定,扫描起止角度误差仅为1.44角秒,扫描速度稳定度为±0.5%,扫描成像过程时间误差为83μs,回扫时间误差为250μs,整个扫描周期时间偏差小于1倍像元积分时间(355μs),扫描效率达86%,在提高了扫描效率的同时减小对扫描机构的冲击与振动,满足成像要求。正弦加速度快速回扫方法对机载红外扫描成像系统快速回扫运动设计也具有一定指导意义。     

步进扫描光刻机硅片台连续扫描时间优化算法

为减少步进扫描光刻机连续曝光扫描运动的扫描过渡时间(扫描时间和步进时间),将硅片台扫描方向曝光扫描运动分解为逻辑步进运动和逻辑扫描运动,提出扫描和步进运动时间重叠的轨迹规划算法(时间重叠算法)处理连续曝光扫描运动。在不破坏运动约束条件下(恒速运动要求以及速度、加速度边界限制),根据时间重叠算法重新计算并推导不同扫描运动路径下连续扫描运动过程的步进和扫描运动转折点。经理论分析和硅片曝光场连续曝光实例计算表明：基于时间重叠算法的轨迹规划可获得时间优化的硅片台连续曝光扫描,比传统扫描方法减少曝光扫描运动过程中的无效率时间,提高步进扫描光刻机生产率,为步进扫描光刻机工程实践提供理论基础。     

SLS快速成形扫描动态轨迹误差的仿真

对SLS快速成形系统XY直线导轨高速扫描进给的动态轨迹误差进行研究 ,分析产生误差的原因 ,基于MATLAB的仿真计算方法 ,给出激光扫描运动在不同进给速度下的动态轨迹误差的仿真建模和计算方法。仿真结果表明 ,SLS快速成形XY直线导轨扫描的动态轨迹误差所引起的工件成形误差是不可忽略的因素     

基于连续扫描方式的激光共焦扫描显微镜的研制

研发了一套基于连续扫描的激光共焦扫描显微镜(laser confocal scanning microscopy,LCSM)系统。该系统采用工作台连续运动方式实现扫描,提出了利用单次采集的数据滤除随机噪声的方法,避免了多帧取平均对成像速度造成的影响。实现连续扫描的关键在于解决工作台运动与数据采集的同步问题,利用采集卡有限采集模式,合理匹配工作台参数和采集参数,成功解决了这一问题。详细介绍了影响分辨率的因素,通过合理选取探测器针孔直径,取样间隔,确保了实现高分辨率的要求。系统利用Visual C#开发的控制平台,成功地对生物细胞进行了扫描成像。实验结果表明:基于连续扫描的LCSM具有较高的分辨率,生成的显微图像没有任何畸变,并且成像速度有了大幅度提高。     

光刻机多项式扫描运动轨迹规划算法

针对于步进扫描投影光刻机提出了一种多项式扫描运动轨迹规划算法。为实现工程中特定的应用场景,在三阶扫描轨迹算法的基础上设计出多项式扫描运动轨迹规划算法。多项式扫描运动轨迹速度曲线段采用贝塞尔曲线原理实现。根据给定的动力学约束,以保证最大加速度与最大速度不超限且多项式运动轨迹加、减速段与速度曲线段位移、速度衔接要求,建立多项式扫描运动轨迹规划的约束基准。依据该基准,推导出多项式扫描运动加、减速段轨迹拐点公式。由三阶步进运动辅助完成轨迹位移衔接。最后仿真实验证明了该算法的可行性与合理性。     

光刻机步进扫描运动轨迹重叠规划算法

研究一种步进扫描投影光刻机的步进运动与扫描运动的轨迹重叠规划算法。根据给定的系统动力学约束,以保证最大加速度与最大速度不超限为目标,建立步进运动与扫描运动轨迹重叠规划的约束基准。依据该基准,分析步进运动与扫描运动轨迹重叠规划的各种可能情形,推导在最大程度上缩短运动执行时间的轨迹拐点调整计算公式。以此为基础,提出步进运动与扫描运动的轨迹重叠规划算法。通过仿真计算验证算法的正确性与有效性。实际应用证明该算法能在保证运动精度基础上,极大地提高生产率。该算法已被100 nm步进扫描投影光刻机工作台超精密运动控制系统所采用。     

