Experimental Model Validation of High Aspect Ratio Through-Hole Filling by Additive-Assisted Copper Electrodeposition

Abstract

A multi-element, time-dependent model developed by Childers et al. [A.S. Childers, M.T. Johnson, J. Ramírez-Rico, and K.T. Faber, J. Electrochem. Soc., 160:3093-3102, 2013] for copper infiltration of large (∼50–200 µm diameter), high aspect ratio (∼60) through-hole channels was experimentally tested for validity. The model built on the work of Akolkar and Landau [R. Akolkar and U. Landau, J. Electrochem. Soc., 151:702-711, 2004] for copper deposition in micro-scale integrated circuitry. Childers' model broadens the original by including the transport and adsorption of all electrolyte species - inhibitors, accelerators, and copper ions. The resulting model is tested experimentally with wood-derived biomorphic carbon materials. Results indicate that model predictions of premature pore choke off are in agreement with quantitative observations of copper infiltration and qualitative imaging of plated pore profiles. Low accelerator concentrations (0.002 ppm) yielded the highest quantity of copper infiltration without premature closure.

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