Optimization of reactive ion etching processes using desirability

Abstract

This work discusses the potential of process optimization of reactive ion etching processes by the help of desirability. The idea is a model based approach due to the complexity of the chemical and physical operational sequence within the plasma during the etching. The whole etching process is considered as black box with input and output factors. Instead of searching for local optimums concerning the single process parameters during the conventional optimization a response surface methodology describes the black box by the help of an appropriate model with a desirability index which is afterwards optimized by the help of nonlinear optimization algorithms. The method is introduced and evaluated by using the example of a polysilicon etch process with the gases sulfur hexafluoride and oxygen.