Phenomenological model for predicting C _x H _y F _z ⁺ ion etching yields of SiO₂ and SiN _x substrates

Abstract

In this study, a novel phenomenological model is developed to predict the etching yields of SiO2 and SiNx substrates by fluorocarbon (FC) and hydrofluorocarbon (HFC) ions. The CF layer thickness and reactive layer chemistry are described, which significantly affect the etching yields. The study focuses on the dependence of the atomic component of the ion and the incident ion energy of the ion on the etching yield. Some assumptions enable the calculation of ion etching yields in a short turn-around-time. The proposed model can predict the etching yields of other larger species at the higher incident ion energy. The obtained simulation results are in good agreement with the experimental data. The optimal etching ions for high aspect ratio etching are comprehensively investigated using the proposed model, providing a better understanding of the differences in the underlying material and the atomic component of the ion.

High aspect ratio SiO2/SiN (ON) stacked layer etching using C3HF5, C4H2F6, and C4H4F6

“…10,[24][25][26][27][28][29][30][31] Kawamoto et al predicted C x H y F z + ion etching yields for SiO 2 and SiN using a phenomenological model. 32) Their work suggested that C x H y F z + ions with x = 2-5 have relatively high etch yields for SiO 2 , and C x H y F z + ions with x = 2-3 would have relatively high etch yields for SiN. Based on this, we assumed that the C x H y F z gases with x = 3-5 would exhibit high plasma dissociation into the previously mentioned fragments.…”