Organic-Functionalized Pure-Silica-Zeolite MFI Low-k Films

For all of the inorganic porous spin-on low-k films being developed today, a post-spin-on hydrophobic treatment is needed to reduce their moisture sensitivity. In the present work, we demonstrate that, for pure-silica-zeolite MFI spin-on low-k films, this extra hydrophobic treatment step can be potentially eliminated by using organic-functionalized pure-silica-zeolite MFI (OF PSZ MFI) nanoparticle suspension. Specifically, methyltrimethoxysilane was simply added to the synthesis solution for a PSZ MFI nanoparticle suspension that contains tetraethyl orthosilicate, tetrapropylammonium hydroxide, ethanol, and water. This approach takes advantage of the hydrophobic methyl groups in the zeolite nanocrystal framework as well as in amorphous silica in the low-k film. The improvement of the hydrophobicity of the spin-on film from this OF PSZ MFI nanoparticle suspension was demonstrated by the higher water contact angle of the film and less moisture sensitivity of the k value in an ambient atmosphere.