基于白光倾斜扫描干涉术的微结构测量方法

针对白光垂直扫描干涉技术由于测试系统中物镜视场和移相器的行程限制,使其不能进行较大横向范围的测试.本文使用白光倾斜扫描干涉术代替垂直扫描,以扩展其横向测量范围,提高测试效率.基于纳米测量机(NMM)搭建了测试系统,由NMM代替传统的压电陶瓷(PZT)带动被测物体进行倾斜扫描.分析了倾斜扫描的测量原理,针对本系统提出了倾...     

基于有效信号提取的白光干涉信号快速处理方法

针对白光扫描干涉术在垂直大范围扫描过程中的测量效率问题,提出了一种基于有效信号提取的白光信号快速处理方法。使用白光LED光源,建立了双峰频谱分布模型,并使用该模型进行了仿真实验,给出了不同算法在特定采样步长下所需的最小采样区间长度确定方法,在不改变测量精度的条件下减少了解算所需的数据量,并使得轮廓解算可以在采样结束前开始。针对垂直大范围扫描过程中的背景值波动问题,给出了一种基于背景集合的白光干涉信号背景分离方法,并通过与几种常见信号处理方法的比较,证明了背景值提取的完整性,有效消除了背景值波动现象对测量精度造成的影响。最后将上述方法应用于自主设计开发的白光轮廓仪,使用傅里叶变换法精确测量了U盘接口表面形貌特征。测量结果表明:从扫描开始到获得表面高度信息的总时间减少了49.02%。     

采用变速白光扫描干涉术测量大尺度台阶结构

针对传统白光扫描干涉术在对一些垂直尺度较大器件的测试中,存在测量时间长、信号利用率低等问题,本文提出了应用于白光扫描干涉测量的变速扫描策略,并开发了基于预定义模式的变速扫描和基于自动对焦模式的变速扫描两种具体的实现方式。本文方法能够控制测量系统仅在有干涉条纹存在的空间区域采集图像,而在其它区域加速运行,从而提高了测试效率。测量过程中,通过编写的测量软件控制纳米测量机(NMM),并利用NMM的高精度定位能力实现变速扫描。实验测试了一个100μm台阶结构,相对传统固定步长扫描法,变速扫描在保持高精度的基础上提高了测量效率。     

利用白光干涉垂直扫描法测量波片延迟量

将白光偏振干涉、迈克耳孙干涉仪和垂直扫描系统相结合,提出了一种利用白光干涉垂直扫描测量波片延迟量(包括级次信息)的方法。准直的白光经偏振干涉系统形成两束偏振方向相同的线偏光,它们进入迈克耳孙干涉仪后分别被两干涉臂的平面镜反射形成四束光,在压电传感器(PZT)驱动干涉仪动镜垂直扫描的过程中,它们两两干涉,形成3组白光干涉包络。根据CCD各像素记录的白光干涉信号,计算白光干涉包络之间的光程差,即可获取被测延迟量。实验测量了一多级波片的延迟量,其结果(4268.1nm)与使用光谱扫描法测量得到的结果(4269.9nm)相吻合。     

微表面形貌大视场检测相移显微干涉仪研制

基于相移干涉术,研制了立式大视场Mirau相移显微干涉仪,它包括干涉成像和照明系统、竖直方向上的压电陶瓷传感器(PZT)微位移系统、被测面的两维扫描系统、图像采集和处理系统,是无限筒长显微镜结构和Mirau干涉结构的叠加。大视场表面形貌通过多孔径扫描拼接实现。单片机串口控制电路控制电控平移台的精确位移,实现了被测面的两维扫描,最小的横向位移为0.039μm,扩展后的视场达到12.5mm×12.5mm。测量了光纤连接器端面的表面形貌,重复测量精度小于2nm。     

猫眼波前定位虚实结合干涉非球面参数误差测量 (特邀)

非球面广泛应用于光学系统中。表征非球面的基本参数包括顶点曲率半径、圆锥系数以及高阶非球面系数,它们贯穿了非球面的设计、制造、检测、装调过程。对非球面参数的高精度测量是加工和装调的前提。提出了一种基于虚实结合干涉仪的部分补偿非球面参数误差测量系统。在该系统中,采用部分补偿干涉法测量剩余波前,复用干涉仪利用轴向扫描透镜的猫眼波前定位法测量补偿镜与被测镜之间的间距,采用虚实结合迭代算法进行参数误差求解。该系统仅需在部分补偿干涉光路中引入会聚透镜,装调简单,测量精度高。通过一个四次非球面参数误差测量实验验证了该方法的有效性和精度。     

白光干涉垂直扫描测量算法综述

白光干涉测量是采用具有一定光谱宽度的白光代替单色光作为干涉光源进行测量的特殊干涉测量技术。根据白光干涉信号的相干长度短、相干峰非常明显的特性,采用了垂直扫描干涉测量的方式获取干涉信号。相干峰寻址法是在垂直扫描测量的基础上提出的,具有较高的计算精度和较大的适用性。本文将相干峰寻址法的11种算法分为直接求解法、包络曲线拟合法和加权平均法三类进行阐述,并通过仿真每种算法分析各种算法的优缺点以及适用性和局限性。     

一种超精密非球面在位测量方法

高面形精度非球面加工,离不开面形测量和误差补偿加工。离线测量容易导致工件装夹误差,并带来非加工时间增加。为解决这一问题,采用一种利用接触式的微小测头与激光干涉位移测量计相结合的在位形状测量装置,直接对磨削后的工件表面进行在位形状误差测量。介绍了该在位测量方法的原理及非球面测量过程,探讨了回转对称轴在半径方向的误差与测头倾角误差对测量误差的影响,并进行了补偿加工实验。对加工后的微小非球面进行了在位测量,并与超精密离线测量系统测量结果进行了比较。     

基于变速扫描技术的大尺寸台阶测量

为了提高大尺寸台阶结构的单边测量精度、缩短测量时间，基于变速扫描技术，并利用傅里叶变换提取法及单边台阶评价算法进行扫描干涉信号的处理，提出并搭建了具有变速扫描功能的白光干涉测量系统。并且利用该系统对标称值为9.9760.028 m的台阶标准样板进行了测量，10次重复性测量结果为9.971 m，标准偏差量为0.007 m，测量时间仅为35 s，远小于常规扫描方法的222 s，大大缩短了测量时间，因此说明了该系统在大尺寸台阶结构测量中，具有较高的精确性与高效性。     

白光扫描干涉仪用于保偏光纤偏振耦合检测

采用白光扫描干涉法,利用Michelson干涉仪中移动臂的移动补偿保偏光纤中产生的光程差,从而实现对保偏光纤绕组中偏振耦合点的耦合强度及空间位置分布的有效检测。分析了白光干涉仪的原理、结构以及干涉条纹特点,进行了保偏光纤环的扫描测量。结果表明,第一个保偏光纤环的质量优于其他各环,证明了仪器设计理论和实验结果相符。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks