Abstract: Interconnects of integrated circuits (ICs) utilize low-k dielectrics, copper metal lines, dual damascene processing and amplified photoresist chemistry to build ICs with features smaller than 100 nm. Photolithographic processing of interconnects with these elements are subject to resist poisoning from nitrogen in etch stop and hard mask dielectric layers. Attempts to solve this problem cause lower IC circuit performance or higher fabrication process cost and complexity. This invention comprises a method of fabricating interconnects in an IC using layers of silicon carbide doped oxide (SiCO) in a via etch stop layer, in a trench etch stop layer, as a via etch hard mask and as a trench etch hard mask.