Process and equipment simulation of dry silicon etching in the absence of ion bombardment
The dependence of the etch rate uniformity across the wafer on the reactor design and various process parameters was investigated for the reactive ion etching (RIE) of silicon using pure sulphur hexafluoride (SF6). The experiments were carried out in two different single wafer reactors without ion bombardment to determine the chemical component of the etch rate. The influence of pressure, gas flow, rf power, and loading on the radial course of the etch rate was measured and compared with the respective results of numerical simulation. The commercially available PHOENICS-CVD simulation tool was used for the solution of the fluid dynamic transport equations after some adaptations for its application to etching. A simple chemical model is proposed for the description of gas phase and surface plasma reactions, respectively. The values of the reaction rate parameters were fitted from the experimental data. The simulation represents the main experimental trends and can be applied to process and equipment optimization.
simulation silicon etching sf6 plasma