A method for forming a damascene structure by providing a single process solution for resist ashing while avoiding and repairing plasma etching damage as well as removing absorbed moisture in the dielectric layer, the method including providing a substrate comprising an uppermost photoresist layer and an opening extending through a thickness of an inter-metal dielectric (IMD) layer to expose an underlying metal region; and, carrying out at least one supercritical fluid treatment comprising supercritical CO2, a first co-solvent, and an additive selected from the group consisting of a metal corrosion inhibitor and a metal anti-oxidation agent to remove the uppermost photoresist layer, as well as including an optional dielectric insulating layer bond forming agent.