Closed porosity aluminosilicate for electronic packaging applications

The electrical properties of sol-gel prepared aluminosilicate films were investigated for suitability in electronic applications. The aluminosilicate films exhibited apparent closed porosity and a dielectric constant as low as = 5 with processing temperatures from 373 K to 873 K. The porosity was inaccessible to nitrogen at 77 K, helium at 293 K, and water vapor at 293 K. Both bulk and thin-film samples were analyzed for hydroxyl and carbon contents to elucidate the relative dependence of the measured electrical properties on processing conditions. Experiments indicate it is possible to vary the porosity in bulk material in ways that should improve electrical properties.