On stress-affected kinetics of intermetallic compound growth in the presence of electromigration

Influence of Temperature and Current Stressing on Cu‐Sn Intermetallic Compound Growth Characteristics of Lead‐Free Microbump

“…[ 3 ] However, minute‐sized solder joints have to withstand a heavier current density, and its mechanical properties, electrical properties are also different. [ 4 ] Further, rich Sn in lead‐free exacerbates the Cu‐Sn interface reaction that causes the excessive growth of IMCsand changes the evolution mechanism. The interfacial reaction equation can be expressed as: [ 5,6 ] $$$$\begin{equation} \def\eqcellsep{&}\begin{array}{l} \hspace*{6.5pc}6Cu + 5Sn \to C{u_6}S{n_5}\\[4pt] \hspace*{6.5pc}9Cu + C{u_6}S{n_5} \to 5C{u_3}S{\rm{n}} \end{array} \end{equation}$$$$…”

“…Under the long‐term effects of temperature and current, the growth of Cu‐Sn IMCs is accompanied by the formation of voids and cracks. [ 4 ] It severely decreases the reliability of microbump interconnects.…”