紫外光固化银包铜粉导电胶的制备及研究

以银包铜粉和环氧丙烯酸树脂为原料制备导电胶浆料,采用丝网印刷将浆料涂覆到载玻片上,置于紫外光下固化获得导电涂层。利用SEM和四探针电阻测试仪对固化后导电胶的微观结构和电学性能进行表征。结果表明:当银包铜粉质量分数为70%,导电胶固化完全,制得的导电胶电阻率最低为1.135×10~(–3)?·cm,涂层厚度为140μm。     

倒装封装用各向异性导电胶专利技术综述

如今IC器件的封装集成度越来越高,芯片的封装朝着小间距、高密度的方向发展.利用各向异性导电胶来实现高密度、高稳定性的倒装封装成为近几年的研究热点.本从国内外专利申请量、申请人等多方面进行统计分析.最后总结了在倒装封装用各向异性导电胶领域的国际、国内专利申请分布情况,并对该领域的发展路线进行了梳理.     

各向异性导电胶粘接可靠性研究进展

介绍各向异性导电胶导电机理和粘接工艺,以及影响它的粘接可靠性因素和最佳参数的研究,如粘接温度、固化时间、粘接压力、粒子含量等。对各向异性导电胶粘接可靠性中的开路、短路、接触电阻与粘接压力和温度循环的关系进行了讨论,并介绍了各向异性导电胶可靠性的理论计算模型。     

各向异性导电胶互连技术的研究进展

随着微电子封装技术的发展,各向异性导电胶作为一种绿色的连接材料,广泛应用于电子产品中。文中主要介绍各向异性导电胶互连器件的粘接原理和影响其可靠性的各种因素,如粘接工艺参数、外界环境的干扰、各向异性导电胶的物理特性等。     

ACF各向异性导电胶的工艺评价方法

ACF作为一种实装材料,可以方便地实现精细电极的导通连接。其原理是通过加热、加压、树脂受热固化、ACF中的导电粒子连接上下电极,从而实现电极固定和电极导通。实际上受ACF成份的影响,每种ACF的特性都不一样,而在生产应用中,温度、压力、时间、位置、辅助材料等因素又会对连接的效果产生影响。为了确保ACF适用于厂内的工艺,把ACF的应用风险降低。评价一种ACF的过程,通常分为单体评价、工艺评价和产品评价。文中将以屏侧ACF为例,讨论ACF工艺评价的方法。     

LED阵列型紫外光固化光源系统

提出了一种适用于紫外光固化的新型光源系统.该系统以大功率紫外光LED和光学系统组成阵列结构来实现固化光源的高辐照度,大功率LED阵列由多路可控恒流源系统控制,根据固化材料的特点外部设定驱动电流,控制光源发光强度.与常用的高压汞灯相比,该系统无需高压驱动和冷却设备,具有操作简单、固化效率高和绿色无污染等优点.实验结果表明,该系统能够发出均匀稳定的高强度紫外光.     

各向异性导电胶倒装封装电子标签的可靠性

各向异性导电胶(ACA)广泛用于RFID电子标签芯片封装,具有芯片对位方便、热压温度低和工艺时间短的优点.但ACA互连本质上是机械接触,其互连可靠性强烈依赖于粘接界面性质、胶水粘接力及环境稳定性.本文试验表明,168 h高温高湿和D20 mm心轴弯曲对芯片粘接点的电接触性能有所影响;铜模组良品率显著高于铝天线Inlay.     

使用各向异性导电胶实现封装叠加的方法

文章阐述了一种新型的基底结构,通过使用各向异性导电胶来连接两层基底,从而实现封装叠加。这种基底结构来源于一种传统的折叠基底结构,不同的是,它采用各向异性导电胶代替折叠基底结构中的弯曲区域来实现两层基底的电路和物理连接。折叠基底结构中的弯曲区域是一个弱点,其本身存在很高的断裂几率,需要大量冗余线路支撑来提高物理强度。新的基底结构不但降低了断裂几率,消除了冗余线路,而且拓广了适用性并降低成本。     

各向异性导电胶粘结工艺技术研究

分析了影响各向异性导电胶粘结可靠性的各因素,通过正交实验优化工艺参数,并在150℃高温贮存以及-65℃～150℃温度循环后对导电胶的剪切强度和接触电阻进行了可靠性实验。结果表明:影响ACA可靠性的主要因素导电粒子体积比例为15%,粘结温度200℃,时间10s,粘结压力为39.2N时,导电胶的剪切强度为286.2N,凸点的接触电阻为35mΩ。在可靠性试验后,导电胶的剪切强度满足GJB548B-2005的要求,接触电阻变化率小于5%。     

基于各向异性导电胶的板间垂直互连研究

提出一种基于各向异性导电胶(ACA)的封装方法,即利用ACA实现介质基板之间垂直互连过渡。该方法与传统的锡铅焊料工艺相比,ACA板间互连工艺具有互连距离短、固化温度低、工艺流程简单、绿色环保等特点。测试结果表明,ACA在垂直互连过程中拥有良好的微波传输性能。在0.1~19.0GHz内,回波损耗小于-10dB,插入损耗小于1.5dB;在26~30GHz频段范围内,回波损耗小于-10dB,插入损耗小于3dB。测试结果与电磁仿真结果吻合。     

Physical Factors Determining Thermal Conductivities of Isotropic Conductive Adhesives

The thermal conductivities of a typical isotropic conductive adhesive (ICA) composed of an epoxy-based binder containing flake-shaped and spherical Ag particles have been studied. The ICA specimens exhibit anisotropy in their thermal conductivities between the vertical and in-plane directions. In addition, their thermal conductivities apparently depend on their thermal history during the curing and subsequent annealing processes, even if they are fully cured during the preliminary curing stage. The thermal conductivities tend to increase with decreasing electrical resistivities. The experimental values for the thermal conductivities of the ICA specimens were apparently higher than␣those predicted using Bruggemann’s equation. Analysis using the Wiedemann–Franz (W–F) law indicates that their thermal conductivities increase with increasing contribution from electrical conduction. In order to discuss the thermal conductivities of ICA specimens that exhibit relatively low electrical resistivities (below 10⁻³ Ω cm), the contribution of the conducting electrons must be included.     

