COMPUTATIONAL CHALLENGES IN CONDENSED MATTER APPLICATIONS
Our paper focuses on computer simulation of the transport processes in nanoporous systems. This systems are considerably more complex than diffusion in homogeneous phases or in macroporous systems. The pathways in nanoporous systems are, by design, similar to the dimensions of the diffusing species. Adsorbate-adsorbate and adsorbate-adsorbent interactions are enhanced. The energetic of transport differs from molecular theory often to reflect activated processes with apparent activation energies. Entropic factors also play an increasing role in the transport. Dissolution as well as diffusion between chains must be considered in polymers. Adsorbent flexibility is a factor of varying significance in both inorganic and organic solids. Simple extensions of homogeneous theories are inadequate, as these specific interactions need to be included. This paper deals with an empirical algorithm, which analyses the physical parameters over the copolymer network properties as a relation between the molecular ratios of copolymer sequences. We also present the performance of the proposed method in relation to the fitness function and the local twist.
Amphyphylic copolymers as water delivery systems
Abstract Various polydimethylsiloxane-co-poly(methacrylic acid) networks were prepared by initiating the radical polymerization of methacrylic acid in presence of azoester containing polydimethylsiloxane (PDMS) and of ethyleneglicole dimethacrilate as crosslinking agent. The chemical structure and the thermal behavior of these hydrophobic–hydrophilic gels were established by IR spectroscopy, scanning electron microscopy and differential scanning calorimetry. Also, the water delivery tests were performed and the possibility to use amphyphilic copolymers as systems to mention humidity in soil is discussed. According to the experimental results a mechanism of water delivery were proposed where the hydrophilic (poly(methacrylic acid)) and hydrophobic (PDMS) sequences have different rolls in this mechanism.
Bevel RIE application to reduce defectivity in copper BEOL processing
Bevel etch used during wafer fabrication for semiconductor devices is discussed. In this case, the bevel etch process was utilized in middle of the line processing (MOL) to reduce back end of line (BEOL) defectivity. Tungsten and titanium nitride films, from the formation of contacts to the transistors, extend into the bevel region of the wafer and have been shown to initiate arcing. This can spread foreign material defects on the front side of the wafer in various BEOL post processing steps including subsequent reactive ion etching, SEM metrology and film depositions. The bevel etch tool confines a plasma etch to the outer edge of the front side of the wafer (which can be individually adjusted) and can remove dielectric, organic and Ti/TiN/W films using a fluorine based chemistry.