Effect of Potassium Ferricyanide in the Acid Solution on Performance of Tungsten Chemical Mechanical Planarization

We investigated the effect of the oxidizer K3Fe(CN)(6) on the performance of chemical mechanical planarization (CMP) of tungsten film using the acid slurry. The addition of K3Fe(CN)(6) in the acid slurry formed the K2WO4 layer on the tungsten film surface, thereby increasing the polishing rate and decreasing the surface roughness of the tungsten film after CMP, which demonstrated better CMP performance than the oxidizer Fe(NO3)(3). Furthermore, the addition of H2O2 in the acid solution including K3Fe(CN)(6) enhances the chemical dissolution rate of the K2WO4 layer on the tungsten film surface, considerably increasing the polishing rate and decreasing surface roughness of the tungsten film. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.010204jes] All rights reserved.This investigation was financially supported by the Brain Korea 21 Project in 2011, the IT R&D program of MKE/KEIT (KI002189, Technology Development of 30 nm level High Density Perpendicular STT-MRAM). The authors thank Sumco Corp. for helping with the experiments