Effect of electron density in RF-discharge on etching rate in plasma-chemical reactor

The effect of O
2
additive concentration on silicon etching process in tetrafluoromethane — oxygen mixture is investigated on the base of numerical modeling. The calculations were carried out with using an advanced mathematical model of plasma-chemical reactor. The model takes into account peculiarities of plasma kinetics in RF-discharge. The gas flow describes by the equations of multicomponent hydrodynamics including convective-diffusion transfer and production of all mixture components. In the paper an electron density influence the main characteristics of silicon etching are presented. It was shown that the fall of average density of energetic electrons in the reactor due to oxygen addition can decrease the etching rate in a range up to 30% but in any case the etching rate in mixture stays essentially more high that one in pure tetrafluoromethane.