埋置型叠层微系统封装技术

包含微机电系统(MEMS)混合元器件的埋置型叠层封装,此封装工艺为目前用于微电子封装的挠曲基板上芯片(COF)工艺的衍生物。COF是一种高性能、多芯片封装工艺技术,在此封装中把芯片包入模塑塑料基板中,通过在元器件上形成的薄膜结构构成互连。研究的激光融除工艺能够使所选择的COF叠层区域有效融除,而对封装的MEMS器件影响最小。对用于标准的COF工艺的融除程序进行分析和特征描述,以便设计一种新的对裸露的MEMS器件热损坏的潜在性最小的程序。COF/MEMS封装技术非常适合于诸如微光学及无线射频器件等很多微系统封装的应用。     

系统级封装中焊点失效分析技术

针对系统级封装(Si P)结构中的互连可靠性检测,提出了叠层封装中焊点失效分析的原则和程序。对采用3D X-ray和金相技术的焊点缺陷分析方法进行了对比,验证了3D X-ray分析复杂Si P封装焊点和互连缺陷的可行性。讨论了失效的模式和失效机理,并从设计和工艺角度提出降低各种失效机理的改进措施。     

真空炉金锡封焊

文章在介绍半导体金锡焊料封装工艺的基础上,重点对金锡焊料、炉温曲线设置等工艺技术问题进行了深入研究。基于大量的金锡焊料真空焊接封装实验及理论分析,研究了器件气密封装技术。讨论了封焊夹具、管帽镀层、合金状态、封接面表面、压块、焊料厚度以及加热程序对焊接质量的影响。密封后的产品在经过环境试验和机械试验考核后,封装气密性能很好地满足要求。并且结合应用背景证明了所采用的合金及封装工艺的可行性。     

我国微电子封装研发能力现状

对从事微电子封装技术与培训、封装外壳与特种器件封装、封装设备、封装可靠性与标准化、封装材料、测试技术研发的科研院所进行了分析;对高等院校的微电子封装科研及人才培养机构进行了分析,对从事微电子封装研究、开发和服务的其他机构进行了分析。最后对我国封装研发和产业发展能力的培养进行了探讨。     

DirectX程序开发中的实用技术方法

DirectX是目前基于Windows平台的多媒体程序开发的主要接口,但由于其自身对开发人员技能要求极高而造成了开发应用中的局限性。介绍了封装DirectX的SDK中最为出色的一个类库CDX,通过分析介绍CDX及其应用的特点,提出和实现了大为简化的DirectX多媒体程序开发的方法,并通过相应的程序示例运行结果证明其良好的动画效果。     

并行预处理有限元方法及其在系统级封装结构电磁模拟中的应用

针对系统级封装结构的电磁兼容、信号完整性分析等应用,由于结构的复杂、多尺度和多材料的特性,其大规模电磁问题模拟一直难以实现.本文中,主要展示了基于并行支撑框架JAUMIN研发的高性能电磁计算程序JEMS-CDS及其在系统级封装结构电磁仿真中采用的高效算法.针对系统级封装结构电磁仿真,我们构建了两种预处理技术:区域分解方...     

封装环境的水汽含量控制

本文通过具体的试验尝试，配合一系列控制程序如封装环境控制、工艺加工控制等控制方法，摸索出一种较佳的封装工艺控制程序，为封装环境的水汽含量控制提供参考。     

照明用大功率LED的封装与出光

研究了照明用大功率LED封装对出光的影响,分析了大功率LED封装结构对提高外量子效率的影响,同时比较了不同LED封装材料对LED出光的影响。提出了用左手材料替代目前广泛采用的电极和封装材料的大功能LED封装思路,并分析了其可行性。     

一种节能型伺服泵半导体封装压机

介绍了芯片封装的生产工艺和难点,以及普通封装压机和节能型伺服泵半导体封装压机的区别,分析了伺服系统对封装工艺的适应性,总结了使用节能型伺服泵半导体封装压机进行芯片封装的优势。     

MEMS器件封装技术

综述了微电子机械系统(MEMS)封装主流技术,包括芯片级封装、器件级封装和系统及封装技术进行了。重点介绍了圆片级键合、倒装焊等封装技术。并对MEMS封装的技术瓶颈进行了分析。     

新闻评论节目的电视发展战略窥探——以《老梁观世界》为例

随着电视新闻行业在新媒体时代引擎下的迅速发展,新闻评论节目近年来在影视领域逐渐备受关注,金飞、周立波等新闻明星也进入广大观众的视野之内。梁宏达老师主持的《老梁观世界》等新闻评论节目,以其目光的敏锐、观点的犀利,得到时事爱好者和新闻关注者的普遍认同,但也招致一定争议。以《老梁观世界》为研究对象,通过对老梁评论艺术的分析研讨,试图以点带面窥探新媒体时代新闻评论节目的电视发展战略。     

High performance epitaxial HgCdTe photodiodes for 2.7 µm applications

High performance photovoltaic devices tailored for 2.7 µm cut-off have been fabricated on liquid phase epitaxial HgCdTe/CdTe. The peak external quantum efficiency is measured to be 67% without any AR-coating. The measured zero-bias resistance-area (R0A) product is 5 ∼ 10⁴µ-cm²at 195K and µ10⁷Ω-cm²at 140K. The demonstrated performance of HgCdTe photovoltaic devices tailored for a 2.7 µm cut-off is considerably better than conventional PbS photodetectors, which have appeared in available literature and which are currently in wide use in this spectral range.     

