Nanoporous organosilicate glass films via chemical vapor deposition onto colloidal crystal templates

Templated nanoporous organosilicate glass (OSG) films with extremely low dielectric constants and refractive indeces, as low as 1.4 and 1.067 respectively, were fabricated via chemical vapor deposition. Well-ordered assemblies of polymer nanospheres serve as templates for the pores. To enable three-dimensional crystal templates to form on substrate areas larger than 10 cm(2), a method using rapid evaporation-induced self-assembly of polystyrene (PS) nanospheres was developed. Conformal plasma-enhanced CVD using dimethylsilane and oxygen precursors fills the interstices of the colloidal crystal to form the OSG matrix. With subsequent annealing at 500 degrees C the labile polymer beads decompose, resulting in a nanoporous organosilicate thin film.