温度梯度作用下的Ni/Sn/Cu焊点界面反应分析

Analysis on interfacial reaction of Ni/Sn/Cu solder joint under temperature gradient

采用Ni/Sn/Cu互连焊点作为研究对象,在不涉及电迁移效应条件下,设置温度梯度为TG=1 046℃/cm,研究在热迁移作用下镍为热端、铜为冷端时界面金属间化合物(intermetallic compound,简称IMC)的显微组织变化.结果表明,随着热迁移加载时间的增加,冷、热两端界面IMC的厚度都增加,但冷端界面IMC的生长速率大于热端.EDS分析表明,界面IMC是(Cu,Ni)_6Sn_5相,并且热端IMC中的Ni元素含量高于冷端.另外,在冷端的界面(Cu,Ni)_6Sn_5相中观察到大量的空洞,且在(Cu,Ni)_6Sn_5/Cu界面之间没有观察到Cu_3Sn.

The growth behaviors of the interfacial intermetallic compounds( IMCs) in Ni/Sn/Cu solder joints with Ni as hot end and Cu as cold end were systematically investigated under a temperature gradient of 1 046 ℃/cm without any electromigration. The result showed that the thicknesses of IMC at both cold and hot end increased with loading time under thermomigration,and the growth rate of IMC at cold end was larger than hot end. It was also indicated that the IMC was the( Cu,Ni)_6Sn_5 phase,and the Ni content at hot end was higher than cold end by EDS analysis. In addition,a large number of voids were observed in the interfacial( Cu,Ni)_6Sn_5 phase at cold end,and no Cu_3Sn phase was observed between the interfacial( Cu,Ni)_6Sn_5 and Cu substrate.