步进扫描光刻机扫描运动轨迹规划及误差控制

研究一种步进扫描投影光刻机工作台扫描运动超精密轨迹规划算法及误差控制策略。在分析三阶扫描运动与步进运动轨迹规划异同点的基础上,提出三阶扫描运动轨迹规划算法。针对扫描运动精确性与严格同步性要求,分析扫描运动轨迹规划误差补偿的几个关键问题。根据扫描运动轨迹算法离散实现存在的误差,结合内部整数积分策略,提出扫描运动轨迹规划加减速段与扫描速度稳定段运动距离的离散积分策略误差控制方法。此外,为克服切换时间圆整引起的扫描曝光匀速段位置误差,提出一种基于常速扫描运动段位置修正因子的误差补偿方法。以上方法共同实现光刻机工作台扫描运动轨迹规划精度控制。实例证明提出算法是有效和精确的。该算法成功应用于100nm步进扫描投影光刻机工作台的超精密运动控制系统中。     

一种基于最小二乘法的离散点螺旋线式拟合算法

针对数控加工中,小线段刀路轨迹数据量较大的问题,提出了一种利用阿基米德螺线拟合小线段轨迹（离散点）的算法,分析了阿基米德螺线参数与切矢、径矢夹角的关系,给出了拟合误差的计算方法。基于最小二乘原理,通过前寻、回溯离散点集,在满足精度要求的前提下,用较少段螺旋线拟合该离散点集。仿真结果表明,阿基米德螺线拟合离散点具有数据量小、拟合精度较高的优势。     

基于遗传算法的多主轴头加工空行程轨迹规划

针对多主轴头五轴机床加工时需手动规划空行程的问题,提出一种空行程轨迹自动规划方法。在机床运动学建模的基础上,针对刀位点轨迹和刀轴矢量,分别提出基于最短路径的刀位点轨迹规划和无碰撞刀轴矢量规划,将空行程规划问题转化为参数优化问题。为了简化碰撞检测,提出两级相交检测算法。通过加权系数法建立空行程规划的目标函数,并采用遗传算法求解,规划出一条无碰撞、运动时间最短、旋转轴角度变化量最小、末端轨迹最短的具有柔性的理想轨迹。在Vericut建立的仿真平台上,验证了该方法的可行性和有效性。所提方法具有拓展性,通过多次分解轨迹求取棱交点能够实现复杂工件的空行程规划。     

数字切片扫描技术浅析

详细阐述了现有4种数字切片扫描技术的原理及特点,并对比了优缺点。其中微物镜阵列扫描方案速度快,但实现复杂,成本高;线扫方案可以实现较快的速度,但对控制要求也较高,也容易出现扫描失败的问题;基于面阵传感器扫描的方案,实现较为简单,灵活性较好,可工作于连续运动和走停两种模式,连续运动模式可以提供与线扫接近的扫描速度,走停模式可以提高扫描成功率并获得更好的图像质量。     

航空摆扫相机转弯成像像移分析及补偿

为保证航空摆扫相机转弯成像过程中的成像质量,对其像移计算及补偿方法进行了研究。根据航空摆扫相机的成像原理,利用几何建模及速度矢量分解建立了转弯成像像移计算模型,给出了基于均值补偿的转弯前向像移补偿方法。转弯前向像移补偿分析表明:相机焦距为500 mm,曝光时间为0.01 s,速高比为0.02 rad/s,纵向视场角为10°,转弯角速度为0.5(°)/s时,最大前向像移补偿残差量为2.22μm;转弯角速度为1.5(°)/s时,最大前向像移补偿残差量为3.36μm。另外,转弯横向像移补偿分析表明:横向像移量随纵向视场角幅值的增加而增大,曝光时间为0.005 s,横向视场角为30(°),转弯角速度为1(°)/s时,横向像移量在纵向视场角为4.5°时达到3μm。转弯成像试飞实验结果表明:得到的图像像质优良,无几何形变,前向像移补偿良好,验证了本文提出的转弯成像像移补偿方法的正确性。     

