In this study, we report the first chemical characterization of a plasma-deposited model fluoropolymer on low-k dielectric nanostructure and its decomposition in UV/O2 conditions. Carbonyl incorporation and progressive removal of fluorocarbon fragments from the polymer were observed with increasing UV (≥230 nm) irradiation under atmospheric conditions. A significant material loss was achieved after 300 s of UV treatment and a subsequent wet clean completely removed the initially insoluble fluoropolymer from the patterned nanostructures. A synergistic mechanism of UV light absorption by carbonyl chromophore and oxygen incorporation is proposed to account for the observed photodegradation of the fluoropolymer.
Keywords: UV irradiation; fluorocarbon polymer; low-k dielectrics; photosensitization; postetch residue removal; singlet oxygen.