一种Sawyer马达驱动二维运动平台测量和控制系统设计

介绍一种使用Sawyer马达驱动的平台和表面编码器组成的精密定位系统．该平台包括一个台板和若干线性脉冲马达推动器．台板由防腐钢板制成，在其表面加工了齿牙．线性脉冲马达推动器靠空气支承悬浮在台板上，用以驱动平台．每一驱动器均由一个永久磁铁和两个驱动线圈组成，用以产生X向和Y向的平台驱动力．设计了一种表面编码器用以测量和控制平台的运动．一个正弦格栅装在台板上，一个传感组件装在平台驱动器上．在该传感组件中有三个光学传感器，用以测量三个分离点上的X和Y方向的位置，平台的θz向位置可以从传感器输出求得．开发了一种反馈控制系统用以控制平台运动．测量和反馈控制实验证明了该精密系统的可行性．     

基于激光测距的管壳件圆柱度测量系统

本文设计并实现了一种基于激光位移传感器的管壳类零件圆柱度误差的非接触测量系统.利用电动旋转台带动激光位移传感器在圆柱件内部旋转一圈,即可获得该测量截面的轮廓信息,调整传感器的上下高度即可获得零件多个截面轮廓信息.将测量得到的多个截面数据点投影到XOY平面,根据圆柱度的定义,使用粒子群优化算法,拟合得到包括所有测量截面数...     

基于Visual Basic的磁灵敏度三维球坐标图像模拟算法的研究与实现

在新的国际标准ISO/16063-33"振动与冲击传感器磁灵感度测试方法"中,要求传感器多平面固定,测试磁场360°旋转,自动测试装置记录并绘制磁灵敏度的三维成像图形。本文研究探讨了基于Visual Basic在二维平面坐标系中对三维图形的进行模拟绘制的算法原理以及可实现程序,从而在二维平面显示器上准确模拟出传感器磁灵敏度的三维成像图形,并可绕X轴、Y轴及Z轴旋转成像。     

集成线性编码器的高精度大行程原子力显微镜探针结构的设计和构建

提出了一种高精度、大行程的原子力显微镜探针结构,可用于测量大面积的微观结构表面.该探针结构包括一个硅悬臂梁和一个环形的预压型电(PZT)执行器,执行器沿Z轴的行程为70μm,其内部集成了一个具有纳米级分辨率的小型线性编码器,可用于测量PZT执行器的位移,编码器的刻度沿执行器的轴向(Z轴)排列以消除阿贝误差.此线性编码器使原子力显微镜探针PZT执行器的行程范围内具有1nm的分辨率,原子力显微镜探针结构联接有两个线性平移台,可用于X和Y方向扫描样本,扫描面积为50mm(X)×40mm(Y).X向平移台和Y向平移台的移动量可由线性编码器测得,分辨率为纳米级.进行了正弦曲面的测量实验.     

基于AFM的靶丸表面轮廓仪设计及其测量精度分析

基于商用原子力显微镜（AFM）建立了靶丸表面轮廓测量仪系统，并对该系统的精密回转轴系进行了结构设计．为了评价系统的测量不确定度，进行了气浮轴系回转精度测试，确定了回转轴系的误差曲线，其最小二乘圆度误差为48 nm；同时对安装回转轴系后AFM的测量噪声进行了测试，并通过结构改进使静态噪声幅值降为约10nm．应用这一系统进行了靶丸表面圆周迹线的测量实验，实验测量出该系统运转测量时噪声幅值约13 nm，综合测量误差约49．7 nm，此测量精度可以通过回转轴系的误差分离来进一步提高．     

机床主轴回转误差补偿信号的测量理论和方法

本文提出了一种机床主轴回转误差补偿信号的实时测量方法。该方法采用两组差动电容传感器，直接相对主轴表面进行测量，传感器的极板设计成弧形以消除被测截面的形状误差分量。文中分析了测量方法的原理，介绍了简单、实用的测试系统。     

LabVIEW平台的平面螺纹测量系统研制

基于极径变化,建立了平面螺纹螺旋线误差测量与评价模型,基于LabVIEW平台,研制了一套高准确度动态测量盘丝平面螺纹测量系统.本系统采用高准确度线性光栅及圆光栅系统测量平面螺纹的极径和极角,采用PLC系统控制伺服电机来带动精密气浮主轴旋转,采用CCD激光位移传感器配合线性光栅在测量前对平面螺纹进行调平调心,以提高测量准确度.与三坐标测量机(CMM)测量结果比对表明,本系统已达到预期设计要求,可在计量部门和企业推广使用.     

