Asymmetric low temperature bonding structure using ultra-thin buffer layer technique for 3D integration

Wafer-level Sn/In-Cu bonding structure with Ni ultra-thin buffer layer is investigated to achieve a reduction in solder thickness, bonding temperature and duration. Furthermore, the asymmetric bonding structure is able to separate the manufacturing process of solder and electrical isolation layer. It is a promising approach for the application on hybrid bonding of three-dimensional integration.