Multi-objective optimal design of high frequency probe for scanning ion conductance microscopy

Scanning ion conductance microscopy(SICM) is an emerging non-destructive surface topography characterization apparatus with nanoscale resolution. However, the low regulating frequency of probe in most existing modulated current based SICM systems increases the system noise, and has difficulty in imaging sample surface with steep height changes. In order to enable SICM to have the capability of imaging surfaces with steep height changes, a novel probe that can be used in the modulated current based hopping mode is designed. The design relies on two piezoelectric ceramics with different travels to separate position adjustment and probe frequency regulation in the Z direction. To further improve the resonant frequency of the probe, the material and the key dimensions for each component of the probe are optimized based on the multi-objective optimization method and the finite element analysis. The optimal design has a resonant frequency of above 10 kHz. To validate the rationality of the designed probe, microstructured grating samples are imaged using the homebuilt modulated current based SICM system. The experimental results indicate that the designed high frequency probe can effectively reduce the spike noise by 26% in the average number of spike noise. The proposed design provides a feasible solution for improving the imaging quality of the existing SICM systems which normally use ordinary probes with relatively low regulating frequency.     

激光共焦高速扫描显微成像的高帧速重构算法

针对激光共焦扫描显微镜的往复式逐行扫描成像方式带来的帧图像数据分割难的问题,在分析系统扫描方式、振镜的实际运动方式与理论运动方式差异的基础上,利用相邻两帧图像相似性大的特点,提出了一套完整的高帧速重构算法。该算法通过连续帧特征区域差分的方式实现了一维信号序列的自适应分割,即实现了对一维信号序列进行动态排列及分割成二维阵列图像数据,从而重构出多帧高精度图像。实验表明,该算法的成像误差低于1.6%,适用于成像速度高达300帧/s的激光共焦扫描显微成像。     

Analysis and comparison of laser cutting performance of solar float glass with different scanning modes

Cutting quality and efficiency have always been important indicators of glass laser cutting. Laser scanning modes have two kinds, namely, the spiral and concentric circle scanning modes. These modes can achieve high-performance hole cutting of thick solar float glass using a 532-nm nanosecond laser. The mechanism of the glass laser cutting under these two different scanning modes has been described. Several experiments are conducted to explore the effect of machining parameters on cutting efficiency and quality under these two scanning modes. Results indicate that compared with the spiral scanning mode, the minimum area of edge chipping (218340 µm²) and the minimum Ra (3.01 µm) in the concentric circle scanning mode are reduced by 9.4% and 16.4% respectively. Moreover, the best cutting efficiency scanning mode is 14.2% faster than that in the spiral scanning mode. The best parameter combination for the concentric circle scanning mode is as follows: Scanning speed: 2200 mm/s, number of inner circles: 6, and circle spacing: 0.05 mm. This parameter combination reduces the chipping area and sidewall surface roughness by 8.8% and 9.6% respectively at the same cutting efficiency compared with the best spiral processing parameters. The range of glass processing that can be achieved in the concentric circle scanning mode is wider than that in the spiral counterpart. The analyses of surface topography, white spots, microstructures, and sidewall surface element composition are also performed. The study concluded that the concentric circle scanning mode shows evident advantages in the performance of solar float glass hole cutting.     

Note: A novel atomic force microscope fast imaging approach: variable-speed scanning

Imaging speed is one of the key factors limiting atomic force microscope's (AFM) wide applications. To improve its performance, a variable-speed scanning (VSS) method is designed in this note for an AFM. Specifically, in the VSS mode, the scanning speed is tuned online according to the feedback information to properly distribute imaging time along sample surface. Furthermore, some practical mechanism is proposed to determine the best time of moving the AFM tip to the next scanned point. The contrast experiment results show that the VSS method speeds up the imaging rate while ensuring image quality.     

