计算多芯片多基片模块稳态热场的层次模型

提出的层次模型将包括多芯片多基片模块的复杂热场模拟，分解为有确定耦合关系的形状简单的层次单元的热场计算，通过迭代将分区计算结果连成模块的热场.在计算一个层次单元(芯片、基片或底座)的热场时，将其所在的层次单元(母层次单元)的上表面温度，作为该层次单元下表面的边界条件，而把它上表面上的层次单元(子层次单元)的下表面的向下热流作为置于它上表面的等效热源.通过芯片→基片→底座→基片→芯片→基片…的几轮迭代就可收敛到正确值.提出的层次单元间的耦合强度(即每轮计算中，母层次单元上表面的温度改变不是全部，而是部分用于更新其子层次单元的下表面的边界条件)保证了所有情况下的迭代收敛.层次模型算法不仅速度数量级地高于普通的模块一体计算，而且热场与产生它的热源关系清楚，便于指导模块设计.计算与测量在实验误差(5℃)内符合.     

模拟器件稳态热场正确性的判断方法

对稳态热场 ,二个水平剖面 A和 B所夹的薄层上的温差必须严格等于本文提出的平均值定理的计算值 .当芯片、基片和底座的截面大小一样时 ,可以直接根据平均值定理计算出芯片、基片和底座的每一水平剖面上的平均温度 ,通常可以手工完成 ;当芯片、基片和底座的截面大小不一样时 ,可以通过数据合成根据平均值定理计算出芯片、基片和底座的每一水平剖面上的平均温度 .如果计算中有的参数如沟道长度不十分清楚时 ,应作模拟了解该参数对热斑温度的影响 ,必要时对该参数进一步了解以保证模拟精度 .     

模拟器件稳态热场正确性的判断方法

对稳态热场,二个水平剖面A和B所夹的薄层上的温差必须严格等于本文提出的平均值定理的计算值．当芯片、基片和底座的截面大小一样时,可以直接根据平均值定理计算出芯片、基片和底座的每一水平剖面上的平均温度,通常可以手工完成;当芯片、基片和底座的截面大小不一样时,可以通过数据合成根据平均值定理计算出芯片、基片和底座的每一水平剖面上的平均温度．如果计算中有的参数如沟道长度不十分清楚时,应作模拟了解该参数对热斑温度的影响,必要时对该参数进一步了解以保证模拟精度．     

MCM—L:多层PCB的一个动态演变

采用现有元器件封装技术的表面安装设计正很快接近基片(substrate,以下同)密度限制。一个可能的解决办法是使用多芯片模块(MCM)或更确切地说,是层压基片的改型,称作(MCM-L)。MCM-L技术还处于初期,它要从现有表面安装技术(SMT)中吸取优点,并突破现有技术。从设计和制造角度看,MCM-L是多层印制板(PCB)应用中元器件组装的下一个合乎逻辑的步聚。     

精确预计SiBJT微波功率器件峰值结温的方法

三维全热程热电一体地模拟了 Si BJT微波功率器件 .热场计算包括从芯片的有源区经芯片 -粘接层 -基片 -粘接层 -底座直到固定于 70℃的安装台面的整个散热过程 .在处理热电正反馈时把有源区的 6 0个基本单元 (子胞 )当成 6 0个并联子胞晶体管进行建模 ,子胞模型包括子胞晶体管本身、基区横向扩展电阻、发射区横向扩展电阻 .热电一体分析除了涉及 Vbe随温度变化外 ,还有子胞发射极有效面积随子胞发射极电流上升而下降的效应 (以下称面积效应 ) .与对有源区各点直接进行分析相比 ,子胞建模不仅大大简化了计算 ,而且摸拟结果与器件结构、版图结构、工艺参     

表面响应法在埋置型大功率多芯片微波组件热布局中的应用研究

该文将有艰元模拟与基于统计试验的表面响应法(RSM)相结合,应用于特定需求的埋置型大功率多芯片微波组件热布局分析中,先通过ANSYS温度场分析,得出大功率芯片布局是影响整体温度和芯片结温的关键因素,再对一含有四个大功率芯片的微波组件模块进行了表面响应分析,得到了关于芯片坐标的线性回归方程,利用该方程可预测坐标组合下芯片...     

挠性多层板上的多芯片模块

Teledyne电子技术印制电路技术商业公司对高密度互联过程进行了开发。这种新的电子封装形式,叫作挠性多层板上的多芯片模块(MCM—LF),允许半导体器件直接连到多层挠刚印制电路上。MCM—LF使多芯片封装能在一块低成本基片上完成。这将允许工程人员缩小电子模块的总尺寸,从而提高了其可靠性。MCM—LF由一些类似于当前用来制造     

用有限元法讨论光抽运垂直外腔面发射半导体激光器的散热性能

多物理场耦合有限元方法被用来模拟光抽运垂直外腔面发射半导体激光器(OPS-VECSEL)内部的热分布情况,特别对OPS-VECSEL芯片帽层表面与金刚石散热片毛细键合(capillary bond)的情况做了计算.计算表明,在没有金刚石散热片的情况下,从窗口以下首个量子阱到末个量子阱的温差达到150 K;在有金刚石散热片的情况下,器件中各个量子阱的温差很小,其共振波长差只有几纳米;在芯片的分布式布拉格反射镜(DBR)一侧焊接有硅微通道冷却器的情况下,各量子阱间的温差进一步减小,器件性能得到最大改善.模拟计算也表明,在抽运功率不变的情况下,适当增加抽运光的半径,可显著降低器件的热效应,尤其热透镜效应.     

基于热-流-力耦合计算的多芯片组件布局构形优化

基于构形理论和多物理场耦合数值计算方法,建立了自然对流条件下均匀产热的多芯片组件模型,给定印刷电路板面积和芯片总占地面积为约束条件,分别以最高温度、最大应力和最大形变为优化目标,以芯片个数及芯片长宽比为设计变量,研究了芯片布局演化对系统性能的影响.结果 表明:不同优化目标下,最优构形均为芯片长宽比为2.1的8芯片布局方式,多芯片组件的最高温度、最大应力和最大形变分别最多可降低16.5％,28.3％和26.9％.对芯片个数和芯片长宽比双自由度的优化效果要明显优于仅对芯片长宽比的单自由度优化.     

多芯片组件热分析技术研究

多芯片组件(MCM)是实现电子系统小型化的重要手段之一。由于封装密度大、功耗高，MCM内部热场对器件的性能和可靠性的影响日益严重。文章讨论了MCM内部热场影响器件可靠性的机理，比较了MCM热场计算的方法和特点，研究了有限元分析的方法和求解过程，进行了实际计算，并提出了几种有效的降低MCM结温的方法。     

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.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.