Molecular Templating of Nanoporous Ultra Low-Dielectric Constant (~1.5) Organosilicates by Tailoring the Microphase Separation of Triblock Copolymers

Triblock polymers,poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) (PEO-b-PPO-b-PEO), are used as molecular templates in poly(methyl silsesquioxane) (MSQ) matrices to fabricate nonporous organosilicates. Initially homogeneous blends of the triblock copolymer and the MSQ precursor picrophase separate during a curing step when the MSQ becomes increasingly hydrophobic. The polymer domain size the MSQ composites, (3-10) nm, depends on the polymer architecture and loading percentage. Extremely small pores, (1-5) nm are generated after heating the film to remove the template material. These materials can attain ultra low-dielectric constants (k = 1.5) with superior electrical and mechanical properties.