Multi-probe scanning system comprising three laser interferometers and one autocollimator for measuring flat bar mirror profile with nanometer accuracy

This paper describes a multi-probe scanning system comprising three laser interferometers and one autocollimator to measure a flat bar mirror profile with nanometer accuracy. The laser interferometers probe the surface of the flat bar mirror that is fixed on top of a scanning stage, while the autocollimator simultaneously measures the yaw error of the scanning stage. The flat bar mirror profile and horizontal straightness motion error are reconstructed by an application of simultaneous linear equations and least-squares method. Measurement uncertainties of the flat bar mirror profile were numerically evaluated for different installation distances between the laser interferometers. The average measurement uncertainty was found to be only 10 nm with installation distances of 10 and 21 mm between the first and second, and first and third interferometers, respectively. To validate the simulation results, a prototype system was built using an X–Y linear stage driven by a stepper motor with steps of 1 mm along the X direction. Experiments were conducted with fixed interferometers distances of 10 and 21 mm, as in the simulation, on a flat bar mirror with a profile known to an accuracy of λ = 632.8 nm. The average value of two standard deviations (95%) of the profile calculated over ten experiments was approximately 10 nm. Other results from the experiment showed that the system can also measure the yaw and horizontal straightness motion errors successfully at a high horizontal resolution. Comparing with the results measured by ZYGO's interferometer, our measured data excluding some edge points showed agreement to within approximately 10 nm. Therefore, we concluded that our measurement profile has an accuracy in the nanometer range.     

Nanometer profile measurement of large aspheric optical surface by scanning deflectometry with rotatable devices: Uncertainty propagation analysis and experiments

High-accuracy mirrors and lenses with large dimensions are widely used in huge telescopes and other industrial fields. Interferometers are widely used to measure near flat surfaces and spherical optical surfaces because of their high accuracy and high efficiency. Scanning deflectometry is also used for measuring optical near flat surfaces with sub-nanometer uncertainty. However, for measuring an aspheric surface with a large departure from a perfect spherical surface, both of these methods are difficult to use. The key problem for scanning deflectometry is that high-accuracy autocollimators usually have a limited measuring range less than 1000″, so it cannot be used for measuring surfaces having a large slope. We have proposed a new method for measuring large aspheric surfaces with large slopes based on a scanning deflectometry method in which rotatable devices are used to enlarge the measuring range of the autocollimator. We also proposed a method to connect the angle data which is cut by the rotation of the rotatable devices. An analysis of uncertainty propagation in our proposed method was done. The result showed that when measuring a large aspheric surface with a diameter over 300 mm and a slope of 10 arc-deg, the uncertainty was less than 10 nm. For the verification of our proposed method, experimental devices were set up. A spherical optical mirror with a diameter of 35 mm and curvature radius of 5000 mm was measured. The measuring range of the autocollimator was successfully enlarged by our proposed method. Experimental results showed that the average standard deviation of 10 times measurement was about 20 nm.     

High-throughput characterization of stresses in thin film materials libraries using Si cantilever array wafers and digital holographic microscopy

We report the development of an advanced high-throughput stress characterization method for thin film materials libraries sputter-deposited on micro-machined cantilever arrays consisting of around 1500 cantilevers on 4-inch silicon-on-insulator wafers. A low-cost custom-designed digital holographic microscope (DHM) is employed to simultaneously monitor the thin film thickness, the surface topography and the curvature of each of the cantilevers before and after deposition. The variation in stress state across the thin film materials library is then calculated by Stoney's equation based on the obtained radii of curvature of the cantilevers and film thicknesses. DHM with nanometer-scale out-of-plane resolution allows stress measurements in a wide range, at least from several MPa to several GPa. By using an automatic x-y translation stage, the local stresses within a 4-inch materials library are mapped with high accuracy within 10 min. The speed of measurement is greatly improved compared with the prior laser scanning approach that needs more than an hour of measuring time. A high-throughput stress measurement of an as-deposited Fe-Pd-W materials library was evaluated for demonstration. The fast characterization method is expected to accelerate the development of (functional) thin films, e.g., (magnetic) shape memory materials, whose functionality is greatly stress dependent.     

