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 N2 and H2 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 N2 and H2. The number of carbon dangling bonds were greater in processes where H2 was present. The passivation of carbon dangling bonds leads to CH3, NH3, and CN functionalities, which are the precursors for etching products that are desorbed, which includes volatile forms such as HCN and C2N2.