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。     

柔性银包铜基导电线路的制备与性能

针对导电银浆价格高、导电铜浆易氧化等问题,采用银包铜粉作为导电填料,聚氨酯改性丙烯酸树脂为树脂基体,通过丝网印刷在聚酰亚胺薄膜上印制导电线路,并用热固化的方式进行固化,从而获得导电性能优良的柔性银包铜基导电线路。结果表明:当银包铜粉的含量为65%(质量分数)时,制备的导电胶各项性能达到最佳值,满足丝印要求,平均膜厚为29.25μm,固化后得到的导电膜电阻率达到最低值1.06×10~(-3)Ω·cm。     

DAD—87导电胶的特性和应用

一、前言 1967年美国首先采用一种银-环氧导电胶进行半导体器件的装片。这种新工艺的操作温度在室温至200℃之间,比传统的金-硅共晶,锡焊和银浆烧结温度低,可以避免高温对芯片特性的损伤;芯片背面和管座式引线框架不必镀金,可用镀银或镀镍;粘接牢度超过银浆烧结;操作简便,适合大批量生产和自动化作业。从而保证了半导体器件的质量,提高器件的合格率和工效,降低成本。七十年代由于世界黄金价格的上涨,用导电胶装片的工艺得到了普     

电镀废液回收铜粉的化学镀银工艺及其电磁屏蔽性能

采用高频超声脉冲电解法从电镀铜废液中回收制备枝晶状的铜粉,并在铜粉表面进行化学镀银以制备电磁屏蔽用银包铜粉,采用SEM、EDS、XRD、TEM等对其进行形貌和组分分析,研究了银包铜粉复合涂层的导电性能和电磁屏蔽性能。结果表明,经过表面化学镀银可以有效地避免铜粉的氧化;涂层的电磁屏蔽性能与银包铜粉的添加量紧密相关,当涂层中银包铜粉质量分数为60%时,其电磁屏蔽效率高达52 dB。     

纤维状铜粉导电填料的制备及性能研究

采用水溶液配位沉淀-热分解法制备了纤维状铜粉,利用XRD和SEM对粉末物相和形貌进行了表征,并采用热重-差热-红外联用仪(TG-DSC-FTIR)分析了草酸铜盐的热分解过程。以该铜粉为导电填料,配制了铜导电胶,通过测定导电胶的渗流曲线和固化曲线对其导电性能进行了研究。结果表明,配位沉淀产物为棒状草酸氨铜,其在N2和H2混合气氛中的热分解依次经历两次脱氨、脱结晶水、草酸铜热分解四个阶段,产物为直径约1μm、长径比20的纤维状铜粉;在铜粉与环氧树脂质量比为3:1、常温固化24 h的条件下所制备的铜导电胶的电阻率最小,为4.45×10–3?·cm。     

银包铜粉的制备及其性能

采用置换法还原络合银离子,在铜粉颗粒表面沉积金属银。着重研究了还原剂、络合剂和分散剂种类和用量等制备条件对包覆效果的影响;分析了银包覆程度及银-铜结合强度及复合粉体的抗氧化性。实验表明:银包铜粉体在w(银)为5.00%～18.00%时,与普通铜粉相比,氧化温度可提高40～140℃,具有良好的抗氧化性。     

高导电片状银包铜粉的制备技术研究

采用[Ag(NH3)]+溶液对片状铜粉进行包覆,研究了铜粉粒径、[Ag(NH3)]+溶液浓度、包覆温度、分散剂含量等因素对银包铜粉银含量和电阻率等的影响。结果表明:通过控制包覆温度(60℃)、银氨络离子浓度(0.8mol·L–1)以及分散剂含量(1.0g·L–1),得到了电阻率为0.8×10–3?·cm的银包铜粉。XRD分析表明,该银包铜粉只有Ag和Cu相,不含中间产物。银包铜粉松装密度为0.50g·cm–3左右,比表面积为3.1~3.3m2·g–1。     

微波器件用导电胶变色机理及其对接触电阻的影响

针对导电胶变色的现象,分析了变色导电胶的外观、微观结构及成分,研究了导电胶变色现象对接触电阻的影响。找出了导电胶变色的原因,导电胶固化后裸露在环氧树脂表面的银粒子被硫化生成黑色的硫化银所致,且随着硫化银的增多颜色由浅变深。试验结果表明导电胶变色现象对接触电阻无影响。     

纳米二氧化硅对镀银铜粉导电性能的影响研究

文章研究了纳米SiO2作为涂料添加剂对丙烯酸树脂导电涂料导电性能的影响,测试了加入不同量纳米SiO2时涂层的体积电阻;用扫描电镜观察了导电涂层的表面及截面形貌,用XRD研究了镀银铜粉的结构特性。结果表明在镀银铜粉涂料中加入适量的纳米SiO2可以提高其导电性能,同时还观察到纳米SiO2可以加快涂料的固化速度,增加膜层与基板的结合度。     

DJB—823保护剂试验与应用

镀银层变色是一个普遍现象，试验表明目前国内防银变色材料中，ＤＪＢ－８２３保护剂效果最好。因此曾把它应用于某出口雷达铸铝镀银、镀银屏蔽盒和某雷达插头插座上。     

导电银胶触变性的研究

以环氧树脂为基体,银粉为填料,制备出IC封装用导电银胶。研究了环氧树脂与银粉的比例、银粉的形貌和粒径以及触变剂SiO2的用量对导电银胶触变性的影响。结果表明,银胶触变性随树脂/银粉质量比的减小而增大,当其为0.2时,触变指数达到5.68。在一定粒径范围内,银胶的触变性与银粉粒径呈反比关系;银胶触变性随SiO2的用量增大而增大。     

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。     

Conductivity mechanisms of isotropic conductive adhesives (ICAs)

