Effects of Micro Solder Joint Geometry on Interfacial IMC Growth Rate

摘要

The effects of micro solder joint geometry on intermetallic compound (IMC) growth and electromigration during thermal aging and current stressing have been investigated using three groups of specimens: sandwich structure with solder layer of 10 mu m to 50 mu m, wire butt with solder layer of 60 mu m to 240 mu m, and solder ball with diameter of 200 mu m to 500 mu m, each having Cu/Sn/Cu structure. The results indicated that the geometrical size of the micro solder joint clearly affected the interfacial element diffusion and IMC evolution. Furthermore, when the solder layer thickness was less than 30 mu m, the growth rate of the IMC layer decreased significantly with decreasing solder layer thickness, because Sn element was nearly exhausted in the micro solder joint during thermal aging.