Micromechanical sensor for studying heats of surface reactions, adsorption, and cluster deposition processes

We present a newly designed highly sensitive micromechanical sensor devoted to thermodynamic studies involving supported clusters. The thermally sensitive element of the sensor consists of a micromachined silicon cantilever array, onto which a thin metal film is evaporated. Due to the difference between the thermal expansion coefficients of silicon and the metal employed, thermal bending is observed when heat is exchanged with the cantilever. The sensitivity and the response time of the cantilever are studied as a function of the film material (gold or aluminum) and the thickness of the metal film. With our routinely prepared cantilevers, a minimum power of 120 nW is measurable with a submillisecond response time, corresponding to a limit of detection in the femtojoule range. The high sensitivity of the sensor is demonstrated by measuring the heat exchange which occurs during the deposition of clusters on the cantilever. Experimentally, we illustrate the 1,3-butadiene hydrogenation reaction using a cluster model catalysts created by soft-landing palladium clusters onto the cantilever surface.     

SK—1刚架梁式应变计参数测定装置

本文提出的ＳＫ－１刚架梁式应变计参数测定装置，同目前国际上一般采用简支纯弯矩梁和等强度悬臂梁原理制成的这类装置这一样。该装置是采用刚架梁原理研制而成，并按作者新提出的标定梁图柱面形状误差和标定梁纯度误差两概念，对其进行误差分析和精度检定，实现了以ＳＫ－１装置为主机组合式配套能测Ｋ、Ｚ、θ、Ｈ等１０个参数的高精度应变计参数标定装置。     

三维姿态角高精度测量装置

基于二维自准直仪和坐标系旋转变换矩阵,提出一种高精度、高稳定性三维姿态角(偏摆角、俯仰角和滚转角)测量方法,并设计了一种三维测角装置。介绍了该装置的工作原理和结构组成。建立了三维测角模型,根据自准直测角原理和坐标旋转矩阵推导了理论算法。基于测量要求设计了光学系统,采用现场可编程门阵列(FPGA)单芯片实现了实时双CMOS图像传感器的驱动成像、像点识别与细分定位、三维转角计算及与USB的快速通信。提出了三维测角装置的标定方法,保证了实际设备参数与理论设计数据的统一。最后对提出的滚转角测量算法进行了实验验证,并分析了影响测角精度的因素及其影响程度。标定和试验结果表明:在±20′的视场范围内,三维测角装置的偏摆角、俯仰角和滚转角的测量精度分别达到了2.2″,2.5″和8.7″。该结果验证了设计的装置结构简单、稳定可靠、精度高,且易工程实现三维姿态角的测量。     

Calibration of AFM cantilever spring constants

In this paper we present two simple, reliable and readily applicable methods for calibrating cantilevers and measuring the thickness of thin gold films. The spring constant calibration requires knowledge of the Young's modulus, density of the cantilever and resonant frequency. The thickness of thin gold layers was determined by measuring changes in the resonant frequency and Q-factor of beam shaped AFM cantilevers before and after coating.The techniques for measuring the spring constant and thin film thickness provide accuracy on the order of 10-15%.     

双盘式渐开线测试仪齿廓偏差测量的采样分析

在标准齿轮若干精度指标的检测中,渐开线齿廓检验是一个重要且难度较大的检测项目,双盘式渐开线测试仪就是测量标准齿轮渐开线齿廓的高精度仪器之一。本文简要介绍了双盘式渐开线测试仪的测量原理,并利用采样定理着重分析了在测量过程中的数据采样问题,为渐开线齿廓检验中采样间隔的确定提供了依据。     

无导轨高精度位移平台的结构设计

为了完善高精度位移平台性能,提高平台位移直线度和定位精度,研制了制造成本较低的高精度无导轨位移平台机构.根据平行四边形和比例杆运动原理,设计了无导轨平台结构.介绍了平台的工作原理,并对其运动部件进行了有限元分析.用自准直平行光管和高精度测量头分别检测了平台的位移直线度和升、降位移误差,实验结果得出,该机构的位移直线度误差小于1",升、降位移误差小于0.02 mm,达到了平台设计要求.应用结果表明,该平台安装方便、体积小、易于养护,在有无重力的条件下均能正常使用,可应用于航天或其它领域的高精度位移系统中.     

