Formation of electroless barrier for all-wet process of TSV in 3D-LSI technology and evaluation of its adhesion property

The fabrication of thin barrier metal layer in a high aspect ratio TSV using electroless plating with Pd nanoparticles (NPs) as a catalyst was investigated. We succeeded in the formation of thin continuous electroless barrier metal layer for a high aspect ratio TSV with addition of adequate amount of additives. Adhesion strength of Co-W-B barrier metal increased with decreasing film thickness. The adhesion strength of barrier film increased with annealing at 200°C, and it was strong enough for practical application.