Investigation of static corrosion between W Metals and TiN_x Barriers in a W chemical-mechanical-polishing slurry

In order to control the polishing qualities of tungsten (W) and titanium nitride (TiN_x) films in W chemical-mechanical-polishing (WCMP) processes, the electrochemical behavior between the W and the TiN_x films deposited at various N2 flow rates was examined in this study. Metrologies, including X-ray diffractrometry, Auger electron spectrometry, and scanning electron microscopy, were used to verify the physical properties of the TiN_x films, while electrochemical analyses, including electrochemical impedance spectroscopy, potential dynamic curves, and potential difference measurements, were used to characterize the mechanism of galvanic corrosion between the W and the TiN_x films deposited at various N2 flow rates. The results show that the N content of the TiN_x films influences not only the physical properties of the TiN_x films but also the chemical activity in the WCMP slurries. The equivalent circuit, including the charge-transfer resistance and the titanium-oxide resistance associated with tantalum-oxide capacitance, was built to characterize the mechanism of the galvanic corrosion between the W and the TiN_x metals.