机械密封润滑膜分布的超声检测技术

针对机械密封润滑膜分布检测问题,利用超声原理建立了机械密封润滑膜分布的多点测量模型。构建了由信号发生、超声发射-接收、数据采集及数据存储-显示等模块组成的润滑膜分布测量系统,并配备了模拟测量装置。在模拟测量装置上对厚度为5 μm、10 μm和20 μm的润滑膜进行了检测。结果表明：采用超声原理可对润滑膜分布进行精确测量,单点测量误差范围为0.2～1.1 μm,膜厚5 μm的检测精度最高。     

五角棱镜90°偏转角的高精度测量

本文介绍了一种五角棱镜90°偏转角的高精度测量原理和方法。它是根据五角棱镜90°偏转角为一定值这一基本特性,巧妙地应用光电自准直仪达到高精度的,该测量原理简单易行,测量精度可高达0.2″以上。     

脉冲激光沉积薄膜的残余应力测量

为了测量脉冲激光沉积法制备的小面积薄膜的残余应力,并解决Stoney公式在特定情况下误差较大的问题,本文提出了一种基于悬臂梁结构和数值计算的薄膜残余应力测量方法。该方法以初始曲率为零的原子力显微镜探针作为衬底梁,在衬底梁上使用脉冲激光沉积方法沉积被测薄膜,并记录衬底梁在薄膜沉积前后的翘曲形貌变化,再结合薄膜厚度、衬底梁几何尺寸、所涉及材料的杨氏模量与泊松比等其他参数,借助数值计算对实验数据进行分析,得出被测薄膜的残余应力。使用该方法测出:基于脉冲激光沉积法在高温环境下制备的二氧化钒薄膜的残余应力为-340 MPa,与文献报道的结果相符。本文提出的基于悬臂梁结构和数值计算的薄膜残余应力测量方法具有适用范围广、准确度好、实验成本低的优点。     

Pressure cell for investigations of solid-liquid interfaces by neutron reflectivity

We describe an apparatus for measuring scattering length density and structure of molecular layers at planar solid-liquid interfaces under high hydrostatic pressure conditions. The device is designed for in situ characterizations utilizing neutron reflectometry in the pressure range 0.1-100 MPa at temperatures between 5 and 60?°C. The pressure cell is constructed such that stratified molecular layers on crystalline substrates of silicon, quartz, or sapphire with a surface area of 28 cm(2) can be investigated against noncorrosive liquid phases. The large substrate surface area enables reflectivity to be measured down to 10(-5) (without background correction) and thus facilitates determination of the scattering length density profile across the interface as a function of applied load. Our current interest is on the stability of oligolamellar lipid coatings on silicon surfaces against aqueous phases as a function of applied hydrostatic pressure and temperature but the device can also be employed to probe the structure of any other solid-liquid interface.     

核燃料组件自适应柔性检测装置及其误差补偿方法

定期对核燃料组件变形状态及其表面氧化膜厚度开展高精度检测已成为保障核电站安全运营的重要举措。针对现有核燃料组件检测装置普遍存在的被动自适应性能欠佳、接触与测量柔性不足、检测精度与效率亟待提升等突出问题,通过设计引入基于变异虎克铰的自适应对中机构、融合接触力动态反馈的主/被动柔性检测单元和基于串并混联的高精度检测机构,创新研制出一款集变形与膜厚高精度检测功能于一体的核燃料组件被动自适应柔性检测装置。在此基础上,通过深入分析装置变形与膜厚检测机理,基于构建的串并混联闭环检测回路,融合制定的概率化传感误差协同补偿策略,提出了一种基于参数动态整合的测量误差补偿方法。样机测试实验结果表明研制装置能够自适应对中各向异性随机变形下的核燃料组件,满足检测过程中的柔性接触与柔性测量要求,配合提出的测量误差补偿方法,可实现核燃料组件变形及氧化膜厚度的高精度检测,有效提升了核燃料组件的检测精度、检测效率与检测安全。     

