(3cl) Hierarchical and Nanostructured Zeolite Materials for Computer Microprocessors and Biomass Conversion

Zeolite thin films and membranes have been widely investigated over the last 15 years, mainly as separation membranes and membrane reactors.  Their uniform microporosity and the ability to fine-tune their chemical composition and physical architecture lead to important macroscopic properties that can be exploited in a growing number of applications.  The diversity in their use is demonstrated in this work through the exploration of zeolites as low-dielectric constant (low-k) films for computer microprocessors and as catalysts for biomass conversion.

Next-generation microprocessors require smaller feature sizes, but the slow development of new low-k films with better material properties is reducing progress toward improved computing performance.  Pure-silica-zeolites (PSZ) are a strong candidate for replacement low-k materials because their intrinsic porosity and crystallinity give them a low k value and strong mechanical properties.  Several other characteristics, including hydrophobicity, wet-etch chemical resistance, pore size distribution, and thermal conductivity were evaluated and optimized for low-k applications.  In order to obtain the desired aforementioned properties, PSZ films were carefully engineered through different synthesis and modification techniques, including pre- and post-synthesis functionalization techniques and “on-wafer” crystallization synthesis methods at ambient pressures.  Successful device integration of a viable new low-k alternative requires that all of these properties meet minimum specifications.  As a result of the methods developed in this work, PSZ low-k films are a leading low-k candidate and considerably outperform other alternative materials.

As an essential catalyst in the oil refining industry, zeolites may also play a key role in the conversion of biomass to fuels and commodity chemicals.  Studies are currently being performed to investigate the interaction between the kinetics and molecular dimensions of Sn-containing zeolites and biomass-derived sugars.  New and novel nanostructured zeolite catalysts are also being prepared through the use of hierarchical synthesis strategies and innovative organic structure-directing agents.  These zeolites with designed architectures may be useful as multifunctional catalysts or as thin films with unique optical and structural properties.