Chemical Mechanical Polishing of TiN Film with Potassium Permanganate and L-Aspartic Acid in Alkaline Slurry

Titanium nitride (TiN) is preferred for use as the bottom electrode contact due to its excellent thermal stability and suitable electrical conductivity. We have studied the effect of using potassium permanganate (KMnO4), L-Aspartic Acid (L-Asp) and alumina abrasives as slurry in chemical mechanical polishing (CMP) of TiN film. Different concentrations of potassium permanganate and different concentrations of L-aspartic acid additives were applied to the CMP of TiN. The results show that KMnO4 and L-Asp can increase removal rate and improve the surface smoothness of TiN. The removal mechanism of TiN was analyzed by XPS and electrochemical tests, and the TiN film was characterized by atomic force microscope and scanning electron microscope.