Room temperature desorption of Self Assembly Monolayer (SAM) passivated Cu for lowering the process temperature Cu-Cu bonding of 3-D ICs

Success of 3-D ICs technology depends upon the reduction of Cu-Cu bonding temperature. Contamination and oxidation of Cu surface is major bottleneck of reduce the bonding temperature. In this study we investigated the passivation property of Self Assembly Monolayer (SAM) by using Alkyl thiol (Hexanethiol, six carbon chain, C₆) on freshly deposited Copper surface and thereafter desorption of the monolayer using cold Helium plasma. Protection of Copper surface using SAM will minimize the possibility of forming Copper oxide. Cold plasma desorption will help in getting back the clean and pure Copper surface on room temperature. This will provide the platform for low temperature bonding (<;200°C) for 3D IC technology.