Articles you may be interested inFeature profile evolution during shallow trench isolation etch in chlorine-based plasmas. II. Coupling reactor and feature scale models Coupling reactor-scale models of plasma etching equipment to device-scale models of feature profile evolution offers the potential for increased levels of virtual design of both capital equipment and process recipes. In this article, a combined reactor-and feature-scale model of crystalline silicon feature profile evolution is described, and simulation results of isolated trench and isolated line etching with Cl 2 and HBr plasmas are compared to experimental data. By incorporating reactor-scale predictions of plasma properties along with assumptions concerning the details of energetic particle scattering from surfaces, we are able to predict both the etch rate and the shape of evolving features. Important in the comparison to experiment is the proper prediction of ''microtrench''-free high aspect ratio trench etching in the case of HBr, contrasted with the occurrence of deep microtrenching when Cl 2 plasmas were used. These results suggest that a thorough knowledge of the details of energetic ion scattering from all evolving surfaces is required before accurate feature profile evolution predictions can be made.

Articles you may be interested inModeling of fluorine-based high-density plasma etching of anisotropic silicon trenches with oxygen sidewall passivation J. Appl. Phys. 94, 6311 (2003); 10.1063/1.1621713Effect of neutral transport on the etch product lifecycle during plasma etching of silicon in chlorine gas Feature profile evolution simulations of plasma etching rely to first order on the accurate prediction of ion fluxes to all points on the evolving surface. Previous experimental and theoretical work strongly suggests that dielectric charging effects play a key role in a type of anomolous feature evolution known as ''notchings.'' This involves charging of newly exposed gate dielectric material, subsequent ion trajectory bending, and notch formation due to localized ion flux enhancement. Few researchers, however, have considered charging of masking dielectrics ͑e.g., SiO 2 hardmasks͒ and its associated effects on feature evolution, even though such charging is likely to occur in modern high-density plasma etching systems. In this article, we develop a combined reactor-and feature-scale model of Cl 2 plasma etching of crystalline silicon, allowing for the possibility of hardmask charging and ion trajectory deflection. We show via comparison of simulation results to cross-sectional scanning electron micrographs of silicon trenches that these charging effects can explain the formation of wide, ''triangular,'' microtrenches seen when etching silicon at 2 mTorr pressure and low rf-bias power. Furthermore, the model correctly predicts the disappearance of these microtrenches when the rf-bias power is raised.