AVS 51st International Symposium
    Plasma Science and Technology Monday Sessions
       Session PS1-MoA

Paper PS1-MoA10
A Model of Multilayer Surface Reactions and Simulation of the Feature Profile Evolution in Etching of Silicon in Chlorine Plasmas

Monday, November 15, 2004, 5:00 pm, Room 213A

Session: Plasma Surface Interactions in Etching
Presenter: Y. Osano, Kyoto University, Japan
Authors: Y. Osano, Kyoto University, Japan
K. Ono, Kyoto University, Japan
Correspondent: Click to Email
A phenomenological model has been made to simulate the feature profile evolution of nanometer-scale etching of Si in Cl@sub 2@. The model incorporates an atomistic picture into the model, to analyse the complex surface reactions in the ion-enhanced etching and investigate their effect to the profile evolution, which involves profile anomalies such as bowing, tapering, and microtrenching. To simulate the reaction process at an atomic scale, we employ a feature profile modeling with two-dimensional array of atomic size cell in the entire computational domain. Monte Carlo calculation of the trajectory and stopping of the incoming Cl@super +@ ion within the surface layers of Si substrate is then performed, on the basis of kinetics of two-body elastic collision. For surface reactions of Cl neutral reactants, we take into account their adsorption on the very surface layer. The removal of Si atom is assumed to be caused by the reaction on the chlorinated surface in terms of this adsorption process Si@sub (s)@+4Cl@sub (s)@ -> SiCl@sub 4(g)@, where (s) and (g) represent the solid and the gas, respectively. Simulation of the feature profile evolution is performed for etching of sub-100 nm patterns. The effect of neutral-to-ion flux ratio is studied in this calculation. The present model illustrates that changes of the flux ratio have a significant effect on surface anomalies, such as sidewall bowing and tapered feature near the bottom, associated with surface chlorination on the feature surface which varies by the flux ratio and the location within the feature pattern.