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Chem. Mater. 2005, 17, 2520-2529
Low-k Interlayer Dielectric Materials: Synthesis and Properties of Alkoxy-Functional Silsesquioxanes Kai Su,* Duane R. Bujalski, Katsuya Eguchi, Glenn V. Gordon, Duan-Li Ou, Pierre Chevalier, Sanlin Hu, and Ronald P. Boisvert Dow Corning Corporation, Midland, Michigan 48686-0995 ReceiVed June 24, 2004. ReVised Manuscript ReceiVed January 6, 2005
Two new types of silsesquioxanes, (HSiO3/2)x[(tBuO)SiO3/2]z or THQ and (HSiO3/2)x(RSiO3/2)y[(tBuO)SiO3/2]z or THTRQ (R ) octadecyl), were synthesized and studied as low-k dielectric materials for electronic applications. The materials were prepared by cohydrolysis and condensation of alkoxy monomers, (AcO)2Si(OtBu)2, HSi(OEt)3, and CH3(CH2)17Si(OMe)3. Spectroscopic data supported retention of tertiary alkoxy groups [(tBuO)SiO3/2 or (tBuO)2SiO2/2] and presence of silanol. The molecular weight of (HSiO3/2)x[(tBuO)SiO3/2]z increased with the T/Q ratio, while that for (HSiO3/2)x(RSiO3/2)y[(tBuO)SiO3/2]z exhibited less dependence on composition. The tert butoxy groups were eliminated in both materials at low temperatures (
