Interaction of vacuum ultraviolet light with a low-k organosilicate glass film in the presence of NH3

Abstract

In situ x-ray photoemission spectroscopy (XPS) and ex situ Fourier transform infrared spectroscopy (FTIR) were used to characterize effects on organosilicate films of 147 nm irradiation in the presence of 10−4 Torr NH3. XPS and FTIR data indicate SiO and SiC bond scission, with nitridation only at Si sites. Photoirradiation causes the surface layer to become enriched in sp2 carbon. FTIR spectra of silanol formation upon exposure to ambient indicate reactive sites in the bulk have lifetimes of up to six days. XPS data indicate lifetimes of ∼minutes for surface states. Nitrogen uptake passivates with longer exposure times, indicating surface densification.