PCB板对准度设计能力研究

从PCB设计对位精度，制程中影响，找出影响层间对位偏差的因子，在生产过程中控制关键因子，满足PCB设计的对准度要求。提升层间对准度能力，并以30层板验证对准度控制≤0.127 mm（5 mil）。     

雷达用多层微波综合背板制造工艺研究

对多种型号雷达用多层微波综合背板材料CLTE-XT进行了性能及特点介绍。创新性运用埋置膜电阻技术、金属化孔制造的反钻孔技术,实现了多层微波综合背板的制造。并对其制造过程中所涉及的层间定位、多层化制造、孔金属化实现等关键技术进行了详细阐述,对此类微波多层背板的制造具有指导意义。     

背板加工技术简述

背板作为印制电路板的一种,因其结构特性、应用领域等,挑战常规印制电路板多项加工技术。本文浅谈背板加工流程之压合层间对准度、钻孔背钻、孔金属化深镀能力及最终表面工艺方面的技术及控制项,供同行参考与借鉴。     

大背板层偏短路失效模式研究与对策

大背板在压合过程中个别芯板偏移,导致通孔金属化后与层偏层次短路,形成层偏。本文从层偏的影响因素、机理出发,分析出失效模式,然后采取各种有效的预防措施加以控制,针对内层、层压的各关键控制点进行分析跟进,解决层偏错位问题。提供了一套清晰完整的大背板层偏的控制方法,大大提高背板的一次合格率。     

控制底片尺寸的变化

在多层印制板制造成中，层与层之间的对准度产生差有许多原因。一个更带有共同性的问题就是底片尺寸的不准。尽管这些共同性的问题，但人们长期以来并不了解影响尺寸的主要因素和如何进行控制它。所以，要更有意识的控制它的动态变化，关键就是要充分了解底片尺寸变化的原因和底片出现变化的影响因素。     

多层板涨缩性层偏改善方法及监控方式解析

随着线路板压合结构的复杂化,差异较大的内层芯板常被设计在一起。但由于芯板特性,工艺流程,菲林涨缩的差异,会导致在压合过程中,芯板由于伸缩比例不一致,而出现层间对准度偏移,以致内短报废的风险。本文通过对此类叠构层偏失效模式分析、验证,最终确认真因是由于层间涨缩差异导致。而针对涨缩性层偏,本文详细介绍了分层补偿方法,原则,相关治工具孔平移,两组同心圆层偏监控方式等,并将这一套改善对策导入实验板进行验证,最终得出本文介绍的涨缩性层偏改善方法及监控方式对改善层间涨缩性层偏有效,且效果明显。     

沉铜质量控制方法

化学镀铜（Electroless Plating Copper）俗称沉铜。印制电路板孔金属化技术是印制电路板制造技术的关键之一。严格控制孔金属化质量是确保最终产品质量的前提,而控制沉铜层的质量却是关键。日常用的试验控制方法如下：     

标准串行交换技术蔚为主流 洞悉PCI Express与先进交换标准特性

背板互连特性 背板是位于机架内的互连装置,它可能具备或不具备智能功能,通常其上可以有各种插卡和电路板插在插槽上.被动式背板电路可能需要使用电阻、处理器或一些控制驱动器电路.过去,背板互连一直是附加的物理端口如插头、插座或无线端口,如发射器、接收器等装置.大部分情况下,背板上都会为交换卡保留1～2个插槽作为背板的基础架构和逻辑层.     

印制电路板孔金属化工艺

带有金属化孔的印制电路板,随着电子工业的飞速发展用量越来越大。为了满足电子设备高密度组装,高传输速度的需要,不但研制出高密度的多层印制板而且又出现了结构更为新颖的多层布线板。虽然它们的结构形式有所不同,但层间信号线的互联都采用了金属化孔技术。金属化孔镀层质量已成为互联是否可靠的关键。本文将以多层印制板孔金属化工艺为例对化学镀铜的各个工艺环节进行讨论。     

计算机的三级装联及接插件的应用（下）

二、插件级装联及其接插件这级装联主要任务是按照系统的逻辑要求各个功能插件可靠地互连起来构成完整的功能部件。插件的互连方法主要有三种:同轴电缆连接;双绞线连接以及背板(Backplane)连接。目前以背板连接的使用最为广泛。背板根据其制造方法不同分成两种:一种是控制阻抗的多层印制板(Mulfilayer PrintedCircuif Backplane),另一种是多层布线背板(mulfiwiresBackplane)。分别简称为MPCB和MWB。在背板连接中,由于印制背板具有走线短、板与板之间的特性差别小(成品一致性强),印制走线底图一经定型,就再不会有人为布线的错误,且     

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.     

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.     

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.     

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