[CCoE Notice] Colloquium Announcement * March 12, 2010 * Thomas Moffat * National Institute of Standards & Technology

[Lewis, Lindsay R]

***** Colloquium *****
Center for Integrated Bio and Nano Systems
Houston Chapter of IEEE Nanotechnology Council and Houston Chapter of IEEE Magnetics Society
Friday, March 12, 2010
12:30 p.m. (Refreshments served at noon)
Room: E223  Building D3 (Note the room change!)
 
Superconformal Film Growth: Mechanism and Quantification 

Thomas P. Moffat
 
National Institute of Standards & Technology, Gaithersburg, MD 20899

State of the art manufacturing of semiconductor devices involves electrodeposition of copper for device wiring and more recently for through silicon vias (TSVs). The process depends on the use of electrolyte additives that affect the local deposition rate thereby resulting in superconformal, or bottom-up "superfilling" of trenches and vias. This remarkable deposition process is explained by the recently developed curvature enhanced accelerator coverage (CEAC) mechanism. The model stipulates that 1) the growth velocity is proportional to the local accelerator, or catalyst, surface coverage and 2) the catalyst remains segregated at the metal/electrolyte interface during copper deposition. For growth on non-planar geometries this leads to enrichment of the accelerator on advancing concave surfaces and dilution on advancing convex sections; thereby giving rise to bottom-up superfilling of sub-micrometer trenches and vias. In this talk the robustness of the CEAC model is explored by characterizing the kinetics of catalyst accumulation and consumption in a series of electroanalytical and surface analytical experiments on planar electrodes. The ability of the model to explain the use of leveling agents to control undesirable bump formation above filled feature will also be described. These experiments are complemented by studies of competitive additive adsorption on single crystal Cu surfaces in the absence of metal deposition.

More recently, interest in applying superfilling processes to materials beyond coinage metals and applications beyond passive conductors has developed. In this talk exploratory work on possible additives and superfilling mechanisms applicable Fe, Ni, Co, and alloys thereof, will also be briefly discussed. 

 
Bio of Dr. Moffat:
 
Dr. Moffat is a member of the Thin Film and Nanostructure Processing Group in the Metallurgy Division at National Institute of Standards and Technology (NIST). He received B.E. and M.Sc. degrees from Vanderbilt University in 1982 and 1984, respectively and an Sc.D. degree in materials science and engineering from the Massachusetts Institute of Technology in 1989. He then spent two years as a postdoctoral associate in A.J. Bard's laboratory at the University of Texas, Austin. Dr. Moffat joined NIST in 1991 to study thin film deposition processes. In 2001 he received the Gold Medal of the U.S. Department of Commerce for his work in the area of superconformal film growth. He is also the recipient of the 2006 Research Award of the Electrodeposition Division of The Electrochemical Society. He is an author or coauthor of more than 100 technical papers. Dr. Moffat is an active member of the Electrochemical Society, the International Society of Electrochemistry, the Materials Research Society and the American Association for the Advancement of Science. He will Chair the 2008 Gordon Research Conference on Electrodeposition. Currently he is exploring the use of electrochemical processing for advanced metallization in microelectronics, magnetic devices, and the synthesis of alloy electrocatalyst.

Contact Prof. Stanko Brankovic (stanko.brankovic at mail.uh.edu) if you would like to arrange for a time to meet with Dr. Moffat.




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