Characterization of Porous Silicate Low-k Films by Ellipsometric Porosimetry and Variable-energy Positron Annihilation Spectroscopy

ABSTRACTWe a pplied ellipsometric porosimetry and variable-energy positron annihilation spectroscopy to the pore characterization of spin-on-glass silicon-oxide-backboned porous thin films with different relative dielectric constants between 2.3 and 3.2. It was found that the relative dielectric constant decreases linearly with increasing open porosity deduced by ellipsometric porosimetry. Comparison of the open porosity with the average pore size deduced by positron annihilation lifetime spectroscopy suggested that mesopores less contribute to open porosity and are not so effective in decreasing film relative dielectric constant in comparison with micropores.