Characterization of ultra-low k porous organosilica thin films

Porous organosilica thin films using 1,2-bis (triethoxysily) ethane, triethoxymethylsilane and a poly (ethylene oxide)-poly (propylene oxide)-poly (ethylene oxide) triblock copolymer template have been prepared by spin-on technique. The films were characterized by cross-sectional scanning electron microscopy, x-ray diffraction and Fourier-transform infrared spectroscopy. After thermal treatment at 350 °C in N₂ for two hours, the films show well ordered porous structure as well as uniform and crack-free surface. The dielectric constant (k) as low as 2.0 was obtained at 100k Hz, and kept good thermal stability up to 500 °C. Meanwhile, the resulting low-k porous films also exhibit low leakage current densities, e.g., 3.0 × 10^-8 A/cm² at 1 MV/cm, and good mechanical properties with elastic modulus of 4.7 GPa and hardness of 0.56 GPa in the case of 500°C annealing.