Au／In等温凝固芯片焊接工艺研究

本文研究了Ａｕ／Ｉｎ等温凝固芯片焊接工艺。对机械振动,压力,Ａｕ,Ｉｎ镀层厚度,衬底的表面平整度等因素对焊层的剪切强度,结构和热疲劳可靠性的影响进行了分析和优化。     

Au/In合金在陶瓷封装装片中的应用

本文用等温凝固技术研究了Ａｕ－Ｉｎ合金正在陶瓷封装装片中的应用。结果表明，通过一种多层结构设计和机械振动的作用，硅芯片可在２５０℃￣３００℃、２．１Ｎ／ｍｍ＾２的静态加载压力和流量为０．５１／ｍｉｎ的氮气环境下焊接到氧吕衬底上，绝大多数样品的剪切强度符合ＭＩＬＳＴＤ８８３Ｄ美国军方标准，焊层具有良好的可能性，在－５５℃￣＋１２５℃之间１７５０周热循环试验后，剪切强度仅有微量下降。同时，用金相方法对     

Cu/Sn等温凝固芯片键合工艺研究

研究了Cu/Sn等温凝固芯片键合工艺,对等离子体处理、键合气氛、压力以及Sn层厚度等因素对焊层的键合强度的影响进行了分析和优化。实验表明,等离子体处理过程的引入是保证键合质量的重要因素,在功率500W、时间200s的处理条件下,得到了最大的键合强度;而键合气氛对键合质量有显著的影响,在真空环境下,能得到最佳的键合质量;压力对键合质量的影响较小,施加较小的压力(0.05MPa)即能得到较大的剪切强度;而Sn层厚度对键合质量的影响极小,而较薄的厚度能够缩短键合时间。在最优化条件下,得到的键合强度值全部达到了美军标规定的6.25MPa的强度要求(对于2mm×2mm芯片)。     

钛合金焊接凝固结晶控制的研究

由于焊缝金属中粗大的柱状β晶粒组织严重影响其力学性能及耐蚀性,钛合金焊接凝固结晶方面的研究工作一直颇受重视。综述了该方向有代表性的研究成果,并介绍了本人利用电子束扫描控制焊接凝固结晶取得的一些结果。     

快速凝固耐热铝合金焊接技术的研究现状

阐述了快速凝固耐热铝合金焊接研究现状,分析了快速凝固耐热铝合金的焊接性,讨论了钨极氩弧焊、电容放电焊、电子束焊、激光焊、摩擦焊以及钎焊在快速凝固耐热铝合金材料连接中的应用和存在的问题,指出具有高能量密度、低能量输入的电子束焊、激光焊以及摩擦焊适于快速凝固耐热铝合金的焊接.     

带式输送机滚筒失效原因分析及其焊接工艺研究

带式输送机是用于散料输送的重要设备,滚筒作为带式输送机中的重要组成部件,其结构性能、可靠性和使用寿命直接影响到带式输送机的性能,其作用更是举足轻重。而焊接工序是滚筒加工制作中的重中之重,该文通过对带式输送机滚筒失效原因进行分析并对焊接工艺进行了研究,在保证焊接质量的前提下,制定出了满足生产需求的焊接工艺。     

高温锅炉管T22/TP347H异种钢焊接接头早期失效原因

采用化学成分分析、力学性能测试、金相检验和硬度测试等方法，分析了T22/TP347H异种钢焊接接头早期失效的原因。结果表明：在T22钢侧熔合区发现了氧化缺口；T22钢与焊缝的边界附近存在元素浓度梯度，产生了马氏体脆化层。建议选用合金元素含量更高的焊材或者镍基焊材，避免早期失效的发生。     

舰用锅炉耐火纤维材料的失效模式和失效机理研究

针对舰用锅炉现用硅酸铝质耐火纤维材料，采用晶相显微分析、X-射线衍射分析(XRD)和激光粒度分析(LMS)等现代材料分析手段对其失效模式和失效机理进行了研究分析，研究结果为新型耐火材料的研制或改进提供了重要依据．     

基于客户机/服务器模式的航空产品失效案例共享系统

在对国内外航空产品失效案例进行收集和整理的基础上,设计和开发了基于客户机/服务器(C/S)体系结构的航空产品失效案例共享系统.该系统由客户端程序、应用服务器程序以及后台数据库三部分组成,采用SQL Server 2000作为数据库管理系统,采用VC++作为客户端程序和应用服务器程序的开发工具.对系统体系结构、功能模块、...     

