Determination of the pore size distribution and porosity of porous low-dielectric-constant films by grazing incidence x-ray scattering

Abstract

An extended technique to determine the pore size distribution and porosity of porous low-dielectric-constant (low-k) films using the grazing incidence small-angle x-ray scattering measurement method has been developed. The method employs a laboratory x-ray source. The calculation of the scattering intensity from the pores has also been modified for quantitative analysis. Taking account of the reflections and refractions at the film surface and interfaces, the method utilizes calculations based on the distorted-wave Born approximation. The obtained pore size distributions of silica-based porous low-k films agreed well with that of the N2 gas adsorption technique. The porosity and wall density of the porous low-k films were determined by using the scattering intensities and the film density. Furthermore, the anisotropic pore size distributions were detected by comparing the scattering curves along the parallel and the normal to the surface directions for an organic porous low-k film.