Low-k Interlayer Dielectric Materials:  Synthesis and Properties of Alkoxy-Functional Silsesquioxanes

Abstract

Two new types of silsesquioxanes, (HSiO 3/2 ) x [( t BuO)SiO 3/2 ] z or T H Q and (HSiO 3/2 ) x (RSiO 3/2 ) y [( t BuO)SiO 3/2 ] z or T H T R Q (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) 2 Si(O t Bu) 2 , HSi(OEt) 3 , and CH 3 (CH 2 ) 17 Si(OMe) 3 . Spectroscopic data supported retention of tertiary alkoxy groups [( t BuO)SiO 3/2 or ( t BuO) 2 SiO 2/2 ] and presence of silanol. The molecular weight of (HSiO 3/2 ) x [( t BuO)SiO 3/2 ] z increased with the T/Q ratio, while that for (HSiO 3/2 ) x (RSiO 3/2 ) y [( t BuO)SiO 3/2 ] z exhibited less dependence on composition. The tert butoxy groups were eliminated in both materials at low temperatures (<450 °C), and subsequent decomposition of octadecyl group (R) in (HSiO 3/2 ) x (RSiO 3/2 ) y -[( t BuO)SiO 3/2 ] z occurred through cleavage and re-distribution of carbon-carbon bonds (430-550 °C). Heating at 450 °C for 2 h afforded porous solids. The total pore volume of materials derived from (HSiO 3/2 ) x [( t BuO)SiO 3/2 ] z determined by nitrogen sorption porosimetry increased with increasing Q content up to 0.313 cm 3 /g or 38% porosity by volume. The porosity for (HSiO 3/2 ) x (RSiO 3/2 ) y [( t BuO)SiO 3/2 ] z ranged from 32 to 54% (0.349-0.701 cm 3 /g), which represented an ∼10% increase over (HSiO 3/2 ) x [( t BuO)SiO 3/2 ] z . Thin films prepared from (HSiO 3/2 ) x [( t BuO)SiO 3/2 ] z exhibited a modulus between 10 and 19 GPa, but had a high dielectric constant due to residual silanol. Incorporation of RSiO 3/2 group allowed for formation of porous materials with low silanol contents. The dielectric constant and modulus of (HSiO 3/2 ) x (RSiO 3/2 ) y -[( t BuO)SiO 3/2 ] z were in the range of 1.7-2.6 and 1.8-4.7 GPa, respectively.

Photoluminescence of as‐synthesized and heat‐treated phenyl‐containing polysilylcarbodiimides: role of crosslinking and free carbon formation in polymer‐derived ceramics

“…The 29 Si{ 1 H} CP MAS NMR spectrum exhibits several resonances in the range of −130 to +10 ppm that were simulated with five Gaussian peaks with δ iso at −72, −60, −46, −21 and 3 ppm. These fives coordination environments correspond to PhSi(NCN) 3 , HSi(NCN) 3 , HPhSi(NCN) 2 , HPhSiCl(NCN) and (Me) 3 Si(NCN) groups, respectively …”

Free-standing, polysilsesquioxane-based inorganic/organic hybrid membranes for gas separations

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New poly(arylene ether)s containing phthalimidine group in the main chain

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