基于栅结构谐振器的X和Y轴加速度及Z轴角速度的组合测量

本文利用一由两个相互垂直的加速度计组成的栅结构谐振器来同时测量z轴和Y轴的加速度以及z轴的输入角速度．此谐振器利用变面积电容进行检测,具有良好的线性度及快速的信号响应．此谐振器的x轴及Y轴的加速度计的谐振频率分别为1．9315kHz和1．8403kHz．在初始状态下,Ⅳ轴的加速度计被驱动进入谐振状态,且Y轴的加速度随着x轴的加速度计一起振动．当=轴存在角速度输入时,Y轴的加速度计会相应地沿Y轴进行振动,而x轴及Y轴的加速度会改变相应轴上加速度计的平衡位置．测试结果表明,此器件的z轴角速度灵敏度为16mV／（（9）·s-1）,x和Y轴的加速度灵敏度分别为49mV／g和244mV／g．z轴角速度输出的噪声等效角速度为0．0138（s·／Hz-1）,x和Y轴加速度输出的噪声等效加速度为0．42X10-3g／／Hz和0．074X10-3。g／√Hz．     

大平面平面度测量系统

本文提出一种新的高精度大型平面扫描仪。利用双光束补偿系统，扫描头由一特殊光路组成。当入射光发生角漂或扫描头发生摆动等，输出的两束光发生对称上下漂移，其中心线扫描形成的基准平面保持不变。测量不确定度小于２．５×１０－６。     

激光扫描实验回波信号的分析

利用激光回波信号的强度变化来测量物体边缘轮廓的新型激光雷达,并利用二维扫描、直接探测等技术建立了一套激光扫描实验系统。振镜在X、Y方向分别以不同的频率振动,当激光经过振镜反射后,就以X、Y方向进行二维扫描,激光二极管接收到的信号经过滤波后被分为两个不同频率的信号,分析这两个不同频率的信号,就可以得到物体的轮廓信息。实验测量表明,通过测量回波强度变化来测量物体边缘轮廓的方案是可行的。     

Nano-strip grating lines self-organized by a high speed scanning CW laser

After a laser annealing experiment on Si wafer, we found an asymmetric sheet resistance on the surface of the wafer. Periodic nano-strip grating lines (nano-SGLs) were self-organized along the trace of one-time scanning of the continuous wave (CW) laser. Depending on laser power, the nano-trench formed with a period ranging from 500 to 800 nm with a flat trough between trench structures. This simple method of combining the scanning laser with high scanning speed of 300 m min(-1) promises a large area of nanostructure fabrication with a high output. As a demonstration of the versatile method, concentric circles were drawn on silicon substrate rotated by a personal computer (PC) cooling fan. Even with such a simple system, the nano-SGL showed iridescence from the concentric circles.     

Measurement of profiles along a circle on two flat surfaces by use of a Fizeau interferometer with no standard

A method for measuring profiles along a circle on a flat surface with no standard is described. For the measurement, two unknown surfaces are placed almost parallel, and the distance between them is measured many times along a circle by rotation of one of the surfaces. Profiles of the two surfaces can be determined from the distance data. In this study the measuring method is explained: The space between two surfaces measured with a Fizeau interferometer. Four measuring experiments are carried out for determining the profile of a precision-grade half-mirror; in each experiment a different ordinary mirror with unknown profile is used as the second mirror. Profiles of the precise mirrors obtained by these experiments agree closely, with deviations of approximately 2 nm. A similar experiment with many concentric circles was carried out with a precise half-mirror and another precise mirror. Although the profiles of many concentric circles were independent of one another, the result shows that the high-frequency component of a whole plane can be estimated.     

Photoelectric inclination sensor and its application to themeasurement of the shapes of 3D objects

A method for obtaining the tilt angle and direction in a two-dimensional plane, by using a photoelectric inclination sensor consisting of an LED, a hemispherical spirit level, and a photodiode array is explained. An application of the sensor to the measurement of the shape of a 3-D object is also described. Light from the LED projects a bubble in the spirit level and throws a shadow onto the surface of an array composed of four equivalent p-n junction diodes, isolated from each other by a cross on a wafer. The tilt angle and direction in a two-dimensional plane are obtained by combining the diode outputs. By positioning the sensor on the crosspoints of the lines drawn longitudinally and latitudinally at an interval on the surface of a small mountain in a Japanese garden, the x and y components of the tilt angle can be obtained and its shape is reconstructed by a computer. The principle of the sensor, the system to display the tilt angle and its x and y components, and the application of the system to the measurement of the shape of a mountain are explained     

A run-to-run controller for product surface quality improvement

In semiconductor manufacturing, the surface quality of silicon wafers has a significant impact on the subsequent processes that produce devices using the wafers as a component. The surface quality of a wafer is characterised by a two-dimensional (2-D) data structure: the geometric requirement for the wafer surface is smooth and flat and the thickness should fall within certain specification limits. Therefore, both low deviation and high uniformity are desirable for control over the wafer quality. In this work, we develop a run-to-run control algorithm for improving wafer quality. Considering the unique 2-D data structure, we first construct a model that encompasses the spatial correlation of the observations on the wafer surface to link the wafer quality with the process variables, and subsequently develop a recursive algorithm to generate optimal set points for the controllable factors. More specifically, a Gaussian-Kriging model is used to characterise the spatial dependence of the thickness measures of the wafer and a recursive least square method is employed to update the estimates of the model parameters. The performance of the new controller is studied via simulation and compared with existing controllers, which demonstrates that the newly proposed controller can effectively reduce the surface variations of the silicon wafers.     

