Influence of NH3 plasma treatment on chemical bonding and water adsorption of low-k SiCOH film

Carbon-doped silicon oxide (SiCOH) dielectrics are one of the most suitable candidates for advanced low-dielectric-constant (low-k) interlayer material. To improve water adsorption resistance, the plasma-enhanced chemical vapor deposited SiCOH films have been post-treated by the NH3 plasma for various times, and the resulting SiCOH films are thus examined by water adsorption experiments. The results indicate that the SiCOH films treated by the NH3 plasma exhibit enhanced resistance against water adsorption. Further, Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy are used to characterize the chemical composition and bonding states of the pristine and NH3 plasma treated SiCOH films. It is revealed that the plasma surface treatment leads to the formation of Si–N, C(sp3)–N, C(sp2)N, (N–)nSi–C (n = 1–3) configurations, and loss of carbon atoms.