Isotropic conductive adhesives (ICAs) are usually composites of adhesive resins with conductive fillers (mainly silver flakes). The adhesive pastes before cure usually have low electrical conductivity. The conductive adhesives become highly conductive only after the adhesives are cured and solidified. The mechanisms of conductivity achievement in conductive adhesives were discussed. Experiments were carefully designed in order to determine the roles of adhesive shrinkage and silver (Ag) flake lubricant removal on adhesive conductivity achievement during cure. The conductivity establishment of the selected adhesive pastes and the cure shrinkage of the corresponding adhesive resins during cure were studied. Then conductivity developments of some metallic fillers and ICA pastes with external pressures were studied by using a specially designed test device. In addition, conductivity, resin cure shrinkage, and Ag flake lubricant behavior of an ICA which was cured at room temperature (25°C) were investigated. Based on the results, it was found that cure shrinkage of the resin, rather than lubricant removal, was the prerequisite for conductivity development of conductive adhesives. In addition, an explanation of how cure shrinkage could cause conductivity achievement of conductive adhesives during cure was proposed in this paper     

钽电容器用石墨导电胶的研究

以石墨粉和热固性树脂混合配成导电胶,分析了石墨粉、稀释剂的用量,固化温度,固化时间等与电阻的关系。结果表明:当石墨含量在25%～35%,稀释剂含量在20%～25%(均为质量分数)时,在150℃下固化2～3 h得到的导电胶导电性最好,能够满足作为钽电容器阴极引出材料的需要。并用“逾渗理论”解释了导电胶的导电机理,与实验所得结论相符。     

银粉形貌与尺寸对导电胶电性能的影响

从导电性角度考查银粉颗粒形貌和粒径大小对导电胶电阻率的影响。用不同形貌和不同平均粒径的银粉,按相同配方制成导电胶,比较其体电阻率。结果发现不同形貌的银粉体系的电阻率存在数量级上的差异;填充片状银粉的体系电阻率与银粉平均粒径成反比,在5~12μm内,平均粒径越大电阻率越低。     

Inkjettable conductive adhesive for use in microelectronics and microsystems technology

Ink jet is an accepted technology for dispensing small volumes of material (50–500 picolitres). Currently traditional metal-filled conductive adhesives cannot be processed by ink jetting (owing to their relatively high viscosity and the size of filler material particles). Smallest droplet size achievable by traditional dispensing techniques is in the range of 150 μm, yielding proportionally larger adhesive dots on the substrate. Electrically conductive inks are available on the market with metal particles (gold or silver) <20 nm suspended in a solvent at 30–50 wt%. After deposition, the solvent is eliminated and electrical conductivity is enabled by a high metal ratio in the residue. Some applications include a sintering step. These nano-filled inks do not offer an adhesive function. Work reported here presents materials with both functions, adhesive and conductive. This newly developed silver filled adhesive has been applied successfully by piezo-ink jet and opens a new dimension in electrically conductive adhesives technology.The present work demonstrates feasibility of an inkjettable, isotropically conductive adhesive in the form of a silver loaded resin with a two-step curing mechanism: In the first-step, the adhesive is dispensed (jetted) and precured leaving a ‘dry’ surface. The second step consists of assembly (wetting of the 2nd part) and final curing.     

低温固化银系导电油墨导电性能的影响因素

为了提高低温固化银系导电油墨的导电性,对导电机理进行了研究。通过实验研究了聚合物分子结构,银粉的含量、形貌、粒径,溶剂种类对导电性能的影响。得出:氯化聚乙酸乙烯为主体树脂,以片状与球状混合银粉(质量比为9:1)为导电填料,并以酮和酯组成混合溶剂,调制的导电油墨导电性最好,其Rs达9 mΩ/□。     

Correlation of silver migration to the pull out strength of silver wire embedded in an adhesive matrix

The substantial growth in the electronics industry has created a need for environmental and user-friendly alternatives to tin/lead (Sn/Pb) solders for attaching encapsulated surface mount components on rigid and flexible printed circuit boards (PCBs). Electronically conductive adhesives (ECAs) have been explored in this manner to establish mechanical as well as electrical joints between PCBs and surface mount components. Applications of conductive adhesive are limited due to serious concerns associated with the long-term reliability data of current commercial ECAs. One critical concern in wire bonding applications is the significant decrease in the bond strength and consequent loss of the conducting properties of adhesive due to silver migration. In this study, an effort is made to understand and model long-term silver migration phenomenon with respect to different parameters (duration of the migration, dry and wet conditions), and pull-out strength of silver wire embedded in an epoxy adhesive matrix. Morphology of embedded silver wire after migration and pull-out was also studied using scanning electron micrographs. Migration area increased with the duration of migration, and reduction in the pull-out strength was significant in wet condition as compared to dry condition. The increase in migration area was consistent with the reduction in pull-out strength in both wet and dry conditions.     

Characterization of electroplated bismuth-tin alloys for electrically conducting materials

Electrically conducting adhesive materials are promising alternatives for lead (Pb)-containing solders in microelectronic applications. However, most common silver-filled epoxy materials have various limitations to meet the requirements of the solder joints yet. To overcome these limitations, several new formulations have been developed recently. Among them, a new high conductivity Pb-free, conducting adhesive developed for low temperature applications has been previously reported. This conducting adhesive contains a conducting copper filler powder coated with a low melting point metal or alloy, such as Sn or BiSn alloys. The low melting point layer serves as a joining material among the filler particles as well as to the substrate. In this paper, characterization of electroplated BiSn alloys on a Cu substrate is reported for their microstructure, electrical properties, oxidation behavior, and others. The experimental results have provided a better understanding of the joining mechanism of the newly developed Pb-free conductive adhesive materials.