Development of SF6/O2/Si plasma etching topography simulation model using new flux estimation method

A new topography simulation method has been developed for SF₆/O₂/Si plasma etching of trench gates in IGBTs. This method calculates the ion and fluorine radical flux parameters required for the topography simulation from the etching rate and selectivity obtained from simple basic experiments. The O radical flux was assumed as a function of the operating conditions and the function form was determined by fitting etching profiles of the topography simulation to those of the experiment. The model used in the topography simulation was improved in terms of the etching yield dependence on the ion incidence angle. As a result, a large variety of profiles could be simulated accurately under different operational conditions.