Low Permittivity SiO2/Void Nanocomposite Films

Abstract

AbstractA novel approach for preparing porous SiO2 thin films by sputter deposi-tion is being developed. The porosity is introduced to reduce the dielectric permittivity of the film to less than 3 for potential use in packaging high speed VLSIs. In the first approach, amorphous silicon is initially deposited to produce a columnar structure with a thickness of 25μm, followed by etching and thermal oxidation to result in closely spaced SiO2 pillars. Capping the structure by a thin film (0.1μm), silica gel layer provides the support for strip line traces. In the second approach, porous SiO2 films are prepared by reactive sputtering. The dielectric properties of the sputter deposited SiO2 films are presented.