新型多功能膜/基结合力测定仪的研制

采用改进划痕法原理及切向力检测临界载荷方法，研制了一种新型多功能膜／基结合力测定仪。该仪器结构新颖，实用简便，不仅能测定金属膜层与基体的结合强度，还能对金属膜层进行模拟单颗粒磨损试验。试验表明，该仪器具有较高的可靠性。     

Development of a laser-guiding-type deep small-sized hole-measurement system: Measurement accuracy

In this study, a system for measuring small-sized holes with a 17–21 mm diameter and 1000 mm length was constructed. The system comprises a laser interferometer to detect hole accuracy, a probe connected to a measurement bar, and an optical apparatus for detecting the probe attitude (position and inclination). The probe was supported by supporting pads. A steel workpiece with 18 -mm diameter and 800 mm length was used for the performance test. During the experiment, errors were found in terms of hole deviation and roundness profile. Further experiments, using new experimental apparatus and analysis, revealed the causes of errors: electrical noise that increased with time, two periodic stylus swings in the longitudinal direction of the hole per rotation of the measurement unit, and the excessive spring force pushing the tip of the stylus, causing a large frictional force with the hole wall, etc. If these errors are corrected, high accuracy in the measurement of hole deviation and roundness can be achieved.     

薄膜Lamb波传感器用于胃蛋白酶原I检测

为满足大规模胃癌早期筛查对胃蛋白酶原I(PGI)检测高灵敏度、高效率、操作简单、样品量少的需求,本文构建了一种PGI抗体功能化薄膜型Lamb波生物传感器。对传感器检测腔薄膜进行PGI抗体自组装修饰,传感器检测腔表面修饰的PGI抗体将样品中PGI抗原特异性的捕获并固定在检测腔薄膜表面,Lamb波传感器薄膜表面质量增加导致其A0模式中心频率发生移动,且频率移动量与检测腔表面吸附物质质量增加量正相关,实现对样本中PGI抗原浓度的检测。实验结果表明:PGI抗体功能化薄膜Lamb波生物传感器对PGI抗原实测灵敏度约为102.114 Hz/ng/mL,理论最低检测限(LOD)为0.176ng/mL,单个样本检测时间为40min,与现有基于光学检测法PGI检测技术相比,具有检测系统简单、操作简单、不需要专业人员操作等显著优势,且比多数光学检测法LOD更低,比电化学法PGI检测技术LOD低两个数量级。结果表明,本文提出的PGI抗体免疫功能化薄膜型Lamb波生物传感器对PGI检测且具有检测下限低、灵敏度高、检测效率高、操作简单、无需样品预处理等特点,满足大规模早期胃癌筛查的基本需求。     

薄膜应力的测定

本文介绍一种利用长焦距显微镜观察玻璃薄片由镀膜淀积引起的形变来测量薄膜应力的方法。对于该实验装置的几个主要结构部份、测量的原理及方法和提高测量精度所采取的主要措施作了较详细的描述。最后给出了在不同真空度和蒸发速率时硫化锌膜、氟化镁膜及硫化锌—氟化镁多层膜的应力分别随薄膜几何厚度而变化的实验结果。     

用自准直仪测量孔的同轴度

以V16柴油机机体主轴承孔同轴度的测量为例,介绍了用自准直仪测量同轴度的原理与方法。该方法可直接在生产现场对大孔径零件或大型零件的同轴度进行快速、准确地测量,且不受被测孔径表面质量的影响。     

Three-dimensional imaging of undercut and sidewall structures by atomic force microscopy

Sidewall surface roughness is an important parameter in electronic device manufacture. At present, no high resolution technique exists to quantitatively characterize this property for undercut structures created by semiconductor processing techniques. We developed a three-dimensional atomic force microscope (3D-AFM) to measure the surface roughness of undercut sidewalls with nanometer precision. Decoupled from the positional scanner, the 3D-AFM probe had a variable tilt up to 40° off the normal. Nonorthogonal scans resolved the sidewall surface roughness, base width, and acute critical angle for undercut structures, including a metal overhang and the transmission line of a photonic device. Compatible with standard cantilevers, the 3D-AFM demonstrates great potential for characterizing the sidewalls of soft materials such as photoresist.