用于微电子组装的导电胶粘接剂的研究现状

综述了当前电子组装业中导电胶粘接剂的研究情况,主要介绍国外正在重点研究的几大类导电胶粘接剂及其组成,与传统锡铅焊料的对比,以及它们的电性能、机械性能、热性能等,并简要介绍其发展趋势。     

微电子封装用导电胶的研究进展

介绍了导电胶的组成、分类及与传统锡-铅焊料相比导电胶的优点。阐述了导电胶的导电机理、失效机理以及国内外的研究现状。     

导电胶粘剂的研究

文章综述了当前电子组装业中导电胶粘剂的研究情况,主要介绍国外正在重点研究的几大类导电胶粘剂及其组成,与传统锡铅焊料的对比,以及它们的电性能、机械性能、热性能等。同时简要介绍其发展趋势。     

Electrical Properties of Isotropic Conductive Adhesives Composed of Silicone-Based Elastomer Binders Containing Ag Particles

The electrical properties of isotropic conductive adhesives (ICAs) with two different types of silicone-based binder containing Ag particles were examined. The ICAs were printed on glass substrates in order to prepare specimens for evaluating the electrical properties. In the case of adhesives containing a denatured silicone binder, both the curing and cooling steps in the isothermal curing process generated electrical conductivity. Adhesives that were cured at 120°C to 200°C exhibited similar values of electrical resistivity regardless of the different curing temperatures. By contrast, electrical conductivity was generated only during the cooling step when adhesives containing a dimethyl methylvinyl siloxane were isothermally cured. In this case, adhesives cured above 160°C exhibited high electrical resistivity. In evaluating the temperature dependence of the electrical resistivity, we found physical annealing to have significantly different effects on these specimens. In addition, we were able to make small sensitive variations in the properties of silicone-based ICAs by controlling the isothermal annealing and thermal cycling processes.     

各向异性导电胶粘剂膜的研究进展

介绍了ACF的结构、原理、组成、应用及发展前景,详述了导电粒子、粘结剂、添加剂等组分在体系中的作用和对ACF性能的影响,综述了热固性树脂中离子聚合树脂型ACF和自由基聚合树脂型ACF的现状,并指出自由基聚合树脂型ACF是将来的发展趋势。     

基于导电性能退化数据的导电胶可靠性评估

性能退化表征的是产品的工作能力随时间逐渐降低的现象。提出用指数退化模型来描述导电胶导电性能退化过程,并根据退化数据给出了一个某型导电胶在任意时河的性能特征值的分布模型。根据这个分布模型,提出了两种可靠性评估的方法：1）相对于传统的寿命分布模型,所推导的可靠度函数中的参数易以通过实时跟踪测量性能参数时间序列数据估计得到;2）给出了针对不同样本量时的可靠性评估方法,且简便易行。最后通过试验数据对导电胶在使用环境下的可靠性进行了评估。     

Highly Conductive,Flexible, Polyurethane‐Based Adhesives for Flexible and Printed Electronics

Flexible interconnects are one of the key elements in realizing next‐generation flexible electronics. While wire bonding interconnection materials are being deployed and discussed widely, adhesives to support flip‐chip and surface‐mount interconnections are less commonly used and reported. A polyurethane (PU)‐based electrically conductive adhesive (ECA) is developed to meet all the requirements of flexible interconnects, including an ultralow bulk resistivity of ≈1.0 × 10^?5 Ω cm that is maintained during bending, rolling, and compressing, good adhesion to various flexible substrates, and facile processing. The PU‐ECA enables various interconnection techniques in flexible and printed electronics: it can serve as a die‐attach material for flip‐chip, as vertical interconnect access (VIA)‐filling and polymer bump materials for 3D integration, and as a conductive paste for wearable radio‐frequency devices.     

The Dependence on Thermal History of the Electrical Properties of an Epoxy-Based Isotropic Conductive Adhesive

The effect of thermal history on the electrical resistivity of a typical isotropic conductive adhesive (ICA) composed of an epoxy-based binder has been investigated in the present work. The electrical resistivities of test specimens were found to be different depending on the curing temperature, even if they exhibited similar degrees of conversion, although the values of T _g for the ICA specimens were determined by their degree of conversion, regardless of the curing temperature. Postannealing effects in terms of decreased electrical resistivity could be induced at a temperature in the vicinity of the glass transition temperature (T _g ), even if the specimens already achieved full conversion during the preliminary curing process. The magnitude of the annealing effect was found to depend on the preliminary curing and postannealing temperatures. When the specimens exhibit conversions of greater than 25% prior to the postannealing process, the preliminary curing state of the binder can influence the electrical resistivity of the ICA that is obtained after annealing.