Effect of Etching Parameters on Gate Profile by Anisotropic Chemical Etching

This pioneer study presents the phenomena of anisotropic chemical etching in the range of the linewidth 15nm-100nm. In this study, a phase-field model is established and a resist mask is appointed on the surface to simulate a chemical etching process with a gate geometry. In the numerical simulations, the isotropic and anisotropic etching conditions are both evaluated to explore the fine chemical etching circumstances. In addition, the influences of etching parameters, such as the etching rate and the strength of the anisotropy, on the characteristics of gate profile are also demonstrated. From the simulation results, it shows that a larger loss of linewidth or a higher etch bias is involved with the increase of the etching rate. While an anisotropic etching is considered, a facetedetching profile would be generated and simultaneously the etch bias could be suppressed during the etching process. As the anisotropy is strengthened, the characteristic profile becomes more distinct with a less loss of the linewidth. These numerical simulations could provide a methodical guidance to concisely control the fine etching profile, and broaden the applications of chemical etching in the advanced robust manufacturing technologies.