空间结构压杆的套管加固失效模式试验研究

空间结构压杆失稳是结构失效的重要原因之一。利用套管加固空间结构压杆以抑制压杆屈曲,增加构件的极限承载能力和延性。通过对不同壁厚、套管与内压杆间隙和内压杆外伸段长度的12根试件进行轴压试验,得到加固前后试件的极限承载能力、破坏模式和延性变化。加固后试件的极限承载能力最大提高了147%,且外套管壁厚越大,内压杆外伸段越短,承载力越高;内压杆与外套管间隙越大,承载力略有下降。加固试验中构件的破坏模式由加固前的整体屈曲失稳变化为加固后的整体失稳、内压杆端部外伸段失稳和两种耦合失稳,且壁厚越小,易发生整体失稳,外伸段越长,易发生内压杆端部失稳,间隙对失稳形态影响不明显。此外,加固后试件延性均大于未经加固内压杆,经过合理设计延性指标能够增加一倍以上。     

The Au/Si bonding interface studied by infrared microscope

The interface of Au/Si(100) eutectic bonding was studied by infrared microscope. During Au/Si(100) bonding, the dissolution of the Si(100) surface primarily occurs by the formation of the craters which result in many square black spots in the IR images. The formation of the craters is ascribed to the anisotropic nature of Au/Si reaction that results in three-dimensional dissolution behavior on the bare Si(100) side. In order to further test the anisotropy hypothesis, Au/Si(111) bonding was also studied. Under the same bonding conditions, triangular black spots were observed in the IR images and triangular pits were found on the Si(111) surface.     

Effects of boron and silicon on microstructure and isothermal solidification during TLP bonding of a duplex stainless steel using two Ni–Si–B insert alloys

Abstract

The influence of B and Si on microstructure and isothermal solidification during transient liquid phase (TLP) bonding of a duplex stainless steel using MBF-30 (Ni–4·5Si–3·2B, wt-%) and MBF-35 (Ni–7·3Si–2·2B, wt-%), was investigated. Based on experimental studies, the formation of Ni₃B within the joint centreline is dependent on B content; the morphology of Ni₃Si is dominated by Si concentration. There was a deviation between the times for complete isothermal solidification obtained by the experiment and the conventional TLP bonding model. Isothermal solidification of the liquid dependent on different solidification regimes is suggested to be a controlling factor contributing to the change in the rate of isothermal solidification observed using the two filler metals.     

两步镀膜Ti/Al/Ti/Au的n型GaN欧姆接触研究

报道了一种可靠稳定且低接触电阻的n型GaN欧姆接触。首先在掺硅的n型GaN(3×1018cm-3)蒸镀Ti(30nm)/Al(500nm),然后在氮气环境530℃合金化3min,最后蒸镀Ti(100nm)/Au(1000nm)用于保护Al层不被氧化。该接触电极有良好的欧姆接触特性,比接触电阻率为8.8×10-5Ωcm2,表面平坦、稳定、易焊线,可应用于制作高性能的GaN器件.     

直流磁控溅射法制备金钆多层膜

本文介绍了直流磁控溅射方法制备Au／Gd多层膜，探索了多层膜的制备工艺参数，利用X射线衍射表征了多层膜的界面结构及混和膜的晶型结构，原子力显微镜观察了膜的表面形貌和粗糙度。成功地制备了膜层厚度控制精确、界面清晰和表面光洁的Au／Gd多层膜。     

A hybrid approach for identification of root causes and reliability improvement of a die bonding process—a case study

This paper presents an industrial case study on reliability improvement of the die bonding machine in the semiconductor industry. A hybrid approach combining dynamic analysis, process decomposition, and a structured fault tree was used to analyze the die bonding process. Firstly, the process was analyzed technically and decomposed into several stages according to different motions. Then, the die movement and force balance at each stage were analyzed according to physical laws, to identify the root causes of die rotation. A structured fault tree was then constructed to trace all possible causes and effects. A qualitative approach was used to identify critical events (root causes) for further analysis. Experiments were conducted to modify the bonding process to reduce the effects of the critical events. Finally, further process modification was proposed for simplification of the fault tree. This case study combined the knowledge in control and reliability engineering and presented a hybrid approach, which is very useful for practising engineers.     

地聚合物固化/稳定化重金属的影响因素及作用机制

地聚合物是指采用天然矿物或固体废弃物及人工硅铝化合物为原料,在碱性条件下通过矿物缩聚而形成的三维网状聚合胶凝材料。地聚合物独特的结构与性质使其在固化/稳定化重金属方面具有明显优势,近年来已成为国内外研究热点。针对地聚合物固化/稳定化重金属,重点阐述了影响地聚合物固化/稳定化重金属效果的重要因素,并综述了国内外研究者对地聚合物固化/稳定化重金属作用机制的研究成果。     

Low cycle fatigue behavior of a eutectic 80Au/20Sn solder alloy

The eutectic 80Au/20Sn solder alloy is widely used in high power electronics and optoelectronics packaging. In this study, low cycle fatigue behavior of a eutectic 80Au/20Sn solder alloy is reported. The 80Au/20Sn solder shows a quasi-static fracture characteristic at high strain rates, and then gradually transforms from a transgranular fracture (dominated by fatigue damage) to intergranular fracture (dominated by creep damage) at low strain rates with increasing temperature. Coffin-Manson and Morrow models are proposed to evaluate the low cycle fatigue behavior of the 80Au/20Sn solder. Besides, the 80Au/20Sn solder has enhanced fatigue resistance compared to the 63Sn/37Pb solder.