【作者】 袁忠发；

【导师】 吴懿平；

【作者基本信息】 华中科技大学 ， 材料学， 2005， 硕士

【摘要】 本文以ACF-这种新型无铅互连材料的合成为主线,以柔性导电微球的合成为主要内容,综述了ACF 在电子封装中的地位与发展现状,开发了ACF 制造的核心技术-单分散高分子微球的制备以及表面金属覆层技术。本文选用苯乙烯为反应单体、AIBN 为引发剂、PVP 为分散剂、无水乙醇/水体系为分散介质,研究了分散聚合动力学、微球粒径增长规律; 对研究的薄弱点-反应物添加方式、苯乙烯内含阻聚剂、氮气保护等因素对聚苯乙烯微球粒径以及粒径分布的影响加以研究,并成功合成了平均粒径为4.1μm,分散系数为1.63%的单分散聚苯乙烯微球; 最后通过工艺稳定性试验以及工艺放大试验,确定了较成熟的大批量单分散聚苯乙烯微球合成工艺。在微球增长规律的讨论中,首次提出微球粒径增长的两个决定因素,一个是粒子密度,另一个是转化率。结合动力学曲线分析粒径增长过程,得出微球并不是由内向外逐层长大的,而是一个密度与体积都逐渐加大的增长过程。本文开发了微球覆镍导电层技术,通过试验优化,获得了最佳的工艺方法。在具体工作中,验证了微球表面镍的沉积模式与大块非导电材料相同; 提出了两种镀层表面形貌的控制方法,一种是通过镀液酸碱性控制镀层表面形貌,另一种是通过镀液自分解程度控制镀层表面形貌。本文提出了一种新型的ACF 填充粒子,该粒子是带突起的高分子覆镍导电微球,在互连的过程中,通过加压可以刺穿电极的氧化膜,实现高密度互连,并用两种镀层表面形貌的控制方法成功实现了新型ACF 填充粒子的合成。更多还原

【Abstract】 This thesis was organized by the clue of preparation of anisotropic conductive film (ACF) and all the experimentations were focused on the synthesis of conductive micro-spheres for ACF. After the introduction of the basic knowledge and current development of ACF in electronic package, the key technologies of conductive micro-spheres for anisotropic conductive film (ACF) were developed, and the technologies were consisted of two parts, including the preparation of monodisperse polymer micro-spheres and the technology of nickel coating on the micro-spheres. In the part of the preparation of monodisperse polymer micro-spheres, polystyrene (PS) micro-spheres with mean particle size about 4.1μm and coefficient of variation about 1.63% were firstly prepared by dispersion polymerization using poly vinyl pyrroidone (PVP)as dispersant, AIBN as initiator and water/ethanol system as dispersing medium. And then the influence factors on particle size and size distribution such as inject means of reactant, influence of inhibitor in polystyrene and the others were studied in this thesis. Finally, the technology stability experiment and scale-up showed that the process was of stability and can successfully scaled up for 3 times. During the study, two decisive factors of the particle sizes increasing including particle density and monomer conversion, with which the increasing process of the micro-spheres was explained in detail, were advanced, and it was showed that the micro-spheres were not a process increasing from inside to outside gradually, but one with its density and volume increasing meanwhile. In the other part, nickel coating on the micro-spheres was successfully prepared by electroless plating, and a mature process was also obtained by optimization. In this study, it was showed the nickel disposition mode on micro-spheres was same to on block polymer materials. And then two controlling methods of the coating appearance were also advanced. A novel conductive micro-sphere with projections for ACF was prepared in this thesis. As projections mentioned above can be used to break through the oxide film of the electrodes, the ACF filled with the novel conductive micro-sphere can successful applied to fine pitch interconnection structure of electrodes with oxide film.更多还原