Fast scanning mode and its realization in a scanning acoustic microscope

The scanning speed of the two-dimensional stage dominates the efficiency of mechanical scanning measurement systems. This paper focused on a detailed scanning time analysis of conventional raster and spiral scan modes and then proposed two fast alternative scanning modes. Performed on a self-developed scanning acoustic microscope (SAM), the measured images obtained by using the conventional scan mode and fast scan modes are compared. The total scanning time is reduced by 29% of the two proposed fast scan modes. It will offer a better solution for high speed scanning without sacrificing the system stability, and will not introduce additional difficulties to the configuration of scanning measurement systems. They can be easily applied to the mechanical scanning measuring systems with different driving actuators such as piezoelectric, linear motor, dc motor, and so on. The proposed fast raster and square spiral scan modes are realized in SAM, but not specially designed for it. Therefore, they have universal adaptability and can be applied to other scanning measurement systems with two-dimensional mechanical scanning stages, such as atomic force microscope or scanning tunneling microscope.     

基于电流偏差补偿模型的SICM自适应控制

扫描离子电导显微镜(SICM)能够在非接触条件下获取样品表面纳米级形貌特性信息,可以在生理液态环境下实现对活体细胞等柔软样品无损成像。但是通过前期大量实验结果,发现在使用连续扫描模式时SICM扫描图像存在"拖尾"现象,导致图像失真,并限制了扫描成像速度。针对这一问题,结合SICM成像原理进行分析,得出电流逼近曲线高度非线性是产生这一现象的主要原因,并提出一种基于电流偏差补偿模型的SICM自适应控制方法。主要思想是建立电流偏差补偿模型,利用上一行扫描高度数据作为先验知识预测当前扫描点位置,并输入补偿模型得到新的电流偏差作为系统被控量。最后分别用新旧控制算法对标准栅格扫描图像进行成像效果对比,实验结果验证了该算法在一定扫描速度范围内能够有效地解决"拖尾"现象,明显减小图像失真,为进一步提高SICM系统成像质量和成像速度提供了一种有效的技术方法。     

MRT Letter: An extended scanning probe microscopy system for macroscopic topography imaging

Enlightened by the principle of scanning probe microscopy or atomic force microscope (AFM), we proposed a novel surface topography imaging system based on the scanning of a piezoelectric unimorph cantilever. The height of sample surface can be obtained by recording the cantilever's strain using an ultra‐sensitive strain gauge and the Z‐axis movement is realized by electric bending of the cantilever. This system can be operated in the way similar to the contact mode in AFM, with the practical height detection resolution better than 100 nm. Imaging of the inner surface of a steel tube and on a transparent wing of a honey bee were conducted and the obtained results showed that this proposed system is a very promising solution for in situ topography mapping. Microsc. Res. Tech. 77:749–753, 2014. © 2014 Wiley Periodicals, Inc.     

非平衡宽覆盖像面扫描系统的神经网络控制

为扩大遥感仪器像面覆盖宽度,从现有的CCD拼接方法入手,提出了凸轮驱动的动态扫描拼接方法。将电机与凸轮同轴安装,两者做等速旋转运动,带动4片线阵TDI CCD在像面上做往复直线运动,相邻线阵CCD在扫描方向上的成像区域保持一定重叠率,从而实现了动态扫描拼接。分析了由凸轮结构的特殊性造成的系统负载力矩的非平衡特性进行了分析,针对采用常规稳速方法时,凸轮转速在负载变化阶段产生较强波动的情况,提出了常规稳速控制和神经网络相结合的自适应控制方法,并进行了实验分析。分析表明:作用于凸轮轴上的负载力矩与相机位角、凸轮转速成正比。与常规稳速方法相比,应用神经网络自适应控制方法后,系统稳速精度提高了41%,非平衡负载引起的速度波动降低了20%,满足工程需要。