大规模红外探测器冷箱结构的优化设计

针对大规模红外探测器的封装需求,介绍了冷箱封装结构的设计方法和特点。根据不同类型的大规模红外探测器组件的用途和需求,对其封装结构、重量、热负载以及可靠性等进行了分析,并针对某型大规模红外探测器组件的封装结构开展了优化设计。以轻量化、低功耗为设计思路,采用有限元仿真工具对封装结构进行了优化设计,使其能够满足设计要求。     

热光效应的微流体光波导结构分析

提出了一种基于微流控芯片由热光效应引起的微流体光波导结构。光波导芯层及覆层材料均为微通道中同种不同温度的液体。在微通道的上下面分别设计金属铜电极,在电极两端施加电压,对通道内液体加热。通过液体热传导,使得接近沟道壁边缘层与沟道中间层之间产生由高到低的温度分布。根据液体热光效应,液体在不同温度下折射率不同,沿着通道壁边缘层到通道中间层之间折射率由低到高,实现折射率渐变型平面光波导。电极两端所施加的电压大小及加热时间长短控制微沟道内温度高低,温度的高低决定了液体折射率分布,从而调节光波导实现单/多模传输。这种可调谐光波导结构可望在微流控光学器件中得到应用。     

方兴未艾的OLED

OLED的相关技术 OLED器件的结构通常如图1所示,在每个像素的阴阳电极之间包括有五层薄膜：HIL、HTL、EML、ETL和EIL,这五层薄膜的总厚度只有100～200nm左右。整个镀膜制程是在高真空环境下完成的;像素与像素之间用绝缘材料隔开,以防止加电时的相互串扰;由于有机材料和金属阴极对水气和氧气特别敏感,因此在封装制程中使用了水蒸气和氧气渗透率极低的密封胶和封盖,并在器件内部加了干燥剂用于吸收内部极少量的水蒸气和氧气成分,同时为了保证能充分将其隔离,封装制程必须在纯度高达99．999％的氮气环境下完成。     

关于LED单灯正向电压VF不良的探讨

文章基于LED芯片和LED单灯的工作原理和制程工艺,探讨了LED芯片封装以后正向电压K升高和降低的常见原因,并提出了改善措施。对于GaN基双电极芯片,由于芯片工艺制程或后续封装工艺因素,造成芯片表面镀层（ITO或Ni／Au）与P—GaN外延层之间的结合被破坏,欧姆接触电阻变大。对于GaAS基单电极芯片,由于封装材料和工艺因素,导致芯片背金（N—electrode）与银胶,或银胶与支架之间的接触电阻变大,从而LED正向电压VF升高。LED正向电压VF降低最常见的原因为芯片PN结被ESD或外界大电流损伤或软击穿,反向漏电过大,失去了二极管固有的I-V特性。     

威刚A-DATA DDR2 533内存

威刚A-DATA DDR2 533内存的标准规格为240针脚、1．8V工作电压，且依据JEDEC（美国电子工程设计发展联合协会）的标准规范，采用最先进的0．10微米制程、FBGA封装的DDR2颗粒，成功减少IC颗粒与电路板的球面接触点，并有效降低高频工作温度与资料杂讯。且大幅提高资料传输速率并透过内建的ODT内部中断电阻设计，让主机板不用在内存旁边增加一排电阻，减少PCB的使用空间。OCD讯号校正技术让电压的上升与下降有最小的DQ—DQS SKEW（时钟讯号偏离），提升讯号质量。以及提高汇流排效率的Posted CAS功能，使DDR2 533成功突破DDR的速度限制，缔造出每秒资料访问与输出量比DDR高出一倍的优异效果，真正达到每秒3．2G的极速资料传输带宽。     

铝合金封装用微矩形连接器气密焊接工艺

铝合金是微波组件封装的优选材料,微距形连接器是高密度电子封装中的关键元器件.但是由于铝合金与柯伐外壳的微距形连接器之间存在严重热失配,导致封装不具备长期气密性.针对此问题,设计了四种集成微矩形连接器的铝合金封装方案,通过有限元分析、仿真分析和试验验证,制定了最佳的封装方案.     

面向引线框架封装的热阻建模与分析

针对通用的QFP48引线框架封装,首先探讨了封装中的热传输机制,给出了热阻的理论计算结果;接着利用Ansys Icepak软件建立起QFP48的有限元模型,热阻仿真结果较好地验证了热传输机制的理论分析;最后讨论了减小封装热阻、提高热可靠性的方法。结果表明:适当提高塑封材料的热传导率、增加PCB面积和施加一定风速的强迫对流均可降低QFP48封装的热阻,提高散热效果。     

