Stability Of Silicon-Oxygen-Fluorine And Carbon-Fluorine LOW-K DIELECTRICS WITH RESPECT TO ATTACK BY WATER

Abstract

ABSTRACTAb initio configuration interaction calculations have been previously used to account for the relatively large decreases in the static dielectric constant of Si-O-F alloys with low alloy concentrations of F-atoms, ∼ 22%for F concentrations of ∼ 10 at.%. The present study addresses the stability of these alloy films and carbon-fluorine films with respect to attack of Si-F bonds or C-F bonds by water molecules. The present calculations show that the reaction: H20 + 2 Si-F - 2 HF + Si-O-Si is exothermic by about 0.7 eV. However, the reaction of H20 + 2 C-F - 2 HF + CO-C is calculated to be endothermic by 1.6 eV. Our calculations focus on the reaction energetics and geometries as a function of the distance between the F-atoms of the Si-F and C-F groups and water molecule.