The integration reliability of mechanically robust, ultra low-k spin-on-glass poly(methyl)silsesquioxanes incorporating incompletely condensed methyl-POSS were examined for next generation microelectronics.

A series of organic-inorganic hybrid spin-on-glass polymethylsilsesquioxanes were synthesized utilizing a cyclic siloxane precursor, 1,3,5,7-tetramethyl-1,3,5,7-tetrahydroxyl cyclosiloxane (MT4-OH), copolymerized with methyltriethoxysilane (MTES) at various comonomer ratios. By selectively introducing this 2-D cyclic crosslinker, we were able to obtain spin-on-glass hybrimers with low dielectric constant (2.5-2.7), high nanoindentation modulus (5-10.5 GPa), with high thermal stability (>700 C) without the use of porogens or additives. The use of the cyclic monomer MT4-OH greatly increased the mechanical properties, which allowed for impeccable reliability of a variety of patterns obtained through etching and chemical mechanical planarization processes, while maintaining optimal gap-filling properties. Due to the superior dielectric, mechanical, and integrated processing of these materials, these hybrids derived from MT4-OH may be utilized as next generation spin-on-glass low-dielectric constant materials. † Electronic supplementary information (ESI) available: Dielectric constant values and mechanical properties of as-cast MT4-OH resins. See Scheme 1 Synthesis of (a) MT4-OH and (b) MT4-MSSQ spin-on-glass resins. 66512 | RSC Adv., 2015, 5, 66511-66517 This journal is