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. [ABSTRACT FROM AUTHOR]