Characterization of carbon-doped SiO2 low k thin films -: Preparation by plasma-enhanced chemical vapor deposition from tetramethylsilane

Carbon-doped SiO2 low k thin films were prepared by radio frequency plasma-enhanced chemical vapor deposition at 400 degreesC from polymerization of tetramethylsilane (4MS) and copolymerization of tetramethylsilane and silane (SiH4) precursor. with nitrous oxide as the oxidant gas. Copolymer thin films from 4MS and SiH4 precursor show much higher deposition rates than polymer thin films from 4MS, if all other parameters are kept the same. The addition of SiH4 can significantly promote the plasma polymerization of 4MS. The structure and composition of these films were characterized using Fourier transform infrared and X-ray photoelectron spectroscopy. The physical properties of the films have been investigated by dielectric constant, refractive index. and thermal stability measurements. The two kinds of films have similar chemical composition and structure. The film as prepared shows excellent thermal stability at temperatures as high as 400 degreesC and a dielectric constant of about 3, which indicates that it has potential as a low k dielectric for advanced interconnect applications. (C) 2001 The Electrochemical Society.