Surface reactions during etching of organic low-k films by plasmas of N2 and H2

Surface reactions during etching of organic low-$k$ film by ${\mathrm{N}}_2$ and ${\mathrm{H}}_2$ plasmas were studied through observations of the surface resident species using in situ infrared spectroscopy and in vacuo electron-spin-resonance techniques. We observed surface modifications by the formation of CN and NH bonds after exposure to plasmas generated from ${\mathrm{N}}_2$ and ${\mathrm{H}}_2$ . The number of carbon dangling bonds were greater in processes where ${\mathrm{H}}_2$ was present. The passivation of carbon dangling bonds leads to $\mathrm{C}{\mathrm{H}}_3$ , $\mathrm{N}{\mathrm{H}}_3$ , and CN functionalities, which are the precursors for etching products that are desorbed, which includes volatile forms such as HCN and ${\mathrm{C}}_2{\mathrm{N}}_2$ .