Precursor chemistry for ULK CVD

A way to get a low dielectric constant is to decrease the weight density of the bulk material, keeping the same material family, by choosing complex precursors. Voids inside the bulk material could be obtained with macropores or larger (air gap), mesopores (xerogels, SOD) or micropores up to free volume. In that case, cyclic chain precursors and/or a porogen approach can be selected in agreement with plasma experimental conditions to synthesise low density plasma-polymers with intrinsic free volume or with microporosity revealed by a post treatment.