Plasma Parameters and Kinetics of Reactive Ion Etching of SiO2 and Si3N4 in an HBr/Cl2/Ar Mixture

A. M. Efremov; Ефремов А. М.; V. B. Betelin; Бетелин В. Б.; K.-H. Kwon; Kwon K.-H.

doi:10.31857/S0544126923700217

Plasma Parameters and Kinetics of Reactive Ion Etching of SiO2 and Si3N4 in an HBr/Cl2/Ar Mixture

Authors: Efremov A.M.¹, Betelin V.B.², Kwon K.³
Affiliations:
1. Ivanovo State University of Chemical and Technology
2. Federal State Institution “Federal Scientific Center Research Institute for System Research,” Russian Academy of Sciences
3. Korea University
Issue: Vol 52, No 2 (2023)
Pages: 152-159
Section: ТЕХНОЛОГИЯ
URL: https://journals.rcsi.science/0544-1269/article/view/138496
DOI: https://doi.org/10.31857/S0544126923700217
EDN: https://elibrary.ru/PYKANE
ID: 138496

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Abstract

The parameters of the gas phase and the kinetics of reactive ion etching of SiO2 and Si3N4 under conditions of an induction RF (13.56 MHz) discharge with a varying HBr/Cl2 ratio is studied. The study includes plasma diagnostics using Langmuir probes, plasma modeling to find stationary concentrations of active particles, measuring velocities, and analyzing etching mechanisms in the effective interaction prob-ability approximation. It is found that the substitution of HBr by Cl2 at a constant argon content (a) is accompanied by a noticeable change in the electrical parameters of the plasma; (b) leads to a weak increase in the intensity of ion bombardment of the treated surface; and (c) causes a significant increase in the total concentration and flux density of reactive particles. It is shown that the etching rates of SiO2 and Si3N4 increase monotonically as the proportion of Cl2 increases in a mixture, while the main etching mechanism is an ion-stimulated chemical reaction. The model description of the kinetics of such a reaction in the first approximation assumes (a) the additive contribution of bromine and chlorine atoms and (b) the direct pro-portional dependence of their effective interaction probabilities on the intensity of ion bombardment. The existence of an additional channel of heterogeneous interaction with the participation of HCl molecules is proposed.

Keywords

HBr, Cl2, plasma parameters, active particles, ionization, dissociation, etching, kinetics, mechanism

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