Selectivity investigation of HfO2 to oxide using wet etching

Experiments indicate that higher HfO₂/oxide etching selectivity in IPA/HF solution as compared to DI water/HF solution. Although DI water/HF solution is acceptable for some HfO₂ and CVD oxide films, from an integration point of view, the process window is smaller than IPA/HF solution. It is believed that adequately damaged HfO₂ and annealed CVD oxides will result in considerably high HfO₂/CVD oxide etching selectivity in IPA/HF solution.