A method of forming an interconnect structure comprising: forming a sacrificial inter-metal dielectric (IMD) layer over a substrate, wherein the sacrificial IMD layer comprising a carbon-based film, such as amorphous carbon, advanced patterning films, porous carbon, or any combination thereof; forming a plurality of metal interconnect lines within the sacrificial IMD layer; removing the sacrificial IMD layer, with an oxygen based reactive process; and depositing a non-conformal dielectric layer to form air gaps between the plurality of metal interconnect lines. The metal interconnect lines may comprise copper, aluminum, tantalum, tungsten, titanium, tantalum nitride, titanium nitride, tungsten nitride, or any combination thereof. Carbon-based films and patterned photoresist layers may be simultaneously removed with the same reactive process. Highly reactive hydrogen radicals processes may be used to remove the carbon-based film and simultaneously pre-clean the metal interconnect lines prior to the deposition of a conformal metal barrier liner.