Protection of Activated Au Surface using Self-assembled Monolayer for Room Temperature Bonding

Surface activated bonding (SAB) achieves Au-Au direct bonding at room temperature by cleaning and activating the bonding surfaces. However, the effect of the surface activation expires within a few hours due to the re-adsorption of the carbonaceous contaminants. In this work, we report the protection of the activated surface from re-adsorption by using a self-assembled monolayer (SAM). The activated Au surface by Ar fast atomic bombardment is successfully bonded at room temperature even though the activated surface is exposed to ambient air for 100 h. The presented approach will broaden the applicability of the SAB technique.