多波长集成光源阵列封装用微波馈线设计

针对多波长集成光源阵列封装设计了一种具有低传输损耗、低串扰的阵列微波馈线。通过分析微带线和接地共面波导在传输高频微波信号时的优缺点,设计了一种桥型微波馈线结构。同时利用有限元法,对馈线尺寸参数进行仿真优化。在30GHz范围内,得到了反射系数低于-17dB、传输损耗小于0.4dB、相邻信号电极间串扰小于-26dB的仿真结果。设计了基于金线键合的阵列芯片方案,并通过有限元法仿真确定了传输性能良好的封装间距。     

晶圆级树脂基低成本W波段封装天线微系统

面向W波段探测与通信系统的小型化、低成本应用需求,本文采用晶圆级树脂基扇出型封装工艺,通过对有源封装天线集成架构、互连传输结构和天线阵列进行设计与仿真,设计了一款工作频率为94 GHz的封装天线微系统。该封装天线微系统集成了4×4磁电偶极子阵列天线和16通道幅相多功能射频芯片。通过Ansys HFSS全波仿真,系统波束扫描范围在E面≥±30°,H面≥±40°,在7.1 mm×8.3 mm×1.2 mm封装尺寸内实现了封装天线等效全向辐射功率≥39.1 dBm。该封装天线微系统具备规模扩展能力,可广泛应用于探测、通信以及安检等领域。     

高速BGA封装与PCB差分互连结构的设计与优化

随着电子系统通信速率的不断提升,BGA封装与PCB互连区域的信号完整性问题越来越突出。针对高速BGA封装与PCB差分互连结构进行设计与优化,着重分析封装与PCB互连区域差分布线方式,信号布局方式,信号孔/地孔比,布线层与过孔残桩这四个方面对高速差分信号传输性能和串扰的具体影响。利用全波电磁场仿真软件CST建立3D仿真模型,最后时频域仿真验证了所述的优化方法能够有效改善高速差分信号传输性能,减小信号间串扰,实现更好的信号隔离。     

Gold Stud Bumps Flip-Chip Bonded onto Copper Electrodes with Titanium and Silver Layers

The purpose of this study was to develop the thermosonic flip-chip bonding process for gold stud bumps bonded onto copper electrodes on an alumina substrate. Copper electrodes were deposited with silver as the bonding layer and with titanium as the diffusion barrier layer. Deposition of these layers on copper electrodes improves the bonding quality between the gold stud bumps and copper electrodes. With appropriate bonding parameters, 100% bondability was achieved. Bonding strength between the gold stud bumps and copper electrodes was much higher than the value converted from the standards of the Joint Electron Device Engineering Council (JEDEC). The effects of process parameters, including bonding force, ultrasonic power, and bonding time, on bonding strength were also investigated. Experimental results indicate that bonding strength increased as bonding force and ultrasonic power increased and did not deteriorate after prolonged storage at elevated temperatures. Thus, the reliability of the high-temperature storage (HTS) test for gold stud bumps flip-chip bonded onto a silver bonding layer and titanium diffusion barrier layer is not a concern. Deposition of these two layers on copper electrodes is an effective and direct method for thermosonic flip-chip bonding of gold stud bumps to a substrate, and ensures excellent bond quality. Applications such as flip-chip bonding of chips with low pin counts or light-emitting diode (LED) packaging are appropriate.     

先进封装和MEMS应用的超厚抗蚀剂光刻技术(英文)

微电子机械系统(MEMS)制造和先进的封装技术更需要厚抗蚀剂层。在MEMS应用领域包括体硅微机械加工、表面微机械加工和有源器件结构的实际制作。对先进的封装技术,应用再分布和蚀化层以及金属焊凸微成型。各种用途要求抗蚀剂厚度能达到和超过1000μm。为适当地获得这些厚度,制造商开发了适当的涂层材料。这些材料包括AZP4620.ShipleySPR220\AIPLP100XT、JSRTHB611P和SU-8。最终开发了处理这些材料的设备,制作了专用的涂胶设备和接触?接近式曝光机。     

Increasing the bonding strength of chips on flex substrates using thermosonic flip-chip bonding process with nonconductive paste

Thermosonic flip-chip bonding process with a nonconductive paste (NCP) was employed to improve the processability and bonding strength of the flip-chip onto flex substrates (FCOF). A non-conductive paste was deposited on the surface of the copper electrodes over the flex substrate, and a chip with eight gold bumps bonded onto the copper electrodes by the thermosonic flip-chip bonding process.For the chips and flex substrates assembly, ultrasonic power is important in the removal of some of the non-conductive paste on the surface of copper electrodes during thermosonic bonding. Accordingly, gold stud bumps in this study were directly bonded onto copper electrodes to form successful electrical paths between chips and the flex substrate. A particular ultrasonic power resulted in some metallurgical bonding between the gold bumps and the copper electrodes, increasing the bonding strength. The ultrasonic power was not only to remove the NCP from the copper electrodes, but also formed metallurgical bonds during the thermosonic flip-chip bonding process with NCP.In this study, the parameters of the bonding of chips onto flex substrates using thermosonic flip-chip bonding process with NCP were a bonding force of 4.9 N, a curing time of 40 s, a curing temperature of 140 °C and an ultrasonic power of 14.46 W. The processability and bonding strength of flip-chips on flex substrates using thermosonic bonding process with NCP was verified in this study. This process has great potential to be applied to the packaging of consumed electronic products.     

