Annual Report 2004- 2005 | Center for Advanced Materials Processing (CAMP) | Clarkson University | Potsdam

	>STATE-FUNDED RESEARCH PROJECTS
	Thirteen research projects were supported by the Centers for Advanced Technology (CAT) Program of New York State’s Office of Science, Technology, and Academic Research (NYSTAR) in the 2004 - 2005 fiscal year. Project titles and principal investigators are listed below for each research area.
	Particle Synthesis and Properties Enzymatic Synthesis of Polymers -A. Mueller Modeling of Synthesis of Well-Defined Nanosize Particles and Monodispersed Colloids -V. Privman Polymer-Titanium Dioxide Nanocomposites for Dye-Sensitized Solar Cells -D. Shipp Thin Films and Coatings Low-Temperature and Low-Pressure Diamond Deposition - L. Regel Particle Transport, Deposition, and Removal Non-Contact Technique for Particle-Surface Adhesion Force Measurements & Air-Coupled Acoustic Method for Characterization of Small Objects -C. Cetinkaya Transport, Deposition and Removal of Charged Nanoparticles & Aerodynamic Lens for Nanoparticles -G. Ahmadi	Chemical-Mechanical Planarization (CMP) Time Resolved Impedance Studies of Slurry-Effects and Galvanic Corrosion in CMP of Cu,Ta, and TaN - D. Roy Fundamental Issues in Chemical-Mechanical Polishing - R.S. Subramanian Nanosystems Biosensing for Process Control -I. Suni Conductive Nanofiber-Nanoparticle Composites - S. Minko Study of Self-Assembled Nanoporous Glass Films on the Surfaces of Optical Fibers and Synthesis of Self-Assembled Dye Lasers -I. Sokolov Supporting Technologies New Fluorinated Polymers for Ultrasound Imaging Applications & Direct Patterning on Photocurable low k Dielectric Films - Y. Li Measurement Tools for Lost Foam Casting Process - K. Janoyan
	CAMP Professor Shipp’s Student Receives Many Honors Halimatu Mohammed of the Bronx, NY, a chemistry major at Clarkson University working in Professor Devon Shipp’s laboratory, received many honors. She won an Acres of Diamonds Award from the Minority Trainee Research Forum in 2004 and a $35,000 Science Initiative Scholarship Award sponsored by the United Negro College Fund and Merck and Co. in 2005. In addition she was a co-recipient of the Brunauer Award from the Department of Chemistry at Clarkson University for her thesis titled “ Synthesis and Characterization of Sub-Micron Multifunctional Polymeric Spheres.” This award, which is presented to a graduating senior who has written an outstanding senior thesis in chemistry, is the highest professional honor that the Chemistry Department can bestow. Halimatu’s research, carried out under the supervision of Professor Shipp, shows how sub-micron polymer spheres can be functionalized to effectively coordinate and remove metal ions from aqueous environments.

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Several complexing agents were investigated systematically. It was shown that pH of the dispersion is a dominant factor. The surface composition and morphology of both Cu and Ta are strongly influenced by pH. Amine groups are more active at alkaline conditions, while carboxyl moieties are active in the acidic range. Cu removal rates, both dissolution and polish rates, and their pH dependence can be scaled using molar concentrations of the functional groups, but not necessarily of the parent molecular agent. They have also explored the modulation of these rates when both amine and carboxyl groups are present in the same molecule, as in the case of an amino acid like glycine. Investigation of complexing agents like α -alanine, β -alanine, α -aminobutyric acid (ABA), γ -ABA, and succinic acid and comparing them with glycine and ethylene diamine showed that the relative position of the amine and carboxyl groups as well as the chain length are factors that determine removal rates. For example, increased chain length increased Cu removal rates at acidic conditions but lowered them in alkaline conditions. γ -ABA and β -alanine based dispersions also had the very attractive combination of very low dissolution and very high polish rates. The potential-pH diagrams prepared for these systems, in collaboration with Dr. Serdar Aksu, were used to evaluate these results further.

Results obtained with oxalic acid based dispersions demonstrated the potential usefulness of this system as an abrasive-free slurry for Cu CMP, since the high removal rates were reduced only slightly when the silica abrasives were eliminated from the dispersion. The best results –high Cu removal and low dissolution rates- for this system were found around a pH of 3.

Professor Babu and his group have also identified some surfactants that can act as very efficient dissolution inhibitors for Cu CMP. This ability persists even under electrical activation though in some cases, especially under high voltages, a small amount of BTA significantly enhanced this protective ability. The associated reduction in removal rates even at low down forces is relatively small. These reagents may also help to minimize defects and with wafer cleaning.

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 using composite abrasives to low-k films.