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。     

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。     

高性能非银导电胶粘剂研究及应用

介绍了ＧＳＤ－Ｔ型铜粉导电胶粘剂各组分的选择，特殊铜粉的制备、配方和使用工艺条件，还列举了各种性能的测试数据。该导电胶粘剂在电子产品和厢式通信车上得到了初步应用。能满足使用要求。为电子产品的导电连接的通信车的电磁屏蔽提供了一种新的材料。     

填加型导电粘合剂

本文阐述了填加型导电粘合剂的导电机理，介绍了其组成、种类、固化条件及应用性，分析了其基本特性。     

金属银导电油墨的研究进展

金属银导电油墨是印制电子技术中的关键材料,随着电子产品向小型化、柔性化方向发展,传统的微米级金属银导电油墨已不能满足低加工温度和更小特征尺寸的要求,在此情况下,纳米银油墨和有机银油墨被开发出来。综述了纳米银导电油墨、有机银导电油墨各自的特点以及最新研究进展,并介绍了导电油墨新品种——银杂化油墨。     

纳米阴离子导体离子导电性能的研究进展

介绍了纳米技术在氧离子导体和氟离子导体的制备及导电性能研究方面的应用。纳米尺度的氧化物在烧结过程中致密化温度可降低50～200℃,最终产物的晶粒尺寸可小于1μm,离子电导率较高,可达到10–1S·cm–1量级。纳米氟离子导体与传统粗晶氟离子导体相比,具有明显的纳米尺寸效应,导电激活能可降低30%,离子电导率可提高1～2个数量级。     

钌基厚膜电阻导电机理的国内外研究状况

较全面的对国内外厚膜电阻导电机理的研究状况进行了综述，介绍了均匀分布模型，均匀通道模型。非隧道势垒模型，隧道势垒模型及其优缺点。对隧道壁垒模型进行深入的分析和讨论。并运用这些理论解释了厚膜电阻的温度特性、电场特性和热电效应。     

喷墨印制导电墨水研究进展

喷墨印制电子技术是一种无接触式、无压力、无需印版的电子产品制造技术。因具有制造速度快、环境友好、工艺过程简单、成本低、功能多样化、基材适用性广以及定位精确等特点受到人们的广泛关注,成为电子制造产业发展的新方向。导电墨水作为导电图形的基础材料,是印制电子技术发展的瓶颈,直接影响着电子产品的性能及质量。本文介绍了喷墨印制用导电墨水的导电机理、物理参数,以及碳系和银系墨水、液体金属墨水等的最新研究进展,并分析了导电墨水在RFID、PCB电路、太阳能电池、有机发光二极管、薄膜晶体管等领域的应用概况。分析表明,目前导电墨水的制备技术已取得一定进步,但相关的制备理论不成熟,缺乏优良的助剂和价格适宜的喷墨印制设备,未来急需开发具有低处理温度、高稳定性的喷墨印制导电墨水。     

石墨烯复合导电剂在锂离子电池中的应用研究进展

石墨烯具有极高的电导率、良好的力学性能和优异的热学性能,被认为是锂离子电池的新型高端导电剂。然而,石墨烯有着2630 m~2/g的超高比表面积,以及π-π共轭的作用使其在实际应用过程中更加易于团聚,影响锂离子电池容量的发挥。因此,本文结合导电炭黑、碳纳米管和石墨烯的结构特性,综述了石墨烯复合导电剂在锂离子电池中的应用及研究进度,并对未来石墨烯复合导电剂的应用趋势和工作方向进行了展望。     

A novel approach to stabilize contact resistance of electrically conductive adhesives on lead-free alloy surfaces

Electrically conductive adhesive (ECA) is an alternative for the toxic lead-based solders. However, unstable electrical conductivity has long been a haunting problem. Galvanic corrosion at the ECA/pad interface has recently been found to be the major mechanism for this decay. Applying a more active metal or alloy on a dissimilar metal couple in contact can prohibit galvanic corrosion. In this study, powders of aluminum, magnesium, zinc, and two aluminum alloys were added in an ECA and applied on five pad surfaces. The aging of the bulk resistivity and contact resistance of the ECA/metal surface pairs were studied. The two alloys significantly suppressed the increase of the contact resistance on all tested metal surfaces.     

