Processing and Characterization of Ultra Low-Dielectric Constant Organosilicates

A class of organosilicate has been developed that can reach ultra low-dielectric constant (k=2). In this approach, a series of triblock polymers, poly (ethylene oxide-b-propylene oxide-b- ethylene oxide) (PEO-b-PPO-b-PEO), are used as sacrificial materials in silicon based spin-on matrices, poly (methyl silsesquioxane) (MSQ) to generate pores when heated above 400C. To improve the electrical and mechanical properties, different parameters, such as temperatures, heating rates, polymer molecular weighs, copolymer compositions and the molecular weight of MSQ precursors were studied. Heating temperatures and ramping rates have no large effect on dielectric constants and dielectric breakdown strength. However at higher temperature, 500C, the mechanical properties are found stronger than those from 400C. A higher molecular weight of MSQ precursor will lead to higher mechanical properties of the final porous MSQ, while no temperature effect is observed. Block copolymers with different molecular weights and compositions give similar dielectric constants depending on the polymer loading in MSQ, and no substantial change in the dielectric strength of the films with different compositions.