Investigation of tilted etching of Si3N4 using CF4/O2 plasma: Process development and mechanism study

This study focuses on the tilted etching technique for silicon nitride (Si3N4) material in a CF4/O2 plasma environment. This method effectively achieves smooth etching morphology and tilt control by controlling the lateral photoresist etch-back rate and the vertical Si3N4 etching rate during the etching process. In the experimental section, we delved into the impact of etching gases on the sidewall angle of Si3N4. By precisely controlling the ratio of etching gases and the etching time, we were able to efficiently and accurately obtain the desired morphology angle. In addition, we further investigated the specific impacts of radio frequency power and chamber pressure on the bevel angle morphology and found that an increase in either power or pressure helped to enlarge the sidewall angle. Finally, we conducted research and analysis on patterns of different sizes to verify the applicability and stability of this technology. These research findings not only deepen our understanding of the Si3N4 etching mechanism but also provide new technical pathways and theoretical support for the field of semiconductor micro/nano processing.