Analytical equations for predicting the thermal properties of isotropic conductive adhesives

This paper investigates a set of theoretical equations for analyzing the thermal properties of isotropic conductive adhesives (ICAs) containing several types of Cu filler particles. The thermal conductivity of ICAs containing randomly dispersed filler particles can be simulated well by Bruggeman’s equation for spherical particles and by Kanari’s equation for flake particles. The effect on the thermal conductivity of any residual voids can be taken into account in the analysis by the additional application of Bruggeman’s or Kanari’s equations with the appropriate shape factor. The linear thermal expansion coefficient of the ICAs was analyzed using Schapery’s scheme. The thermal expansion coefficients of ICAs with 40–50 vol.% of filler particles range between Schapery’s upper and lower limits. As the particle size of the filler decreases, the thermal expansion coefficient starts to approach the lower limit at a lowr volume fraction of the filler particles. The transition behavior of the thermal expansion coefficient is related to the characteristics of the network structure formed by percolating the filler particles.     

Novel interconnection method using electrically conductive paste with fusible filler

A new class of electrically conductive adhesives (ECAs) was developed using fusible filler particles. Differential scanning calorimetry (DSC) was used to examine the curing behavior of the base resin material and the melting behavior of the filler particles. The formation of the interconnection before and after the curing process was observed by means of a microfocus x-ray system. The cross-sectional morphology of the electrical conduction path was investigated by optical microscopy. It is believed that the wetting and coalescence behavior of the molten filler particles are the main driving forces leading to the production of the interconnection between the electrodes. In addition, the metallurgical connections both between the particles and between the particles and the copper substrate were observed using scanning electron microscopy and electron probe microanalysis (EPMA).     

快速计算电大尺寸目标双站电磁散射的方法

提出利用等效边缘电磁流方法快速计算复杂形体电大尺寸目标的双站ＲＣＳ。该方法运算速度快,考虑了边缘绕射和遮挡,计算精度高。在计算尖锥柱等典型散射体的ＲＣＳ的基础上,计算了一导弹模型在不同方位角下的双站ＲＣＳ,证实了本方法的可行性。     

A study of electrically conductive adhesives as a manufacturing solder alternative

Soldering processes using tin/lead solder are standard interconnection technologies for electronic manufacturing. These processes are currently under threat from the Waste Electrical and Electronic Equipment and the Restriction of Hazardous Substances (RoHS) environmental directives, issued by the European Union in 2000. These directives explain that solder is to be free from lead by 1986, as lead has been recognized by the European Union as an environmentally harmful material. One solder alternative that has been investigated by the electronics industry is the area of electrically conductive adhesives (ECAs). This paper outlines the electrical and mechanical analysis of two isotropic conductive adhesives where the main properties of joint resistance and adhesive strength were examined before and after different environmental treatments. Joint resistance was measured with a four-probe tester and adhesive strength was examined with the use of shear testing. Cross-sectional and scanning electron microscopy analyses were used to determine problems such as oxidation and moisture absorption that may have an affect on the adhesive properties of the connection. An experimental design was carried out to examine the adhesives on a standard production line. Taguchi analysis was used to determine the build parameters required to produce an optimal adhesive joint. The results show that although ECAs can pass a functionality test, the electrical properties of ECAs are inferior to that of solder with ECAs having a high joint resistance. They also exhibit poor mechanical strength when shear or drop tested and illustrate that current visual inspection techniques used to examine solder joints are not applicable to conductive adhesives.     

