1.0%Zn,Ni对Sn-3.5Ag/Cu界面反应及化合物生长的影响

Effects of 1.0% Zn or Ni additions on interfacial reaction and growth of intermetallics in Sn-3.5Ag/Cu joint

在微电子互连结构中,反应界面化合物层的形貌及厚度是决定焊点可靠性的一个重要因素。通过向Sn-3.5Ag共晶钎料中添加第三元素,分别研究元素Zn和Ni对Sn-3.5Ag/Cu界面反应的影响。结果表明,对于Sn-3.5Ag/Cu界面,液态反应初始生成物为Cu6Sn5,在随后的热老化阶段形成Cu3Sn化合物层;Zn元素不影响界面的初始生成相及其厚度,但在150℃老化阶段,Cu3Sn化合物的形成受到抑制,取代的是非连续的Cu5Zn8化合物层,并且,化合物层增厚速度减慢;然而,当添加1·0%(质量分数)的Ni元素后,界面初始生成相为(Cu,Ni)6Sn5,该化合物层厚度明显大于前者,老化阶段界面无其它相生成。

The morphology and thickness of the intermetallic compounds (IMCs) layer become one of the dominant factors which determine the reliability of the soldered joints in integrate circuit. The effects of Zn and Ni on the reaction of Sn-3.5Ag/Cu interface were investigated by adding 1.0% Zn or Ni addition into the eutectic Sn-3.5Ag solder. It is found that, for Sn-3.5Ag/Cu interface, the initial product was Cu 6Sn 5 IMC, and Cu 3Sn IMC layer was formed at the following 150 ℃ thermal aging period. Although Zn addition had little effect on the thickness of reaction lagers, the Cu 3Sn IMC in the reaction layer was found to be depressed, at the some time, non-continuous Cu 5Zn 8 IMC layer was formed, moreover, the thickening rate of the IMC layer decreased. Whereas, the original product was (Cu,Ni) 6Sn 5 as Ni was added, in addition, the initial thickness of the IMC layer was much thicker. However, there was no other product at the aging stage.