摘要
Sn镀层表面在某些情况下会长出长达数百微米的晶须,在电子器件服役过程中会导致电路短路等严重的可靠性问题。目前普遍认为内部压应力是导致Sn晶须生长的主要动力之一;晶须生长所需的Sn原子主要以扩散方式或位错运动方式提供,而温度因素既影响原子扩散速度,又影响镀层的应力松弛。预镀Ni或者预先热处理以形成扩散阻挡层来抑制晶须生长的方法较为常用。温度循环是加速晶须生长的一种有效手段。
Sn whiskers up to hundreds of microns in length grow spontaneously from the surface of pure Sn lead-free finish in some cases, resulting in serious reliability problems such as short circuit in the lifetime of electronic devices. It was widely accepted that Sn whisker growth was mostly driven by compressive stress. Sn whiskers grow from Sn atoms migration through diffusion or dislocation mechanism. Diffusion barriers formed by Ni finish layer and/or heat treatment to suppress whisker growth were practical used. Temperature cycling was commonly used in Sn whisker accelerated growth test.
出处
《功能材料》
EI
CAS
CSCD
北大核心
2005年第7期971-974,共4页
Journal of Functional Materials
基金
国家自然科学基金资助项目(10474024)
中港基金NSFC/RGC资助项目(60318002)
关键词
晶须
无铅
可靠性
电迁移
封装
Compressive stress
Crystal growth
Diffusion
Dislocations (crystals)
Electromigration
Electronic equipment
Recrystallization (metallurgy)
Reliability
Short circuit currents
Tin
