倒装芯片互连时SnAg/95Pb5Sn焊料间的互扩散行为及Ni阻挡层的作用

INTERDIFFUSION BEHAVIOR OF SnAg/95Pb5Sn FLIP-CHIP JOINT AND THE INFLUENCE OF Ni AS A DIFFUSION BARRIER

本文研究了共晶ＳｎＡｇ／９５ＰｂＳｎ 扩散偶在２５０ ℃下的扩散行为。发现由于９５Ｐｂ５Ｓｎ 中的Ｐｂ 向熔融共晶ＳｎＡｇ 焊料中扩散而部分生成三元共晶Ｐｂ － Ｓｎ－ Ａｇ 相，其熔点约为１７８℃。化学镀Ｎｉ 层可以有效地阻止共晶ＳｎＡｇ 和９５Ｐｂ５Ｓｎ 间的互扩散，防止Ｐｂ－ Ｓｎ－ Ａｇ 共晶相的生成，从而提高焊点的耐热温度。文中还研究了与共晶ＳｎＡｇ／Ｎｉ／９５Ｐｂ５Ｓｎ 结构相关的相变及力学性能。

The interdiffusion behavior of eutectic SnAg/95Pb5Sn diffusion couple was investigated. Experimental results showed that a ternary eutectic Pb-Sn-Ag phase with melting temperature near 178℃ was formed as a result of the diffusion of Pb from 95Pb5Sn to eutectic SnAg. An electroless Ni layer can effectively prevent the interdiffusion between eutectic SnAg and 95Pb5Sn. In addition, the phase transformations and mechanical properties of eutectic SnAg/Ni/95Pb5Sn were investigated.