微量沉积氯对焊点腐蚀过程的影响  

Effect of Micro Deposited Chlorine on Solder Joint Corrosion Process

作　　者：刘美 王志杰 徐艳博 孙志美 牛继勇 LIU Mei;WANG Zhijie;XU Yanbo;SUN Zhimei;NIU Jiyong(NXP Semiconductor(Tianjin),Inc.,Tianjin 300385,China)

机构地区：[1]恩智浦半导体(天津)有限公司,天津300385

出　　处：《电子与封装》2023年第6期19-26,共8页Electronics & Packaging

摘　　要：不同金属间存在电位差,被硫、氯等污染的焊点易产生原电池腐蚀,这将降低焊接产品的可靠性,缩短产品的寿命。因此,焊点的腐蚀问题受到人们的高度重视。以镀钯铜线的球栅阵列(BGA)产品为研究对象,通过能谱仪(EDS)、X射线衍射(XRD)、X射线光电子能谱(XPS)等实验手段,首先分析了多焊点同时被氯腐蚀的影响因素,再将焊点表面划分为上表面、侧表面以及界面3个区域,并对各区域进行腐蚀分析和验证,最后得出氯腐蚀焊点的腐蚀机理。实验结果表明:1)氯腐蚀难易程度的主要影响因素为IMC的致密度和镀钯层上的铜露出面积,IMC的致密度越小,镀钯层上的铜露出面积越大,氯腐蚀越容易发生;2)焊点腐蚀路径表现为氯沿铜球表面向铜球与IMC的界面迁移的过程;3)焊点烘烤时间越短,焊点表层上钯的覆盖率越大,焊点被氯腐蚀的概率越低。There is a potential difference between different metals,and it is easy to produce galvanic corrosion on the solder joints polluted by sulfur and chlorine,which will reduce the reliability of bonding products and shorten the life of products.Therefore,the problem of corrosion on solder joints is highly valued by people.The ball grid array(BGA)products with palladium-plated copper wire are taken as the research object.By experimental means of energy dispersive spectrometer(EDS),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS)etc.,the factors affecting the simultaneous corrosion of multiple solder joints by chlorine are firstly analyzed,and then the surface of solder joints are divided into three regions:The upper surface,the side surface and the interface.The corrosion analysis and verification of each region are conducted,and the corrosion mechanism of chlorine corroded solder joints is finally obtained.The experimental results show that:1)The main influencing indicators of difficulty of chlorine corrosion are the density of IMC and the exposed area of copper on the palladium-plated layer.The smaller the density of IMC is,and the larger the area of copper exposed on palladium-plated layer is,the more likely chlorine corrosion will be.2)The corrosion paths of solder joints show that chlorine migrates along the surface of copper sphere to the interface between copper sphere and IMC.3)The shorter the baking time of the solder joints is,and the greater the palladium coverage on the surface layer of the solder joints is,the lower the probability of chlorine corrosion of the solder joints will be.

关 键 词：沉积氯 烘烤时间 湿气 多焊点 原电池腐蚀 

分 类 号：TN305.94[电子电信—物理电子学]