Etch properties of hf-based high-k dielectrics using inductively coupled plasma

In this work, we investigated etching characteristics of HfO2 thin film and Si using inductive coupled plasma (ICP) system. The maximum etch rate of HfO2 is 85.5 nm/min at a BCl3/(Ar+BCl3) of 20% and decreased with further addition of BCl3 gas. From the QMS measurements, the most dominant positive ion energy distributions (IEDs) showed a maximum at 20% of BCl3. These tendency was very similar to the etch characteristics. This result agreed with the universal energy dependency of ion enhanced chemical etching yields. From the mass spectra, the Hf chloride and bromine oxide must be included in the etching by-products as volatile species.