Theoretical investigation of an in situ k-restore process for damaged ultra-low-k materials based on plasma enhanced fragmentation

The authors present theoretical investigations of a k-restore process for damaged porous ultra-low-k (ULK) materials. The process is based on plasma enhanced fragmented silylation precursors to replace k-value damaging, polar Si-OH and Si-H bonds by k-value lowering Si-CH₃ bonds. The authors employ density functional theory to determine the favored fragments of silylation precursors and show the successful repair of damaged bonds on our model system. This model system consists of a small set of ULK-fragments, which represent various damaged states of ULK materials. Our approach provides a fast scanning method for a wide variety of possible repair reactions. Further, the authors show that oxygen containing fragments are required to repair Si-H bonds and fragments with dangling Si-bonds are most effective to repair polar Si-OH bonds.