EXPERIMENTAL-STUDY AND COMPUTER-SIMULATION OF ASPECT RATIO-DEPENDENT EFFECTS OBSERVED IN SILICON REACTIVE ION ETCHING

The aspect ratio dependent etching of deep trenches in silicon is inve stigated as a function of polymer deposition rate which, in turn, depe nds on the C2Cl3F3 content in a SF6/C2Cl3F3 gas mixture. The experimen tal results are compared to computer simulations. A model which takes into account simultaneous ion-enhanced etching and polymer deposition is developed to explain the observed two-dimensional effects such as f eature size dependent profile evolution, RIE lag, and inverse RIE lag. Computer program includes different transport mechanisms of ions, rea ctive neutrals, polymer precursors and some parameters, namely, the an gular distributions of species, sticking coefficients, and re-emission functions. The influence of these parameters on aspect ratio dependen t etching is considered.