High Density Plasma Deposition Modeling Using Level Set Methods

Several silicon dioxide chemical vapor deposition processes using high density plasma sources have been recently proposed in the literature [11, 7] for deposition of self-planarizing inter-level dielectric deposition. All these processes exhibit the competitive effect of simultaneous deposition and etching mechanisms. This paper describes the use of a robust simulation technique that can include all physical mechanisms involved in these processes. The techniques rely on level set methods [20] for tracking evolving interfaces. These techniques are based on solving a Hamilton-Jacobi type equation for a propagating level set function, using techniques borrowed from hyperbolic conservation laws. Topological changes, corner and cusp development, and accurate determination of geometric properties such as curvature and normal direction are naturally obtained in this setting. The equations of motion of a unified model, including the effects of isotropic and unidirectional deposition and etching, visibility, surface diffusion, reflection, and material dependent etch/deposition rates are presented and adapted to a level set formulation. In the case of isotropic etching/deposition, a particularly fast marching level set method can be employed. Using these techniques, we demonstrate results applied to two and three-dimensional problems analyzing isotropic deposition, ion milling, simultaneous etching and deposition, and multiple effects of re-emission and redeposition.