Preparation and properties of electroless deposited NiB as barrier layer

In this paper, electroless-NiB film was deposited on insulator/Si activated with PdCl₂ as the barrier layer to prevent the diffusion of Cu into Si. This was done without any conventional pretreatment as modified by self-assembled monolayer (SAM). The results show that the NiB layer is highly uniform and the defects of the NiB layer is decreases with the increasing deposition time. After annealed at various temperature, the surface morphology of NiB film was obtained by SEM to observe its thermal stability. The results of XRD reveal that the as-deposited NiB layer is amorphous and becomes crystalline after annealing at 400°C. The barrier property of the NiB layer was evaluated based on the results obtained by XRD at several annealing temperatures after electroplating Cu layer on the NiB layer. It was confirmed that electroless NiB film blocked Cu diffusion under annealing temperature of up to 500°C. We conclude that the electroless-NiB has good coverage and barrier properties.