SUPERCONFORMAL ELECTRODEPOSITION OF SILVER FROM A KAg(CN)2-KCN-KSeCN
ELECTROLYTE

Brett Baker, Thomas Moffat, Daniel Josell and
Daniel Wheeler
National Institute of Standards and Technology
Gaithersburg, MD 20899
 

Successful superfilling of lines and vias will be shown with a
silver-cyanide electrolyte that contains one additional species,
potassium selenocyanate. Hysteretic i-V behavior on planar
electrodes is used to extract parameters that quantify the kinetics
of the deposition process. These parameters are used in the curvature
enhanced accelerator coverage (CEAC) model to quantitatively predict
filling of features on patterned substrates. The fundamental premise
of the CEAC model is that area reduction at the bottom of filling
features leads to increased local coverage of adsorbed catalyst and
thus local deposition rate. It has previously been shown to
accurately predict superconformal copper electrodeposition for
sulfate-based electrolytes with thiols as catalysts. This work
examines the model's generality through application to a
cyanide-based electrolyte and selenium catalyst. A novel deposition
technique of derivitizing the silver substrate at open circuit with
the Se based catalyst and subsequently plating in an additive-free
electrolyte will also be presented.