Control of Pore Structures in Periodic Porous Silica Low-k Films

Abstract

The structure of nanometer-size pores in periodic porous silica low-dielectric-constant (low- k ) films was investigated by in-plane and out-of-plane X-ray scattering and diffraction. The periodic porous silica films were prepared by spin coating of a tetraethoxysilane (TEOS)-based precursor solution mixed with self-organizing surfactant sacrificial template molecules. TEOS vapor treatment before the removal of the sacrificial templates was shown to help maintain the periodically ordered structure during the template removal process at 673 K. It was demonstrated that a successful control of pore structure is feasible by the selection of pore-generating surfactant template molecules. Namely, the pore diameter, porosity and dielectric constant were controlled successfully by varying the alkyl chain length in the surfactant template molecules.