For a realistic simulation of sputtering processes and the topography changes associated, we combined the 3-D topography simulator ANETCH with the Monte-Carlo ion implantation program MC_SIM. The coupling between the programs provides the possibility to study the results of physical sputtering processes for nearly arbitrary ion/target combinations without a priori knowledge about the respective yield from experiments. As a first application, simulations were carried out to optimize process parameters of sputtering experiments. In a second application, the topography of a trench after FIB preparation is compared to simulations. The side-wall evolution at an edge due to ion irradiation is studied as a third application.

We demonstrate the coupling of plasma reactor equipment simulation and feature-scale profile simulation for dry etching of silicon in a chlorine plasma. Equipment simulation delivers fluxes of ions and neutrals, as well as the angular characteristics of the ions. These quantities are fed into a feature-scale simulator based on a Monte Carlo approach for determining relevant quantities on the feature surface, i.e. the concentration of adsorbed neutrals and the number of removed silicon atoms due to chemical sputtering. Using the coupled simulation system, we are able to study the influence of equipment parameters on the resulting etching profiles. As an example, we show the etching of polysilicon for gate formation and determine profile variations according to different positions on the wafer and according to varying bias applied to the substrate in the etching reactor.

We demonstrate the coupling of Monte Carlo sputter simulation with feature-scale simulation of profile evolution during sputter etching. With the Monte Carlo sputter simulation, the dependence of the sputter yield on the angle of incidence and on the energy of ions impinging onto the surface is determined. The yield curves obtained thereby are fed into a feature-scale etching profile simulator which predicts the local etch rates based on these sputter yield curves and on ion fluxes which are calculated for a substrate placed in a sputter reactor. For validating the simulations, a process sequence consisting of deposition and back etching (in an argon plasma) of silicon oxide between metal lines has been studied. Assuming an ion energy of 250 eV allows us to consistently reproduce profiles observed experimentally.

For the simulation of etching processes, a key step is the calculation of the etch rates depending on the specific model and depending on the specific geometry of the feature. In this work, we demonstrate the calculation of etch rates using a Monte Carlo, a flux balancing, and an analytical approach. For a relatively simple model for etching of polysilicon in chlorine-based chemistry, the three approaches are compared and microtrenching is studied which results from the specular reflection of ions and depends on different parameters. The results for the different approaches are in good agreement for the cases studied.