Corrosion of Si-O based porous low-k dielectrics

The corrosion behavior of low-k dielectric films used in today's microelectronic interconnects is reported. We study the dielectric constant, k, range 2.7 to 2.05, with all materials based on a Si-O-Si network. A corrosion mechanism based upon the reaction of water molecules with strained crack-tip bonds is used to model crack velocity vs. applied strain energy release rate curves and to extract key atomistic parameters for each dielectric. It is found that bond strength is invariant and bond density varies linearly with k. The data indicate that no new mechanism plays a part in the corrosion of these Si-O-Si based films with dielectric constants down to ∼2.