Optimization of gas utilization in plasma processes

The reduction of chemical usage in semiconductor manufacturing has been a topic of wide discussion over the past several years. The aim of this study is to optimize plasma efficiency as chemical reactions by using the Taguchi method. In short, the function of plasma is to serve as an etchant that reacts with films. The results of the reaction are discharged. The main point of optimization was to use a main etchant to increase the amount of desirable main reaction and to decrease the amount of unreacted gas in order to keep the undesirable side reaction to a minimum. We found chemical vapor deposition cleaning conditions that improve plasma efficiency up to 200%, perfluorocompounds (PFC) gas usage to one-third, and PFC gas emission to 25%. We also found nitride etching conditions that improve plasma efficiency up to 350%, SF₆ usage to 25%, SF₆ emission to 22%, and selectivity to oxide up to 145% over the previous conditions.