Abstract

Dr. Tom Moffat
National Institute of Science and Technology
Materials Science and Engineering Laboratory

October 22, 2007
3:30- 4:30pm
MEC Rm. 339

"Superconformal Film Growth:
Mechanism and Quantification"

ABSTRACT:

Authors: T.P. Moffat, D. Wheeler, and D. Josell

State of the art manufacturing of semiconductor devices involves electrodeposition of copper for device wiring. 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 catalyst on advancing concave surfaces and dilution on advancing convex sections; thereby giving rise to bottom-up superfilling of submicrometer 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 (STM and XPS) experiments on planar electrodes. The CEAC model is then used to successfully predict interface shape evolution during feature filling in a variety of experiments using no adjustable parameters.

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