Room-Temperature Wafer Direct Bonding Using Ne-Beam Surface-Activation

Abstract

In the surface activated bonding (SAB) at room temperature, the surfaces of wafers are sputter etched by high-energy ion/atom beams of inert gases to remove surface contaminants and create active surfaces, which are ready to form inter-atomic bonds even at room temperature. For the purpose Ar has been used. However, sputter etching by Ar high-energy ion/atom beam causes increase of surface roughness. We have examined the applicability of fast-atom-beam (FAB) of Ne and Xe to SAB of Si wafers at room temperature. We confirmed that Ne-FAB does not cause surface roughening and Si wafers are successfully bonded by Ne-beam surface activation. In addition, we found that Ne-FAB sputter etching has surface smoothing effect which can improve various properties of the bonding interface.