Burnout of the organic vehicle in an electrically conductive thick-film paste

The burnout of the organic vehicle in a silver-particle, glass-free, electrically conductive, thick-film paste during firing in air was studied. For a vehicle consisting of ethyl cellulose dissolved in ether, burnout primarily involves the thermal decomposition of ethyl cellulose. The presence of ether with dissolved ethyl cellulose facilitates the burnout of ethyl cellulose. Excessive ethyl cellulose hinders the burnout. A high heating rate results in more residue after burnout. By interrupting the heating at 160°C for 15 min, the residue after subsequent burnout is diminished probably because of reduced temporal overlap of the processes of organic burnout and silver particle necking. By interrupting the heating at either 300°C or 385°C for 30 min, the temperature required for complete burnout is reduced. The addition of silver particles facilitates drying at room temperature and burnout upon heating.     

金属粉末-聚合物复合导电胶研究进展

随着电子封装工艺的发展,越来越多的人们致力于研发更高性能、环境友好的新连接材料,以聚合物为基体的复合导电胶在电子封装领域的应用也由此越来越广泛。文章介绍了导电胶的分类和组成,以及改善导电胶性能的方法与技术,从宏观和微观角度对导电机理进行了探讨并对研究前景做了展望。     

纳米银线柔性透明导电薄膜研究进展

随着时代的发展,柔性电子产品的应用越来越广。柔性透明导电薄膜是柔性电子器件中的重要组成部分,由于氧化铟锡并不适合应用到柔性电子器件中,寻找新一代材料引起了研究者的广泛关注。纳米银线作为一种新型的纳米材料,在纳米尺度上有很多新奇的性能,其优良的导电性及良好的光学性能被认为是替代氧化铟锡的最佳材料。本文主要综述了纳米银线柔性导电薄膜的研究进展,主要包括纳米银线导电油墨的物化性能、纳米银线柔性透明导电薄膜的常用制备方法以及主要应用领域。此外,还结合国内外纳米银线柔性透明导电膜的研究现状,指出该研究方向仍存在的一些挑战。     

Electrical characterization of isotropic conductive adhesive under mechanical loading

Isotropic conductive adhesive (ICA) is a strong candidate for replacing toxic lead-based solders. Before wide application of this new technology can occur, the degradation mechanisms must be thoroughly understood. In this work, we investigated the electrical characteristics of a commercial ICA under mechanical loading. The results showed that the resistance rose monotonically with the joint strain in the lap shear test, while it increased steadily with the number of cycles in the low-cycle fatigue test. To elucidate the experimental observations, two-dimensional finite-element modeling (FEM) was carried out, and the effects of mechanical loading on the initial intimate interaction among silver fillers were analyzed. Additionally, based on modeling, the possible electrical degradation mechanisms were discussed.     

Anisotropic conductive adhesives with enhanced thermal conductivity for flip chip applications

This paper presents the development of new anisotropic conductive adhesives (ACAs) with enhanced thermal conductivity for improved reliability of adhesive flip chip assembly under high current density condition. As the bump size in the flip chip assembly is reduced, the current density through the bump also increases. This increased current density causes new failure mechanisms, such as interface degradation due to intermetallic compound formation and adhesive swelling resulting from high current stressing. This process is found especially in high current density interconnection in which the high junction temperature enhances such failure mechanisms. Therefore, it is necessary for the ACA to become a thermal transfer medium that allows the board to act as a new heat sink for the flip chip package and improve the lifetime of the ACA flip chip joint. We developed the thermally conductive ACA of 0.63 W/m·K thermal conductivity by using a formulation incorporating the 5-μm Ni-filled and 0.2-μm SiC-filled epoxy-based binder system. The current carrying capability and the electrical reliability under the current stressing condition for the thermally conductive ACA flip chip joints were improved in comparison to conventional ACA. This improvement was attributed to the effective heat dissipation from Au stud bumps/ACA/PCB pad structure by the thermally conductive ACA.