用于3D封装的带TSV的超薄芯片新型制作方法

提出了一种应用于3D封装的带有硅通孔(TSV)的超薄芯片的制作方法。具体方法为通过刻蚀对硅晶圆打孔和局部减薄,然后进行表面微加工,最后从硅晶圆上分离出超薄芯片。利用两种不同的工艺实现了TSV的制作和硅晶圆局部减薄,一种是利用深反应离子刻蚀(DRIE)依次打孔和背面减薄,另一种是先利用KOH溶液湿法腐蚀局部减薄,再利用DRIE刻蚀打孔。通过实验优化了KOH和异丙醇(IPA)的质量分数分别为40%和10%。这种方法的优点在于制作出的超薄芯片翘曲度相较于CMP减薄的小,而且两个表面都可以进行表面微加工,使集成度提高。利用这种方法已经在实验室制作出了厚50μm的带TSV的超薄芯片,表面粗糙度达到0.02μm,并无孔洞地电镀填满TSV,然后在两面都制作了凸点,在表面进行了光刻、溅射和剥离等表面微加工工艺。实验结果证实了该方法的可行性。     

Silicon-based micromachined packages for high-frequencyapplications

A novel low-cost packaging approach is presented in this paper, which is appropriate for high-frequency electronic circuits in discrete, as well as integrated, configurations. This approach is based on silicon micromachining and can effectively provide on-wafer and discrete packaging for high-quality high-precision miniature components. The required fabrication techniques are compatible with standard integrated-circuit processing and, for this reason, are low in fabrication costs. As an example, this paper presents the development of a Ka-band package that can shield and electromagnetically isolate monolithic-microwave integrated-circuit components, such as a phase shifter. The performance of this package is compared to that of a ceramic one and demonstrates excellent electrical response in addition to high design versatility     

梁式封装二极管的微组装技术

该文介绍了梁式封装二极管(BED)的微组装技术(MPT)的现状及其问题,重点对超声热压倒装焊与粘胶互联进行了实验与仿真,分析了不同电极与基板镀层等因素对装配方案的影响,并通过受力实验进行验证。提出了有效规范的装配方案和可靠、易行的工程结论,解决了梁式封装二极管装配方案混乱,批量一致性差,调试难度大,成本高等问题。     

Fully packaged, broad-band LiNbO3 modulator with lowdrive voltage

A low drive voltage of ~5 V at 40 GHz has been achieved in a fully packaged, broad-band LiNbO₃ modulator. The excellent response is attributed to nearly perfect velocity and impedance matching, along with very long electrodes (41 mm), low electrode losses, and minimal packaging effects. Very accurate frequency-dependent drive voltages are obtained by the use of independent sets of measurements     

纳米、亚微米的超窄脉宽微细电化学加工

通过分析超窄脉冲实现纳米、亚微米级精度微细电解加工的机理和特点,说明脉冲电源的脉冲宽度减小至纳秒时,可将提高电解加工精度的方法综合运用,如小间隙电解加工、低浓度电解液、加工间隙的实时检测和调整控制等,从而增强电化学反应的定域蚀除能力,减小两电极的极间间隙,显著提高加工精度。构建了微细电化学加工系统,包括微细加工机床、纳秒脉冲电源、电解液循环系统、运动控制部分和加工检测部分,进行了微细加工试验。这种方法在微细成形加工、微小孔加工等方面已经取得了很好的应用效果,与其他特种微细加工技术相比具有一定的优势,在微米、纳米制造领域有着很大的发展潜能。     

Soldering method using longitudinal ultrasonic

An efficient ultrasonic soldering method of inserting the metal bumps into the solder is investigated in this work for electronic packaging. The effects of the process parameters such as the ultrasonic frequency, amplitude, dimensions of the metal bump and solder are analyzed through the viscoelastic modeling. The ultrasonic soldering was conducted using the Cu and Au bumps, and the acceptable bonding condition was determined from the tensile strength. Localized heating of the solder was achieved and the stirring action due to the ultrasonic influences the bond strength and microstructure of the eutectic solder. Since higher temperature is obtained with smaller solder, the proposed ultrasonic soldering method appears to be applicable to the high-density electronic packaging.     

飞秒激光在材料微加工中的应用

本文介绍了飞秒激光的特性以及超短脉冲激光与材料相互作用的机理，并着重指出了其与长脉冲激光的区别。飞秒激光可产生超高光强、具有精确的损伤阈值(并且损伤阈值较低较低)、很小的热影响区、几乎可精密加工所有种类材料，并且，加工精度极高，可进行亚微米尺寸的精密加工。通过分析飞秒激光材料微加工的特性，综述超短脉冲激光材料微加工的应用研究现状。