纳米银无压封装互连技术

纳米银无压烧结技术作为一种新型封装互连技术,凭借烧结银层的优异性能,逐步在第三代半导体器件的封装互连领域应用和推广。目前,无压烧结银技术只适用于芯片级别小面积互连领域,在基板级别大面积互连领域存在若干瓶颈,有待深入研究。文章详细介绍了现有的小面积无压烧结纳米银互连工艺以及可靠性,在此基础上,针对大面积无压烧结银工艺所面临的瓶颈,引入一种双层印刷焊膏(双印法)的低温无压烧结工艺。采用超声扫描成像技术对烧结质量进行表征,获得双印法中使用的两层银焊膏的成分优化配比并对其烧结机理进行分析,为纳米银基板级大面积无压烧结互连提供一种可行方案。最后,展望了基板级别大面积无压烧结银工艺的发展趋势和应用前景。     

多芯片基板高频信号传输特性分析

基于陶瓷板材,完成了一种多芯片基板的设计,讨论了基板上高频信号线的传输线效应、互连延迟引起的时序问题以及串扰等信号完整性问题.根据二端口等效电路理论,提出了建立基板高频互连线Spice模型的方法,为芯片-封装协同设计提供了依据.     

多芯片COB封装LED的基板温度分布

发光二极管(LED)的工作温度对其性能和寿命有很大影响,对于多芯片板上贴装(COB)的LED面光源,还存在基板温度分布不均匀的问题。基于一款多芯片COB封装LED的封装基板,用ANSYS仿真分析软件模拟其温度场,并证实了模拟的可靠性,探讨了基板表面和厚度方向的温度分布情况,对比了铝基板和铜基板的温度场。结果表明,多芯片COB封装LED的基板温度分布在芯片集中区存在很大的不均匀性,而基板边缘区温度则基本均匀,用铜基板代替铝基板,可以降低基板温度,且芯片集中区基板温度梯度也减小,铜基板整体的温度分布均匀性要好于铝基板。     

两种多芯片封装设计及电性能分析比较

集成电路发展迅速,为了提高芯片的集成度,高速高密的封装技术显得越来越重要。设计并分析了两种多芯片的封装实例,一种是二维多芯片封装,另一种是基于柔性基板的三维多芯片封装,并通过三维电磁仿真软件分别对它们进行了频域和时域的仿真。研究了关键信号的传输特性以及驱动和接收芯片间的信号眼图。对于两种封装形式,仿真结果表明在关键信号传输质量方面前者稍好于后者,但后者在减小封装面积和重量方面具有优势。     

柔性基板弯曲度对信号质量影响分析

柔性基板具有机械柔韧性和高密度互连的特点,现采用柔性基板来实现封装结构的也越来越多.柔性基板由于其机械弯曲引起的信号完整性问题和电磁干扰问题是柔性基板应用于高速高密电子封装的重要制约因素.针对该问题,应用三维仿真分析方法,分别从频域和时域研究了柔性基板在不同弯曲半径下的信号完整性与电磁干扰性的问题.仿真结果显示,弯曲半径增加一倍,插入损耗减小约0.9 dB,回波损耗减小约2 dB,电场辐射越弱,眼图的上升时间退化越小;即柔性基板弯曲半径越大,高速信号的传输质量越好.该结果为使用柔性基板实现三维高速高密封装提供理论依据.     

超高速低功耗4:1复接器设计、封装及测试

采用CSM 0.35 μm CMOS 工艺,设计了低功耗2.5～3.125 Gbit/s 4∶1复接器.该芯片既可以应用于光纤通信系统SDH STM-16(2.5 Gbit/s)速率级别的光发射机,又可以应用于万兆以太网IEEE 802.3ae 10GBASE-X(3.125 Gbit/s)速率级别的通道接口发送器.系统采用树型结构,核心电路由锁存器、选择器、分频器组成,并采用了CMOS逻辑实现.最高工作速率可达3.5 Gbit/s.芯片供电电压3.3 V,核心功耗为25 mW.该芯片采用SOP-16封装.芯片封装后焊接在高速PCB板上进行测试,封装后芯片最高工作速率为2.3 Gbit/s.     

一种三维多层1TxR阻变存储器设计

提出一种适用于未来高密度应用的三维多层可堆叠1TxR阻变存储器设计.采用新型的多个存储电阻共享一个选通管的存储单元,选通管制作在硅片表面与标准逻辑工艺兼容,存储电阻堆叠在不同的互连金属层之间,构成三维存储结构.在0.13μm工艺下,以一个使用8层金属堆叠的1TxR（x=64）结构为例,其存储密度比传统的单层1T1R结构...     

芯片高密度封装互连技术

电子封装正朝着高密度封装的方向发展,以满足市场对高性能、高可靠性、低成本、微型化的电子产品的需求.高密度封装具有多学科交叉的特点.综述课题组多年来在芯片高密度封装互连技术,包括倒装芯片(flip chip,FC)凸点制备／转移技术、导电胶高密度互连技术、叠层芯片封装技术及封装可靠性方面的研究工作,并指出未来高密度封装技...     

基于柔性基板的异构多芯片三维封装散热仿真与优化设计

随着移动终端的广泛应用,射频多芯片系统封装结构的小型化、系统的集成化将导致功率密度的直线上升,同时,芯片各异性的特点将产生温度分布不均的现象,从而催生亟需解决的热管理问题。针对包含5款芯片的典型的射频前端系统,在POP封装基础上,提出柔性基板封装结构设计方案,并应用ANSYS ICEPAK三维数值分析法进行仿真计算,验证得到如下结果:1柔板同层的温差降低到POP结构的6%,异层的温差降低到POP结构的4%,避免了热点的出现;2柔板封装结温随下层屏蔽罩的厚度增大而减小,但尺寸的变化对其影响相对较小;3与铝基相比,铜屏蔽罩能够起到更好的散热作用。研究结果为射频异构多芯片三维封装优化设计提供了参考方案。     

基于TSV的3D IC层次化物理实现技术

随着集成电路特征尺寸逼近物理极限,硅通孔（TSV）实现层间互连的三维集成电路（3D IC）成为延续摩尔定律的一种趋势.但现有集成电路设计工具、工艺库、设计方法尚不成熟,难以实现三维集成中超大尺寸基板芯片的时序收敛问题.为此,本文提出了一种利用现有传统的EDA工具完成基于TSV的3D IC物理设计的流程.首先,用热应力模型将三维硅通孔投影成二维阻挡层,从而将三维集成电路设计转化成若干含阻挡层的二维集成电路分别实现;其次,针对超大尺寸基板芯片的时序收敛困难问题,提出了一种标准单元布局方法,通过在版图中划定若干固定放置区用于限定关键时序单元的摆放,并迭代确定这些关键单元在固定放置区中的位置,实现大尺寸芯片的时序收敛.基于所提出的三维集成电路设计流程完成了一款三维集成的网络路由芯片基板芯片的设计,结果表明,相比传统的设计流程,提出的3D IC物理设计流程可使超大尺寸基板芯片从时序无法收敛优化到可收敛并满足时序要求,验证了所提出的3D IC物理设计流程的可行性.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with