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J. Electrochem. Soc. 2013volume 160, issue 12,D3197-D3205.
Ibro Tabakovic. Steve Riemer.Ming Sun.Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota 55435, USA and Seagate Technology, Bloomington, Minnesota 55435, USA and Western Digital, Fremont, California 94539, USA
Abstract
This paper reports an experimental investigation of 3-N, N-dimethylaminodithiocarbamoyl-1-propane sulfonic acid (DPS) additive behavior attached to copper as a self-assembled monolayer (SAM) prior to electrodeposition of copper. Rotating disk electrode (RDE) voltammetry and linear sweep cyclic voltammetry (LSCV) revealed that the extent of derivatization of a Cu electrode is time-dependent and it can be controlled. The monitoring of copper deposition rate for 25 min on DPS-SAM derivatized electrode in PEG and DPS free electrolyte plating solution indicates that DPS-SAM remains attached at the electrode surface. It was demonstrated that the deactivation of DPS-SAM on Cu RDE during Cu deposition in acidic copper electrolyte (Cu+2 + PEG + Cl−) without DPS is dependent the on potential and rotation rate of the RDE. The superfilling of trenches with different width (0.5 um and 50 um) was demonstrated using a two-step process including DPS-derivatization of Cu seed layer on 6 inch patterned wafers, followed by copper electrodeposition.
