Paper PS-ThP20
Study of Micro-Trenching and Bowing with a Dry Etching Profile Simulator in a High-Density, Low-Pressure Plasma

Thursday, October 18, 2007, 5:30 pm, Room 4C

Sub-micron technologies are crucial for present and future communication systems. The complexity of device fabrication processes requires a deep understanding of the fabrication issues, especially when dealing with new materials and complex device geometry. Plasma etching is one of the necessary tools to realize such devices. Numerical simulations are of great interest for providing insights into the physics underlying plasma etching processes and are therefore helpful for optimizing the experimental conditions. In this work, we propose a 2-dimensional plasma etching simulator. According to our cellular approach, each cell is characterized by its state, namely etched, unetched, mask, mask surface and material surface. This state evolves according to the interaction between the cell and the incident particles. Monte-Carlo methods are used to define particle trajectories and the nature of interacting particles (ion or neutral). The etched profiles achieved from our numerical simulations favorably compare with those corresponding to various experimental conditions (physical sputtering, ion-assisted etching, mask geometry and angular ion distribution) as found in the literature. In particular, micro-trenching and bowing of the side-wall for Si and SiO₂ are observed. The validation of our numerical approach through this comparison enables us to further apply it for more complex materials of interest for photonic applications, such as VO₂ and SrTiO₃. The next step in this study will be to examine the role of plasma parameters on the etching characteristics of such materials, in order to optimize profile accuracy (low micro-trenching, low bowing and large aspect ratio).