ELD NiB for microbumps passivation and wirebonding

In this paper the role of electroless NiB as capping layer for the microbumps in preventing oxidation and improving the solder wetting and wirebonding is discussed. Surface properties of such a layer is analyzed by XPS analysis technique and the mechanical properties such as modulus and hardness are studied using nanoindentation tool. Deposition quality of NiB is investigated using TEM and EDX mapping and at the end the electrical data and cross section SEM images of the stacked samples are discussed when using H
₂
plasma cleaning and capping layers for both pre-applied under fill and wafer level UF.