一种新型无铅焊膏抗冷热循环性能

张琦 孙凤莲

摘要：对一种新型低银SnAgCuBiNi（SACBN07）焊膏与市场上的SAC305焊膏进行抗冷热循环性能对比分析。比较冷热循环前后的微焊点的剪切强度和纳米压痕硬度、分析微量元素对界面组织以及力学性能的影响。结果表明：由于SACBN07中Bi元素的固溶强化和弥散强化的作用，冷热循环前SACBN07剪切强度和纳米压痕硬度值高于SAC305，SACBN07的剪切强度和体钎料的纳米压痕硬度受冷热循环影响较小，经过600h冷热循环后SACBN07焊点硬度降低了174%，剪切强度降低了153%，而SAC305焊点硬度降低了313%，剪切强度降低了23%。SACBN07中Ni元素的加入减缓了界面化合物的生长速度，经过600h冷热循环后SACBN07焊点界面IMC层厚度小于SAC305焊点。SACBN07的抗冷热循环性能优于SAC305。

关键词：

无铅焊膏;冷热循环;剪切強度;硬度

DOI：10.15938/j.jhust.2018.05.022

中图分类号： TG42

文献标志码： A

文章编号： 1007-2683（2018）05-0130-04

Abstract：The performance of resistance to hot and cold cycle of a new low silver solder paste SnAgCuBiNi （SACBN07） and SAC305 solder paste on the market were compared and analyzed The shear strength and nanohardness of micro solder joints before and after hot and cold cycles were compared， and the effect of trace elements on the microstructure of the interface and mechanical properties was analyzed The results show that the shear strength and nanoindentation hardness of SACBN07 are higher than that of SAC305 due to the solid solution strengthening and dispersion strengthening of Bi element in SACBN07 Because of the shear strength of SACBN07 and the nanoindentation hardness of bulk solder affected little by hot and cold cycles， the hardness of solder joint is reduced by 174% and the shear strength is decreased by 153% on the SACBN07 solder joint after 600h hot and cold cycle， while the SAC305 solder hardness decreased by 313%， the shear strength decreased by 23%The Ni element added in SACBN07 solder paste slows down the growth rate of the interfacial compound， and the thickness of the IMC layer on the SACBN07 solder joint is less than that of SAC305 solder joint after 600h hot and cold cycle In a word， we get that the performance of SACBN07 solder paste is better than that of SAC305 solder paste

Keywords：leadfree solder paste; hot and cold cycle; shear strength; hardness

0序言

近年来电子产品朝着性能更优良、更小型化的方向发展，输入/输出（I/O）端口越来越密集，使得焊点数量越来越多、尺寸越来越小，对电子元器件的组装技术提出了更高的要求。[1]并且电子器件在服役的条件下环境温度难以避免的发生着变化，元器件在频繁的周期性的热循环条件下工作时容易造成印刷电路板、钎料和元器件之间由于热膨胀系数差异较大导致焊点内裂纹的生长和扩展，致使强度降低[2-3]。随着世界范围内的禁铅，在无铅钎料系列中，SAC305钎料市场应用最为广泛[4]。但由于Ag的价格昂贵而且Ag含量过高在钎料中会生成大片的Ag3Sn使钎料可靠性降低[5-6]。本文以一种新型低银钎料SACBN07（Sn07Ag05Cu+BiNi）和某助焊剂混合制备的锡膏作为研究对象，通过与市场上广泛应用的SAC305锡膏作对比，研究了冷热循环对钎料的剪切强度和纳米压痕硬度的影响，分析了影响力学性能的微观机理。……