An Investigation of Copper Dissolution and the Formation of Intermetallic Compounds in Molten Tin and Tin-Silver Solders
An Investigation of Copper Dissolution and the Formation of Intermetallic Compounds in Molten Tin and Tin-Silver Solders
复制标题
熔融锡和锡银焊料中铜溶解和金属间化合物形成的研究
DOI：
10.1115/ht2003-47477
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
G. Wang
中科院分区：
文献类型：
--
作者：
M. Faizan;R. A. Mccoy;D. Lin;T. Srivatsan;G. Wang
本文介绍了铜在熔融锡和锡银 (Sn-Ag) 焊料中的溶解以及焊料/铜界面处 Cu-Sn 金属间化合物的形成和存在的实验研究。在实验过程中，将涂有 RMA 助焊剂的铜（纯度为 99.9%）样品垂直浸入熔融焊料中，浸泡时间从 5 秒到 10 分钟不等。对于纯锡，熔融焊料的温度分别保持在232℃、250℃和300℃；对于Sn-3.5%Ag，熔融焊料的温度分别保持在221℃、250℃和300℃。然后将样品切割、清洁并在环境温度下冷安装在环氧树脂中。利用机械研磨、精抛光、蚀刻和光学金相程序来检查抛光和蚀刻样品的微观结构。测定金属间化合物的平均厚度和溶解的铜量。实验结果表明，熔融焊料的温度可以控制铜的溶解速率以及界面处金属间化合物的形成和存在。在给定的焊料温度下，铜在焊料中的溶解速率随着铜在焊料中停留时间的增加而呈上升趋势。对于短接触时间，溶解速率低且金属间化合物的厚度小。随着停留时间的增加，铜的溶解速率迅速增加并最终达到稳定水平。铜溶解的开始导致在铜基材周围形成一层 Sn-Cu 金属间化合物。这又防止了铜基板与熔融焊料的直接接触。金属间化合物层的形成速率显示出类似的趋势。根据实验结果，确定了两种焊料控制金属间化合物生长的动力学参数。这些参数可用于估计焊接过程中铜溶解和金属间化合物形成的动力学。版权所有 © 2003 ASME
This paper presents an experimental study of copper dissolution in molten tin and tin-silver (Sn-Ag) solders and the formation and presence of the Cu-Sn intermetallic compound at solder/copper interfaces. During the experiments, copper (99.9% pure) samples, coated with a RMA flux, were dipped vertically in a molten solder for different time periods ranging from 5 seconds to 10 minutes. The molten solder was maintained at temperatures of 232°C, 250°C and 300°C for pure tin and 221°C, 250°C, and 300°C for Sn-3.5%Ag respectively. The samples were then cut, cleaned and cold mounted in epoxy at ambient temperature. Mechanical grinding, finish polishing, etching, and optical metallographic procedures were utilized for examining the microstructures of the polished and etched samples. The average thickness of the intermetallic compound and the amount of copper dissolved was determined. Experimental results indicate the temperature of molten solder to control the rate of dissolution of copper and the formation and presence of intermetallic compounds at the interfaces. At a given temperature of the solder temperature, the rate of dissolution of copper in the solder revealed a rising trend with an increase in dwell time of copper in the solder. For short contact time periods, the dissolution rate is low and the thickness of the intermetallic compound is small. With an increase in dwell time, the dissolution rate of copper rapidly increases and eventually reaches a plateau. Initiation of dissolution of copper causes a layer of the Sn-Cu intermetallic compound to form around the copper substrate. This in turn prevents direct contact of the copper substrate with the molten solder. The rate of formation of the layer of intermetallic compound reveals a similar trend. Based on experimental results, the kinetic parameters involved in governing the growth of the intermetallic were determined for the two solders. The parameters can be used to estimate the kinetics of copper dissolution and intermetallic compound formation during soldering.Copyright © 2003 by ASME