The ozone ash treatment has been demonstrated to effectively remove the organic template at 200-300 degrees C as well as to enhance the mechanical strength of mesoporous silica films. The resulting films are of ordered pore structure, strong mechanical strength, and smooth surface. After reacting with hexamethyidisilazane, the silica film has been modified to hydrophobic from hydrophilic and exhibits an ultra-low dielectric constant (k <= 2) and a low leakage current density (10(-7) A/cm(2)) with good electrical reliability. (c) 2005 Elsevier B.V. All rights reserved.