Cu表面Ni基复合镀层对无铅焊料钎焊性能及界面可靠性的影响

发布时间：2018-01-05 00:12

本文关键词：Cu表面Ni基复合镀层对无铅焊料钎焊性能及界面可靠性的影响　出处：《北京理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：近年来，随着传统SnPb共晶焊料逐渐被Sn-Ag-Cu系无铅焊料取代，Sn与Cu之间的界面反应及其带来的可靠性问题引起了人们的重视，一方面高熔点的Sn-Ag-Cu系无铅焊料使钎焊温度提高，另一方面无铅焊料中大量Sn会与Cu发生反应，导致无铅焊料/Cu之间形成过厚的界面金属间化合物(IMC)层，给电子元器件使用可靠性带来危害。在Cu基板或引脚表面镀覆一层扩散阻挡层，减缓Sn与Cu反应程度、减小无铅焊料/Cu界面IMC层的厚度，是提高无铅焊料焊点可靠性的有效手段。本论文采用化学镀工艺，在Cu基板表面分别制备Ni镀层、添加纳米SiO2粒子的Ni基复合镀层以及添加SiC的Ni基复合镀层，系统研究了Ni基复合镀层中粒子添加浓度对Sn-3.0Ag-0.5Cu(SAC305)焊料的润湿性能、界面IMC生长和钎焊接头剪切强度的影响规律，同时对比研究了在无铅焊料中添加纳米SiO2粒子对其在Cu基板、Ni镀层以及Ni基复合镀层上的润湿性能、界面IMC生长和钎焊接头剪切强度的影响。获得了以下研究结果：（1）由于Ni/Sn反应比Cu/Sn之间的反应慢，降低了SAC305焊料在镀镍Cu基板上的润湿力，但Cu基板表面的Ni镀层可以有效抑制焊料/基板界面间IMC的生长，并提高接头的剪切强度。（2）在Ni镀层中添加SiO2或SiC颗粒均能有效抑制SAC305/基板间界面IMC的生长，但与添加SiC粒子的Ni复合镀层相比，添加纳米SiO2的效果更好。在Ni镀层中添加SiO2粒子不仅能有效抑制SAC305/基板间界面IMC的生长，还能明显提高SAC305焊料在基板上的润湿性能和钎焊接头的剪切强度，SiO2粒子在Ni镀层中的最佳添加量为6g/L。（3）相比于SAC305焊料，通过向SAC305焊料中添加0.05wt.%的SiO2粒子，，可明显改善焊料在Cu基板及镀镍Cu基板的润湿性能，界面间IMC的生长速率常数ε更小，钎焊接头的剪切强度更高。但，向焊料中纳米SiO2粒子降低了其在Ni-SiO2复合镀层上的润湿性，减弱了复合镀层对界面IMC生长的抑制作用，同时也降了钎焊接头的剪切强度。
[Abstract]:In recent years, with the traditional SnPb eutectic solder gradually replaced by Sn-Ag-Cu lead-free solder, the interface reaction between Sn and Cu and the reliability problems caused by it have attracted much attention. On the one hand, the high melting point of Sn-Ag-Cu system lead-free solder increases the brazing temperature, on the other hand, a large amount of Sn in lead-free solder will react with Cu. A thick intermetallic intermetallic compound (IMC) layer is formed between lead free solder / copper, which endangers the reliability of electronic components. A diffusion barrier layer is coated on the Cu substrate or pin surface. It is an effective method to improve the reliability of lead-free solder joint by slowing down the reaction between Sn and Cu and decreasing the thickness of IMC layer at the lead-free solder / Cu interface. In this paper, Ni coating was prepared on Cu substrate by electroless plating, Ni based composite coating with nano SiO2 particles and Ni base composite coating with SiC were prepared. The wettability of Sn-3.0 Ag-0.5CuSAC305) solder in Ni based composite coating was studied systematically. The effect of interfacial IMC growth and shear strength of brazed joints on the Cu substrate was studied by comparing the addition of nano-sized SiO2 particles in lead-free solder. The wettability, interfacial IMC growth and shear strength of brazing joint on Ni coating and Ni-base composite coating were studied. 1) because the reaction of Ni/Sn is slower than that of Cu/Sn, the wettability of SAC305 solder on Ni-Cu substrate is decreased. However, Ni coating on Cu substrate can effectively inhibit the growth of IMC between solder and substrate interface and improve the shear strength of the joint. (2) addition of SiO2 or SiC particles to Ni coating can effectively inhibit the growth of IMC at the interface between SAC305 / substrate, but compared with Ni composite coating with SiC particles. The addition of nano SiO2 can not only inhibit the growth of IMC at the interface of SAC305 / substrate effectively, but also increase the effect of adding SiO2 particles in Ni coating. The wettability of SAC305 solder on the substrate and the shear strength of brazing joint can be improved obviously. The optimum addition amount of SiO2 particles in Ni coating is 6g / L. Compared with SAC305 solder, 0. 05 wt.% SiO2 particles were added to SAC305 solder. The wettability of solder on Cu substrate and Ni Cu substrate can be improved obviously. The growth rate constant 蔚 of IMC between interfaces is smaller and the shear strength of brazed joint is higher. Nano SiO2 particles in the solder decreased its wettability on the Ni-SiO2 composite coating, weakened the inhibition of IMC growth on the interface, and reduced the shear strength of the brazed joint.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG454;TG174.4

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