Control of Overfill Bumps in Damascene Cu Electrodeposition
Soo K. Kim, Daniel Wheeler, Daniel Josell, Thomas P. Moffat
Electroanalytical measurements and feature filling experiments have been conducted to study the effect of dodecyltrimethylammonium chloride (DTAC) and branched polyethyleneimine (PEI) on Cu deposition as levelers in the presence of various combinations of superfilling additives. Saturated surface by leveler yields substantial inhibition of Cu deposition reaction that is similar in magnitude to that provided by PEG-C1. The addition of levelers to the superfilling electrolyte leads to quenching of the characteristic voltammetric hysteresis of the PEG-C1 SPS system. This behavior is attributed to ion-pairing between the cationic functional groups of levelers and anionic sulfonate tail group of SPS that results in deactivation of SPS. Deactivation may occur either by leveler accumulation from the electrolyte or by lateral interaction during area reduction in accordance with curvature enhanced adsorbate coverage mechanism. The combined process may be optimized to enable the bottom-up filling dynamic to be sustained while overfull bump formation is effectively attenuated.
copper, electrodeposition, leveling, superfill
, Wheeler, D.
, Josell, D.
and Moffat, T.
Control of Overfill Bumps in Damascene Cu Electrodeposition, ECS Transactions
(Accessed May 28, 2023)