Patterned Platinum Etching Studies in an Argon High-Density Plasma

Plasma etching of platinum was investigated using a high-density surface-wave argon plasma operated in the low pressure regime. The substrate was RF biased up to 150 V. The influence of the ion density and of the DC selfbias voltage on the sputter-etching characteristics was investigated at a gas pressure of 1 mTorr. It was found that, at this low pressure, the etch rate is an increasing function of both the ion density and the self-bias voltage. High etch rates with a good selectivity over resist, good Pt sidewall angle and fence-free submicron features have been achieved using bias voltages lower than 150 V.