【作者】 邓涛；

【导师】 刘文胜； 马运柱；

【作者基本信息】 中南大学 ， 材料科学与工程， 2012， 硕士

【摘要】 随着电子产品向微型化、薄型化、高精度化的方向发展,表面组装技术(SMT)成为电子组装行业里最流行的技术和工艺之一。焊膏是SMT中不可缺少的材料,其性能直接影响到焊接品质,决定着电子产品的质量。本论文从助焊剂基质及有效成分的优化入手,制备出了性能优良的免清洗助焊剂,并对所配置的Sn-3.OAg-0.5Cu焊膏综合性能进行了研究。采用旋转流变仪对焊膏粘度进行测试,采用力学试验机对焊点剪切强度进行测试,采用扫描电子显微镜(SEM)对焊点微观结构及断口形貌进行观察,采用EDS能谱仪对焊点组织结构的成分进行测试分析。主要研究结果如下：1)助焊剂由基质和有效成分组成。助焊剂基质组成为：氢化松香和聚合松香复配质量比2：3；二甘醇、乙二醇单丁醚、溶剂A复配体积比1：2：1；ST、H作为触变剂,复配松香：H：ST：复配溶剂的质量比为50：2：3.5：35。以腐蚀性、润湿性为主要衡量指标,选择了丁二酸、己二酸作为主要活性剂,活性剂A作为辅助活性剂,三乙醇胺作为pH缓冲剂；丁二酸与己二酸的总量为5wt%,复配质量比3：2；活性剂A的添加量为0.3wt%；三乙醇胺的添加量为3wt%；苯并三氮唑和8-羟基喹啉复配质量比为1：1,添加量为1wt%。2)所研制的松香基无卤素免清洗助焊剂呈乳白色粘稠膏体,物理性能稳定,pH值为6.0,无卤素,腐蚀性小,不挥发物含量为31.5%,铺展面积38.18mm2,性能优良。3)与商用焊膏PNF306和ALPHA OM338焊膏相比,自制焊膏ZZO1具有适宜的粘度,优良的触变性能,可满足高端细间距印刷的要求；三种焊膏均具有优异的抗冷塌陷性能,ALPHAOM338焊膏抗热塌陷性能最佳,ZZO1焊膏次之；ALPHAOM338焊膏和ZZO1焊膏锡珠测试合格,PNF306焊膏锡珠测试不合格。三种焊膏的铺展面积依次为38.24mm2、36.05mm2、40.01mm2,ZZO1焊膏锡膏残留最少且薄而透明；ZZO1焊膏焊点IMC层薄、而且均匀致密；三种焊膏的剪切强度依次为45.12MPa、40.22MPa和48.82MPa,断裂模式为韧性断裂。更多还原

【Abstract】 With the development of electronic products oriented to microstructure, thin type and high precision, Surface Mount Technology (SMT) has been one of the most popular technologies in electronic mounting industry. Solder paste, whose performance directly influences the quality of welding and decides the quality of products, is the inevitable material in SMT. In this thesis, no-clean flux with excellent performance was produced, starting optimization and performance testing of flux and its effective composition. In addition, the synthetic performance of Sn-3.0Ag-0.5Cu was investigated.Viscosity of solder paste was tested by using a rotaty thermometer. Shear strength of solder joint was measured by using mechanical testing machine. Microstructure and fracture of solder joint were observed by using Scanning Electron Microscopy (SEM), and the composition of solder joint were tested and analyzed by Energy Dispersive Spectrometer (EDS). The results were following as:1) The homemade clean-free flux includes matrix and effective components. The composition of flux matrix are including: hydrogenated rosin and polymerized rosin compound, whose mass ratio is2:3; diethylene glycol, ethylene glycol monobutyl ether and solvent A compound, whose volume ratio is1:2:1; ST, H as thixotropic agents, the quality ration of compund rosin:H:ST:mixed solvent is50:2:3.5:35.Take the causticity of the active agent on the copper and solder spread area as an index:select succinic acid, adipic acid as the main active agents, surfactant A as a secondary active agent, triethanolamine as a pH buffer; the total amount of succinic acid and adipic acid is5wt%, whose compound mass ratio is3:2; the dosage of active agent A is0.3wt%; the dosage of triethanolamine is3wt%; the mass ratio of benzotriazole and8-hydroxyquinoline is1:1and the total dosage of them is1wt%.2) The rosin-based halogen-free no-clean flux is a milky viscous paste, which have stable physical properties, pH6.0, halogen-free, low corrosivity, non-volatile content of31.5%, the spreading area of38.18 mm2, and excellent performance.3) Compared with commercial PNF306solder paste and ALPHA OM338solder paste, homemade ZZ01solder paste has a suitable viscosity and excellent thixotropy, which can meet the requirements of high-end fine-pitch printing. All the three kinds of solder paste have excellent anti-cold collapse performance and thermal subsidence properties, ALPHA OM338solder paste> ZZ01solder paste>PNF306solder paste. ALPHA OM338solder paste and the ZZ01paste solder passed the solder balling test, while PNF306solder paste failed. The spreading area of ZZ01solder paste, PNF306solder paste and ALPHA OM338solder paste are38.24mm2,36.05mm2,40.01mm2, respectively. ZZ01solder paste with least residues is thin and transparent. IMC layer by ZZ01solder paste solder joint is thin, dense and uniform. The shear strength of ZZ01solder paste, PNF306solder paste, and ALPHA OM338solder paste is45.12MPa,40.22MPa and48.82MPa, respectively. All of fracture modes are ductile fracture.更多还原