微电子封装中芯片焊接技术及其设备的发展

概述了微电子封装中引线键合、载带自动键合、倒装芯片焊料焊凸键合、倒装芯片微型焊凸键合等芯片焊接技术及其设备的发展 ,同时报告了世界著名封装设备制造公司芯片焊接设备的现状及发展趋势。     

叠层芯片应用的封装挑战与解决方法

叠层管芯封装的不断发展导致该技术能有效地在同一基底内增大电子器件的功能和容量,作为单个芯片。蜂窝电话及其它消费类产品中叠层芯片封装的应用增长促使能够在给定封装尺寸中封装多层芯片。介绍了叠层芯片封装技术中最主要是满足总封装高度的要求。用于叠层芯片封装的技术实现方法包括基片减薄、薄裸芯片贴装、小形貌引线键合、与无支撑的边缘键合以及小偏倒成形等。集中介绍了叠层管芯互连要求。介绍了倒装芯片应用中的正向球形键合、反向球形键合和焊凸凸焊技术,讨论了优点和不足。说明球形键合机的发展能够满足叠层芯片封装的挑战,即超低环形状、长引线跨距和悬空键合等。     

用硅压阻应力传感器研究倒装芯片封装应力

电子封装是集成电路产品制造过程中的重要环节,而电子封装所产生的应力则可能会对芯片的性能及可靠性产生影响,因而受到业界的广泛关注。利用半导体压阻效应制造硅压阻应力传感器阵列芯片,将其倒装键合至印刷电路板,填充不同类型的下填料进行固化。通过测量应力传感器芯片上的力敏电阻变化,计算倒装键合和下填料固化等封装工艺引入的应力,并讨论了下填料的性能参数对芯片应力大小的影响。此外,在标定力敏电阻及压阻系数温度效应的基础上,对下填料固化过程的应力变化进行了实时监测,分析了下填料固化工艺引起的应力。     

金凸点键合工艺在国产陶瓷外壳中的应用

国产陶瓷外壳已经逐渐应用于高可靠要求的各类电子元器件的封装上。在IC封装过程中, 随着封装密度的提高,因其键合指状引线的质量难以满足键合工艺要求,为使其能达到工艺控制要求, 我们开发出一些相应的封装技术,提高了产品的可靠性。金凸点键合工艺用于提高国产陶瓷外壳键合指 上的键合引线强度有非常明显的效果,是一项较新的技术。     

先进封装技术的发展趋势

先进封装技术不断发展变化以适应各种半导体新工艺和材料的要求和挑战。在半导体封装外部形式变迁的基础上,着重阐述了半导体后端工序的关键-封装内部连接方式的发展趋势。分析了半导体前端制造工艺的发展在封装技术上的反映。提出了目前和可预见的将来引线键合作为半导体封装内部连接的主流方式与高性能/高成本的倒装芯片长期共存,共同和硅片键合应用在SiP、MCM、3D等新型封装当中的预测。     

BGA封装技术

本文简述了BGA封装产品的特点、结构以及一些BGA产品的封装工艺流程,对BGA封装中芯片和基板两种互连方法——引线键合/倒装焊键合进行了比较以及对几种常规BGA封装的成本/性能的比较,并介绍了BGA产品的可靠性。另外,还对开发我国BGA封装技术提出了建议。     

采用热压焊工艺实现金凸点芯片的倒装焊接

金凸点芯片的倒装焊接是一种先进的封装技术.叙述了钉头金凸点硅芯片在高密度薄膜陶瓷基板上的热压倒装焊接工艺方法,通过设定焊接参数达到所期望的最大剪切力,分析研究互连焊点的电性能和焊接缺陷,实现了热压倒装焊工艺的优化.同时,还简要介绍了芯片钉头金凸点的制作工艺.     

倒装芯片的底部填充材料和涂布

倒装芯片是当今半导体封装领域的一大热点,它既是一种芯片互连技术,更是一种理想的芯片粘接技术。以往后级封装技术都是将芯片的有源区面朝上,背对基板粘贴后键合(如引线键合和载带自动键合TAB)。而倒装芯片则是将芯片有源区面对基板,通过芯片上呈阵列排列的焊料凸点来实现芯片与衬底的互连。显然,这种芯片互连的方式能够提供更高的I/O密度。     

引线键合技术进展

引线键合以工艺简单、成本低廉、适合多种封装形式而在连接方式中占主导地位.对引线键合工艺、材料、设备和超声引线键合机理的研究进展进行了论述与分析,列出了主要的键合工艺参数和优化方法,球键合和楔键合是引线键合的两种基本形式,热压超声波键合工艺因其加热温度低、键合强度高、有利于器件可靠性等优势而取代热压键合和超声波键合成为键合法的主流,提出了该技术的发展趋势,劈刀设计、键合材料和键合设备的有效集成是获得引线键合完整解决方案的关键.     

高密度集成技术与电子装备小型化

小型化和一体化是未来电子装备的主流发展方向。电子装备的小型化和一体化离不开高密度集成技术,三维芯片堆叠、芯片倒装焊接、高密度多层布线基板和SIP封装等高密度集成技术在国内的研究正在兴起。未来的电子装备不仅仅是由一个个元器件组装而成,而是电路和封装密不可分的一个3D互连系统。     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

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.     

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.