Fabrication of humidity sensors by multi-walled carbon nanotubes

Humidity sensors have multi-walled carbon nanotubes (MWNTs) as the sensing material is demonstrated. The sensor was fabricated on a silicon dioxide coated silicon wafer with metal electrodes. MWNTs were deposited and interlinked with the electrodes by means of the dielectrophoresis technique. The sensing device has the function of a hygrometer when measuring resistance variations to the local relative humidity percentage (RH%) through MWNTs. By measuring the MWNT resistances, we find that higher RH% results in a decrease of conductivity. The results indicate that electron transports in MWNTs are affected by water molecules adsorption on the outermost nanotube surface. A miniature thermocouple sensor was also fabricated and integrated with the humidity sensor. This allowed us to simultaneously sense environmental humidity and temperature. Hence, accurate humidity measurements were achieved with this prototype by calibrating the electrical resistance and temperature levels to carry out the tests with the humidity percentages.     

Improvement of Heater Surface Flatness and Uniformity of TiN Film Deposition

The deposition rate and the thickness uniformity of chemical vapor deposition (CVD) titanium nitride films depend on wafer temperatures. The heater surface conditions, such as flatness, roughness, and surface imperfections, can greatly affect heat transfer efficiency from the heater surface to the wafer, and the process performance. Because heater surface imperfections or “hot spots” that caused poor uniformity had to be eliminated, the origin of “hot spots” was identified by a detailed study of heater surface profiles. A better visualization of “hot spots” could be obtained by comparing wafer-chucking patterns with deposition patterns. Thus, the time needed to locate “hot spots” could be shortened. The manufacturing process was revised to prevent “hot spots” and improve heater performance.     

矢量线阵二维波达方位估计的方法

声矢量传感器南声压传感器和质点振速传感器组成,它可以空间共点、时间同步测量声场的声压标量和振速矢量信息。钏对声压线阵无法同时分辨目标的方位角和俯仰角,而三维矢量传感器线阵会带来成本的增加和工程应用上的困难．利用二维矢量传感器组成的直线阵对目标的二维波达方位进行联合估计,详细推导了矢量阵MUSIC算法的数学表达式,并着重对矢量线阵在三维坐标不同轴上时对方位估计的影响进行了研究。仿真结果表明二维矢量线阵布放在水平的X轴或Y轴上时存在方位模糊．而布放在垂直的Z轴上时可以实现全空间无模糊定向,且对双目标也有较高的分辨率。     

Measurement and Modeling of the Bidirectional Reflectance of SiO2 Coated Si Surfaces

An understanding of the variation of directional radiative properties of rough surfaces with dielectric coatings is important for temperature measurements and heat transfer analysis in many industrial processes. An experimental study has been conducted to investigate the effect of coating thickness on the bidirectional reflectance distribution function (BRDF) of rough silicon surfaces.Silicon dioxide films with thicknesses of 107.2, 216.5, and 324.6 nm were deposited using plasma-enhanced chemical vapor deposition onto the rough side of two Si wafers. The wafer surfaces exhibit distinct anisotropic characteristics as a result of chemical etching during the manufacturing process. A laser scatterometer measures the BRDF at a wavelength of 635 nm, after improvement of the signal-to-noise ratio. The slope distribution function obtained from the measured BRDF of uncoated Si surfaces was used in an analytical model based on geometric optics for rough surface scattering and thin-film optics for microfacet reflectance. The predicted BRDFs are in reasonable agreement with experimental results for a large range of coating thicknesses. The limitations of the geometric optics for modeling the BRDF of coated anisotropic rough surfaces in the specular direction are demonstrated. The results may benefit future radiative transfer analysis involving complicated surface microstructures with thin-film coatings.     

Improved SERS Intensity from Silver‐Coated Black Silicon by Tuning Surface Plasmons

An economical method of fabricating large‐area (up to a 100‐mm wafer) silver (Ag)‐coated black silicon (BS) substrates is demonstrated by cryogenic deep reactive ion etching with inductively coupled plasma. This method enables a simple adjustment of the spike structure (e.g., height, width, sidewall slope and density of the spikes) on the silicon substrate, which thus offers the advantages of accurate tuning the density and amplitude of the localized surface plasmons after Ag coating. Using this method, an enhancement factor of 10⁹ is achieved for the probe molecule of rhodamine 6G (around two orders of magnitude higher than previous results based on Ag‐coated BS) in surface‐enhanced Raman scattering (SERS) measurement. The presented results pave the way to make Ag‐coated BS substrates as economic and large‐area platforms for diverse surface plasmon related applications (such as SERS and surface plasmon based biosensors).     

硅表面钝化及对异质结太阳电池特性的影响

研究了不同的晶体硅表面钝化方法,测试分析了硅片的少数载流子寿命以及对晶体硅/非晶硅异质结(HIT)太阳电池性能的影响。发现适当时间的HF溶液处理、氢等离子体处理和表面覆盖约3nm的本征非晶硅层能有效提高硅片的少子寿命,从而提高HIT太阳电池的开路电压。对电池制备工艺综合优化后,得到了基于n型晶体硅的光电转换效率为16.75%(Voc=0.596V,Jsc=41.605mA/cm2,FF=0.676,AM1.5,25℃)的HIT太阳电池。