Electronic conductance in binomially tailored quantum wire

We have studied the electronic transmission properties through binomially tailored waveguide quantum wires with Dirac delta function potentials. The potential's strength is weighted according to the binomial distribution law. We have assumed that single free-electron channel is incident on the structure and the scattering of electrons is solely from the geometric nature of the problem. We have used the transfer matrix method to study the electron transmission. We found that this structure pattern allows us to have well-defined allowed conduction bands due to transmission resonance. We also found that the electronic conductance spectrum depends on the number of the Dirac delta function potential in the quantum wire. When the number of Dirac delta function potentials in the structure and their strengths are increased, both well-defined conductance bands and sharper and narrower forbidden bands are formed.     

Low-Power Application-Specific Processor for FFT Computations

In this paper, a processor architecture tailored for radix-4 and mixed-radix FFT computations is described. The processor has native support for power-of-two transform sizes. Several optimizations have been used to improve the energy-efficiency of the processor and experiments show that a programmable solution can possess energy-efficiency comparable to fixed-function ASICs.     

Establishing academic programs in integrated media systems

For four years, we have been developing a wide range of graduate and undergraduate degree programs related to integrated media systems on behalf of the Integrated Media Systems Center (IMSC), for the School of Engineering at the University of Southern California (USC). The IMSC is a National Science Foundation Engineering Research Center (ERC) that became operational in 1996. It is not an academic department; however, one of its important missions is education. Most of the developed degree programs have been for engineering students, but one is available to all students. These degree programs are administered either by an academic department (e.g., computer science) or by an assistant dean of the School of Engineering. The purpose of this article is to not only describe these degree programs, but to also provide some lessons that have been learned along the way, lessons that may help expedite the development of similar programs at other universities     

Skeletonisation of binary patterns: a heuristic approach

Conventional algorithms which have been proposed for the skeletonisation of digital patterns or pictures suffer from basic problems (for example, endpoint identification, connectivity) deriving from the rigid application of fixed rules. This letter introduces a heuristic approach to the problem which overcomes such difficulties and may be tailored to suit different types of data.     

Predictors of support for doctoral programs in media information technologies

This study assesses interest in curricular development in new technologies among communication faculty, with a focus on doctoral-level programs. Diffusion of innovations theory explains both individual- and organizational-level factors that may account for adoption of innovations, including those stemming from new technologies. In the field of communication, media information technology programs represent an organizational-level innovation of clear importance but with uncertain faculty support, due to individual factors (e.g., interest area, age) and departmental constraints (e.g., lack of resources). In light of this, several research questions are advanced to address: (1) the current level of support for media information technology programs among communication faculty members and (2) predictors of faculty interest in having more media information technology programs. Data were collected through a random sample of faculty members who filled out a survey on the World Wide Web. Results indicate that media information technology programs are viewed by faculty as the most needed type of program in the field of communication. Findings from a logistic regression analysis also reveal several predictors of support for new technology programs, including male gender, support for organizational communication programs, support for programs focusing on mass communication, and the belief that multimedia teaching facilities are important. The implications of these findings are discussed, with an emphasis on their relevance to faculty working in communication and related fields.     

用多线程技术实现Windows 95下异步串行通信

Windows 95是当今用户最为喜爱的操作系统,基于其上的应用程序具有统一的风格和极其友好的界面。本文分析了基于Windows 95平台上的异步串行通讯程序开发方法,并结合工作实践,给出编程的一般步骤。     

The role of computer modeling and simulation in electric and hybrid vehicle research and development

Computer modeling and simulation is widely used in support of electric and hybrid vehicle research and development. Many modeling-assisted studies and assessments, involving candidate technology comparisons, have been performed to provide information for management planning and research decisions. Modeling has also been extensively used in engineering activities including preliminary and final design optimization. A wide range of programs has been developed including small ones for use on hand-held programmable calculators and large programs involving more than 11 000 lines. Many programs exist in the public domain, and two major programs are available on commercial time-sharing systems.     

Biomimetic Carbon Nanotube Films with Gradient Structure and Locally Tunable Mechanical Property

Naturally existing materials often acquire unique functions by adopting a gradient structure with gradual change in their microstructure and related properties. Imparting such an elegant structural control into synthetic materials has been a grand challenge in the field. Here, the concept of gradient structure into macroscopic carbon nanotube (CNT) films is employed and the CNT arrangement from well‐aligned array to completely random distribution, in a continuous and smooth way, is changed. Gradient films with tailored aligned‐to‐random transition rate or multilevel hierarchical structures with repeated transition have been fabricated. Local deformation and mechanical properties are directly related to the arrangement of CNTs and can be tailored by Herman's orientation factor; in particular, the elastic modulus and stiffness span over several orders of magnitude from aligned to random regions within a single monolithic film. Controlled synthesis of macroscopic CNT gradient structures with tunable mechanical properties opens a potential route toward manufacturing biomimetic functional materials with locally optimized design.