  We present theoretical investigations of a k-restore process for damaged
pourous 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-CH$_{3}$ bonds. We employ density functional
theory (DFT) 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, we 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.
