国外工艺文献导读

20 0 2 0 5 0 1　新的无铅焊膏和再流焊技术—ＪｉｍＲａｂｙ ,ＤａｖｉｄＨｅｌｌｅｒ.ＣｉｒｃｕｉｔｓＡｓｓｅｍｂｌｙ ,2 0 0 2 ,13(3) :2 8～ 30(英文 )本文是一实验研究报告。这一研究评价了最新的无铅配方、焊剂、改进的温度曲线形状和焊盘金属化等 ,目的是减少焊点空洞的产生。研究选用两种普通无铅合金ＳｎＡｇＢｉ和ＳｎＡｇＣｕ ,均采用免清洗和水溶性焊剂。焊盘选用裸铜板和浸渍锡板。结果这两种焊料合金给出良好的结果 ,产生很少的空洞。2 0 0 2 0 5 0 2　ＣＣＧＡ设计参数及对可靠性的影响—ＭａｒｉｅＳＣｏｌｅ ,Ｅｌｌｙ…     

SMT焊盘设计中关键技术的分析

主要针对表面组装技术（ＳＭＴ）焊盘设计技术的原则，以及易造成失误的实质性问题开展分析，为相关设计者提供参考。     

重视每个工艺环节 提高SMT质量

文章从多年的ＳＭＴ工艺研究与生产实践中，总结了如何从ＰＣＢ焊盘图形设计，材料及元器件选择，涂敷焊这，贴装ＳＭＤ，检验等工艺方面提高了ＳＭＴ的组装质量。     

表面组装PCB焊盘图形的设计与布排

本文介绍了各种ＳＭＤ在ＰＣＢ上的焊盘设计及其布排等一系列经验性数据。表面焊装工艺不同，其焊盘的尺寸就不同。焊锡熔化时的表面张力是造成元件移位和直立的原动力。     

SMT焊点形态对热应力分布影响的有限元分析

采用线性有限元方法研究了ＳＭＴ焊点形态与热应力之间的关系，得到了不同外观形状和元件－焊盘间隙的ＳＭＴ焊点在受交变热作用时焊点内部的热应力分布情况。结果表明，焊点内的应力集中受到这两个形态参数的影响并且存在着最佳的区间，这一结果对于ＳＭＴ－ＰＣＢ上的焊盘设计和优化以及进一步的钎焊工艺规范的制定都具指导意义。     

SMT焊盘设计中关键技术的分析

主要针对表面组装技术（ＳＭＴ）焊盘设计技术的原则,以及易造成失误的实质性问题展开分析,为相关设计者提供参考。     

细间距焊接技术应用研究

首先简要分析了表面组装技术（SMT）细间跨焊接的工艺方法,然后重点讨论了焊盘设计、丝印、贴片、再流焊各种参数对焊接质量的影响,以及对不良焊点的分析及解决办法,最后简要分析了再流焊焊接理论。     

陶瓷封装集成电路芯片焊盘设计

在设计陶瓷封装集成电路芯片的焊盘时,需要考虑到引线键合工艺对芯片焊盘设计的一些要求,诸如焊盘尺寸、焊盘布置、焊盘间距、焊盘引出金属条、焊盘到周围布线或元件间的距离等。文中对这些设计给出了一些参考数据。     

技术集成的未来趋势

整个有关如何在系统芯片（ＳｏＣ） 方案中集成知识产权（ＩＰ）模块的争论中，多数讨论都集中在ＩＰ的设计和传递机制上。很明显，ＩＰ是未来ＳｏＣ设计的核心，但还必须考虑一个重要的问题基础——硅芯片制造技术本身。 目前，多数的注意力都集中在选择单层多元而又成熟的ＣＭＯＳ技术做为ＳｏＣ器件的传递机制。确实，ＣＭＯＳ技术近期仍将是主导技术。ＣＭＯＳ技术适用的范围不断改变，深亚微米技术和硅工艺设计以及封装技术的革新使器件密度达到了前所未有的高度。为在一块硅片（或封装单元）内实现一个电子系统所有功能的梦想提供新的…     

国外工艺文摘

９９０５００１　ＣＳＰ的高速组装—ＪｕｌｉａｎＰＰａｒｔｒｉｄｇｅ,ＶｅｒｎＳｏｌｂｅｒｇ．ＳＭＴ,１９９８,１２（１１）：７６～８１（英文）芯片尺寸ＢＧＡ,也叫做ＣＳＰ,其凸点间隙为０．５ｍｍ,最大高度１．２ｍｍ,正常的焊点直径０．３ｍｍ。本文以ＣＳＰ器件在闪存ＰＣ卡上的高速组装为例,详细介绍了ＣＳＰ的高速组装,内容包括：ＣＳＰ和测试运载装置、板子的精整、ＳＭＴ线的集成、ＣＳＰ器件的湿敏性、焊膏和模版的选择、焊膏量要求、贴装技术、射片机、检测和自对准、双面ＣＳＰ组装、返修技术等。９９０５００２…     

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