With the increase of the number of transistors on a chip, there is growing interest in developing low-dielectric-constant (low-k) materials since the low-k materials are essential to build faster microprocessors by lowering cross-tralk noises and power consumption. Pure-silica-zeolite is a good candidate for low-k material due to its intrinsically uniform pore size and distribution, high hydrophobicity, strong mechanical strength and chemical stability. In our previous work, spin-on MEL zeolite nanocomposite thin films consisting of crystalline zeolites and zeolitic-amorphous silicas have been demonstrated to have superior mechanical and dielectrical performance. While the MEL zeolite crystals give the material the low-k value due to their crystalline and porous framework, the role of the zeolitic-amorphous silica in the nanocomposite is not well understood. In this study, zeolitic-amorphous silica was separated from the MEL zeolite suspension and compared with non-zeolitic-amorphous silica. Detailed parametric study is performed on spin-on zeolitic-amorphous silica films, non-zeolitic-amorphous silica films, the blending of zeolite crystal and zeolitic-amorphous silica films, and the blending of variable amount ratio of zeolite crystal to non-zeolitic-amorphous silica films. The reduced elastic modulus and hardness of the films were measured with nano-indentation. And the crystallinity of the films was studied using X-ray diffraction (XRD) and high resolution transmission electron microscopy (TEM). The mechanical property and crystallinity results reveal that zeolitic-amorphous silica has a nanoporous quasi-crystalline structure, which is different from the dense non-zeolitic-amorphous silica. Since comparing with zeolite suspension, zeolitic-amorphous silica can yield smoother film with tunable crystallinity and mechanical strength via spin coating, our finding might open a new and promising route for preparing zeolite low-k materials.

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