Investigation into the Structural and Electrical Properties of a-SiCO:H as a Diffusion Barrier to Copper

Abstract

In this study, we attempted to deposit low dielectric constant a-SiCO:H as a copper diffusion barrier by the plasma-enhanced chemical vapor deposition method using an organosilicon precursor, bis(trimethylsilylmethane) (BTMSM, C 7H 20Si 2). The dielectric constant of the a-SiCO:H films increased from 2.54 to 3.25 as the deposition temperature was increased from room temperature to 280°C. The refractive index increased gradually with increasing deposition temperature, indicating that the film has a denser structure as well as a higher dielectric constant at higher deposition temperatures. The Fourier transform infrared and X-ray photoelectron spectroscopy analyses indicated that the chemical structure of the Si atoms in the films changed from the D moiety to the T moiety with increasing deposition temperature. The electrical conduction mechanism of the a-SiCO:H films was determined to be a Schottky emission current in the high field region (E > 0.4 MV/cm). © 2006 The Electrochemical Society. All rights reserved.