ElectroplatingEffect and Oscillatory Behavior during Copper

The electrochemical behavior of levelers was studied and compared for two commercial Cu plating chemistries in an effort tocorrelate the electrochemical behaviors with their impacts on bottom-up filling, impurity incorporation, and grain structures. Whilea strong complexing between leveler and accelerator resulted in a leveler-sensitive bottom-up filling rate and low impurity levelin the deposit, a traditional non-interacting leveler showed little impact on the filling performance and yielded a high impurityincorporation. An oscillatory behavior was reported for the strongly-interacting leveler chemistry during galvanostatic plating, thisoscillation manifested itself in both the potential and impurity incorporation. High impurity incorporation is known to inhibit the Cugrain growth; a laminated structure with alternating layers of big and fine Cu grains was obtained by annealing the Cu films platedwith the oscillatory behavior.© 2012 The Electrochemical Society. [DOI: 10.1149/2.020209jes] All rights reserved.Manuscript submitted May 18, 2012; revised manuscript received June 11, 2012. Published August 14, 2012. This was paper 2445presented at the Vienna, Austria, Meeting of the Society, October 4–9, 2009.