Joint reliability study of solder capped metal pillar bump interconnections on an organic substrate

Flip chip technology is widely used on the electronic packaging, and the market forces drive toward finer pitch interconnection. Cu pillar bump structure is a currently trend of the fine pitch flip chip package with less than 100μm bump pitch. But there is a solder volume limitation on solder capped Cu pillar bump structure. In addition, Cu may easily react with Sn-based solder into intermetallic compounds (IMCs). So it may be difficult for much finer pitch application with the structure. © 2012 IEEE.