Characterization of titanium nitride etch rate and selectivity to silicon dioxide in a Cl₂ helicon-wave plasma

The etch rates of TiN and SiO₂ and TiN/SiO₂ selectivity as a function of Cl₂ and N₂ flow rate, bias power, and pressure were studied. The bias power affected the etch rate and the selectivity between TiN and SiO₂ can be achieved at low bias power. The etch rate increased with increasing pressure while the etch selectivity decreased as the pressure increased. This may be due to the atomic Cl radical density, the ion flux and the ion energy. Chlorine and nitrogen flow rate have no significant effect on etch selectivity and etch rate, respectively.