IBM Senior Vice President & Director of Research Dr. Paul Horn Delivers Shipley Lecture

Dr. Paul M. Horn, senior vice president and director of research for IBM (a CAMP Corporate Sponsor) presented the 10th Shipley Distinguished Lectureship at Clarkson University during the month of October. He presented "Global Technology Outlook," IBM's projection of the future for information technology, which included forecasts of software, hardware and new uses and capabilities for the information technology industry. According to Horn, these new technologies have the potential to radically transform the performance and characteristics of tomorrow's information processing systems and provide new business value for customers. His lecture was sponsored by Clarkson's Center for Advanced Materials Processing.

From left: CAMP Director S. V. Babu, Professor Egon Matijevic' (the Victor K. LaMer Chair in Colloid and Surface Science), Dr. Paul Horn (Senior Vice President and Director of Research, IBM), and Clarkson University President Anthony Collins.

NanoDynamics and Clarkson Collaborate on Multiple Levels

NanoDynamics is a "start-up" company in the sense that it was legally formed two years ago. However, the company is unlike nearly all others in that category for the simple reason that the founders and executives have been doing this sort of thing for over a quarter century. Keith Blakely, the CEO and cofounder of NanoDynamics, is well-known to the Clarkson faculty and administration. He has led several advanced materials companies over the past 25 years and they have all been involved with Clarkson University at one time or another.

NanoDynamics, however, has taken the relationship to a new level. Beginning in late 2002, the company began working with Professor Dan Goia to develop a novel processing method to synthesize highly controlled metal powders in the micron, submicron, and nanosize range. Following an early success in copper, the relationship expanded to include other metals, such as nickel and silver, with many more currently under development. NanoDynamics and Clarkson have established a broad technology licensing arrangement covering the work and are anticipating significant benefits to both organizations in the coming years.

In late 2003, Keith approached Senior University Professor Richard Partch about the prospect of his consulting for the company on a broad range of topics, but with an initial interest in carbon nanotubes. From those discussions, a collaboration between Clarkson and NanoDynamics was established which involved the efforts of Dr. Sudha Rani, a post-doc in Partch's laboratory. Dr. Rani agreed to carry out investigative work for NanoDynamics using a novel CNT reactor and then shuttled back and forth to Potsdam to carry out characterization studies using the unique high resolution SEM capability of CAMP. Following a successful research effort, NanoDynamics offered a full-time position to Dr. Rani on their research staff.

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Smart Colloids and More

Professor Sergiy Minko, the Egon Matijevic' Chaired Professor of Chemistry, is an expert in colloid and polymer science and has done extensive work involving "Smart Responsive Functional Materials Based on Self Assembly in Polymer and Colloidal Systems." His CAMP-related research interests include smart/responsive polymer materials, smart colloids, nanostructured thin polymer films, nanotemplates and nanomembranes, formation of nanowires and nanoparticles, adhesion, wetting, adsorption phenomena , single molecule devices, and combinatorial methods in material science.

Novel Polymerization Techniques and New Polymer Nanocomposite Materials

Research in Professor Devon Shipp's laboratories centers on novel polymerization techniques and new polymer materials, in particular nanocomposites. Over the past year a number of new developments have taken place in these areas.

The synthesis of polymer-layered silicate nanocomposites, where the polymers have well-defined molecular weights and molecular weight distributions (i.e. predictable average molecular weights and low polydispersities) has been achieved using three variations of living radical polymerization, viz. atom transfer radical polymerization (ATRP), nitroxide-mediated polymerization (NMP) and reversible addition-fragmentation chain transfer (RAFT) polymerization. Nanocomposites containing homopolymers of styrene, n-butyl acrylate (BA), methyl methacrylate (MMA) and vinyl acetate (VAc) have been produced using montmorillonite as the layered silicate material. This is the first work in which RAFT has been used to produce polymer-layered silicate nanocomposites.

Block copolymer nanocomposites of polystyrene-block-poly(MMA) and polystyrene-block-poly(BA) have been produced using ATRP. These block copolymer materials represent the first successful production of block copolymer-silicate nanocomposites using living radical polymerization. These are expected to exhibit interesting phase separation behavior, in addition to the well-documented improvement in physical properties such as modulus, gas barrier properties, impact strength, and lighter weights. The work on homopolymer and block copolymer nanocomposites made by ATRP has been recently published (Chem. Mater. 2003, 15, 2693-2695; Polymer 2004, 45, 4473-4481; J. Polym. Sci. Part A: Polym. Chem. 2004, 42, 916-924).

Another nanocomposite project in Professor Shipp's laboratory that utilizes the group's expertise in polymer synthesis is the synthesis of polymer modified TiO2 particles for potential use in photovoltaic cells. A novel method of TiO2 nanoparticles surface modification has been developed. The modified surface contains either a radical polymerization initiating or propagating group, and therefore the polymer chains can be grafted onto the nanoparticles. It is believed that by using monomers that are able to coordinate with metal ions, the polymer coating can form a light absorbing dye and thus act as an antenna for a dye-sensitized solar cell (DSSC). The use of the polymer-grafted nanoparticles should alleviate the problem of reduced stability at moderate-to-high temperatures currently experienced by other DSSCs.


Chemical-Mechanical Planarization

Professor S.V. Babu's research group is continuing the investigation of various aspects of chemical-mechanical planarization (CMP) of metal and dielectric films. Recent emphasis has been on mixed abrasives and 'engineered' particles in different chemical environments and defect mitigation and identifying polishing mechanisms. It was discovered that some of the problems associated with the use of a single abrasive slurry, such as poor polish selectivity, surface defects and slurry instability, can be overcome by combining two or more different abrasives. It was shown that by using different particle sizes and taking advantage of differing surface charges on the abrasives, both selectivity and polished surface roughness can be improved systematically. These results were presented at several conferences and in journal papers.

Several new results have also been obtained with high selectivity ceria-based mixed slurries for STI planarization, including poly silicon reduced scratching and other defects. New results include the identification of Ta polishing mechanisms at alkaline conditions and Cu polishing mechanisms at both acidic and alkaline conditions in the presence of various amino acids as well as the role of amine and carboxyl groups. Initial work on ECMP is also underway.

The effects of abrasive shape, size and morphology in CMP are being investigated in collaboration with Professor Matijevic' and supported by Intel through the Semiconductor Research Corporation (SRC), who renewed their contract through 2006. Well-defined dispersions using monodispersed spherical silica particles, ellipsoidal hematite particles of different anisometries coated with silica, and silica particles coated with ceria have been prepared and evaluated as abrasives for CMP as a function of particle size and shape. This work is being extended to low - k films. (continued on page 7)


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