Numerical modeling of silicon processing technology in CF4/H2 plasma

Abstract

In the frame of hydrodynamical approach a technology of plasma-chemical etching silicon in CF₄/H₂ plasma was simulated. The model of plasma-chemical kinetics contained 28 gas-phase reactions including the components F, F₂, CF₂, CF₃, CF₄, C₂F₆, H, H₂, HF, CHF₃, CH₂F₂. In the etching process a most part of fluorine goes on formation of component HF, that essentially reduces the etching rate of silicon. On the wafer surface it is formed the adsorption layer CF₂, which at 40 % H₂ completely covers a silicon surface and stops the etching process.