The present study investigates the cyclic etching of TiO₂ with CF polymer deposition and removal. We find that C₄F₈ plasma treatment forms a CF polymer deposition layer on the TiO₂ and a modified TiO₂ surface under the CF polymer layer. Subsequent O₂ plasma treatment removes the CF polymer and the modified layer at the same time. This sequence is repeated. Accordingly, the TiO₂ film is etched at a rate of 0.67nm per cycle. The CF polymer and modified TiO₂ layer also form on the sidewall TiO₂ surface of a trench pattern. We realize the isotropic TiO₂ etching of a trench pattern having a high aspect ratio exceeding 40 adopting the cyclic C₄F₈ and O₂ plasma process.

本研究研究了通过CF聚合物沉积和去除TiO ₂的循环蚀刻。我们发现，C ₄ F ₈等离子体处理在TiO ₂上形成CF聚合物沉积层，并在CF聚合物层下方形成改性的TiO ₂表面。随后的O ₂等离子体处理可同时去除CF聚合物和改性层。重复此顺序。因此，以每个周期0.67nm的速率蚀刻TiO ₂膜。CF聚合物和改性的TiO ₂层也形成在沟槽图案的侧壁TiO ₂表面上。我们实现了各向同性的TiO ₂采用循环C ₄ F ₈和O ₂等离子工艺蚀刻高深宽比超过40的沟槽图案。